[Intel-gfx] [PATCH 1/3] drm/i915/backlight: extract backlight code to a separate file

[Jani Nikula]

In a long overdue refactoring, split out backlight code to new
intel_backlight.[ch]. Simple code movement, leave renames for follow-up
work. No functional changes.

Cc: Lyude Paul <lyude at redhat.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/Makefile                 |    1 +
 drivers/gpu/drm/i915/display/g4x_dp.c         |    2 +-
 drivers/gpu/drm/i915/display/icl_dsi.c        |    1 +
 .../gpu/drm/i915/display/intel_backlight.c    | 1778 +++++++++++++++++
 .../gpu/drm/i915/display/intel_backlight.h    |   51 +
 .../gpu/drm/i915/display/intel_connector.c    |    4 +-
 drivers/gpu/drm/i915/display/intel_ddi.c      |    2 +-
 drivers/gpu/drm/i915/display/intel_dp.c       |    1 +
 .../drm/i915/display/intel_dp_aux_backlight.c |    2 +-
 drivers/gpu/drm/i915/display/intel_lvds.c     |    1 +
 drivers/gpu/drm/i915/display/intel_opregion.c |    3 +-
 drivers/gpu/drm/i915/display/intel_panel.c    | 1767 +---------------
 drivers/gpu/drm/i915/display/intel_panel.h    |   34 +-
 drivers/gpu/drm/i915/display/vlv_dsi.c        |    1 +
 14 files changed, 1843 insertions(+), 1805 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/display/intel_backlight.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_backlight.h

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index fd997dfa5e32..23612c3a1922 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -249,6 +249,7 @@ i915-y += \
 	display/g4x_dp.o \
 	display/g4x_hdmi.o \
 	display/icl_dsi.o \
+	display/intel_backlight.o \
 	display/intel_crt.o \
 	display/intel_ddi.o \
 	display/intel_ddi_buf_trans.o \
diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
index de0f358184aa..29c0eca647e3 100644
--- a/drivers/gpu/drm/i915/display/g4x_dp.c
+++ b/drivers/gpu/drm/i915/display/g4x_dp.c
@@ -7,6 +7,7 @@
 
 #include "g4x_dp.h"
 #include "intel_audio.h"
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_de.h"
 #include "intel_display_types.h"
@@ -16,7 +17,6 @@
 #include "intel_fifo_underrun.h"
 #include "intel_hdmi.h"
 #include "intel_hotplug.h"
-#include "intel_panel.h"
 #include "intel_pps.h"
 #include "intel_sideband.h"
 
diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
index 43ec7fcd3f5d..9aaa9f2ee601 100644
--- a/drivers/gpu/drm/i915/display/icl_dsi.c
+++ b/drivers/gpu/drm/i915/display/icl_dsi.c
@@ -29,6 +29,7 @@
 #include <drm/drm_mipi_dsi.h>
 
 #include "intel_atomic.h"
+#include "intel_backlight.h"
 #include "intel_combo_phy.h"
 #include "intel_connector.h"
 #include "intel_crtc.h"
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
new file mode 100644
index 000000000000..4b0086ee4851
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -0,0 +1,1778 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#include <linux/kernel.h>
+#include <linux/pwm.h>
+
+#include "intel_backlight.h"
+#include "intel_connector.h"
+#include "intel_de.h"
+#include "intel_display_types.h"
+#include "intel_dp_aux_backlight.h"
+#include "intel_dsi_dcs_backlight.h"
+#include "intel_panel.h"
+
+/**
+ * scale - scale values from one range to another
+ * @source_val: value in range [@source_min.. at source_max]
+ * @source_min: minimum legal value for @source_val
+ * @source_max: maximum legal value for @source_val
+ * @target_min: corresponding target value for @source_min
+ * @target_max: corresponding target value for @source_max
+ *
+ * Return @source_val in range [@source_min.. at source_max] scaled to range
+ * [@target_min.. at target_max].
+ */
+static u32 scale(u32 source_val,
+		 u32 source_min, u32 source_max,
+		 u32 target_min, u32 target_max)
+{
+	u64 target_val;
+
+	WARN_ON(source_min > source_max);
+	WARN_ON(target_min > target_max);
+
+	/* defensive */
+	source_val = clamp(source_val, source_min, source_max);
+
+	/* avoid overflows */
+	target_val = mul_u32_u32(source_val - source_min,
+				 target_max - target_min);
+	target_val = DIV_ROUND_CLOSEST_ULL(target_val, source_max - source_min);
+	target_val += target_min;
+
+	return target_val;
+}
+
+/*
+ * Scale user_level in range [0..user_max] to [0..hw_max], clamping the result
+ * to [hw_min..hw_max].
+ */
+static u32 clamp_user_to_hw(struct intel_connector *connector,
+			    u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	hw_level = scale(user_level, 0, user_max, 0, panel->backlight.max);
+	hw_level = clamp(hw_level, panel->backlight.min, panel->backlight.max);
+
+	return hw_level;
+}
+
+/* Scale hw_level in range [hw_min..hw_max] to [0..user_max]. */
+static u32 scale_hw_to_user(struct intel_connector *connector,
+			    u32 hw_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(hw_level, panel->backlight.min, panel->backlight.max,
+		     0, user_max);
+}
+
+u32 intel_panel_invert_pwm_level(struct intel_connector *connector, u32 val)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
+
+	if (dev_priv->params.invert_brightness < 0)
+		return val;
+
+	if (dev_priv->params.invert_brightness > 0 ||
+	    dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS) {
+		return panel->backlight.pwm_level_max - val + panel->backlight.pwm_level_min;
+	}
+
+	return val;
+}
+
+void intel_panel_set_pwm_level(const struct drm_connector_state *conn_state, u32 val)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	drm_dbg_kms(&i915->drm, "set backlight PWM = %d\n", val);
+	panel->backlight.pwm_funcs->set(conn_state, val);
+}
+
+u32 intel_panel_backlight_level_to_pwm(struct intel_connector *connector, u32 val)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	drm_WARN_ON_ONCE(&dev_priv->drm,
+			 panel->backlight.max == 0 || panel->backlight.pwm_level_max == 0);
+
+	val = scale(val, panel->backlight.min, panel->backlight.max,
+		    panel->backlight.pwm_level_min, panel->backlight.pwm_level_max);
+
+	return intel_panel_invert_pwm_level(connector, val);
+}
+
+u32 intel_panel_backlight_level_from_pwm(struct intel_connector *connector, u32 val)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	drm_WARN_ON_ONCE(&dev_priv->drm,
+			 panel->backlight.max == 0 || panel->backlight.pwm_level_max == 0);
+
+	if (dev_priv->params.invert_brightness > 0 ||
+	    (dev_priv->params.invert_brightness == 0 && dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS))
+		val = panel->backlight.pwm_level_max - (val - panel->backlight.pwm_level_min);
+
+	return scale(val, panel->backlight.pwm_level_min, panel->backlight.pwm_level_max,
+		     panel->backlight.min, panel->backlight.max);
+}
+
+static u32 lpt_get_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return intel_de_read(dev_priv, BLC_PWM_PCH_CTL2) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 pch_get_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return intel_de_read(dev_priv, BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 i9xx_get_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 val;
+
+	val = intel_de_read(dev_priv, BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+	if (DISPLAY_VER(dev_priv) < 4)
+		val >>= 1;
+
+	if (panel->backlight.combination_mode) {
+		u8 lbpc;
+
+		pci_read_config_byte(to_pci_dev(dev_priv->drm.dev), LBPC, &lbpc);
+		val *= lbpc;
+	}
+
+	return val;
+}
+
+static u32 vlv_get_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	if (drm_WARN_ON(&dev_priv->drm, pipe != PIPE_A && pipe != PIPE_B))
+		return 0;
+
+	return intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe)) & BACKLIGHT_DUTY_CYCLE_MASK;
+}
+
+static u32 bxt_get_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	return intel_de_read(dev_priv,
+			     BXT_BLC_PWM_DUTY(panel->backlight.controller));
+}
+
+static u32 ext_pwm_get_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct intel_panel *panel = &connector->panel;
+	struct pwm_state state;
+
+	pwm_get_state(panel->backlight.pwm, &state);
+	return pwm_get_relative_duty_cycle(&state, 100);
+}
+
+static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	u32 val = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, val | level);
+}
+
+static void pch_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	intel_de_write(dev_priv, BLC_PWM_CPU_CTL, tmp | level);
+}
+
+static void i9xx_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp, mask;
+
+	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
+
+	if (panel->backlight.combination_mode) {
+		u8 lbpc;
+
+		lbpc = level * 0xfe / panel->backlight.pwm_level_max + 1;
+		level /= lbpc;
+		pci_write_config_byte(to_pci_dev(dev_priv->drm.dev), LBPC, lbpc);
+	}
+
+	if (DISPLAY_VER(dev_priv) == 4) {
+		mask = BACKLIGHT_DUTY_CYCLE_MASK;
+	} else {
+		level <<= 1;
+		mask = BACKLIGHT_DUTY_CYCLE_MASK_PNV;
+	}
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_CTL) & ~mask;
+	intel_de_write(dev_priv, BLC_PWM_CTL, tmp | level);
+}
+
+static void vlv_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
+	u32 tmp;
+
+	tmp = intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe)) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+	intel_de_write(dev_priv, VLV_BLC_PWM_CTL(pipe), tmp | level);
+}
+
+static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	intel_de_write(dev_priv,
+		       BXT_BLC_PWM_DUTY(panel->backlight.controller), level);
+}
+
+static void ext_pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel;
+
+	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
+	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+}
+
+static void
+intel_panel_actually_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	drm_dbg_kms(&i915->drm, "set backlight level = %d\n", level);
+
+	panel->backlight.funcs->set(conn_state, level);
+}
+
+/* set backlight brightness to level in range [0..max], assuming hw min is
+ * respected.
+ */
+void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
+				    u32 user_level, u32 user_max)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	/*
+	 * Lack of crtc may occur during driver init because
+	 * connection_mutex isn't held across the entire backlight
+	 * setup + modeset readout, and the BIOS can issue the
+	 * requests at any time.
+	 */
+	if (!panel->backlight.present || !conn_state->crtc)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	drm_WARN_ON(&dev_priv->drm, panel->backlight.max == 0);
+
+	hw_level = clamp_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
+
+	if (panel->backlight.device)
+		panel->backlight.device->props.brightness =
+			scale_hw_to_user(connector,
+					 panel->backlight.level,
+					 panel->backlight.device->props.max_brightness);
+
+	if (panel->backlight.enabled)
+		intel_panel_actually_set_backlight(conn_state, hw_level);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static void lpt_disable_backlight(const struct drm_connector_state *old_conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, level);
+
+	/*
+	 * Although we don't support or enable CPU PWM with LPT/SPT based
+	 * systems, it may have been enabled prior to loading the
+	 * driver. Disable to avoid warnings on LCPLL disable.
+	 *
+	 * This needs rework if we need to add support for CPU PWM on PCH split
+	 * platforms.
+	 */
+	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
+	if (tmp & BLM_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "cpu backlight was enabled, disabling\n");
+		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2,
+			       tmp & ~BLM_PWM_ENABLE);
+	}
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
+}
+
+static void pch_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, val);
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
+	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
+}
+
+static void i9xx_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	intel_panel_set_pwm_level(old_conn_state, val);
+}
+
+static void i965_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	struct drm_i915_private *dev_priv = to_i915(old_conn_state->connector->dev);
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, val);
+
+	tmp = intel_de_read(dev_priv, BLC_PWM_CTL2);
+	intel_de_write(dev_priv, BLC_PWM_CTL2, tmp & ~BLM_PWM_ENABLE);
+}
+
+static void vlv_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	enum pipe pipe = to_intel_crtc(old_conn_state->crtc)->pipe;
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, val);
+
+	tmp = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
+	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe),
+		       tmp & ~BLM_PWM_ENABLE);
+}
+
+static void bxt_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, val);
+
+	tmp = intel_de_read(dev_priv,
+			    BXT_BLC_PWM_CTL(panel->backlight.controller));
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       tmp & ~BXT_BLC_PWM_ENABLE);
+
+	if (panel->backlight.controller == 1) {
+		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
+		val &= ~UTIL_PIN_ENABLE;
+		intel_de_write(dev_priv, UTIL_PIN_CTL, val);
+	}
+}
+
+static void cnp_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp;
+
+	intel_panel_set_pwm_level(old_conn_state, val);
+
+	tmp = intel_de_read(dev_priv,
+			    BXT_BLC_PWM_CTL(panel->backlight.controller));
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       tmp & ~BXT_BLC_PWM_ENABLE);
+}
+
+static void ext_pwm_disable_backlight(const struct drm_connector_state *old_conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	panel->backlight.pwm_state.enabled = false;
+	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+}
+
+void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	if (!panel->backlight.present)
+		return;
+
+	/*
+	 * Do not disable backlight on the vga_switcheroo path. When switching
+	 * away from i915, the other client may depend on i915 to handle the
+	 * backlight. This will leave the backlight on unnecessarily when
+	 * another client is not activated.
+	 */
+	if (dev_priv->drm.switch_power_state == DRM_SWITCH_POWER_CHANGING) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "Skipping backlight disable on vga switch\n");
+		return;
+	}
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
+	panel->backlight.enabled = false;
+	panel->backlight.funcs->disable(old_conn_state, 0);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static void lpt_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pch_ctl1, pch_ctl2, schicken;
+
+	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "pch backlight already enabled\n");
+		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
+		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
+	}
+
+	if (HAS_PCH_LPT(dev_priv)) {
+		schicken = intel_de_read(dev_priv, SOUTH_CHICKEN2);
+		if (panel->backlight.alternate_pwm_increment)
+			schicken |= LPT_PWM_GRANULARITY;
+		else
+			schicken &= ~LPT_PWM_GRANULARITY;
+		intel_de_write(dev_priv, SOUTH_CHICKEN2, schicken);
+	} else {
+		schicken = intel_de_read(dev_priv, SOUTH_CHICKEN1);
+		if (panel->backlight.alternate_pwm_increment)
+			schicken |= SPT_PWM_GRANULARITY;
+		else
+			schicken &= ~SPT_PWM_GRANULARITY;
+		intel_de_write(dev_priv, SOUTH_CHICKEN1, schicken);
+	}
+
+	pch_ctl2 = panel->backlight.pwm_level_max << 16;
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, pch_ctl2);
+
+	pch_ctl1 = 0;
+	if (panel->backlight.active_low_pwm)
+		pch_ctl1 |= BLM_PCH_POLARITY;
+
+	/* After LPT, override is the default. */
+	if (HAS_PCH_LPT(dev_priv))
+		pch_ctl1 |= BLM_PCH_OVERRIDE_ENABLE;
+
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
+	intel_de_posting_read(dev_priv, BLC_PWM_PCH_CTL1);
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
+		       pch_ctl1 | BLM_PCH_PWM_ENABLE);
+
+	/* This won't stick until the above enable. */
+	intel_panel_set_pwm_level(conn_state, level);
+}
+
+static void pch_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
+
+	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
+	if (cpu_ctl2 & BLM_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "cpu backlight already enabled\n");
+		cpu_ctl2 &= ~BLM_PWM_ENABLE;
+		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2);
+	}
+
+	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "pch backlight already enabled\n");
+		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
+		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
+	}
+
+	if (cpu_transcoder == TRANSCODER_EDP)
+		cpu_ctl2 = BLM_TRANSCODER_EDP;
+	else
+		cpu_ctl2 = BLM_PIPE(cpu_transcoder);
+	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2);
+	intel_de_posting_read(dev_priv, BLC_PWM_CPU_CTL2);
+	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2 | BLM_PWM_ENABLE);
+
+	/* This won't stick until the above enable. */
+	intel_panel_set_pwm_level(conn_state, level);
+
+	pch_ctl2 = panel->backlight.pwm_level_max << 16;
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, pch_ctl2);
+
+	pch_ctl1 = 0;
+	if (panel->backlight.active_low_pwm)
+		pch_ctl1 |= BLM_PCH_POLARITY;
+
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
+	intel_de_posting_read(dev_priv, BLC_PWM_PCH_CTL1);
+	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
+		       pch_ctl1 | BLM_PCH_PWM_ENABLE);
+}
+
+static void i9xx_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, freq;
+
+	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
+	if (ctl & BACKLIGHT_DUTY_CYCLE_MASK_PNV) {
+		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
+		intel_de_write(dev_priv, BLC_PWM_CTL, 0);
+	}
+
+	freq = panel->backlight.pwm_level_max;
+	if (panel->backlight.combination_mode)
+		freq /= 0xff;
+
+	ctl = freq << 17;
+	if (panel->backlight.combination_mode)
+		ctl |= BLM_LEGACY_MODE;
+	if (IS_PINEVIEW(dev_priv) && panel->backlight.active_low_pwm)
+		ctl |= BLM_POLARITY_PNV;
+
+	intel_de_write(dev_priv, BLC_PWM_CTL, ctl);
+	intel_de_posting_read(dev_priv, BLC_PWM_CTL);
+
+	/* XXX: combine this into above write? */
+	intel_panel_set_pwm_level(conn_state, level);
+
+	/*
+	 * Needed to enable backlight on some 855gm models. BLC_HIST_CTL is
+	 * 855gm only, but checking for gen2 is safe, as 855gm is the only gen2
+	 * that has backlight.
+	 */
+	if (DISPLAY_VER(dev_priv) == 2)
+		intel_de_write(dev_priv, BLC_HIST_CTL, BLM_HISTOGRAM_ENABLE);
+}
+
+static void i965_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
+	u32 ctl, ctl2, freq;
+
+	ctl2 = intel_de_read(dev_priv, BLC_PWM_CTL2);
+	if (ctl2 & BLM_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
+		ctl2 &= ~BLM_PWM_ENABLE;
+		intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2);
+	}
+
+	freq = panel->backlight.pwm_level_max;
+	if (panel->backlight.combination_mode)
+		freq /= 0xff;
+
+	ctl = freq << 16;
+	intel_de_write(dev_priv, BLC_PWM_CTL, ctl);
+
+	ctl2 = BLM_PIPE(pipe);
+	if (panel->backlight.combination_mode)
+		ctl2 |= BLM_COMBINATION_MODE;
+	if (panel->backlight.active_low_pwm)
+		ctl2 |= BLM_POLARITY_I965;
+	intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2);
+	intel_de_posting_read(dev_priv, BLC_PWM_CTL2);
+	intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2 | BLM_PWM_ENABLE);
+
+	intel_panel_set_pwm_level(conn_state, level);
+}
+
+static void vlv_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
+	u32 ctl, ctl2;
+
+	ctl2 = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
+	if (ctl2 & BLM_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
+		ctl2 &= ~BLM_PWM_ENABLE;
+		intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe), ctl2);
+	}
+
+	ctl = panel->backlight.pwm_level_max << 16;
+	intel_de_write(dev_priv, VLV_BLC_PWM_CTL(pipe), ctl);
+
+	/* XXX: combine this into above write? */
+	intel_panel_set_pwm_level(conn_state, level);
+
+	ctl2 = 0;
+	if (panel->backlight.active_low_pwm)
+		ctl2 |= BLM_POLARITY_I965;
+	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe), ctl2);
+	intel_de_posting_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
+	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe),
+		       ctl2 | BLM_PWM_ENABLE);
+}
+
+static void bxt_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
+	u32 pwm_ctl, val;
+
+	/* Controller 1 uses the utility pin. */
+	if (panel->backlight.controller == 1) {
+		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
+		if (val & UTIL_PIN_ENABLE) {
+			drm_dbg_kms(&dev_priv->drm,
+				    "util pin already enabled\n");
+			val &= ~UTIL_PIN_ENABLE;
+			intel_de_write(dev_priv, UTIL_PIN_CTL, val);
+		}
+
+		val = 0;
+		if (panel->backlight.util_pin_active_low)
+			val |= UTIL_PIN_POLARITY;
+		intel_de_write(dev_priv, UTIL_PIN_CTL,
+			       val | UTIL_PIN_PIPE(pipe) | UTIL_PIN_MODE_PWM | UTIL_PIN_ENABLE);
+	}
+
+	pwm_ctl = intel_de_read(dev_priv,
+				BXT_BLC_PWM_CTL(panel->backlight.controller));
+	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
+		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
+		intel_de_write(dev_priv,
+			       BXT_BLC_PWM_CTL(panel->backlight.controller),
+			       pwm_ctl);
+	}
+
+	intel_de_write(dev_priv,
+		       BXT_BLC_PWM_FREQ(panel->backlight.controller),
+		       panel->backlight.pwm_level_max);
+
+	intel_panel_set_pwm_level(conn_state, level);
+
+	pwm_ctl = 0;
+	if (panel->backlight.active_low_pwm)
+		pwm_ctl |= BXT_BLC_PWM_POLARITY;
+
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       pwm_ctl);
+	intel_de_posting_read(dev_priv,
+			      BXT_BLC_PWM_CTL(panel->backlight.controller));
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       pwm_ctl | BXT_BLC_PWM_ENABLE);
+}
+
+static void cnp_enable_backlight(const struct intel_crtc_state *crtc_state,
+				 const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl;
+
+	pwm_ctl = intel_de_read(dev_priv,
+				BXT_BLC_PWM_CTL(panel->backlight.controller));
+	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
+		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
+		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
+		intel_de_write(dev_priv,
+			       BXT_BLC_PWM_CTL(panel->backlight.controller),
+			       pwm_ctl);
+	}
+
+	intel_de_write(dev_priv,
+		       BXT_BLC_PWM_FREQ(panel->backlight.controller),
+		       panel->backlight.pwm_level_max);
+
+	intel_panel_set_pwm_level(conn_state, level);
+
+	pwm_ctl = 0;
+	if (panel->backlight.active_low_pwm)
+		pwm_ctl |= BXT_BLC_PWM_POLARITY;
+
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       pwm_ctl);
+	intel_de_posting_read(dev_priv,
+			      BXT_BLC_PWM_CTL(panel->backlight.controller));
+	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
+		       pwm_ctl | BXT_BLC_PWM_ENABLE);
+}
+
+static void ext_pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
+				     const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
+	panel->backlight.pwm_state.enabled = true;
+	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+}
+
+static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+					   const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	if (panel->backlight.level <= panel->backlight.min) {
+		panel->backlight.level = panel->backlight.max;
+		if (panel->backlight.device)
+			panel->backlight.device->props.brightness =
+				scale_hw_to_user(connector,
+						 panel->backlight.level,
+						 panel->backlight.device->props.max_brightness);
+	}
+
+	panel->backlight.funcs->enable(crtc_state, conn_state, panel->backlight.level);
+	panel->backlight.enabled = true;
+	if (panel->backlight.device)
+		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
+}
+
+void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
+
+	if (!panel->backlight.present)
+		return;
+
+	drm_dbg_kms(&dev_priv->drm, "pipe %c\n", pipe_name(pipe));
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	__intel_panel_enable_backlight(crtc_state, conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+static u32 intel_panel_get_backlight(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 val = 0;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	if (panel->backlight.enabled)
+		val = panel->backlight.funcs->get(connector, intel_connector_get_pipe(connector));
+
+	mutex_unlock(&dev_priv->backlight_lock);
+
+	drm_dbg_kms(&dev_priv->drm, "get backlight PWM = %d\n", val);
+	return val;
+}
+
+/* Scale user_level in range [0..user_max] to [hw_min..hw_max]. */
+static u32 scale_user_to_hw(struct intel_connector *connector,
+			    u32 user_level, u32 user_max)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return scale(user_level, 0, user_max,
+		     panel->backlight.min, panel->backlight.max);
+}
+
+/* set backlight brightness to level in range [0..max], scaling wrt hw min */
+static void intel_panel_set_backlight(const struct drm_connector_state *conn_state,
+				      u32 user_level, u32 user_max)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 hw_level;
+
+	if (!panel->backlight.present)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+
+	drm_WARN_ON(&dev_priv->drm, panel->backlight.max == 0);
+
+	hw_level = scale_user_to_hw(connector, user_level, user_max);
+	panel->backlight.level = hw_level;
+
+	if (panel->backlight.enabled)
+		intel_panel_actually_set_backlight(conn_state, hw_level);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+static int intel_backlight_device_update_status(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct intel_panel *panel = &connector->panel;
+	struct drm_device *dev = connector->base.dev;
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
+		      bd->props.brightness, bd->props.max_brightness);
+	intel_panel_set_backlight(connector->base.state, bd->props.brightness,
+				  bd->props.max_brightness);
+
+	/*
+	 * Allow flipping bl_power as a sub-state of enabled. Sadly the
+	 * backlight class device does not make it easy to differentiate
+	 * between callbacks for brightness and bl_power, so our backlight_power
+	 * callback needs to take this into account.
+	 */
+	if (panel->backlight.enabled) {
+		if (panel->backlight.power) {
+			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
+				bd->props.brightness != 0;
+			panel->backlight.power(connector, enable);
+		}
+	} else {
+		bd->props.power = FB_BLANK_POWERDOWN;
+	}
+
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	return 0;
+}
+
+static int intel_backlight_device_get_brightness(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	intel_wakeref_t wakeref;
+	int ret = 0;
+
+	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref) {
+		u32 hw_level;
+
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+
+		hw_level = intel_panel_get_backlight(connector);
+		ret = scale_hw_to_user(connector,
+				       hw_level, bd->props.max_brightness);
+
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	}
+
+	return ret;
+}
+
+static const struct backlight_ops intel_backlight_device_ops = {
+	.update_status = intel_backlight_device_update_status,
+	.get_brightness = intel_backlight_device_get_brightness,
+};
+
+int intel_backlight_device_register(struct intel_connector *connector)
+{
+	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	struct backlight_properties props;
+	struct backlight_device *bd;
+	const char *name;
+	int ret = 0;
+
+	if (WARN_ON(panel->backlight.device))
+		return -ENODEV;
+
+	if (!panel->backlight.present)
+		return 0;
+
+	WARN_ON(panel->backlight.max == 0);
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_RAW;
+
+	/*
+	 * Note: Everything should work even if the backlight device max
+	 * presented to the userspace is arbitrarily chosen.
+	 */
+	props.max_brightness = panel->backlight.max;
+	props.brightness = scale_hw_to_user(connector,
+					    panel->backlight.level,
+					    props.max_brightness);
+
+	if (panel->backlight.enabled)
+		props.power = FB_BLANK_UNBLANK;
+	else
+		props.power = FB_BLANK_POWERDOWN;
+
+	name = kstrdup("intel_backlight", GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	bd = backlight_device_register(name, connector->base.kdev, connector,
+				       &intel_backlight_device_ops, &props);
+
+	/*
+	 * Using the same name independent of the drm device or connector
+	 * prevents registration of multiple backlight devices in the
+	 * driver. However, we need to use the default name for backward
+	 * compatibility. Use unique names for subsequent backlight devices as a
+	 * fallback when the default name already exists.
+	 */
+	if (IS_ERR(bd) && PTR_ERR(bd) == -EEXIST) {
+		kfree(name);
+		name = kasprintf(GFP_KERNEL, "card%d-%s-backlight",
+				 i915->drm.primary->index, connector->base.name);
+		if (!name)
+			return -ENOMEM;
+
+		bd = backlight_device_register(name, connector->base.kdev, connector,
+					       &intel_backlight_device_ops, &props);
+	}
+
+	if (IS_ERR(bd)) {
+		drm_err(&i915->drm,
+			"[CONNECTOR:%d:%s] backlight device %s register failed: %ld\n",
+			connector->base.base.id, connector->base.name, name, PTR_ERR(bd));
+		ret = PTR_ERR(bd);
+		goto out;
+	}
+
+	panel->backlight.device = bd;
+
+	drm_dbg_kms(&i915->drm,
+		    "[CONNECTOR:%d:%s] backlight device %s registered\n",
+		    connector->base.base.id, connector->base.name, name);
+
+out:
+	kfree(name);
+
+	return ret;
+}
+
+void intel_backlight_device_unregister(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	if (panel->backlight.device) {
+		backlight_device_unregister(panel->backlight.device);
+		panel->backlight.device = NULL;
+	}
+}
+#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
+
+/*
+ * CNP: PWM clock frequency is 19.2 MHz or 24 MHz.
+ *      PWM increment = 1
+ */
+static u32 cnp_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return DIV_ROUND_CLOSEST(KHz(RUNTIME_INFO(dev_priv)->rawclk_freq),
+				 pwm_freq_hz);
+}
+
+/*
+ * BXT: PWM clock frequency = 19.2 MHz.
+ */
+static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	return DIV_ROUND_CLOSEST(KHz(19200), pwm_freq_hz);
+}
+
+/*
+ * SPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 16 (default increment) or 128 (alternate increment selected in
+ * SCHICKEN_1 bit 0). PWM clock is 24 MHz.
+ */
+static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct intel_panel *panel = &connector->panel;
+	u32 mul;
+
+	if (panel->backlight.alternate_pwm_increment)
+		mul = 128;
+	else
+		mul = 16;
+
+	return DIV_ROUND_CLOSEST(MHz(24), pwm_freq_hz * mul);
+}
+
+/*
+ * LPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 128 (default increment) or 16 (alternate increment, selected in
+ * LPT SOUTH_CHICKEN2 register bit 5).
+ */
+static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 mul, clock;
+
+	if (panel->backlight.alternate_pwm_increment)
+		mul = 16;
+	else
+		mul = 128;
+
+	if (HAS_PCH_LPT_H(dev_priv))
+		clock = MHz(135); /* LPT:H */
+	else
+		clock = MHz(24); /* LPT:LP */
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
+}
+
+/*
+ * ILK/SNB/IVB: This value represents the period of the PWM stream in PCH
+ * display raw clocks multiplied by 128.
+ */
+static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	return DIV_ROUND_CLOSEST(KHz(RUNTIME_INFO(dev_priv)->rawclk_freq),
+				 pwm_freq_hz * 128);
+}
+
+/*
+ * Gen2: This field determines the number of time base events (display core
+ * clock frequency/32) in total for a complete cycle of modulated backlight
+ * control.
+ *
+ * Gen3: A time base event equals the display core clock ([DevPNV] HRAW clock)
+ * divided by 32.
+ */
+static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int clock;
+
+	if (IS_PINEVIEW(dev_priv))
+		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
+	else
+		clock = KHz(dev_priv->cdclk.hw.cdclk);
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 32);
+}
+
+/*
+ * Gen4: This value represents the period of the PWM stream in display core
+ * clocks ([DevCTG] HRAW clocks) multiplied by 128.
+ *
+ */
+static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int clock;
+
+	if (IS_G4X(dev_priv))
+		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
+	else
+		clock = KHz(dev_priv->cdclk.hw.cdclk);
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 128);
+}
+
+/*
+ * VLV: This value represents the period of the PWM stream in display core
+ * clocks ([DevCTG] 200MHz HRAW clocks) multiplied by 128 or 25MHz S0IX clocks
+ * multiplied by 16. CHV uses a 19.2MHz S0IX clock.
+ */
+static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	int mul, clock;
+
+	if ((intel_de_read(dev_priv, CBR1_VLV) & CBR_PWM_CLOCK_MUX_SELECT) == 0) {
+		if (IS_CHERRYVIEW(dev_priv))
+			clock = KHz(19200);
+		else
+			clock = MHz(25);
+		mul = 16;
+	} else {
+		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
+		mul = 128;
+	}
+
+	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
+}
+
+static u16 get_vbt_pwm_freq(struct drm_i915_private *dev_priv)
+{
+	u16 pwm_freq_hz = dev_priv->vbt.backlight.pwm_freq_hz;
+
+	if (pwm_freq_hz) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "VBT defined backlight frequency %u Hz\n",
+			    pwm_freq_hz);
+	} else {
+		pwm_freq_hz = 200;
+		drm_dbg_kms(&dev_priv->drm,
+			    "default backlight frequency %u Hz\n",
+			    pwm_freq_hz);
+	}
+
+	return pwm_freq_hz;
+}
+
+static u32 get_backlight_max_vbt(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u16 pwm_freq_hz = get_vbt_pwm_freq(dev_priv);
+	u32 pwm;
+
+	if (!panel->backlight.pwm_funcs->hz_to_pwm) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "backlight frequency conversion not supported\n");
+		return 0;
+	}
+
+	pwm = panel->backlight.pwm_funcs->hz_to_pwm(connector, pwm_freq_hz);
+	if (!pwm) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "backlight frequency conversion failed\n");
+		return 0;
+	}
+
+	return pwm;
+}
+
+/*
+ * Note: The setup hooks can't assume pipe is set!
+ */
+static u32 get_backlight_min_vbt(struct intel_connector *connector)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	int min;
+
+	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
+
+	/*
+	 * XXX: If the vbt value is 255, it makes min equal to max, which leads
+	 * to problems. There are such machines out there. Either our
+	 * interpretation is wrong or the vbt has bogus data. Or both. Safeguard
+	 * against this by letting the minimum be at most (arbitrarily chosen)
+	 * 25% of the max.
+	 */
+	min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
+	if (min != dev_priv->vbt.backlight.min_brightness) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "clamping VBT min backlight %d/255 to %d/255\n",
+			    dev_priv->vbt.backlight.min_brightness, min);
+	}
+
+	/* vbt value is a coefficient in range [0..255] */
+	return scale(min, 0, 255, 0, panel->backlight.pwm_level_max);
+}
+
+static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
+	bool alt, cpu_mode;
+
+	if (HAS_PCH_LPT(dev_priv))
+		alt = intel_de_read(dev_priv, SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY;
+	else
+		alt = intel_de_read(dev_priv, SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY;
+	panel->backlight.alternate_pwm_increment = alt;
+
+	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
+
+	pch_ctl2 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2);
+	panel->backlight.pwm_level_max = pch_ctl2 >> 16;
+
+	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	panel->backlight.pwm_enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
+
+	cpu_mode = panel->backlight.pwm_enabled && HAS_PCH_LPT(dev_priv) &&
+		   !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) &&
+		   (cpu_ctl2 & BLM_PWM_ENABLE);
+
+	if (cpu_mode) {
+		val = pch_get_backlight(connector, unused);
+
+		drm_dbg_kms(&dev_priv->drm,
+			    "CPU backlight register was enabled, switching to PCH override\n");
+
+		/* Write converted CPU PWM value to PCH override register */
+		lpt_set_backlight(connector->base.state, val);
+		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
+			       pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE);
+
+		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2,
+			       cpu_ctl2 & ~BLM_PWM_ENABLE);
+	}
+
+	return 0;
+}
+
+static int pch_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
+
+	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
+	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
+
+	pch_ctl2 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2);
+	panel->backlight.pwm_level_max = pch_ctl2 >> 16;
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
+	panel->backlight.pwm_enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
+		(pch_ctl1 & BLM_PCH_PWM_ENABLE);
+
+	return 0;
+}
+
+static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, val;
+
+	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
+
+	if (DISPLAY_VER(dev_priv) == 2 || IS_I915GM(dev_priv) || IS_I945GM(dev_priv))
+		panel->backlight.combination_mode = ctl & BLM_LEGACY_MODE;
+
+	if (IS_PINEVIEW(dev_priv))
+		panel->backlight.active_low_pwm = ctl & BLM_POLARITY_PNV;
+
+	panel->backlight.pwm_level_max = ctl >> 17;
+
+	if (!panel->backlight.pwm_level_max) {
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+		panel->backlight.pwm_level_max >>= 1;
+	}
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	if (panel->backlight.combination_mode)
+		panel->backlight.pwm_level_max *= 0xff;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	val = i9xx_get_backlight(connector, unused);
+	val = intel_panel_invert_pwm_level(connector, val);
+	val = clamp(val, panel->backlight.pwm_level_min, panel->backlight.pwm_level_max);
+
+	panel->backlight.pwm_enabled = val != 0;
+
+	return 0;
+}
+
+static int i965_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, ctl2;
+
+	ctl2 = intel_de_read(dev_priv, BLC_PWM_CTL2);
+	panel->backlight.combination_mode = ctl2 & BLM_COMBINATION_MODE;
+	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
+
+	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
+	panel->backlight.pwm_level_max = ctl >> 16;
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	if (panel->backlight.combination_mode)
+		panel->backlight.pwm_level_max *= 0xff;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
+
+	return 0;
+}
+
+static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 ctl, ctl2;
+
+	if (drm_WARN_ON(&dev_priv->drm, pipe != PIPE_A && pipe != PIPE_B))
+		return -ENODEV;
+
+	ctl2 = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
+	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
+
+	ctl = intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe));
+	panel->backlight.pwm_level_max = ctl >> 16;
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
+
+	return 0;
+}
+
+static int
+bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl, val;
+
+	panel->backlight.controller = dev_priv->vbt.backlight.controller;
+
+	pwm_ctl = intel_de_read(dev_priv,
+				BXT_BLC_PWM_CTL(panel->backlight.controller));
+
+	/* Controller 1 uses the utility pin. */
+	if (panel->backlight.controller == 1) {
+		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
+		panel->backlight.util_pin_active_low =
+					val & UTIL_PIN_POLARITY;
+	}
+
+	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
+	panel->backlight.pwm_level_max =
+		intel_de_read(dev_priv, BXT_BLC_PWM_FREQ(panel->backlight.controller));
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
+
+	return 0;
+}
+
+static int
+cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+	u32 pwm_ctl;
+
+	/*
+	 * CNP has the BXT implementation of backlight, but with only one
+	 * controller. TODO: ICP has multiple controllers but we only use
+	 * controller 0 for now.
+	 */
+	panel->backlight.controller = 0;
+
+	pwm_ctl = intel_de_read(dev_priv,
+				BXT_BLC_PWM_CTL(panel->backlight.controller));
+
+	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
+	panel->backlight.pwm_level_max =
+		intel_de_read(dev_priv, BXT_BLC_PWM_FREQ(panel->backlight.controller));
+
+	if (!panel->backlight.pwm_level_max)
+		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
+
+	if (!panel->backlight.pwm_level_max)
+		return -ENODEV;
+
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
+
+	return 0;
+}
+
+static int ext_pwm_setup_backlight(struct intel_connector *connector,
+				   enum pipe pipe)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct intel_panel *panel = &connector->panel;
+	const char *desc;
+	u32 level;
+
+	/* Get the right PWM chip for DSI backlight according to VBT */
+	if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
+		panel->backlight.pwm = pwm_get(dev->dev, "pwm_pmic_backlight");
+		desc = "PMIC";
+	} else {
+		panel->backlight.pwm = pwm_get(dev->dev, "pwm_soc_backlight");
+		desc = "SoC";
+	}
+
+	if (IS_ERR(panel->backlight.pwm)) {
+		drm_err(&dev_priv->drm, "Failed to get the %s PWM chip\n",
+			desc);
+		panel->backlight.pwm = NULL;
+		return -ENODEV;
+	}
+
+	panel->backlight.pwm_level_max = 100; /* 100% */
+	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
+
+	if (pwm_is_enabled(panel->backlight.pwm)) {
+		/* PWM is already enabled, use existing settings */
+		pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+
+		level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state,
+						    100);
+		level = intel_panel_invert_pwm_level(connector, level);
+		panel->backlight.pwm_enabled = true;
+
+		drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n",
+			    NSEC_PER_SEC / (unsigned long)panel->backlight.pwm_state.period,
+			    get_vbt_pwm_freq(dev_priv), level);
+	} else {
+		/* Set period from VBT frequency, leave other settings at 0. */
+		panel->backlight.pwm_state.period =
+			NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv);
+	}
+
+	drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n",
+		 desc);
+	return 0;
+}
+
+static void intel_pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	panel->backlight.pwm_funcs->set(conn_state,
+				       intel_panel_invert_pwm_level(connector, level));
+}
+
+static u32 intel_pwm_get_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	return intel_panel_invert_pwm_level(connector,
+					    panel->backlight.pwm_funcs->get(connector, pipe));
+}
+
+static void intel_pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
+				       const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	panel->backlight.pwm_funcs->enable(crtc_state, conn_state,
+					   intel_panel_invert_pwm_level(connector, level));
+}
+
+static void intel_pwm_disable_backlight(const struct drm_connector_state *conn_state, u32 level)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct intel_panel *panel = &connector->panel;
+
+	panel->backlight.pwm_funcs->disable(conn_state,
+					    intel_panel_invert_pwm_level(connector, level));
+}
+
+static int intel_pwm_setup_backlight(struct intel_connector *connector, enum pipe pipe)
+{
+	struct intel_panel *panel = &connector->panel;
+	int ret = panel->backlight.pwm_funcs->setup(connector, pipe);
+
+	if (ret < 0)
+		return ret;
+
+	panel->backlight.min = panel->backlight.pwm_level_min;
+	panel->backlight.max = panel->backlight.pwm_level_max;
+	panel->backlight.level = intel_pwm_get_backlight(connector, pipe);
+	panel->backlight.enabled = panel->backlight.pwm_enabled;
+
+	return 0;
+}
+
+void intel_panel_update_backlight(struct intel_atomic_state *state,
+				  struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state)
+{
+	struct intel_connector *connector = to_intel_connector(conn_state->connector);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+	struct intel_panel *panel = &connector->panel;
+
+	if (!panel->backlight.present)
+		return;
+
+	mutex_lock(&dev_priv->backlight_lock);
+	if (!panel->backlight.enabled)
+		__intel_panel_enable_backlight(crtc_state, conn_state);
+
+	mutex_unlock(&dev_priv->backlight_lock);
+}
+
+int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = to_i915(connector->dev);
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_panel *panel = &intel_connector->panel;
+	int ret;
+
+	if (!dev_priv->vbt.backlight.present) {
+		if (dev_priv->quirks & QUIRK_BACKLIGHT_PRESENT) {
+			drm_dbg_kms(&dev_priv->drm,
+				    "no backlight present per VBT, but present per quirk\n");
+		} else {
+			drm_dbg_kms(&dev_priv->drm,
+				    "no backlight present per VBT\n");
+			return 0;
+		}
+	}
+
+	/* ensure intel_panel has been initialized first */
+	if (drm_WARN_ON(&dev_priv->drm, !panel->backlight.funcs))
+		return -ENODEV;
+
+	/* set level and max in panel struct */
+	mutex_lock(&dev_priv->backlight_lock);
+	ret = panel->backlight.funcs->setup(intel_connector, pipe);
+	mutex_unlock(&dev_priv->backlight_lock);
+
+	if (ret) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "failed to setup backlight for connector %s\n",
+			    connector->name);
+		return ret;
+	}
+
+	panel->backlight.present = true;
+
+	drm_dbg_kms(&dev_priv->drm,
+		    "Connector %s backlight initialized, %s, brightness %u/%u\n",
+		    connector->name,
+		    enableddisabled(panel->backlight.enabled),
+		    panel->backlight.level, panel->backlight.max);
+
+	return 0;
+}
+
+void intel_panel_destroy_backlight(struct intel_panel *panel)
+{
+	/* dispose of the pwm */
+	if (panel->backlight.pwm)
+		pwm_put(panel->backlight.pwm);
+
+	panel->backlight.present = false;
+}
+
+static const struct intel_panel_bl_funcs bxt_pwm_funcs = {
+	.setup = bxt_setup_backlight,
+	.enable = bxt_enable_backlight,
+	.disable = bxt_disable_backlight,
+	.set = bxt_set_backlight,
+	.get = bxt_get_backlight,
+	.hz_to_pwm = bxt_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs cnp_pwm_funcs = {
+	.setup = cnp_setup_backlight,
+	.enable = cnp_enable_backlight,
+	.disable = cnp_disable_backlight,
+	.set = bxt_set_backlight,
+	.get = bxt_get_backlight,
+	.hz_to_pwm = cnp_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs lpt_pwm_funcs = {
+	.setup = lpt_setup_backlight,
+	.enable = lpt_enable_backlight,
+	.disable = lpt_disable_backlight,
+	.set = lpt_set_backlight,
+	.get = lpt_get_backlight,
+	.hz_to_pwm = lpt_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs spt_pwm_funcs = {
+	.setup = lpt_setup_backlight,
+	.enable = lpt_enable_backlight,
+	.disable = lpt_disable_backlight,
+	.set = lpt_set_backlight,
+	.get = lpt_get_backlight,
+	.hz_to_pwm = spt_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs pch_pwm_funcs = {
+	.setup = pch_setup_backlight,
+	.enable = pch_enable_backlight,
+	.disable = pch_disable_backlight,
+	.set = pch_set_backlight,
+	.get = pch_get_backlight,
+	.hz_to_pwm = pch_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs ext_pwm_funcs = {
+	.setup = ext_pwm_setup_backlight,
+	.enable = ext_pwm_enable_backlight,
+	.disable = ext_pwm_disable_backlight,
+	.set = ext_pwm_set_backlight,
+	.get = ext_pwm_get_backlight,
+};
+
+static const struct intel_panel_bl_funcs vlv_pwm_funcs = {
+	.setup = vlv_setup_backlight,
+	.enable = vlv_enable_backlight,
+	.disable = vlv_disable_backlight,
+	.set = vlv_set_backlight,
+	.get = vlv_get_backlight,
+	.hz_to_pwm = vlv_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs i965_pwm_funcs = {
+	.setup = i965_setup_backlight,
+	.enable = i965_enable_backlight,
+	.disable = i965_disable_backlight,
+	.set = i9xx_set_backlight,
+	.get = i9xx_get_backlight,
+	.hz_to_pwm = i965_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs i9xx_pwm_funcs = {
+	.setup = i9xx_setup_backlight,
+	.enable = i9xx_enable_backlight,
+	.disable = i9xx_disable_backlight,
+	.set = i9xx_set_backlight,
+	.get = i9xx_get_backlight,
+	.hz_to_pwm = i9xx_hz_to_pwm,
+};
+
+static const struct intel_panel_bl_funcs pwm_bl_funcs = {
+	.setup = intel_pwm_setup_backlight,
+	.enable = intel_pwm_enable_backlight,
+	.disable = intel_pwm_disable_backlight,
+	.set = intel_pwm_set_backlight,
+	.get = intel_pwm_get_backlight,
+};
+
+/* Set up chip specific backlight functions */
+void
+intel_panel_init_backlight_funcs(struct intel_panel *panel)
+{
+	struct intel_connector *connector =
+		container_of(panel, struct intel_connector, panel);
+	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
+
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI &&
+	    intel_dsi_dcs_init_backlight_funcs(connector) == 0)
+		return;
+
+	if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv)) {
+		panel->backlight.pwm_funcs = &bxt_pwm_funcs;
+	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_CNP) {
+		panel->backlight.pwm_funcs = &cnp_pwm_funcs;
+	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_LPT) {
+		if (HAS_PCH_LPT(dev_priv))
+			panel->backlight.pwm_funcs = &lpt_pwm_funcs;
+		else
+			panel->backlight.pwm_funcs = &spt_pwm_funcs;
+	} else if (HAS_PCH_SPLIT(dev_priv)) {
+		panel->backlight.pwm_funcs = &pch_pwm_funcs;
+	} else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
+		if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI) {
+			panel->backlight.pwm_funcs = &ext_pwm_funcs;
+		} else {
+			panel->backlight.pwm_funcs = &vlv_pwm_funcs;
+		}
+	} else if (DISPLAY_VER(dev_priv) == 4) {
+		panel->backlight.pwm_funcs = &i965_pwm_funcs;
+	} else {
+		panel->backlight.pwm_funcs = &i9xx_pwm_funcs;
+	}
+
+	if (connector->base.connector_type == DRM_MODE_CONNECTOR_eDP &&
+	    intel_dp_aux_init_backlight_funcs(connector) == 0)
+		return;
+
+	/* We're using a standard PWM backlight interface */
+	panel->backlight.funcs = &pwm_bl_funcs;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.h b/drivers/gpu/drm/i915/display/intel_backlight.h
new file mode 100644
index 000000000000..282020cb47d5
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_backlight.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef __INTEL_BACKLIGHT_H__
+#define __INTEL_BACKLIGHT_H__
+
+#include <linux/types.h>
+
+struct drm_connector;
+struct drm_connector_state;
+struct intel_atomic_state;
+struct intel_connector;
+struct intel_crtc_state;
+struct intel_encoder;
+struct intel_panel;
+enum pipe;
+
+void intel_panel_init_backlight_funcs(struct intel_panel *panel);
+void intel_panel_destroy_backlight(struct intel_panel *panel);
+void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
+				    u32 level, u32 max);
+int intel_panel_setup_backlight(struct drm_connector *connector,
+				enum pipe pipe);
+void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state);
+void intel_panel_update_backlight(struct intel_atomic_state *state,
+				  struct intel_encoder *encoder,
+				  const struct intel_crtc_state *crtc_state,
+				  const struct drm_connector_state *conn_state);
+void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state);
+void intel_panel_set_pwm_level(const struct drm_connector_state *conn_state, u32 level);
+u32 intel_panel_invert_pwm_level(struct intel_connector *connector, u32 level);
+u32 intel_panel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
+u32 intel_panel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
+
+#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
+int intel_backlight_device_register(struct intel_connector *connector);
+void intel_backlight_device_unregister(struct intel_connector *connector);
+#else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
+static inline int intel_backlight_device_register(struct intel_connector *connector)
+{
+	return 0;
+}
+static inline void intel_backlight_device_unregister(struct intel_connector *connector)
+{
+}
+#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
+
+#endif /* __INTEL_BACKLIGHT_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_connector.c b/drivers/gpu/drm/i915/display/intel_connector.c
index 9bed1ccecea0..4f49d782eca2 100644
--- a/drivers/gpu/drm/i915/display/intel_connector.c
+++ b/drivers/gpu/drm/i915/display/intel_connector.c
@@ -29,13 +29,13 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_edid.h>
 
-#include "display/intel_panel.h"
-
 #include "i915_drv.h"
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_display_debugfs.h"
 #include "intel_display_types.h"
 #include "intel_hdcp.h"
+#include "intel_panel.h"
 
 int intel_connector_init(struct intel_connector *connector)
 {
diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 1ef7a65feb66..dbd38beece3f 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -29,6 +29,7 @@
 
 #include "i915_drv.h"
 #include "intel_audio.h"
+#include "intel_backlight.h"
 #include "intel_combo_phy.h"
 #include "intel_connector.h"
 #include "intel_crtc.h"
@@ -48,7 +49,6 @@
 #include "intel_hdmi.h"
 #include "intel_hotplug.h"
 #include "intel_lspcon.h"
-#include "intel_panel.h"
 #include "intel_pps.h"
 #include "intel_psr.h"
 #include "intel_snps_phy.h"
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index fd4f7e82e420..71be9f92133e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -44,6 +44,7 @@
 #include "i915_drv.h"
 #include "intel_atomic.h"
 #include "intel_audio.h"
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_ddi.h"
 #include "intel_de.h"
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 6ac568617ef3..d026b9420403 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -34,9 +34,9 @@
  * for some reason.
  */
 
+#include "intel_backlight.h"
 #include "intel_display_types.h"
 #include "intel_dp_aux_backlight.h"
-#include "intel_panel.h"
 
 /* TODO:
  * Implement HDR, right now we just implement the bare minimum to bring us back into SDR mode so we
diff --git a/drivers/gpu/drm/i915/display/intel_lvds.c b/drivers/gpu/drm/i915/display/intel_lvds.c
index e0381b0fce91..8f5741ebd58d 100644
--- a/drivers/gpu/drm/i915/display/intel_lvds.c
+++ b/drivers/gpu/drm/i915/display/intel_lvds.c
@@ -40,6 +40,7 @@
 
 #include "i915_drv.h"
 #include "intel_atomic.h"
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_de.h"
 #include "intel_display_types.h"
diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
index 3855fba70980..3a7a8598d1ec 100644
--- a/drivers/gpu/drm/i915/display/intel_opregion.c
+++ b/drivers/gpu/drm/i915/display/intel_opregion.c
@@ -30,10 +30,9 @@
 #include <linux/firmware.h>
 #include <acpi/video.h>
 
-#include "display/intel_panel.h"
-
 #include "i915_drv.h"
 #include "intel_acpi.h"
+#include "intel_backlight.h"
 #include "intel_display_types.h"
 #include "intel_opregion.h"
 
diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index 074a55f20bcd..083eb774c4bb 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -28,17 +28,13 @@
  *      Chris Wilson <chris at chris-wilson.co.uk>
  */
 
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
 #include <linux/kernel.h>
-#include <linux/moduleparam.h>
 #include <linux/pwm.h>
 
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_de.h"
 #include "intel_display_types.h"
-#include "intel_dp_aux_backlight.h"
-#include "intel_dsi_dcs_backlight.h"
 #include "intel_panel.h"
 
 bool intel_panel_use_ssc(struct drm_i915_private *i915)
@@ -464,1767 +460,6 @@ int intel_gmch_panel_fitting(struct intel_crtc_state *crtc_state,
 	return 0;
 }
 
-/**
- * scale - scale values from one range to another
- * @source_val: value in range [@source_min.. at source_max]
- * @source_min: minimum legal value for @source_val
- * @source_max: maximum legal value for @source_val
- * @target_min: corresponding target value for @source_min
- * @target_max: corresponding target value for @source_max
- *
- * Return @source_val in range [@source_min.. at source_max] scaled to range
- * [@target_min.. at target_max].
- */
-static u32 scale(u32 source_val,
-		 u32 source_min, u32 source_max,
-		 u32 target_min, u32 target_max)
-{
-	u64 target_val;
-
-	WARN_ON(source_min > source_max);
-	WARN_ON(target_min > target_max);
-
-	/* defensive */
-	source_val = clamp(source_val, source_min, source_max);
-
-	/* avoid overflows */
-	target_val = mul_u32_u32(source_val - source_min,
-				 target_max - target_min);
-	target_val = DIV_ROUND_CLOSEST_ULL(target_val, source_max - source_min);
-	target_val += target_min;
-
-	return target_val;
-}
-
-/* Scale user_level in range [0..user_max] to [0..hw_max], clamping the result
- * to [hw_min..hw_max]. */
-static u32 clamp_user_to_hw(struct intel_connector *connector,
-			    u32 user_level, u32 user_max)
-{
-	struct intel_panel *panel = &connector->panel;
-	u32 hw_level;
-
-	hw_level = scale(user_level, 0, user_max, 0, panel->backlight.max);
-	hw_level = clamp(hw_level, panel->backlight.min, panel->backlight.max);
-
-	return hw_level;
-}
-
-/* Scale hw_level in range [hw_min..hw_max] to [0..user_max]. */
-static u32 scale_hw_to_user(struct intel_connector *connector,
-			    u32 hw_level, u32 user_max)
-{
-	struct intel_panel *panel = &connector->panel;
-
-	return scale(hw_level, panel->backlight.min, panel->backlight.max,
-		     0, user_max);
-}
-
-u32 intel_panel_invert_pwm_level(struct intel_connector *connector, u32 val)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
-
-	if (dev_priv->params.invert_brightness < 0)
-		return val;
-
-	if (dev_priv->params.invert_brightness > 0 ||
-	    dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS) {
-		return panel->backlight.pwm_level_max - val + panel->backlight.pwm_level_min;
-	}
-
-	return val;
-}
-
-void intel_panel_set_pwm_level(const struct drm_connector_state *conn_state, u32 val)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *i915 = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	drm_dbg_kms(&i915->drm, "set backlight PWM = %d\n", val);
-	panel->backlight.pwm_funcs->set(conn_state, val);
-}
-
-u32 intel_panel_backlight_level_to_pwm(struct intel_connector *connector, u32 val)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	drm_WARN_ON_ONCE(&dev_priv->drm,
-			 panel->backlight.max == 0 || panel->backlight.pwm_level_max == 0);
-
-	val = scale(val, panel->backlight.min, panel->backlight.max,
-		    panel->backlight.pwm_level_min, panel->backlight.pwm_level_max);
-
-	return intel_panel_invert_pwm_level(connector, val);
-}
-
-u32 intel_panel_backlight_level_from_pwm(struct intel_connector *connector, u32 val)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	drm_WARN_ON_ONCE(&dev_priv->drm,
-			 panel->backlight.max == 0 || panel->backlight.pwm_level_max == 0);
-
-	if (dev_priv->params.invert_brightness > 0 ||
-	    (dev_priv->params.invert_brightness == 0 && dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS))
-		val = panel->backlight.pwm_level_max - (val - panel->backlight.pwm_level_min);
-
-	return scale(val, panel->backlight.pwm_level_min, panel->backlight.pwm_level_max,
-		     panel->backlight.min, panel->backlight.max);
-}
-
-static u32 lpt_get_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	return intel_de_read(dev_priv, BLC_PWM_PCH_CTL2) & BACKLIGHT_DUTY_CYCLE_MASK;
-}
-
-static u32 pch_get_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	return intel_de_read(dev_priv, BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
-}
-
-static u32 i9xx_get_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 val;
-
-	val = intel_de_read(dev_priv, BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
-	if (DISPLAY_VER(dev_priv) < 4)
-		val >>= 1;
-
-	if (panel->backlight.combination_mode) {
-		u8 lbpc;
-
-		pci_read_config_byte(to_pci_dev(dev_priv->drm.dev), LBPC, &lbpc);
-		val *= lbpc;
-	}
-
-	return val;
-}
-
-static u32 vlv_get_backlight(struct intel_connector *connector, enum pipe pipe)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	if (drm_WARN_ON(&dev_priv->drm, pipe != PIPE_A && pipe != PIPE_B))
-		return 0;
-
-	return intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe)) & BACKLIGHT_DUTY_CYCLE_MASK;
-}
-
-static u32 bxt_get_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	return intel_de_read(dev_priv,
-			     BXT_BLC_PWM_DUTY(panel->backlight.controller));
-}
-
-static u32 ext_pwm_get_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct intel_panel *panel = &connector->panel;
-	struct pwm_state state;
-
-	pwm_get_state(panel->backlight.pwm, &state);
-	return pwm_get_relative_duty_cycle(&state, 100);
-}
-
-static void lpt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	u32 val = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2) & ~BACKLIGHT_DUTY_CYCLE_MASK;
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, val | level);
-}
-
-static void pch_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	u32 tmp;
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
-	intel_de_write(dev_priv, BLC_PWM_CPU_CTL, tmp | level);
-}
-
-static void i9xx_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 tmp, mask;
-
-	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
-
-	if (panel->backlight.combination_mode) {
-		u8 lbpc;
-
-		lbpc = level * 0xfe / panel->backlight.pwm_level_max + 1;
-		level /= lbpc;
-		pci_write_config_byte(to_pci_dev(dev_priv->drm.dev), LBPC, lbpc);
-	}
-
-	if (DISPLAY_VER(dev_priv) == 4) {
-		mask = BACKLIGHT_DUTY_CYCLE_MASK;
-	} else {
-		level <<= 1;
-		mask = BACKLIGHT_DUTY_CYCLE_MASK_PNV;
-	}
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_CTL) & ~mask;
-	intel_de_write(dev_priv, BLC_PWM_CTL, tmp | level);
-}
-
-static void vlv_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
-	u32 tmp;
-
-	tmp = intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe)) & ~BACKLIGHT_DUTY_CYCLE_MASK;
-	intel_de_write(dev_priv, VLV_BLC_PWM_CTL(pipe), tmp | level);
-}
-
-static void bxt_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	intel_de_write(dev_priv,
-		       BXT_BLC_PWM_DUTY(panel->backlight.controller), level);
-}
-
-static void ext_pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel;
-
-	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
-}
-
-static void
-intel_panel_actually_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *i915 = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	drm_dbg_kms(&i915->drm, "set backlight level = %d\n", level);
-
-	panel->backlight.funcs->set(conn_state, level);
-}
-
-/* set backlight brightness to level in range [0..max], assuming hw min is
- * respected.
- */
-void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
-				    u32 user_level, u32 user_max)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 hw_level;
-
-	/*
-	 * Lack of crtc may occur during driver init because
-	 * connection_mutex isn't held across the entire backlight
-	 * setup + modeset readout, and the BIOS can issue the
-	 * requests at any time.
-	 */
-	if (!panel->backlight.present || !conn_state->crtc)
-		return;
-
-	mutex_lock(&dev_priv->backlight_lock);
-
-	drm_WARN_ON(&dev_priv->drm, panel->backlight.max == 0);
-
-	hw_level = clamp_user_to_hw(connector, user_level, user_max);
-	panel->backlight.level = hw_level;
-
-	if (panel->backlight.device)
-		panel->backlight.device->props.brightness =
-			scale_hw_to_user(connector,
-					 panel->backlight.level,
-					 panel->backlight.device->props.max_brightness);
-
-	if (panel->backlight.enabled)
-		intel_panel_actually_set_backlight(conn_state, hw_level);
-
-	mutex_unlock(&dev_priv->backlight_lock);
-}
-
-static void lpt_disable_backlight(const struct drm_connector_state *old_conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, level);
-
-	/*
-	 * Although we don't support or enable CPU PWM with LPT/SPT based
-	 * systems, it may have been enabled prior to loading the
-	 * driver. Disable to avoid warnings on LCPLL disable.
-	 *
-	 * This needs rework if we need to add support for CPU PWM on PCH split
-	 * platforms.
-	 */
-	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
-	if (tmp & BLM_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "cpu backlight was enabled, disabling\n");
-		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2,
-			       tmp & ~BLM_PWM_ENABLE);
-	}
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
-}
-
-static void pch_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, val);
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
-	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
-}
-
-static void i9xx_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	intel_panel_set_pwm_level(old_conn_state, val);
-}
-
-static void i965_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	struct drm_i915_private *dev_priv = to_i915(old_conn_state->connector->dev);
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, val);
-
-	tmp = intel_de_read(dev_priv, BLC_PWM_CTL2);
-	intel_de_write(dev_priv, BLC_PWM_CTL2, tmp & ~BLM_PWM_ENABLE);
-}
-
-static void vlv_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	enum pipe pipe = to_intel_crtc(old_conn_state->crtc)->pipe;
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, val);
-
-	tmp = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
-	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe),
-		       tmp & ~BLM_PWM_ENABLE);
-}
-
-static void bxt_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, val);
-
-	tmp = intel_de_read(dev_priv,
-			    BXT_BLC_PWM_CTL(panel->backlight.controller));
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       tmp & ~BXT_BLC_PWM_ENABLE);
-
-	if (panel->backlight.controller == 1) {
-		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
-		val &= ~UTIL_PIN_ENABLE;
-		intel_de_write(dev_priv, UTIL_PIN_CTL, val);
-	}
-}
-
-static void cnp_disable_backlight(const struct drm_connector_state *old_conn_state, u32 val)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 tmp;
-
-	intel_panel_set_pwm_level(old_conn_state, val);
-
-	tmp = intel_de_read(dev_priv,
-			    BXT_BLC_PWM_CTL(panel->backlight.controller));
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       tmp & ~BXT_BLC_PWM_ENABLE);
-}
-
-static void ext_pwm_disable_backlight(const struct drm_connector_state *old_conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	panel->backlight.pwm_state.enabled = false;
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
-}
-
-void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state)
-{
-	struct intel_connector *connector = to_intel_connector(old_conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	if (!panel->backlight.present)
-		return;
-
-	/*
-	 * Do not disable backlight on the vga_switcheroo path. When switching
-	 * away from i915, the other client may depend on i915 to handle the
-	 * backlight. This will leave the backlight on unnecessarily when
-	 * another client is not activated.
-	 */
-	if (dev_priv->drm.switch_power_state == DRM_SWITCH_POWER_CHANGING) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "Skipping backlight disable on vga switch\n");
-		return;
-	}
-
-	mutex_lock(&dev_priv->backlight_lock);
-
-	if (panel->backlight.device)
-		panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
-	panel->backlight.enabled = false;
-	panel->backlight.funcs->disable(old_conn_state, 0);
-
-	mutex_unlock(&dev_priv->backlight_lock);
-}
-
-static void lpt_enable_backlight(const struct intel_crtc_state *crtc_state,
-				 const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 pch_ctl1, pch_ctl2, schicken;
-
-	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "pch backlight already enabled\n");
-		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
-		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
-	}
-
-	if (HAS_PCH_LPT(dev_priv)) {
-		schicken = intel_de_read(dev_priv, SOUTH_CHICKEN2);
-		if (panel->backlight.alternate_pwm_increment)
-			schicken |= LPT_PWM_GRANULARITY;
-		else
-			schicken &= ~LPT_PWM_GRANULARITY;
-		intel_de_write(dev_priv, SOUTH_CHICKEN2, schicken);
-	} else {
-		schicken = intel_de_read(dev_priv, SOUTH_CHICKEN1);
-		if (panel->backlight.alternate_pwm_increment)
-			schicken |= SPT_PWM_GRANULARITY;
-		else
-			schicken &= ~SPT_PWM_GRANULARITY;
-		intel_de_write(dev_priv, SOUTH_CHICKEN1, schicken);
-	}
-
-	pch_ctl2 = panel->backlight.pwm_level_max << 16;
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, pch_ctl2);
-
-	pch_ctl1 = 0;
-	if (panel->backlight.active_low_pwm)
-		pch_ctl1 |= BLM_PCH_POLARITY;
-
-	/* After LPT, override is the default. */
-	if (HAS_PCH_LPT(dev_priv))
-		pch_ctl1 |= BLM_PCH_OVERRIDE_ENABLE;
-
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
-	intel_de_posting_read(dev_priv, BLC_PWM_PCH_CTL1);
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
-		       pch_ctl1 | BLM_PCH_PWM_ENABLE);
-
-	/* This won't stick until the above enable. */
-	intel_panel_set_pwm_level(conn_state, level);
-}
-
-static void pch_enable_backlight(const struct intel_crtc_state *crtc_state,
-				 const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
-	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
-
-	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
-	if (cpu_ctl2 & BLM_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "cpu backlight already enabled\n");
-		cpu_ctl2 &= ~BLM_PWM_ENABLE;
-		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2);
-	}
-
-	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	if (pch_ctl1 & BLM_PCH_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "pch backlight already enabled\n");
-		pch_ctl1 &= ~BLM_PCH_PWM_ENABLE;
-		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
-	}
-
-	if (cpu_transcoder == TRANSCODER_EDP)
-		cpu_ctl2 = BLM_TRANSCODER_EDP;
-	else
-		cpu_ctl2 = BLM_PIPE(cpu_transcoder);
-	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2);
-	intel_de_posting_read(dev_priv, BLC_PWM_CPU_CTL2);
-	intel_de_write(dev_priv, BLC_PWM_CPU_CTL2, cpu_ctl2 | BLM_PWM_ENABLE);
-
-	/* This won't stick until the above enable. */
-	intel_panel_set_pwm_level(conn_state, level);
-
-	pch_ctl2 = panel->backlight.pwm_level_max << 16;
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL2, pch_ctl2);
-
-	pch_ctl1 = 0;
-	if (panel->backlight.active_low_pwm)
-		pch_ctl1 |= BLM_PCH_POLARITY;
-
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1, pch_ctl1);
-	intel_de_posting_read(dev_priv, BLC_PWM_PCH_CTL1);
-	intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
-		       pch_ctl1 | BLM_PCH_PWM_ENABLE);
-}
-
-static void i9xx_enable_backlight(const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 ctl, freq;
-
-	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
-	if (ctl & BACKLIGHT_DUTY_CYCLE_MASK_PNV) {
-		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
-		intel_de_write(dev_priv, BLC_PWM_CTL, 0);
-	}
-
-	freq = panel->backlight.pwm_level_max;
-	if (panel->backlight.combination_mode)
-		freq /= 0xff;
-
-	ctl = freq << 17;
-	if (panel->backlight.combination_mode)
-		ctl |= BLM_LEGACY_MODE;
-	if (IS_PINEVIEW(dev_priv) && panel->backlight.active_low_pwm)
-		ctl |= BLM_POLARITY_PNV;
-
-	intel_de_write(dev_priv, BLC_PWM_CTL, ctl);
-	intel_de_posting_read(dev_priv, BLC_PWM_CTL);
-
-	/* XXX: combine this into above write? */
-	intel_panel_set_pwm_level(conn_state, level);
-
-	/*
-	 * Needed to enable backlight on some 855gm models. BLC_HIST_CTL is
-	 * 855gm only, but checking for gen2 is safe, as 855gm is the only gen2
-	 * that has backlight.
-	 */
-	if (DISPLAY_VER(dev_priv) == 2)
-		intel_de_write(dev_priv, BLC_HIST_CTL, BLM_HISTOGRAM_ENABLE);
-}
-
-static void i965_enable_backlight(const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	enum pipe pipe = to_intel_crtc(conn_state->crtc)->pipe;
-	u32 ctl, ctl2, freq;
-
-	ctl2 = intel_de_read(dev_priv, BLC_PWM_CTL2);
-	if (ctl2 & BLM_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
-		ctl2 &= ~BLM_PWM_ENABLE;
-		intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2);
-	}
-
-	freq = panel->backlight.pwm_level_max;
-	if (panel->backlight.combination_mode)
-		freq /= 0xff;
-
-	ctl = freq << 16;
-	intel_de_write(dev_priv, BLC_PWM_CTL, ctl);
-
-	ctl2 = BLM_PIPE(pipe);
-	if (panel->backlight.combination_mode)
-		ctl2 |= BLM_COMBINATION_MODE;
-	if (panel->backlight.active_low_pwm)
-		ctl2 |= BLM_POLARITY_I965;
-	intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2);
-	intel_de_posting_read(dev_priv, BLC_PWM_CTL2);
-	intel_de_write(dev_priv, BLC_PWM_CTL2, ctl2 | BLM_PWM_ENABLE);
-
-	intel_panel_set_pwm_level(conn_state, level);
-}
-
-static void vlv_enable_backlight(const struct intel_crtc_state *crtc_state,
-				 const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
-	u32 ctl, ctl2;
-
-	ctl2 = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
-	if (ctl2 & BLM_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
-		ctl2 &= ~BLM_PWM_ENABLE;
-		intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe), ctl2);
-	}
-
-	ctl = panel->backlight.pwm_level_max << 16;
-	intel_de_write(dev_priv, VLV_BLC_PWM_CTL(pipe), ctl);
-
-	/* XXX: combine this into above write? */
-	intel_panel_set_pwm_level(conn_state, level);
-
-	ctl2 = 0;
-	if (panel->backlight.active_low_pwm)
-		ctl2 |= BLM_POLARITY_I965;
-	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe), ctl2);
-	intel_de_posting_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
-	intel_de_write(dev_priv, VLV_BLC_PWM_CTL2(pipe),
-		       ctl2 | BLM_PWM_ENABLE);
-}
-
-static void bxt_enable_backlight(const struct intel_crtc_state *crtc_state,
-				 const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
-	u32 pwm_ctl, val;
-
-	/* Controller 1 uses the utility pin. */
-	if (panel->backlight.controller == 1) {
-		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
-		if (val & UTIL_PIN_ENABLE) {
-			drm_dbg_kms(&dev_priv->drm,
-				    "util pin already enabled\n");
-			val &= ~UTIL_PIN_ENABLE;
-			intel_de_write(dev_priv, UTIL_PIN_CTL, val);
-		}
-
-		val = 0;
-		if (panel->backlight.util_pin_active_low)
-			val |= UTIL_PIN_POLARITY;
-		intel_de_write(dev_priv, UTIL_PIN_CTL,
-			       val | UTIL_PIN_PIPE(pipe) | UTIL_PIN_MODE_PWM | UTIL_PIN_ENABLE);
-	}
-
-	pwm_ctl = intel_de_read(dev_priv,
-				BXT_BLC_PWM_CTL(panel->backlight.controller));
-	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
-		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
-		intel_de_write(dev_priv,
-			       BXT_BLC_PWM_CTL(panel->backlight.controller),
-			       pwm_ctl);
-	}
-
-	intel_de_write(dev_priv,
-		       BXT_BLC_PWM_FREQ(panel->backlight.controller),
-		       panel->backlight.pwm_level_max);
-
-	intel_panel_set_pwm_level(conn_state, level);
-
-	pwm_ctl = 0;
-	if (panel->backlight.active_low_pwm)
-		pwm_ctl |= BXT_BLC_PWM_POLARITY;
-
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       pwm_ctl);
-	intel_de_posting_read(dev_priv,
-			      BXT_BLC_PWM_CTL(panel->backlight.controller));
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       pwm_ctl | BXT_BLC_PWM_ENABLE);
-}
-
-static void cnp_enable_backlight(const struct intel_crtc_state *crtc_state,
-				 const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 pwm_ctl;
-
-	pwm_ctl = intel_de_read(dev_priv,
-				BXT_BLC_PWM_CTL(panel->backlight.controller));
-	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
-		drm_dbg_kms(&dev_priv->drm, "backlight already enabled\n");
-		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
-		intel_de_write(dev_priv,
-			       BXT_BLC_PWM_CTL(panel->backlight.controller),
-			       pwm_ctl);
-	}
-
-	intel_de_write(dev_priv,
-		       BXT_BLC_PWM_FREQ(panel->backlight.controller),
-		       panel->backlight.pwm_level_max);
-
-	intel_panel_set_pwm_level(conn_state, level);
-
-	pwm_ctl = 0;
-	if (panel->backlight.active_low_pwm)
-		pwm_ctl |= BXT_BLC_PWM_POLARITY;
-
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       pwm_ctl);
-	intel_de_posting_read(dev_priv,
-			      BXT_BLC_PWM_CTL(panel->backlight.controller));
-	intel_de_write(dev_priv, BXT_BLC_PWM_CTL(panel->backlight.controller),
-		       pwm_ctl | BXT_BLC_PWM_ENABLE);
-}
-
-static void ext_pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
-				     const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
-	panel->backlight.pwm_state.enabled = true;
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
-}
-
-static void __intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
-					   const struct drm_connector_state *conn_state)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	WARN_ON(panel->backlight.max == 0);
-
-	if (panel->backlight.level <= panel->backlight.min) {
-		panel->backlight.level = panel->backlight.max;
-		if (panel->backlight.device)
-			panel->backlight.device->props.brightness =
-				scale_hw_to_user(connector,
-						 panel->backlight.level,
-						 panel->backlight.device->props.max_brightness);
-	}
-
-	panel->backlight.funcs->enable(crtc_state, conn_state, panel->backlight.level);
-	panel->backlight.enabled = true;
-	if (panel->backlight.device)
-		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
-}
-
-void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	enum pipe pipe = to_intel_crtc(crtc_state->uapi.crtc)->pipe;
-
-	if (!panel->backlight.present)
-		return;
-
-	drm_dbg_kms(&dev_priv->drm, "pipe %c\n", pipe_name(pipe));
-
-	mutex_lock(&dev_priv->backlight_lock);
-
-	__intel_panel_enable_backlight(crtc_state, conn_state);
-
-	mutex_unlock(&dev_priv->backlight_lock);
-}
-
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
-static u32 intel_panel_get_backlight(struct intel_connector *connector)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 val = 0;
-
-	mutex_lock(&dev_priv->backlight_lock);
-
-	if (panel->backlight.enabled)
-		val = panel->backlight.funcs->get(connector, intel_connector_get_pipe(connector));
-
-	mutex_unlock(&dev_priv->backlight_lock);
-
-	drm_dbg_kms(&dev_priv->drm, "get backlight PWM = %d\n", val);
-	return val;
-}
-
-/* Scale user_level in range [0..user_max] to [hw_min..hw_max]. */
-static u32 scale_user_to_hw(struct intel_connector *connector,
-			    u32 user_level, u32 user_max)
-{
-	struct intel_panel *panel = &connector->panel;
-
-	return scale(user_level, 0, user_max,
-		     panel->backlight.min, panel->backlight.max);
-}
-
-/* set backlight brightness to level in range [0..max], scaling wrt hw min */
-static void intel_panel_set_backlight(const struct drm_connector_state *conn_state,
-				      u32 user_level, u32 user_max)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 hw_level;
-
-	if (!panel->backlight.present)
-		return;
-
-	mutex_lock(&dev_priv->backlight_lock);
-
-	drm_WARN_ON(&dev_priv->drm, panel->backlight.max == 0);
-
-	hw_level = scale_user_to_hw(connector, user_level, user_max);
-	panel->backlight.level = hw_level;
-
-	if (panel->backlight.enabled)
-		intel_panel_actually_set_backlight(conn_state, hw_level);
-
-	mutex_unlock(&dev_priv->backlight_lock);
-}
-
-static int intel_backlight_device_update_status(struct backlight_device *bd)
-{
-	struct intel_connector *connector = bl_get_data(bd);
-	struct intel_panel *panel = &connector->panel;
-	struct drm_device *dev = connector->base.dev;
-
-	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
-		      bd->props.brightness, bd->props.max_brightness);
-	intel_panel_set_backlight(connector->base.state, bd->props.brightness,
-				  bd->props.max_brightness);
-
-	/*
-	 * Allow flipping bl_power as a sub-state of enabled. Sadly the
-	 * backlight class device does not make it easy to to differentiate
-	 * between callbacks for brightness and bl_power, so our backlight_power
-	 * callback needs to take this into account.
-	 */
-	if (panel->backlight.enabled) {
-		if (panel->backlight.power) {
-			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
-				bd->props.brightness != 0;
-			panel->backlight.power(connector, enable);
-		}
-	} else {
-		bd->props.power = FB_BLANK_POWERDOWN;
-	}
-
-	drm_modeset_unlock(&dev->mode_config.connection_mutex);
-	return 0;
-}
-
-static int intel_backlight_device_get_brightness(struct backlight_device *bd)
-{
-	struct intel_connector *connector = bl_get_data(bd);
-	struct drm_device *dev = connector->base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	intel_wakeref_t wakeref;
-	int ret = 0;
-
-	with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref) {
-		u32 hw_level;
-
-		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-
-		hw_level = intel_panel_get_backlight(connector);
-		ret = scale_hw_to_user(connector,
-				       hw_level, bd->props.max_brightness);
-
-		drm_modeset_unlock(&dev->mode_config.connection_mutex);
-	}
-
-	return ret;
-}
-
-static const struct backlight_ops intel_backlight_device_ops = {
-	.update_status = intel_backlight_device_update_status,
-	.get_brightness = intel_backlight_device_get_brightness,
-};
-
-int intel_backlight_device_register(struct intel_connector *connector)
-{
-	struct drm_i915_private *i915 = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	struct backlight_properties props;
-	struct backlight_device *bd;
-	const char *name;
-	int ret = 0;
-
-	if (WARN_ON(panel->backlight.device))
-		return -ENODEV;
-
-	if (!panel->backlight.present)
-		return 0;
-
-	WARN_ON(panel->backlight.max == 0);
-
-	memset(&props, 0, sizeof(props));
-	props.type = BACKLIGHT_RAW;
-
-	/*
-	 * Note: Everything should work even if the backlight device max
-	 * presented to the userspace is arbitrarily chosen.
-	 */
-	props.max_brightness = panel->backlight.max;
-	props.brightness = scale_hw_to_user(connector,
-					    panel->backlight.level,
-					    props.max_brightness);
-
-	if (panel->backlight.enabled)
-		props.power = FB_BLANK_UNBLANK;
-	else
-		props.power = FB_BLANK_POWERDOWN;
-
-	name = kstrdup("intel_backlight", GFP_KERNEL);
-	if (!name)
-		return -ENOMEM;
-
-	bd = backlight_device_register(name, connector->base.kdev, connector,
-				       &intel_backlight_device_ops, &props);
-
-	/*
-	 * Using the same name independent of the drm device or connector
-	 * prevents registration of multiple backlight devices in the
-	 * driver. However, we need to use the default name for backward
-	 * compatibility. Use unique names for subsequent backlight devices as a
-	 * fallback when the default name already exists.
-	 */
-	if (IS_ERR(bd) && PTR_ERR(bd) == -EEXIST) {
-		kfree(name);
-		name = kasprintf(GFP_KERNEL, "card%d-%s-backlight",
-				 i915->drm.primary->index, connector->base.name);
-		if (!name)
-			return -ENOMEM;
-
-		bd = backlight_device_register(name, connector->base.kdev, connector,
-					       &intel_backlight_device_ops, &props);
-	}
-
-	if (IS_ERR(bd)) {
-		drm_err(&i915->drm,
-			"[CONNECTOR:%d:%s] backlight device %s register failed: %ld\n",
-			connector->base.base.id, connector->base.name, name, PTR_ERR(bd));
-		ret = PTR_ERR(bd);
-		goto out;
-	}
-
-	panel->backlight.device = bd;
-
-	drm_dbg_kms(&i915->drm,
-		    "[CONNECTOR:%d:%s] backlight device %s registered\n",
-		    connector->base.base.id, connector->base.name, name);
-
-out:
-	kfree(name);
-
-	return ret;
-}
-
-void intel_backlight_device_unregister(struct intel_connector *connector)
-{
-	struct intel_panel *panel = &connector->panel;
-
-	if (panel->backlight.device) {
-		backlight_device_unregister(panel->backlight.device);
-		panel->backlight.device = NULL;
-	}
-}
-#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
-
-/*
- * CNP: PWM clock frequency is 19.2 MHz or 24 MHz.
- *      PWM increment = 1
- */
-static u32 cnp_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	return DIV_ROUND_CLOSEST(KHz(RUNTIME_INFO(dev_priv)->rawclk_freq),
-				 pwm_freq_hz);
-}
-
-/*
- * BXT: PWM clock frequency = 19.2 MHz.
- */
-static u32 bxt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	return DIV_ROUND_CLOSEST(KHz(19200), pwm_freq_hz);
-}
-
-/*
- * SPT: This value represents the period of the PWM stream in clock periods
- * multiplied by 16 (default increment) or 128 (alternate increment selected in
- * SCHICKEN_1 bit 0). PWM clock is 24 MHz.
- */
-static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct intel_panel *panel = &connector->panel;
-	u32 mul;
-
-	if (panel->backlight.alternate_pwm_increment)
-		mul = 128;
-	else
-		mul = 16;
-
-	return DIV_ROUND_CLOSEST(MHz(24), pwm_freq_hz * mul);
-}
-
-/*
- * LPT: This value represents the period of the PWM stream in clock periods
- * multiplied by 128 (default increment) or 16 (alternate increment, selected in
- * LPT SOUTH_CHICKEN2 register bit 5).
- */
-static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 mul, clock;
-
-	if (panel->backlight.alternate_pwm_increment)
-		mul = 16;
-	else
-		mul = 128;
-
-	if (HAS_PCH_LPT_H(dev_priv))
-		clock = MHz(135); /* LPT:H */
-	else
-		clock = MHz(24); /* LPT:LP */
-
-	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
-}
-
-/*
- * ILK/SNB/IVB: This value represents the period of the PWM stream in PCH
- * display raw clocks multiplied by 128.
- */
-static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	return DIV_ROUND_CLOSEST(KHz(RUNTIME_INFO(dev_priv)->rawclk_freq),
-				 pwm_freq_hz * 128);
-}
-
-/*
- * Gen2: This field determines the number of time base events (display core
- * clock frequency/32) in total for a complete cycle of modulated backlight
- * control.
- *
- * Gen3: A time base event equals the display core clock ([DevPNV] HRAW clock)
- * divided by 32.
- */
-static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	int clock;
-
-	if (IS_PINEVIEW(dev_priv))
-		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
-	else
-		clock = KHz(dev_priv->cdclk.hw.cdclk);
-
-	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 32);
-}
-
-/*
- * Gen4: This value represents the period of the PWM stream in display core
- * clocks ([DevCTG] HRAW clocks) multiplied by 128.
- *
- */
-static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	int clock;
-
-	if (IS_G4X(dev_priv))
-		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
-	else
-		clock = KHz(dev_priv->cdclk.hw.cdclk);
-
-	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * 128);
-}
-
-/*
- * VLV: This value represents the period of the PWM stream in display core
- * clocks ([DevCTG] 200MHz HRAW clocks) multiplied by 128 or 25MHz S0IX clocks
- * multiplied by 16. CHV uses a 19.2MHz S0IX clock.
- */
-static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	int mul, clock;
-
-	if ((intel_de_read(dev_priv, CBR1_VLV) & CBR_PWM_CLOCK_MUX_SELECT) == 0) {
-		if (IS_CHERRYVIEW(dev_priv))
-			clock = KHz(19200);
-		else
-			clock = MHz(25);
-		mul = 16;
-	} else {
-		clock = KHz(RUNTIME_INFO(dev_priv)->rawclk_freq);
-		mul = 128;
-	}
-
-	return DIV_ROUND_CLOSEST(clock, pwm_freq_hz * mul);
-}
-
-static u16 get_vbt_pwm_freq(struct drm_i915_private *dev_priv)
-{
-	u16 pwm_freq_hz = dev_priv->vbt.backlight.pwm_freq_hz;
-
-	if (pwm_freq_hz) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "VBT defined backlight frequency %u Hz\n",
-			    pwm_freq_hz);
-	} else {
-		pwm_freq_hz = 200;
-		drm_dbg_kms(&dev_priv->drm,
-			    "default backlight frequency %u Hz\n",
-			    pwm_freq_hz);
-	}
-
-	return pwm_freq_hz;
-}
-
-static u32 get_backlight_max_vbt(struct intel_connector *connector)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u16 pwm_freq_hz = get_vbt_pwm_freq(dev_priv);
-	u32 pwm;
-
-	if (!panel->backlight.pwm_funcs->hz_to_pwm) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "backlight frequency conversion not supported\n");
-		return 0;
-	}
-
-	pwm = panel->backlight.pwm_funcs->hz_to_pwm(connector, pwm_freq_hz);
-	if (!pwm) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "backlight frequency conversion failed\n");
-		return 0;
-	}
-
-	return pwm;
-}
-
-/*
- * Note: The setup hooks can't assume pipe is set!
- */
-static u32 get_backlight_min_vbt(struct intel_connector *connector)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	int min;
-
-	drm_WARN_ON(&dev_priv->drm, panel->backlight.pwm_level_max == 0);
-
-	/*
-	 * XXX: If the vbt value is 255, it makes min equal to max, which leads
-	 * to problems. There are such machines out there. Either our
-	 * interpretation is wrong or the vbt has bogus data. Or both. Safeguard
-	 * against this by letting the minimum be at most (arbitrarily chosen)
-	 * 25% of the max.
-	 */
-	min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
-	if (min != dev_priv->vbt.backlight.min_brightness) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "clamping VBT min backlight %d/255 to %d/255\n",
-			    dev_priv->vbt.backlight.min_brightness, min);
-	}
-
-	/* vbt value is a coefficient in range [0..255] */
-	return scale(min, 0, 255, 0, panel->backlight.pwm_level_max);
-}
-
-static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 cpu_ctl2, pch_ctl1, pch_ctl2, val;
-	bool alt, cpu_mode;
-
-	if (HAS_PCH_LPT(dev_priv))
-		alt = intel_de_read(dev_priv, SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY;
-	else
-		alt = intel_de_read(dev_priv, SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY;
-	panel->backlight.alternate_pwm_increment = alt;
-
-	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
-
-	pch_ctl2 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2);
-	panel->backlight.pwm_level_max = pch_ctl2 >> 16;
-
-	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	panel->backlight.pwm_enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE;
-
-	cpu_mode = panel->backlight.pwm_enabled && HAS_PCH_LPT(dev_priv) &&
-		   !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) &&
-		   (cpu_ctl2 & BLM_PWM_ENABLE);
-
-	if (cpu_mode) {
-		val = pch_get_backlight(connector, unused);
-
-		drm_dbg_kms(&dev_priv->drm,
-			    "CPU backlight register was enabled, switching to PCH override\n");
-
-		/* Write converted CPU PWM value to PCH override register */
-		lpt_set_backlight(connector->base.state, val);
-		intel_de_write(dev_priv, BLC_PWM_PCH_CTL1,
-			       pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE);
-
-		intel_de_write(dev_priv, BLC_PWM_CPU_CTL2,
-			       cpu_ctl2 & ~BLM_PWM_ENABLE);
-	}
-
-	return 0;
-}
-
-static int pch_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 cpu_ctl2, pch_ctl1, pch_ctl2;
-
-	pch_ctl1 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL1);
-	panel->backlight.active_low_pwm = pch_ctl1 & BLM_PCH_POLARITY;
-
-	pch_ctl2 = intel_de_read(dev_priv, BLC_PWM_PCH_CTL2);
-	panel->backlight.pwm_level_max = pch_ctl2 >> 16;
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	cpu_ctl2 = intel_de_read(dev_priv, BLC_PWM_CPU_CTL2);
-	panel->backlight.pwm_enabled = (cpu_ctl2 & BLM_PWM_ENABLE) &&
-		(pch_ctl1 & BLM_PCH_PWM_ENABLE);
-
-	return 0;
-}
-
-static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 ctl, val;
-
-	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
-
-	if (DISPLAY_VER(dev_priv) == 2 || IS_I915GM(dev_priv) || IS_I945GM(dev_priv))
-		panel->backlight.combination_mode = ctl & BLM_LEGACY_MODE;
-
-	if (IS_PINEVIEW(dev_priv))
-		panel->backlight.active_low_pwm = ctl & BLM_POLARITY_PNV;
-
-	panel->backlight.pwm_level_max = ctl >> 17;
-
-	if (!panel->backlight.pwm_level_max) {
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-		panel->backlight.pwm_level_max >>= 1;
-	}
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	if (panel->backlight.combination_mode)
-		panel->backlight.pwm_level_max *= 0xff;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	val = i9xx_get_backlight(connector, unused);
-	val = intel_panel_invert_pwm_level(connector, val);
-	val = clamp(val, panel->backlight.pwm_level_min, panel->backlight.pwm_level_max);
-
-	panel->backlight.pwm_enabled = val != 0;
-
-	return 0;
-}
-
-static int i965_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 ctl, ctl2;
-
-	ctl2 = intel_de_read(dev_priv, BLC_PWM_CTL2);
-	panel->backlight.combination_mode = ctl2 & BLM_COMBINATION_MODE;
-	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
-
-	ctl = intel_de_read(dev_priv, BLC_PWM_CTL);
-	panel->backlight.pwm_level_max = ctl >> 16;
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	if (panel->backlight.combination_mode)
-		panel->backlight.pwm_level_max *= 0xff;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
-
-	return 0;
-}
-
-static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 ctl, ctl2;
-
-	if (drm_WARN_ON(&dev_priv->drm, pipe != PIPE_A && pipe != PIPE_B))
-		return -ENODEV;
-
-	ctl2 = intel_de_read(dev_priv, VLV_BLC_PWM_CTL2(pipe));
-	panel->backlight.active_low_pwm = ctl2 & BLM_POLARITY_I965;
-
-	ctl = intel_de_read(dev_priv, VLV_BLC_PWM_CTL(pipe));
-	panel->backlight.pwm_level_max = ctl >> 16;
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	panel->backlight.pwm_enabled = ctl2 & BLM_PWM_ENABLE;
-
-	return 0;
-}
-
-static int
-bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 pwm_ctl, val;
-
-	panel->backlight.controller = dev_priv->vbt.backlight.controller;
-
-	pwm_ctl = intel_de_read(dev_priv,
-				BXT_BLC_PWM_CTL(panel->backlight.controller));
-
-	/* Controller 1 uses the utility pin. */
-	if (panel->backlight.controller == 1) {
-		val = intel_de_read(dev_priv, UTIL_PIN_CTL);
-		panel->backlight.util_pin_active_low =
-					val & UTIL_PIN_POLARITY;
-	}
-
-	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
-	panel->backlight.pwm_level_max =
-		intel_de_read(dev_priv, BXT_BLC_PWM_FREQ(panel->backlight.controller));
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
-
-	return 0;
-}
-
-static int
-cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-	u32 pwm_ctl;
-
-	/*
-	 * CNP has the BXT implementation of backlight, but with only one
-	 * controller. TODO: ICP has multiple controllers but we only use
-	 * controller 0 for now.
-	 */
-	panel->backlight.controller = 0;
-
-	pwm_ctl = intel_de_read(dev_priv,
-				BXT_BLC_PWM_CTL(panel->backlight.controller));
-
-	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
-	panel->backlight.pwm_level_max =
-		intel_de_read(dev_priv, BXT_BLC_PWM_FREQ(panel->backlight.controller));
-
-	if (!panel->backlight.pwm_level_max)
-		panel->backlight.pwm_level_max = get_backlight_max_vbt(connector);
-
-	if (!panel->backlight.pwm_level_max)
-		return -ENODEV;
-
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	panel->backlight.pwm_enabled = pwm_ctl & BXT_BLC_PWM_ENABLE;
-
-	return 0;
-}
-
-static int ext_pwm_setup_backlight(struct intel_connector *connector,
-				   enum pipe pipe)
-{
-	struct drm_device *dev = connector->base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct intel_panel *panel = &connector->panel;
-	const char *desc;
-	u32 level;
-
-	/* Get the right PWM chip for DSI backlight according to VBT */
-	if (dev_priv->vbt.dsi.config->pwm_blc == PPS_BLC_PMIC) {
-		panel->backlight.pwm = pwm_get(dev->dev, "pwm_pmic_backlight");
-		desc = "PMIC";
-	} else {
-		panel->backlight.pwm = pwm_get(dev->dev, "pwm_soc_backlight");
-		desc = "SoC";
-	}
-
-	if (IS_ERR(panel->backlight.pwm)) {
-		drm_err(&dev_priv->drm, "Failed to get the %s PWM chip\n",
-			desc);
-		panel->backlight.pwm = NULL;
-		return -ENODEV;
-	}
-
-	panel->backlight.pwm_level_max = 100; /* 100% */
-	panel->backlight.pwm_level_min = get_backlight_min_vbt(connector);
-
-	if (pwm_is_enabled(panel->backlight.pwm)) {
-		/* PWM is already enabled, use existing settings */
-		pwm_get_state(panel->backlight.pwm, &panel->backlight.pwm_state);
-
-		level = pwm_get_relative_duty_cycle(&panel->backlight.pwm_state,
-						    100);
-		level = intel_panel_invert_pwm_level(connector, level);
-		panel->backlight.pwm_enabled = true;
-
-		drm_dbg_kms(&dev_priv->drm, "PWM already enabled at freq %ld, VBT freq %d, level %d\n",
-			    NSEC_PER_SEC / (unsigned long)panel->backlight.pwm_state.period,
-			    get_vbt_pwm_freq(dev_priv), level);
-	} else {
-		/* Set period from VBT frequency, leave other settings at 0. */
-		panel->backlight.pwm_state.period =
-			NSEC_PER_SEC / get_vbt_pwm_freq(dev_priv);
-	}
-
-	drm_info(&dev_priv->drm, "Using %s PWM for LCD backlight control\n",
-		 desc);
-	return 0;
-}
-
-static void intel_pwm_set_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	panel->backlight.pwm_funcs->set(conn_state,
-				       intel_panel_invert_pwm_level(connector, level));
-}
-
-static u32 intel_pwm_get_backlight(struct intel_connector *connector, enum pipe pipe)
-{
-	struct intel_panel *panel = &connector->panel;
-
-	return intel_panel_invert_pwm_level(connector,
-					    panel->backlight.pwm_funcs->get(connector, pipe));
-}
-
-static void intel_pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
-				       const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	panel->backlight.pwm_funcs->enable(crtc_state, conn_state,
-					   intel_panel_invert_pwm_level(connector, level));
-}
-
-static void intel_pwm_disable_backlight(const struct drm_connector_state *conn_state, u32 level)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct intel_panel *panel = &connector->panel;
-
-	panel->backlight.pwm_funcs->disable(conn_state,
-					    intel_panel_invert_pwm_level(connector, level));
-}
-
-static int intel_pwm_setup_backlight(struct intel_connector *connector, enum pipe pipe)
-{
-	struct intel_panel *panel = &connector->panel;
-	int ret = panel->backlight.pwm_funcs->setup(connector, pipe);
-
-	if (ret < 0)
-		return ret;
-
-	panel->backlight.min = panel->backlight.pwm_level_min;
-	panel->backlight.max = panel->backlight.pwm_level_max;
-	panel->backlight.level = intel_pwm_get_backlight(connector, pipe);
-	panel->backlight.enabled = panel->backlight.pwm_enabled;
-
-	return 0;
-}
-
-void intel_panel_update_backlight(struct intel_atomic_state *state,
-				  struct intel_encoder *encoder,
-				  const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state)
-{
-	struct intel_connector *connector = to_intel_connector(conn_state->connector);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	struct intel_panel *panel = &connector->panel;
-
-	if (!panel->backlight.present)
-		return;
-
-	mutex_lock(&dev_priv->backlight_lock);
-	if (!panel->backlight.enabled)
-		__intel_panel_enable_backlight(crtc_state, conn_state);
-
-	mutex_unlock(&dev_priv->backlight_lock);
-}
-
-int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
-{
-	struct drm_i915_private *dev_priv = to_i915(connector->dev);
-	struct intel_connector *intel_connector = to_intel_connector(connector);
-	struct intel_panel *panel = &intel_connector->panel;
-	int ret;
-
-	if (!dev_priv->vbt.backlight.present) {
-		if (dev_priv->quirks & QUIRK_BACKLIGHT_PRESENT) {
-			drm_dbg_kms(&dev_priv->drm,
-				    "no backlight present per VBT, but present per quirk\n");
-		} else {
-			drm_dbg_kms(&dev_priv->drm,
-				    "no backlight present per VBT\n");
-			return 0;
-		}
-	}
-
-	/* ensure intel_panel has been initialized first */
-	if (drm_WARN_ON(&dev_priv->drm, !panel->backlight.funcs))
-		return -ENODEV;
-
-	/* set level and max in panel struct */
-	mutex_lock(&dev_priv->backlight_lock);
-	ret = panel->backlight.funcs->setup(intel_connector, pipe);
-	mutex_unlock(&dev_priv->backlight_lock);
-
-	if (ret) {
-		drm_dbg_kms(&dev_priv->drm,
-			    "failed to setup backlight for connector %s\n",
-			    connector->name);
-		return ret;
-	}
-
-	panel->backlight.present = true;
-
-	drm_dbg_kms(&dev_priv->drm,
-		    "Connector %s backlight initialized, %s, brightness %u/%u\n",
-		    connector->name,
-		    enableddisabled(panel->backlight.enabled),
-		    panel->backlight.level, panel->backlight.max);
-
-	return 0;
-}
-
-static void intel_panel_destroy_backlight(struct intel_panel *panel)
-{
-	/* dispose of the pwm */
-	if (panel->backlight.pwm)
-		pwm_put(panel->backlight.pwm);
-
-	panel->backlight.present = false;
-}
-
-static const struct intel_panel_bl_funcs bxt_pwm_funcs = {
-	.setup = bxt_setup_backlight,
-	.enable = bxt_enable_backlight,
-	.disable = bxt_disable_backlight,
-	.set = bxt_set_backlight,
-	.get = bxt_get_backlight,
-	.hz_to_pwm = bxt_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs cnp_pwm_funcs = {
-	.setup = cnp_setup_backlight,
-	.enable = cnp_enable_backlight,
-	.disable = cnp_disable_backlight,
-	.set = bxt_set_backlight,
-	.get = bxt_get_backlight,
-	.hz_to_pwm = cnp_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs lpt_pwm_funcs = {
-	.setup = lpt_setup_backlight,
-	.enable = lpt_enable_backlight,
-	.disable = lpt_disable_backlight,
-	.set = lpt_set_backlight,
-	.get = lpt_get_backlight,
-	.hz_to_pwm = lpt_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs spt_pwm_funcs = {
-	.setup = lpt_setup_backlight,
-	.enable = lpt_enable_backlight,
-	.disable = lpt_disable_backlight,
-	.set = lpt_set_backlight,
-	.get = lpt_get_backlight,
-	.hz_to_pwm = spt_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs pch_pwm_funcs = {
-	.setup = pch_setup_backlight,
-	.enable = pch_enable_backlight,
-	.disable = pch_disable_backlight,
-	.set = pch_set_backlight,
-	.get = pch_get_backlight,
-	.hz_to_pwm = pch_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs ext_pwm_funcs = {
-	.setup = ext_pwm_setup_backlight,
-	.enable = ext_pwm_enable_backlight,
-	.disable = ext_pwm_disable_backlight,
-	.set = ext_pwm_set_backlight,
-	.get = ext_pwm_get_backlight,
-};
-
-static const struct intel_panel_bl_funcs vlv_pwm_funcs = {
-	.setup = vlv_setup_backlight,
-	.enable = vlv_enable_backlight,
-	.disable = vlv_disable_backlight,
-	.set = vlv_set_backlight,
-	.get = vlv_get_backlight,
-	.hz_to_pwm = vlv_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs i965_pwm_funcs = {
-	.setup = i965_setup_backlight,
-	.enable = i965_enable_backlight,
-	.disable = i965_disable_backlight,
-	.set = i9xx_set_backlight,
-	.get = i9xx_get_backlight,
-	.hz_to_pwm = i965_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs i9xx_pwm_funcs = {
-	.setup = i9xx_setup_backlight,
-	.enable = i9xx_enable_backlight,
-	.disable = i9xx_disable_backlight,
-	.set = i9xx_set_backlight,
-	.get = i9xx_get_backlight,
-	.hz_to_pwm = i9xx_hz_to_pwm,
-};
-
-static const struct intel_panel_bl_funcs pwm_bl_funcs = {
-	.setup = intel_pwm_setup_backlight,
-	.enable = intel_pwm_enable_backlight,
-	.disable = intel_pwm_disable_backlight,
-	.set = intel_pwm_set_backlight,
-	.get = intel_pwm_get_backlight,
-};
-
-/* Set up chip specific backlight functions */
-static void
-intel_panel_init_backlight_funcs(struct intel_panel *panel)
-{
-	struct intel_connector *connector =
-		container_of(panel, struct intel_connector, panel);
-	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-
-	if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI &&
-	    intel_dsi_dcs_init_backlight_funcs(connector) == 0)
-		return;
-
-	if (IS_GEMINILAKE(dev_priv) || IS_BROXTON(dev_priv)) {
-		panel->backlight.pwm_funcs = &bxt_pwm_funcs;
-	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_CNP) {
-		panel->backlight.pwm_funcs = &cnp_pwm_funcs;
-	} else if (INTEL_PCH_TYPE(dev_priv) >= PCH_LPT) {
-		if (HAS_PCH_LPT(dev_priv))
-			panel->backlight.pwm_funcs = &lpt_pwm_funcs;
-		else
-			panel->backlight.pwm_funcs = &spt_pwm_funcs;
-	} else if (HAS_PCH_SPLIT(dev_priv)) {
-		panel->backlight.pwm_funcs = &pch_pwm_funcs;
-	} else if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
-		if (connector->base.connector_type == DRM_MODE_CONNECTOR_DSI) {
-			panel->backlight.pwm_funcs = &ext_pwm_funcs;
-		} else {
-			panel->backlight.pwm_funcs = &vlv_pwm_funcs;
-		}
-	} else if (DISPLAY_VER(dev_priv) == 4) {
-		panel->backlight.pwm_funcs = &i965_pwm_funcs;
-	} else {
-		panel->backlight.pwm_funcs = &i9xx_pwm_funcs;
-	}
-
-	if (connector->base.connector_type == DRM_MODE_CONNECTOR_eDP &&
-	    intel_dp_aux_init_backlight_funcs(connector) == 0)
-		return;
-
-	/* We're using a standard PWM backlight interface */
-	panel->backlight.funcs = &pwm_bl_funcs;
-}
-
 enum drm_connector_status
 intel_panel_detect(struct drm_connector *connector, bool force)
 {
diff --git a/drivers/gpu/drm/i915/display/intel_panel.h b/drivers/gpu/drm/i915/display/intel_panel.h
index d638c2b47c92..19ffa6175cab 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.h
+++ b/drivers/gpu/drm/i915/display/intel_panel.h
@@ -8,15 +8,13 @@
 
 #include <linux/types.h>
 
-#include "intel_display.h"
-
+enum drm_connector_status;
 struct drm_connector;
 struct drm_connector_state;
 struct drm_display_mode;
+struct drm_i915_private;
 struct intel_connector;
-struct intel_crtc;
 struct intel_crtc_state;
-struct intel_encoder;
 struct intel_panel;
 
 int intel_panel_init(struct intel_panel *panel,
@@ -32,17 +30,6 @@ int intel_pch_panel_fitting(struct intel_crtc_state *crtc_state,
 			    const struct drm_connector_state *conn_state);
 int intel_gmch_panel_fitting(struct intel_crtc_state *crtc_state,
 			     const struct drm_connector_state *conn_state);
-void intel_panel_set_backlight_acpi(const struct drm_connector_state *conn_state,
-				    u32 level, u32 max);
-int intel_panel_setup_backlight(struct drm_connector *connector,
-				enum pipe pipe);
-void intel_panel_enable_backlight(const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state);
-void intel_panel_update_backlight(struct intel_atomic_state *state,
-				  struct intel_encoder *encoder,
-				  const struct intel_crtc_state *crtc_state,
-				  const struct drm_connector_state *conn_state);
-void intel_panel_disable_backlight(const struct drm_connector_state *old_conn_state);
 struct drm_display_mode *
 intel_panel_edid_downclock_mode(struct intel_connector *connector,
 				const struct drm_display_mode *fixed_mode);
@@ -50,22 +37,5 @@ struct drm_display_mode *
 intel_panel_edid_fixed_mode(struct intel_connector *connector);
 struct drm_display_mode *
 intel_panel_vbt_fixed_mode(struct intel_connector *connector);
-void intel_panel_set_pwm_level(const struct drm_connector_state *conn_state, u32 level);
-u32 intel_panel_invert_pwm_level(struct intel_connector *connector, u32 level);
-u32 intel_panel_backlight_level_to_pwm(struct intel_connector *connector, u32 level);
-u32 intel_panel_backlight_level_from_pwm(struct intel_connector *connector, u32 val);
-
-#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
-int intel_backlight_device_register(struct intel_connector *connector);
-void intel_backlight_device_unregister(struct intel_connector *connector);
-#else /* CONFIG_BACKLIGHT_CLASS_DEVICE */
-static inline int intel_backlight_device_register(struct intel_connector *connector)
-{
-	return 0;
-}
-static inline void intel_backlight_device_unregister(struct intel_connector *connector)
-{
-}
-#endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
 
 #endif /* __INTEL_PANEL_H__ */
diff --git a/drivers/gpu/drm/i915/display/vlv_dsi.c b/drivers/gpu/drm/i915/display/vlv_dsi.c
index 0ee4ff341e25..b27738df447d 100644
--- a/drivers/gpu/drm/i915/display/vlv_dsi.c
+++ b/drivers/gpu/drm/i915/display/vlv_dsi.c
@@ -32,6 +32,7 @@
 
 #include "i915_drv.h"
 #include "intel_atomic.h"
+#include "intel_backlight.h"
 #include "intel_connector.h"
 #include "intel_crtc.h"
 #include "intel_de.h"
-- 
2.20.1