[Intel-gfx] [PATCH v3 16/20] drm/i915/icl: Program TA_TIMING_PARAM registers

[Madhav Chauhan]

This patch programs D-PHY timing parameters for the
bus turn around flow(in escape clocks) only if dsi link
frequency <=800 MHz using DPHY_TA_TIMING_PARAM and its
identical register DSI_TA_TIMING_PARAM (inside DSI
Controller within the Display Core).

Signed-off-by: Madhav Chauhan <madhav.chauhan at intel.com>
---
 drivers/gpu/drm/i915/gen11_dsi.c     | 21 +++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dsi.h     |  1 +
 drivers/gpu/drm/i915/intel_dsi_vbt.c |  1 +
 3 files changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/i915/gen11_dsi.c b/drivers/gpu/drm/i915/gen11_dsi.c
index ffc17d1..54077f8 100644
--- a/drivers/gpu/drm/i915/gen11_dsi.c
+++ b/drivers/gpu/drm/i915/gen11_dsi.c
@@ -302,6 +302,27 @@ static void gen11_dsi_setup_dphy_timings(struct intel_encoder *encoder)
 		I915_WRITE(DSI_DATA_TIMING_PARAM(port),
 			   intel_dsi->dphy_data_lane_reg);
 	}
+
+	/*
+	 * If DSI link operating at or below an 800 MHz,
+	 * TA_SURE should be override and programmed to
+	 * a value '0' inside TA_PARAM_REGISTERS otherwise
+	 * leave all fields at HW default values.
+	 */
+	if (intel_dsi->bitrate_khz <= KHz(800)) {
+		for_each_dsi_port(port, intel_dsi->ports) {
+			tmp = I915_READ(DPHY_TA_TIMING_PARAM(port));
+			tmp &= ~TA_SURE_TIME_MASK;
+			tmp |= (TA_SURE_OVERRIDE | TA_SURE_TIME(0));
+			I915_WRITE(DPHY_TA_TIMING_PARAM(port), tmp);
+
+			/* shadow register inside display core */
+			tmp = I915_READ(DSI_TA_TIMING_PARAM(port));
+			tmp &= ~TA_SURE_TIME_MASK;
+			tmp |= (TA_SURE_OVERRIDE | TA_SURE_TIME(0));
+			I915_WRITE(DSI_TA_TIMING_PARAM(port), tmp);
+		}
+	}
 }
 
 static void gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder)
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 12a8154..16964c2 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -101,6 +101,7 @@ struct intel_dsi {
 
 	u16 init_count;
 	u32 pclk;
+	u32 bitrate_khz;
 	u16 burst_mode_ratio;
 
 	/* all delays in ms */
diff --git a/drivers/gpu/drm/i915/intel_dsi_vbt.c b/drivers/gpu/drm/i915/intel_dsi_vbt.c
index 5cc3dd0..a3d71fb 100644
--- a/drivers/gpu/drm/i915/intel_dsi_vbt.c
+++ b/drivers/gpu/drm/i915/intel_dsi_vbt.c
@@ -589,6 +589,7 @@ bool intel_dsi_vbt_init(struct intel_dsi *intel_dsi, u16 panel_id)
 	intel_dsi->pclk = pclk;
 
 	bitrate = (pclk * bpp) / intel_dsi->lane_count;
+	intel_dsi->bitrate_khz = bitrate;
 
 	switch (intel_dsi->escape_clk_div) {
 	case 0:
-- 
2.7.4