[PATCH 2/2] drm: bridge: ldb: Implement simple NXP i.MX8M LDB bridge
Marek Vasut
marex at denx.de
Sun Mar 13 12:38:52 UTC 2022
The i.MX8MP contains two syscon registers which are responsible
for configuring the on-SoC DPI-to-LVDS serializer. Implement a
simple bridge driver for this serializer.
Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: Lucas Stach <l.stach at pengutronix.de>
Cc: Maxime Ripard <maxime at cerno.tech>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Robby Cai <robby.cai at nxp.com>
Cc: Robert Foss <robert.foss at linaro.org>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann at suse.de>
To: dri-devel at lists.freedesktop.org
---
drivers/gpu/drm/bridge/Kconfig | 8 +
drivers/gpu/drm/bridge/Makefile | 1 +
drivers/gpu/drm/bridge/nxp-ldb.c | 343 +++++++++++++++++++++++++++++++
3 files changed, 352 insertions(+)
create mode 100644 drivers/gpu/drm/bridge/nxp-ldb.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index bf58cc997d964..9dfc7bac9270d 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -171,6 +171,14 @@ config DRM_NWL_MIPI_DSI
This enables the Northwest Logic MIPI DSI Host controller as
for example found on NXP's i.MX8 Processors.
+config DRM_NXP_LDB
+ tristate "NXP i.MX8M LDB bridge"
+ depends on OF
+ select DRM_KMS_HELPER
+ select DRM_PANEL_BRIDGE
+ help
+ Support for i.MX8M DPI-to-LVDS on-SoC encoder.
+
config DRM_NXP_PTN3460
tristate "NXP PTN3460 DP/LVDS bridge"
depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index c90fdf1d1d251..0774e289f81b2 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_DRM_LONTIUM_LT9611) += lontium-lt9611.o
obj-$(CONFIG_DRM_LONTIUM_LT9611UXC) += lontium-lt9611uxc.o
obj-$(CONFIG_DRM_LVDS_CODEC) += lvds-codec.o
obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o
+obj-$(CONFIG_DRM_NXP_LDB) += nxp-ldb.o
obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o
obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o
obj-$(CONFIG_DRM_PARADE_PS8640) += parade-ps8640.o
diff --git a/drivers/gpu/drm/bridge/nxp-ldb.c b/drivers/gpu/drm/bridge/nxp-ldb.c
new file mode 100644
index 0000000000000..1d7191d064b1e
--- /dev/null
+++ b/drivers/gpu/drm/bridge/nxp-ldb.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2022 Marek Vasut <marex at denx.de>
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+
+#define LDB_CTRL 0x5c
+#define LDB_CTRL_CH0_ENABLE BIT(0)
+#define LDB_CTRL_CH0_DI_SELECT BIT(1)
+#define LDB_CTRL_CH1_ENABLE BIT(2)
+#define LDB_CTRL_CH1_DI_SELECT BIT(3)
+#define LDB_CTRL_SPLIT_MODE BIT(4)
+#define LDB_CTRL_CH0_DATA_WIDTH BIT(5)
+#define LDB_CTRL_CH0_BIT_MAPPING BIT(6)
+#define LDB_CTRL_CH1_DATA_WIDTH BIT(7)
+#define LDB_CTRL_CH1_BIT_MAPPING BIT(8)
+#define LDB_CTRL_DI0_VSYNC_POLARITY BIT(9)
+#define LDB_CTRL_DI1_VSYNC_POLARITY BIT(10)
+#define LDB_CTRL_REG_CH0_FIFO_RESET BIT(11)
+#define LDB_CTRL_REG_CH1_FIFO_RESET BIT(12)
+#define LDB_CTRL_ASYNC_FIFO_ENABLE BIT(24)
+#define LDB_CTRL_ASYNC_FIFO_THRESHOLD_MASK GENMASK(27, 25)
+
+#define LVDS_CTRL 0x128
+#define LVDS_CTRL_CH0_EN BIT(0)
+#define LVDS_CTRL_CH1_EN BIT(1)
+#define LVDS_CTRL_VBG_EN BIT(2)
+#define LVDS_CTRL_HS_EN BIT(3)
+#define LVDS_CTRL_PRE_EMPH_EN BIT(4)
+#define LVDS_CTRL_PRE_EMPH_ADJ(n) (((n) & 0x7) << 5)
+#define LVDS_CTRL_PRE_EMPH_ADJ_MASK GENMASK(7, 5)
+#define LVDS_CTRL_CM_ADJ(n) (((n) & 0x7) << 8)
+#define LVDS_CTRL_CM_ADJ_MASK GENMASK(10, 8)
+#define LVDS_CTRL_CC_ADJ(n) (((n) & 0x7) << 11)
+#define LVDS_CTRL_CC_ADJ_MASK GENMASK(13, 11)
+#define LVDS_CTRL_SLEW_ADJ(n) (((n) & 0x7) << 14)
+#define LVDS_CTRL_SLEW_ADJ_MASK GENMASK(16, 14)
+#define LVDS_CTRL_VBG_ADJ(n) (((n) & 0x7) << 17)
+#define LVDS_CTRL_VBG_ADJ_MASK GENMASK(19, 17)
+
+struct nxp_ldb {
+ struct device *dev;
+ struct drm_bridge bridge;
+ struct drm_bridge *panel_bridge;
+ struct clk *clk;
+ struct regmap *regmap;
+ bool lvds_dual_link;
+};
+
+static inline struct nxp_ldb *to_nxp_ldb(struct drm_bridge *bridge)
+{
+ return container_of(bridge, struct nxp_ldb, bridge);
+}
+
+static int nxp_ldb_attach(struct drm_bridge *bridge,
+ enum drm_bridge_attach_flags flags)
+{
+ struct nxp_ldb *nxp_ldb = to_nxp_ldb(bridge);
+
+ return drm_bridge_attach(bridge->encoder, nxp_ldb->panel_bridge,
+ bridge, flags);
+}
+
+static int nxp_ldb_atomic_check(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state)
+{
+ /* Invert DE signal polarity. */
+ bridge_state->input_bus_cfg.flags &= ~(DRM_BUS_FLAG_DE_LOW |
+ DRM_BUS_FLAG_DE_HIGH);
+ if (bridge_state->output_bus_cfg.flags & DRM_BUS_FLAG_DE_LOW)
+ bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_HIGH;
+ else if (bridge_state->output_bus_cfg.flags & DRM_BUS_FLAG_DE_HIGH)
+ bridge_state->input_bus_cfg.flags |= DRM_BUS_FLAG_DE_LOW;
+
+ return 0;
+}
+
+static void nxp_ldb_atomic_enable(struct drm_bridge *bridge,
+ struct drm_bridge_state *old_bridge_state)
+{
+ struct nxp_ldb *nxp_ldb = to_nxp_ldb(bridge);
+ struct drm_atomic_state *state = old_bridge_state->base.state;
+ const struct drm_bridge_state *bridge_state;
+ const struct drm_crtc_state *crtc_state;
+ const struct drm_display_mode *mode;
+ struct drm_connector *connector;
+ struct drm_crtc *crtc;
+ bool lvds_format_24bpp;
+ bool lvds_format_jeida;
+ u32 reg;
+
+ /* Get the LVDS format from the bridge state. */
+ bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+
+ switch (bridge_state->output_bus_cfg.format) {
+ case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+ lvds_format_24bpp = false;
+ lvds_format_jeida = true;
+ break;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+ lvds_format_24bpp = true;
+ lvds_format_jeida = true;
+ break;
+ case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+ lvds_format_24bpp = true;
+ lvds_format_jeida = false;
+ break;
+ default:
+ /*
+ * Some bridges still don't set the correct LVDS bus pixel
+ * format, use SPWG24 default format until those are fixed.
+ */
+ lvds_format_24bpp = true;
+ lvds_format_jeida = false;
+ dev_warn(nxp_ldb->dev,
+ "Unsupported LVDS bus format 0x%04x, please check output bridge driver. Falling back to SPWG24.\n",
+ bridge_state->output_bus_cfg.format);
+ break;
+ }
+
+ /*
+ * Retrieve the CRTC adjusted mode. This requires a little dance to go
+ * from the bridge to the encoder, to the connector and to the CRTC.
+ */
+ connector = drm_atomic_get_new_connector_for_encoder(state,
+ bridge->encoder);
+ crtc = drm_atomic_get_new_connector_state(state, connector)->crtc;
+ crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+ mode = &crtc_state->adjusted_mode;
+
+ if (nxp_ldb->lvds_dual_link)
+ clk_set_rate(nxp_ldb->clk, mode->clock * 3500);
+ else
+ clk_set_rate(nxp_ldb->clk, mode->clock * 7000);
+ clk_prepare_enable(nxp_ldb->clk);
+
+ /* Program LDB_CTRL */
+ reg = LDB_CTRL_CH0_ENABLE;
+
+ if (nxp_ldb->lvds_dual_link)
+ reg |= LDB_CTRL_CH1_ENABLE;
+
+ if (lvds_format_24bpp) {
+ reg |= LDB_CTRL_CH0_DATA_WIDTH;
+ if (nxp_ldb->lvds_dual_link)
+ reg |= LDB_CTRL_CH1_DATA_WIDTH;
+ }
+
+ if (lvds_format_jeida) {
+ reg |= LDB_CTRL_CH0_BIT_MAPPING;
+ if (nxp_ldb->lvds_dual_link)
+ reg |= LDB_CTRL_CH1_BIT_MAPPING;
+ }
+
+ if (mode->flags & DRM_MODE_FLAG_PVSYNC) {
+ reg |= LDB_CTRL_DI0_VSYNC_POLARITY;
+ if (nxp_ldb->lvds_dual_link)
+ reg |= LDB_CTRL_DI1_VSYNC_POLARITY;
+ }
+
+ regmap_write(nxp_ldb->regmap, LDB_CTRL, reg);
+
+ /* Program LVDS_CTRL */
+ reg = LVDS_CTRL_CC_ADJ(2) | LVDS_CTRL_PRE_EMPH_EN |
+ LVDS_CTRL_PRE_EMPH_ADJ(3) | LVDS_CTRL_VBG_EN;
+ regmap_write(nxp_ldb->regmap, LVDS_CTRL, reg);
+
+ /* Wait for VBG to stabilize. */
+ usleep_range(15, 20);
+
+ reg |= LVDS_CTRL_CH0_EN;
+ if (nxp_ldb->lvds_dual_link)
+ reg |= LVDS_CTRL_CH1_EN;
+
+ regmap_write(nxp_ldb->regmap, LVDS_CTRL, reg);
+}
+
+static void nxp_ldb_atomic_disable(struct drm_bridge *bridge,
+ struct drm_bridge_state *old_bridge_state)
+{
+ struct nxp_ldb *nxp_ldb = to_nxp_ldb(bridge);
+
+ /* Stop both channels. */
+ regmap_write(nxp_ldb->regmap, LVDS_CTRL, 0);
+ regmap_write(nxp_ldb->regmap, LDB_CTRL, 0);
+
+ clk_disable_unprepare(nxp_ldb->clk);
+}
+
+#define MAX_INPUT_SEL_FORMATS 1
+static u32 *
+nxp_ldb_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+ struct drm_bridge_state *bridge_state,
+ struct drm_crtc_state *crtc_state,
+ struct drm_connector_state *conn_state,
+ u32 output_fmt,
+ unsigned int *num_input_fmts)
+{
+ u32 *input_fmts;
+
+ *num_input_fmts = 0;
+
+ input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+ GFP_KERNEL);
+ if (!input_fmts)
+ return NULL;
+
+ input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+ *num_input_fmts = MAX_INPUT_SEL_FORMATS;
+
+ return input_fmts;
+}
+
+static enum drm_mode_status
+nxp_ldb_mode_valid(struct drm_bridge *bridge,
+ const struct drm_display_info *info,
+ const struct drm_display_mode *mode)
+{
+ struct nxp_ldb *nxp_ldb = to_nxp_ldb(bridge);
+
+ if (mode->clock > (nxp_ldb->lvds_dual_link ? 80000 : 160000))
+ return MODE_CLOCK_HIGH;
+
+ return MODE_OK;
+}
+
+static const struct drm_bridge_funcs funcs = {
+ .attach = nxp_ldb_attach,
+ .atomic_check = nxp_ldb_atomic_check,
+ .atomic_enable = nxp_ldb_atomic_enable,
+ .atomic_disable = nxp_ldb_atomic_disable,
+ .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+ .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+ .atomic_get_input_bus_fmts = nxp_ldb_atomic_get_input_bus_fmts,
+ .atomic_reset = drm_atomic_helper_bridge_reset,
+ .mode_valid = nxp_ldb_mode_valid,
+};
+
+static int nxp_ldb_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *panel_node;
+ struct device_node *port1, *port2;
+ struct drm_panel *panel;
+ struct nxp_ldb *nxp_ldb;
+ int dual_link;
+
+ nxp_ldb = devm_kzalloc(dev, sizeof(*nxp_ldb), GFP_KERNEL);
+ if (!nxp_ldb)
+ return -ENOMEM;
+
+ nxp_ldb->dev = &pdev->dev;
+ nxp_ldb->bridge.funcs = &funcs;
+ nxp_ldb->bridge.of_node = dev->of_node;
+
+ nxp_ldb->clk = devm_clk_get(dev, "ldb");
+ if (IS_ERR(nxp_ldb->clk))
+ return PTR_ERR(nxp_ldb->clk);
+
+ nxp_ldb->regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
+ "syscon");
+ if (IS_ERR(nxp_ldb->regmap))
+ return PTR_ERR(nxp_ldb->regmap);
+
+ /* Locate the panel DT node. */
+ panel_node = of_graph_get_remote_node(dev->of_node, 1, 0);
+ if (!panel_node)
+ return -ENXIO;
+
+ panel = of_drm_find_panel(panel_node);
+ of_node_put(panel_node);
+ if (IS_ERR(panel))
+ return PTR_ERR(panel);
+
+ nxp_ldb->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+ if (IS_ERR(nxp_ldb->panel_bridge))
+ return PTR_ERR(nxp_ldb->panel_bridge);
+
+ /* Determine whether this is dual-link configuration */
+ port1 = of_graph_get_port_by_id(dev->of_node, 1);
+ port2 = of_graph_get_port_by_id(dev->of_node, 2);
+ dual_link = drm_of_lvds_get_dual_link_pixel_order(port1, port2);
+ of_node_put(port1);
+ of_node_put(port2);
+
+ if (dual_link == DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
+ dev_err(dev, "LVDS channel pixel swap not supported.\n");
+ return -EINVAL;
+ }
+
+ if (dual_link == DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS)
+ nxp_ldb->lvds_dual_link = true;
+
+ platform_set_drvdata(pdev, nxp_ldb);
+
+ drm_bridge_add(&nxp_ldb->bridge);
+
+ return 0;
+}
+
+static int nxp_ldb_remove(struct platform_device *pdev)
+{
+ struct nxp_ldb *nxp_ldb = platform_get_drvdata(pdev);
+
+ drm_bridge_remove(&nxp_ldb->bridge);
+
+ return 0;
+}
+
+static const struct of_device_id nxp_ldb_match[] = {
+ { .compatible = "fsl,imx8mp-ldb", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, nxp_ldb_match);
+
+static struct platform_driver nxp_ldb_driver = {
+ .probe = nxp_ldb_probe,
+ .remove = nxp_ldb_remove,
+ .driver = {
+ .name = "nxp-ldb",
+ .of_match_table = nxp_ldb_match,
+ },
+};
+module_platform_driver(nxp_ldb_driver);
+
+MODULE_AUTHOR("Marek Vasut <marex at denx.de>");
+MODULE_DESCRIPTION("NXP i.MX8M LDB");
+MODULE_LICENSE("GPL");
--
2.35.1
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