4 files changed, 583 insertions, 60 deletions

diff --git a/drivers/video/stm32/Kconfig b/drivers/video/stm32/Kconfig
index 78b1facad4b..95d51bb4e96 100644
--- a/drivers/video/stm32/Kconfig
+++ b/drivers/video/stm32/Kconfig
@@ -13,6 +13,15 @@ menuconfig VIDEO_STM32
 	  DSI. This option enables these supports which can be used on
 	  devices which have RGB TFT or DSI display connected.
 
+config VIDEO_STM32_DSI
+	bool "Enable STM32 DSI video support"
+	depends on VIDEO_STM32
+	select VIDEO_BRIDGE
+	select VIDEO_DW_MIPI_DSI
+	help
+	  This option enables support DSI internal bridge which can be used on
+	  devices which have DSI devices connected.
+
 config VIDEO_STM32_MAX_XRES
 	int "Maximum horizontal resolution (for memory allocation purposes)"
 	depends on VIDEO_STM32
diff --git a/drivers/video/stm32/Makefile b/drivers/video/stm32/Makefile
index 7297e5f57a6..f8b42d1a4d1 100644
--- a/drivers/video/stm32/Makefile
+++ b/drivers/video/stm32/Makefile
@@ -6,3 +6,4 @@
 #          Yannick Fertre <yannick.fertre@st.com>
 
 obj-${CONFIG_VIDEO_STM32} = stm32_ltdc.o
+obj-${CONFIG_VIDEO_STM32_DSI} += stm32_dsi.o
diff --git a/drivers/video/stm32/stm32_dsi.c b/drivers/video/stm32/stm32_dsi.c
new file mode 100644
index 00000000000..cb89576e1d6
--- /dev/null
+++ b/drivers/video/stm32/stm32_dsi.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 STMicroelectronics - All Rights Reserved
+ * Author(s): Philippe Cornu <philippe.cornu@st.com> for STMicroelectronics.
+ *	      Yannick Fertre <yannick.fertre@st.com> for STMicroelectronics.
+ *
+ * This MIPI DSI controller driver is based on the Linux Kernel driver from
+ * drivers/gpu/drm/stm/dw_mipi_dsi-stm.c.
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <dsi_host.h>
+#include <mipi_dsi.h>
+#include <panel.h>
+#include <reset.h>
+#include <video.h>
+#include <video_bridge.h>
+#include <asm/io.h>
+#include <asm/arch/gpio.h>
+#include <dm/device-internal.h>
+#include <linux/iopoll.h>
+#include <power/regulator.h>
+
+#define HWVER_130			0x31333000	/* IP version 1.30 */
+#define HWVER_131			0x31333100	/* IP version 1.31 */
+
+/* DSI digital registers & bit definitions */
+#define DSI_VERSION			0x00
+#define VERSION				GENMASK(31, 8)
+
+/*
+ * DSI wrapper registers & bit definitions
+ * Note: registers are named as in the Reference Manual
+ */
+#define DSI_WCFGR	0x0400		/* Wrapper ConFiGuration Reg */
+#define WCFGR_DSIM	BIT(0)		/* DSI Mode */
+#define WCFGR_COLMUX	GENMASK(3, 1)	/* COLor MUltipleXing */
+
+#define DSI_WCR		0x0404		/* Wrapper Control Reg */
+#define WCR_DSIEN	BIT(3)		/* DSI ENable */
+
+#define DSI_WISR	0x040C		/* Wrapper Interrupt and Status Reg */
+#define WISR_PLLLS	BIT(8)		/* PLL Lock Status */
+#define WISR_RRS	BIT(12)		/* Regulator Ready Status */
+
+#define DSI_WPCR0	0x0418		/* Wrapper Phy Conf Reg 0 */
+#define WPCR0_UIX4	GENMASK(5, 0)	/* Unit Interval X 4 */
+#define WPCR0_TDDL	BIT(16)		/* Turn Disable Data Lanes */
+
+#define DSI_WRPCR	0x0430		/* Wrapper Regulator & Pll Ctrl Reg */
+#define WRPCR_PLLEN	BIT(0)		/* PLL ENable */
+#define WRPCR_NDIV	GENMASK(8, 2)	/* pll loop DIVision Factor */
+#define WRPCR_IDF	GENMASK(14, 11)	/* pll Input Division Factor */
+#define WRPCR_ODF	GENMASK(17, 16)	/* pll Output Division Factor */
+#define WRPCR_REGEN	BIT(24)		/* REGulator ENable */
+#define WRPCR_BGREN	BIT(28)		/* BandGap Reference ENable */
+#define IDF_MIN		1
+#define IDF_MAX		7
+#define NDIV_MIN	10
+#define NDIV_MAX	125
+#define ODF_MIN		1
+#define ODF_MAX		8
+
+/* dsi color format coding according to the datasheet */
+enum dsi_color {
+	DSI_RGB565_CONF1,
+	DSI_RGB565_CONF2,
+	DSI_RGB565_CONF3,
+	DSI_RGB666_CONF1,
+	DSI_RGB666_CONF2,
+	DSI_RGB888,
+};
+
+#define LANE_MIN_KBPS	31250
+#define LANE_MAX_KBPS	500000
+
+/* Timeout for regulator on/off, pll lock/unlock & fifo empty */
+#define TIMEOUT_US	200000
+
+struct stm32_dsi_priv {
+	struct mipi_dsi_device device;
+	void __iomem *base;
+	struct udevice *panel;
+	u32 pllref_clk;
+	u32 hw_version;
+	int lane_min_kbps;
+	int lane_max_kbps;
+	struct udevice *vdd_reg;
+	struct udevice *dsi_host;
+};
+
+static inline void dsi_write(struct stm32_dsi_priv *dsi, u32 reg, u32 val)
+{
+	writel(val, dsi->base + reg);
+}
+
+static inline u32 dsi_read(struct stm32_dsi_priv *dsi, u32 reg)
+{
+	return readl(dsi->base + reg);
+}
+
+static inline void dsi_set(struct stm32_dsi_priv *dsi, u32 reg, u32 mask)
+{
+	dsi_write(dsi, reg, dsi_read(dsi, reg) | mask);
+}
+
+static inline void dsi_clear(struct stm32_dsi_priv *dsi, u32 reg, u32 mask)
+{
+	dsi_write(dsi, reg, dsi_read(dsi, reg) & ~mask);
+}
+
+static inline void dsi_update_bits(struct stm32_dsi_priv *dsi, u32 reg,
+				   u32 mask, u32 val)
+{
+	dsi_write(dsi, reg, (dsi_read(dsi, reg) & ~mask) | val);
+}
+
+static enum dsi_color dsi_color_from_mipi(u32 fmt)
+{
+	switch (fmt) {
+	case MIPI_DSI_FMT_RGB888:
+		return DSI_RGB888;
+	case MIPI_DSI_FMT_RGB666:
+		return DSI_RGB666_CONF2;
+	case MIPI_DSI_FMT_RGB666_PACKED:
+		return DSI_RGB666_CONF1;
+	case MIPI_DSI_FMT_RGB565:
+		return DSI_RGB565_CONF1;
+	default:
+		pr_err("MIPI color invalid, so we use rgb888\n");
+	}
+	return DSI_RGB888;
+}
+
+static int dsi_pll_get_clkout_khz(int clkin_khz, int idf, int ndiv, int odf)
+{
+	int divisor = idf * odf;
+
+	/* prevent from division by 0 */
+	if (!divisor)
+		return 0;
+
+	return DIV_ROUND_CLOSEST(clkin_khz * ndiv, divisor);
+}
+
+static int dsi_pll_get_params(struct stm32_dsi_priv *dsi,
+			      int clkin_khz, int clkout_khz,
+			      int *idf, int *ndiv, int *odf)
+{
+	int i, o, n, n_min, n_max;
+	int fvco_min, fvco_max, delta, best_delta; /* all in khz */
+
+	/* Early checks preventing division by 0 & odd results */
+	if (clkin_khz <= 0 || clkout_khz <= 0)
+		return -EINVAL;
+
+	fvco_min = dsi->lane_min_kbps * 2 * ODF_MAX;
+	fvco_max = dsi->lane_max_kbps * 2 * ODF_MIN;
+
+	best_delta = 1000000; /* big started value (1000000khz) */
+
+	for (i = IDF_MIN; i <= IDF_MAX; i++) {
+		/* Compute ndiv range according to Fvco */
+		n_min = ((fvco_min * i) / (2 * clkin_khz)) + 1;
+		n_max = (fvco_max * i) / (2 * clkin_khz);
+
+		/* No need to continue idf loop if we reach ndiv max */
+		if (n_min >= NDIV_MAX)
+			break;
+
+		/* Clamp ndiv to valid values */
+		if (n_min < NDIV_MIN)
+			n_min = NDIV_MIN;
+		if (n_max > NDIV_MAX)
+			n_max = NDIV_MAX;
+
+		for (o = ODF_MIN; o <= ODF_MAX; o *= 2) {
+			n = DIV_ROUND_CLOSEST(i * o * clkout_khz, clkin_khz);
+			/* Check ndiv according to vco range */
+			if (n < n_min || n > n_max)
+				continue;
+			/* Check if new delta is better & saves parameters */
+			delta = dsi_pll_get_clkout_khz(clkin_khz, i, n, o) -
+				clkout_khz;
+			if (delta < 0)
+				delta = -delta;
+			if (delta < best_delta) {
+				*idf = i;
+				*ndiv = n;
+				*odf = o;
+				best_delta = delta;
+			}
+			/* fast return in case of "perfect result" */
+			if (!delta)
+				return 0;
+		}
+	}
+
+	return 0;
+}
+
+static int dsi_phy_init(void *priv_data)
+{
+	struct mipi_dsi_device *device = priv_data;
+	struct udevice *dev = device->dev;
+	struct stm32_dsi_priv *dsi = dev_get_priv(dev);
+	u32 val;
+	int ret;
+
+	debug("Initialize DSI physical layer\n");
+
+	/* Enable the regulator */
+	dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
+	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
+				 TIMEOUT_US);
+	if (ret) {
+		debug("!TIMEOUT! waiting REGU\n");
+		return ret;
+	}
+
+	/* Enable the DSI PLL & wait for its lock */
+	dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
+	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
+				 TIMEOUT_US);
+	if (ret) {
+		debug("!TIMEOUT! waiting PLL\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void dsi_phy_post_set_mode(void *priv_data, unsigned long mode_flags)
+{
+	struct mipi_dsi_device *device = priv_data;
+	struct udevice *dev = device->dev;
+	struct stm32_dsi_priv *dsi = dev_get_priv(dev);
+
+	debug("Set mode %p enable %ld\n", dsi,
+	      mode_flags & MIPI_DSI_MODE_VIDEO);
+
+	if (!dsi)
+		return;
+
+	/*
+	 * DSI wrapper must be enabled in video mode & disabled in command mode.
+	 * If wrapper is enabled in command mode, the display controller
+	 * register access will hang.
+	 */
+
+	if (mode_flags & MIPI_DSI_MODE_VIDEO)
+		dsi_set(dsi, DSI_WCR, WCR_DSIEN);
+	else
+		dsi_clear(dsi, DSI_WCR, WCR_DSIEN);
+}
+
+static int dsi_get_lane_mbps(void *priv_data, struct display_timing *timings,
+			     u32 lanes, u32 format, unsigned int *lane_mbps)
+{
+	struct mipi_dsi_device *device = priv_data;
+	struct udevice *dev = device->dev;
+	struct stm32_dsi_priv *dsi = dev_get_priv(dev);
+	int idf, ndiv, odf, pll_in_khz, pll_out_khz;
+	int ret, bpp;
+	u32 val;
+
+	/* Update lane capabilities according to hw version */
+	dsi->hw_version = dsi_read(dsi, DSI_VERSION) & VERSION;
+	dsi->lane_min_kbps = LANE_MIN_KBPS;
+	dsi->lane_max_kbps = LANE_MAX_KBPS;
+	if (dsi->hw_version == HWVER_131) {
+		dsi->lane_min_kbps *= 2;
+		dsi->lane_max_kbps *= 2;
+	}
+
+	pll_in_khz = dsi->pllref_clk / 1000;
+
+	/* Compute requested pll out */
+	bpp = mipi_dsi_pixel_format_to_bpp(format);
+	pll_out_khz = (timings->pixelclock.typ / 1000) * bpp / lanes;
+	/* Add 20% to pll out to be higher than pixel bw (burst mode only) */
+	pll_out_khz = (pll_out_khz * 12) / 10;
+	if (pll_out_khz > dsi->lane_max_kbps) {
+		pll_out_khz = dsi->lane_max_kbps;
+		dev_warn(dev, "Warning max phy mbps is used\n");
+	}
+	if (pll_out_khz < dsi->lane_min_kbps) {
+		pll_out_khz = dsi->lane_min_kbps;
+		dev_warn(dev, "Warning min phy mbps is used\n");
+	}
+
+	/* Compute best pll parameters */
+	idf = 0;
+	ndiv = 0;
+	odf = 0;
+	ret = dsi_pll_get_params(dsi, pll_in_khz, pll_out_khz,
+				 &idf, &ndiv, &odf);
+	if (ret) {
+		dev_err(dev, "Warning dsi_pll_get_params(): bad params\n");
+		return ret;
+	}
+
+	/* Get the adjusted pll out value */
+	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
+
+	/* Set the PLL division factors */
+	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
+			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
+
+	/* Compute uix4 & set the bit period in high-speed mode */
+	val = 4000000 / pll_out_khz;
+	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
+
+	/* Select video mode by resetting DSIM bit */
+	dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
+
+	/* Select the color coding */
+	dsi_update_bits(dsi, DSI_WCFGR, WCFGR_COLMUX,
+			dsi_color_from_mipi(format) << 1);
+
+	*lane_mbps = pll_out_khz / 1000;
+
+	debug("pll_in %ukHz pll_out %ukHz lane_mbps %uMHz\n",
+	      pll_in_khz, pll_out_khz, *lane_mbps);
+
+	return 0;
+}
+
+static const struct mipi_dsi_phy_ops dsi_stm_phy_ops = {
+	.init = dsi_phy_init,
+	.get_lane_mbps = dsi_get_lane_mbps,
+	.post_set_mode = dsi_phy_post_set_mode,
+};
+
+static int stm32_dsi_attach(struct udevice *dev)
+{
+	struct stm32_dsi_priv *priv = dev_get_priv(dev);
+	struct mipi_dsi_device *device = &priv->device;
+	struct mipi_dsi_panel_plat *mplat;
+	struct display_timing timings;
+	int ret;
+
+	ret = uclass_first_device(UCLASS_PANEL, &priv->panel);
+	if (ret) {
+		dev_err(dev, "panel device error %d\n", ret);
+		return ret;
+	}
+
+	mplat = dev_get_platdata(priv->panel);
+	mplat->device = &priv->device;
+
+	ret = panel_get_display_timing(priv->panel, &timings);
+	if (ret) {
+		ret = fdtdec_decode_display_timing(gd->fdt_blob,
+						   dev_of_offset(priv->panel),
+						   0, &timings);
+		if (ret) {
+			dev_err(dev, "decode display timing error %d\n", ret);
+			return ret;
+		}
+	}
+
+	ret = uclass_get_device(UCLASS_DSI_HOST, 0, &priv->dsi_host);
+	if (ret) {
+		dev_err(dev, "No video dsi host detected %d\n", ret);
+		return ret;
+	}
+
+	ret = dsi_host_init(priv->dsi_host, device, &timings, 2,
+			    &dsi_stm_phy_ops);
+	if (ret) {
+		dev_err(dev, "failed to initialize mipi dsi host\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int stm32_dsi_set_backlight(struct udevice *dev, int percent)
+{
+	struct stm32_dsi_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = panel_enable_backlight(priv->panel);
+	if (ret) {
+		dev_err(dev, "panel %s enable backlight error %d\n",
+			priv->panel->name, ret);
+		return ret;
+	}
+
+	ret = dsi_host_enable(priv->dsi_host);
+	if (ret) {
+		dev_err(dev, "failed to enable mipi dsi host\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int stm32_dsi_probe(struct udevice *dev)
+{
+	struct stm32_dsi_priv *priv = dev_get_priv(dev);
+	struct mipi_dsi_device *device = &priv->device;
+	struct reset_ctl rst;
+	struct clk clk;
+	int ret;
+
+	device->dev = dev;
+
+	priv->base = (void *)dev_read_addr(dev);
+	if ((fdt_addr_t)priv->base == FDT_ADDR_T_NONE) {
+		dev_err(dev, "dsi dt register address error\n");
+		return -EINVAL;
+	}
+
+	if (IS_ENABLED(CONFIG_DM_REGULATOR)) {
+		ret =  device_get_supply_regulator(dev, "phy-dsi-supply",
+						   &priv->vdd_reg);
+		if (ret && ret != -ENOENT) {
+			dev_err(dev, "Warning: cannot get phy dsi supply\n");
+			return -ENODEV;
+		}
+
+		if (ret != -ENOENT) {
+			ret = regulator_set_enable(priv->vdd_reg, true);
+			if (ret)
+				return ret;
+		}
+	}
+
+	ret = clk_get_by_name(device->dev, "pclk", &clk);
+	if (ret) {
+		dev_err(dev, "peripheral clock get error %d\n", ret);
+		goto err_reg;
+	}
+
+	ret = clk_enable(&clk);
+	if (ret) {
+		dev_err(dev, "peripheral clock enable error %d\n", ret);
+		goto err_reg;
+	}
+
+	ret = clk_get_by_name(dev, "ref", &clk);
+	if (ret) {
+		dev_err(dev, "pll reference clock get error %d\n", ret);
+		goto err_clk;
+	}
+
+	priv->pllref_clk = (unsigned int)clk_get_rate(&clk);
+
+	ret = reset_get_by_index(device->dev, 0, &rst);
+	if (ret) {
+		dev_err(dev, "missing dsi hardware reset\n");
+		goto err_clk;
+	}
+
+	/* Reset */
+	reset_deassert(&rst);
+
+	return 0;
+err_clk:
+	clk_disable(&clk);
+err_reg:
+	if (IS_ENABLED(CONFIG_DM_REGULATOR))
+		regulator_set_enable(priv->vdd_reg, false);
+
+	return ret;
+}
+
+struct video_bridge_ops stm32_dsi_ops = {
+	.attach = stm32_dsi_attach,
+	.set_backlight = stm32_dsi_set_backlight,
+};
+
+static const struct udevice_id stm32_dsi_ids[] = {
+	{ .compatible = "st,stm32-dsi"},
+	{ }
+};
+
+U_BOOT_DRIVER(stm32_dsi) = {
+	.name				= "stm32-display-dsi",
+	.id				= UCLASS_VIDEO_BRIDGE,
+	.of_match			= stm32_dsi_ids,
+	.bind				= dm_scan_fdt_dev,
+	.probe				= stm32_dsi_probe,
+	.ops				= &stm32_dsi_ops,
+	.priv_auto_alloc_size		= sizeof(struct stm32_dsi_priv),
+};
diff --git a/drivers/video/stm32/stm32_ltdc.c b/drivers/video/stm32/stm32_ltdc.c
index dc6c88902f6..59ff692b0b4 100644
--- a/drivers/video/stm32/stm32_ltdc.c
+++ b/drivers/video/stm32/stm32_ltdc.c
@@ -7,19 +7,18 @@
 
 #include <common.h>
 #include <clk.h>
+#include <display.h>
 #include <dm.h>
 #include <panel.h>
 #include <reset.h>
 #include <video.h>
+#include <video_bridge.h>
 #include <asm/io.h>
 #include <asm/arch/gpio.h>
 #include <dm/device-internal.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 struct stm32_ltdc_priv {
 	void __iomem *regs;
-	struct display_timing timing;
 	enum video_log2_bpp l2bpp;
 	u32 bg_col_argb;
 	u32 crop_x, crop_y, crop_w, crop_h;
@@ -174,8 +173,8 @@ static u32 stm32_ltdc_get_pixel_format(enum video_log2_bpp l2bpp)
 	case VIDEO_BPP2:
 	case VIDEO_BPP4:
 	default:
-		debug("%s: warning %dbpp not supported yet, %dbpp instead\n",
-		      __func__, VNBITS(l2bpp), VNBITS(VIDEO_BPP16));
+		pr_warn("%s: warning %dbpp not supported yet, %dbpp instead\n",
+			__func__, VNBITS(l2bpp), VNBITS(VIDEO_BPP16));
 		pf = PF_RGB565;
 		break;
 	}
@@ -209,23 +208,23 @@ static void stm32_ltdc_enable(struct stm32_ltdc_priv *priv)
 	setbits_le32(priv->regs + LTDC_GCR, GCR_LTDCEN);
 }
 
-static void stm32_ltdc_set_mode(struct stm32_ltdc_priv *priv)
+static void stm32_ltdc_set_mode(struct stm32_ltdc_priv *priv,
+				struct display_timing *timings)
 {
 	void __iomem *regs = priv->regs;
-	struct display_timing *timing = &priv->timing;
 	u32 hsync, vsync, acc_hbp, acc_vbp, acc_act_w, acc_act_h;
 	u32 total_w, total_h;
 	u32 val;
 
 	/* Convert video timings to ltdc timings */
-	hsync = timing->hsync_len.typ - 1;
-	vsync = timing->vsync_len.typ - 1;
-	acc_hbp = hsync + timing->hback_porch.typ;
-	acc_vbp = vsync + timing->vback_porch.typ;
-	acc_act_w = acc_hbp + timing->hactive.typ;
-	acc_act_h = acc_vbp + timing->vactive.typ;
-	total_w = acc_act_w + timing->hfront_porch.typ;
-	total_h = acc_act_h + timing->vfront_porch.typ;
+	hsync = timings->hsync_len.typ - 1;
+	vsync = timings->vsync_len.typ - 1;
+	acc_hbp = hsync + timings->hback_porch.typ;
+	acc_vbp = vsync + timings->vback_porch.typ;
+	acc_act_w = acc_hbp + timings->hactive.typ;
+	acc_act_h = acc_vbp + timings->vactive.typ;
+	total_w = acc_act_w + timings->hfront_porch.typ;
+	total_h = acc_act_h + timings->vfront_porch.typ;
 
 	/* Synchronization sizes */
 	val = (hsync << 16) | vsync;
@@ -247,14 +246,14 @@ static void stm32_ltdc_set_mode(struct stm32_ltdc_priv *priv)
 
 	/* Signal polarities */
 	val = 0;
-	debug("%s: timing->flags 0x%08x\n", __func__, timing->flags);
-	if (timing->flags & DISPLAY_FLAGS_HSYNC_HIGH)
+	debug("%s: timing->flags 0x%08x\n", __func__, timings->flags);
+	if (timings->flags & DISPLAY_FLAGS_HSYNC_HIGH)
 		val |= GCR_HSPOL;
-	if (timing->flags & DISPLAY_FLAGS_VSYNC_HIGH)
+	if (timings->flags & DISPLAY_FLAGS_VSYNC_HIGH)
 		val |= GCR_VSPOL;
-	if (timing->flags & DISPLAY_FLAGS_DE_HIGH)
+	if (timings->flags & DISPLAY_FLAGS_DE_HIGH)
 		val |= GCR_DEPOL;
-	if (timing->flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
+	if (timings->flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
 		val |= GCR_PCPOL;
 	clrsetbits_le32(regs + LTDC_GCR,
 			GCR_HSPOL | GCR_VSPOL | GCR_DEPOL | GCR_PCPOL, val);
@@ -330,96 +329,120 @@ static int stm32_ltdc_probe(struct udevice *dev)
 	struct video_uc_platdata *uc_plat = dev_get_uclass_platdata(dev);
 	struct video_priv *uc_priv = dev_get_uclass_priv(dev);
 	struct stm32_ltdc_priv *priv = dev_get_priv(dev);
-	struct udevice *panel;
+	struct udevice *bridge = NULL;
+	struct udevice *panel = NULL;
+	struct display_timing timings;
 	struct clk pclk;
 	struct reset_ctl rst;
-	int rate, ret;
+	int ret;
 
 	priv->regs = (void *)dev_read_addr(dev);
 	if ((fdt_addr_t)priv->regs == FDT_ADDR_T_NONE) {
-		debug("%s: ltdc dt register address error\n", __func__);
+		dev_err(dev, "ltdc dt register address error\n");
 		return -EINVAL;
 	}
 
 	ret = clk_get_by_index(dev, 0, &pclk);
 	if (ret) {
-		debug("%s: peripheral clock get error %d\n", __func__, ret);
+		dev_err(dev, "peripheral clock get error %d\n", ret);
 		return ret;
 	}
 
 	ret = clk_enable(&pclk);
 	if (ret) {
-		debug("%s: peripheral clock enable error %d\n",
-		      __func__, ret);
+		dev_err(dev, "peripheral clock enable error %d\n", ret);
 		return ret;
 	}
 
-	ret = reset_get_by_index(dev, 0, &rst);
+	ret = uclass_first_device_err(UCLASS_PANEL, &panel);
 	if (ret) {
-		debug("%s: missing ltdc hardware reset\n", __func__);
-		return -ENODEV;
+		if (ret != -ENODEV)
+			dev_err(dev, "panel device error %d\n", ret);
+		return ret;
 	}
 
-	/* Reset */
-	reset_deassert(&rst);
-
-	ret = uclass_first_device(UCLASS_PANEL, &panel);
+	ret = panel_get_display_timing(panel, &timings);
 	if (ret) {
-		debug("%s: panel device error %d\n", __func__, ret);
-		return ret;
+		ret = fdtdec_decode_display_timing(gd->fdt_blob,
+						   dev_of_offset(panel),
+						   0, &timings);
+		if (ret) {
+			dev_err(dev, "decode display timing error %d\n", ret);
+			return ret;
+		}
 	}
 
-	ret = panel_enable_backlight(panel);
+	ret = clk_set_rate(&pclk, timings.pixelclock.typ);
+	if (ret)
+		dev_warn(dev, "fail to set pixel clock %d hz\n",
+			 timings.pixelclock.typ);
+
+	debug("%s: Set pixel clock req %d hz get %ld hz\n", __func__,
+	      timings.pixelclock.typ, clk_get_rate(&pclk));
+
+	ret = reset_get_by_index(dev, 0, &rst);
 	if (ret) {
-		debug("%s: panel %s enable backlight error %d\n",
-		      __func__, panel->name, ret);
+		dev_err(dev, "missing ltdc hardware reset\n");
 		return ret;
 	}
 
-	ret = fdtdec_decode_display_timing(gd->fdt_blob,
-					   dev_of_offset(dev), 0,
-					   &priv->timing);
-	if (ret) {
-		debug("%s: decode display timing error %d\n",
-		      __func__, ret);
-		return -EINVAL;
-	}
+	/* Reset */
+	reset_deassert(&rst);
 
-	rate = clk_set_rate(&pclk, priv->timing.pixelclock.typ);
-	if (rate < 0) {
-		debug("%s: fail to set pixel clock %d hz %d hz\n",
-		      __func__, priv->timing.pixelclock.typ, rate);
-		return rate;
+	if (IS_ENABLED(CONFIG_VIDEO_BRIDGE)) {
+		ret = uclass_get_device(UCLASS_VIDEO_BRIDGE, 0, &bridge);
+		if (ret)
+			debug("No video bridge, or no backlight on bridge\n");
+
+		if (bridge) {
+			ret = video_bridge_attach(bridge);
+			if (ret) {
+				dev_err(dev, "fail to attach bridge\n");
+				return ret;
+			}
+		}
 	}
 
-	debug("%s: Set pixel clock req %d hz get %d hz\n", __func__,
-	      priv->timing.pixelclock.typ, rate);
-
 	/* TODO Below parameters are hard-coded for the moment... */
 	priv->l2bpp = VIDEO_BPP16;
 	priv->bg_col_argb = 0xFFFFFFFF; /* white no transparency */
 	priv->crop_x = 0;
 	priv->crop_y = 0;
-	priv->crop_w = priv->timing.hactive.typ;
-	priv->crop_h = priv->timing.vactive.typ;
+	priv->crop_w = timings.hactive.typ;
+	priv->crop_h = timings.vactive.typ;
 	priv->alpha = 0xFF;
 
 	debug("%s: %dx%d %dbpp frame buffer at 0x%lx\n", __func__,
-	      priv->timing.hactive.typ, priv->timing.vactive.typ,
+	      timings.hactive.typ, timings.vactive.typ,
 	      VNBITS(priv->l2bpp), uc_plat->base);
 	debug("%s: crop %d,%d %dx%d bg 0x%08x alpha %d\n", __func__,
 	      priv->crop_x, priv->crop_y, priv->crop_w, priv->crop_h,
 	      priv->bg_col_argb, priv->alpha);
 
 	/* Configure & start LTDC */
-	stm32_ltdc_set_mode(priv);
+	stm32_ltdc_set_mode(priv, &timings);
 	stm32_ltdc_set_layer1(priv, uc_plat->base);
 	stm32_ltdc_enable(priv);
 
-	uc_priv->xsize = priv->timing.hactive.typ;
-	uc_priv->ysize = priv->timing.vactive.typ;
+	uc_priv->xsize = timings.hactive.typ;
+	uc_priv->ysize = timings.vactive.typ;
 	uc_priv->bpix = priv->l2bpp;
 
+	if (!bridge) {
+		ret = panel_enable_backlight(panel);
+		if (ret) {
+			dev_err(dev, "panel %s enable backlight error %d\n",
+				panel->name, ret);
+			return ret;
+		}
+	} else if (IS_ENABLED(CONFIG_VIDEO_BRIDGE)) {
+		ret = video_bridge_set_backlight(bridge, 80);
+		if (ret) {
+			dev_err(dev, "fail to set backlight\n");
+			return ret;
+		}
+	}
+
 	video_set_flush_dcache(dev, true);
 
 	return 0;