Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 781 insertions, 0 deletions

diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c
new file mode 100644
index 000000000..a4dba034d
--- /dev/null
+++ b/drivers/gpu/drm/imx/imx-ldb.c
@@ -0,0 +1,781 @@
+/*
+ * i.MX drm driver - LVDS display bridge
+ *
+ * Copyright (C) 2012 Sascha Hauer, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <drm/drmP.h>
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
+#include <linux/regmap.h>
+#include <linux/videodev2.h>
+
+#include "imx-drm.h"
+
+#define DRIVER_NAME "imx-ldb"
+
+#define LDB_CH0_MODE_EN_TO_DI0		(1 << 0)
+#define LDB_CH0_MODE_EN_TO_DI1		(3 << 0)
+#define LDB_CH0_MODE_EN_MASK		(3 << 0)
+#define LDB_CH1_MODE_EN_TO_DI0		(1 << 2)
+#define LDB_CH1_MODE_EN_TO_DI1		(3 << 2)
+#define LDB_CH1_MODE_EN_MASK		(3 << 2)
+#define LDB_SPLIT_MODE_EN		(1 << 4)
+#define LDB_DATA_WIDTH_CH0_24		(1 << 5)
+#define LDB_BIT_MAP_CH0_JEIDA		(1 << 6)
+#define LDB_DATA_WIDTH_CH1_24		(1 << 7)
+#define LDB_BIT_MAP_CH1_JEIDA		(1 << 8)
+#define LDB_DI0_VS_POL_ACT_LOW		(1 << 9)
+#define LDB_DI1_VS_POL_ACT_LOW		(1 << 10)
+#define LDB_BGREF_RMODE_INT		(1 << 15)
+
+struct imx_ldb;
+
+struct imx_ldb_channel {
+	struct imx_ldb *ldb;
+	struct drm_connector connector;
+	struct drm_encoder encoder;
+
+	/* Defines what is connected to the ldb, only one at a time */
+	struct drm_panel *panel;
+	struct drm_bridge *bridge;
+
+	struct device_node *child;
+	struct i2c_adapter *ddc;
+	int chno;
+	void *edid;
+	int edid_len;
+	struct drm_display_mode mode;
+	int mode_valid;
+	u32 bus_format;
+	u32 bus_flags;
+};
+
+static inline struct imx_ldb_channel *con_to_imx_ldb_ch(struct drm_connector *c)
+{
+	return container_of(c, struct imx_ldb_channel, connector);
+}
+
+static inline struct imx_ldb_channel *enc_to_imx_ldb_ch(struct drm_encoder *e)
+{
+	return container_of(e, struct imx_ldb_channel, encoder);
+}
+
+struct bus_mux {
+	int reg;
+	int shift;
+	int mask;
+};
+
+struct imx_ldb {
+	struct regmap *regmap;
+	struct device *dev;
+	struct imx_ldb_channel channel[2];
+	struct clk *clk[2]; /* our own clock */
+	struct clk *clk_sel[4]; /* parent of display clock */
+	struct clk *clk_parent[4]; /* original parent of clk_sel */
+	struct clk *clk_pll[2]; /* upstream clock we can adjust */
+	u32 ldb_ctrl;
+	const struct bus_mux *lvds_mux;
+};
+
+static void imx_ldb_ch_set_bus_format(struct imx_ldb_channel *imx_ldb_ch,
+				      u32 bus_format)
+{
+	struct imx_ldb *ldb = imx_ldb_ch->ldb;
+	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
+
+	switch (bus_format) {
+	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+		if (imx_ldb_ch->chno == 0 || dual)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24;
+		if (imx_ldb_ch->chno == 1 || dual)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+		if (imx_ldb_ch->chno == 0 || dual)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24 |
+					 LDB_BIT_MAP_CH0_JEIDA;
+		if (imx_ldb_ch->chno == 1 || dual)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24 |
+					 LDB_BIT_MAP_CH1_JEIDA;
+		break;
+	}
+}
+
+static int imx_ldb_connector_get_modes(struct drm_connector *connector)
+{
+	struct imx_ldb_channel *imx_ldb_ch = con_to_imx_ldb_ch(connector);
+	int num_modes = 0;
+
+	if (imx_ldb_ch->panel && imx_ldb_ch->panel->funcs &&
+	    imx_ldb_ch->panel->funcs->get_modes) {
+		num_modes = imx_ldb_ch->panel->funcs->get_modes(imx_ldb_ch->panel);
+		if (num_modes > 0)
+			return num_modes;
+	}
+
+	if (!imx_ldb_ch->edid && imx_ldb_ch->ddc)
+		imx_ldb_ch->edid = drm_get_edid(connector, imx_ldb_ch->ddc);
+
+	if (imx_ldb_ch->edid) {
+		drm_connector_update_edid_property(connector,
+							imx_ldb_ch->edid);
+		num_modes = drm_add_edid_modes(connector, imx_ldb_ch->edid);
+	}
+
+	if (imx_ldb_ch->mode_valid) {
+		struct drm_display_mode *mode;
+
+		mode = drm_mode_create(connector->dev);
+		if (!mode)
+			return -EINVAL;
+		drm_mode_copy(mode, &imx_ldb_ch->mode);
+		mode->type |= DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+		drm_mode_probed_add(connector, mode);
+		num_modes++;
+	}
+
+	return num_modes;
+}
+
+static struct drm_encoder *imx_ldb_connector_best_encoder(
+		struct drm_connector *connector)
+{
+	struct imx_ldb_channel *imx_ldb_ch = con_to_imx_ldb_ch(connector);
+
+	return &imx_ldb_ch->encoder;
+}
+
+static void imx_ldb_set_clock(struct imx_ldb *ldb, int mux, int chno,
+		unsigned long serial_clk, unsigned long di_clk)
+{
+	int ret;
+
+	dev_dbg(ldb->dev, "%s: now: %ld want: %ld\n", __func__,
+			clk_get_rate(ldb->clk_pll[chno]), serial_clk);
+	clk_set_rate(ldb->clk_pll[chno], serial_clk);
+
+	dev_dbg(ldb->dev, "%s after: %ld\n", __func__,
+			clk_get_rate(ldb->clk_pll[chno]));
+
+	dev_dbg(ldb->dev, "%s: now: %ld want: %ld\n", __func__,
+			clk_get_rate(ldb->clk[chno]),
+			(long int)di_clk);
+	clk_set_rate(ldb->clk[chno], di_clk);
+
+	dev_dbg(ldb->dev, "%s after: %ld\n", __func__,
+			clk_get_rate(ldb->clk[chno]));
+
+	/* set display clock mux to LDB input clock */
+	ret = clk_set_parent(ldb->clk_sel[mux], ldb->clk[chno]);
+	if (ret)
+		dev_err(ldb->dev,
+			"unable to set di%d parent clock to ldb_di%d\n", mux,
+			chno);
+}
+
+static void imx_ldb_encoder_enable(struct drm_encoder *encoder)
+{
+	struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
+	struct imx_ldb *ldb = imx_ldb_ch->ldb;
+	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
+	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
+
+	if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) {
+		dev_warn(ldb->dev, "%s: invalid mux %d\n", __func__, mux);
+		return;
+	}
+
+	drm_panel_prepare(imx_ldb_ch->panel);
+
+	if (dual) {
+		clk_set_parent(ldb->clk_sel[mux], ldb->clk[0]);
+		clk_set_parent(ldb->clk_sel[mux], ldb->clk[1]);
+
+		clk_prepare_enable(ldb->clk[0]);
+		clk_prepare_enable(ldb->clk[1]);
+	} else {
+		clk_set_parent(ldb->clk_sel[mux], ldb->clk[imx_ldb_ch->chno]);
+	}
+
+	if (imx_ldb_ch == &ldb->channel[0] || dual) {
+		ldb->ldb_ctrl &= ~LDB_CH0_MODE_EN_MASK;
+		if (mux == 0 || ldb->lvds_mux)
+			ldb->ldb_ctrl |= LDB_CH0_MODE_EN_TO_DI0;
+		else if (mux == 1)
+			ldb->ldb_ctrl |= LDB_CH0_MODE_EN_TO_DI1;
+	}
+	if (imx_ldb_ch == &ldb->channel[1] || dual) {
+		ldb->ldb_ctrl &= ~LDB_CH1_MODE_EN_MASK;
+		if (mux == 1 || ldb->lvds_mux)
+			ldb->ldb_ctrl |= LDB_CH1_MODE_EN_TO_DI1;
+		else if (mux == 0)
+			ldb->ldb_ctrl |= LDB_CH1_MODE_EN_TO_DI0;
+	}
+
+	if (ldb->lvds_mux) {
+		const struct bus_mux *lvds_mux = NULL;
+
+		if (imx_ldb_ch == &ldb->channel[0])
+			lvds_mux = &ldb->lvds_mux[0];
+		else if (imx_ldb_ch == &ldb->channel[1])
+			lvds_mux = &ldb->lvds_mux[1];
+
+		regmap_update_bits(ldb->regmap, lvds_mux->reg, lvds_mux->mask,
+				   mux << lvds_mux->shift);
+	}
+
+	regmap_write(ldb->regmap, IOMUXC_GPR2, ldb->ldb_ctrl);
+
+	drm_panel_enable(imx_ldb_ch->panel);
+}
+
+static void
+imx_ldb_encoder_atomic_mode_set(struct drm_encoder *encoder,
+				struct drm_crtc_state *crtc_state,
+				struct drm_connector_state *connector_state)
+{
+	struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
+	struct drm_display_mode *mode = &crtc_state->adjusted_mode;
+	struct imx_ldb *ldb = imx_ldb_ch->ldb;
+	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
+	unsigned long serial_clk;
+	unsigned long di_clk = mode->clock * 1000;
+	int mux = drm_of_encoder_active_port_id(imx_ldb_ch->child, encoder);
+	u32 bus_format = imx_ldb_ch->bus_format;
+
+	if (mux < 0 || mux >= ARRAY_SIZE(ldb->clk_sel)) {
+		dev_warn(ldb->dev, "%s: invalid mux %d\n", __func__, mux);
+		return;
+	}
+
+	if (mode->clock > 170000) {
+		dev_warn(ldb->dev,
+			 "%s: mode exceeds 170 MHz pixel clock\n", __func__);
+	}
+	if (mode->clock > 85000 && !dual) {
+		dev_warn(ldb->dev,
+			 "%s: mode exceeds 85 MHz pixel clock\n", __func__);
+	}
+
+	if (dual) {
+		serial_clk = 3500UL * mode->clock;
+		imx_ldb_set_clock(ldb, mux, 0, serial_clk, di_clk);
+		imx_ldb_set_clock(ldb, mux, 1, serial_clk, di_clk);
+	} else {
+		serial_clk = 7000UL * mode->clock;
+		imx_ldb_set_clock(ldb, mux, imx_ldb_ch->chno, serial_clk,
+				  di_clk);
+	}
+
+	/* FIXME - assumes straight connections DI0 --> CH0, DI1 --> CH1 */
+	if (imx_ldb_ch == &ldb->channel[0] || dual) {
+		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+			ldb->ldb_ctrl |= LDB_DI0_VS_POL_ACT_LOW;
+		else if (mode->flags & DRM_MODE_FLAG_PVSYNC)
+			ldb->ldb_ctrl &= ~LDB_DI0_VS_POL_ACT_LOW;
+	}
+	if (imx_ldb_ch == &ldb->channel[1] || dual) {
+		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+			ldb->ldb_ctrl |= LDB_DI1_VS_POL_ACT_LOW;
+		else if (mode->flags & DRM_MODE_FLAG_PVSYNC)
+			ldb->ldb_ctrl &= ~LDB_DI1_VS_POL_ACT_LOW;
+	}
+
+	if (!bus_format) {
+		struct drm_connector *connector = connector_state->connector;
+		struct drm_display_info *di = &connector->display_info;
+
+		if (di->num_bus_formats)
+			bus_format = di->bus_formats[0];
+	}
+	imx_ldb_ch_set_bus_format(imx_ldb_ch, bus_format);
+}
+
+static void imx_ldb_encoder_disable(struct drm_encoder *encoder)
+{
+	struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
+	struct imx_ldb *ldb = imx_ldb_ch->ldb;
+	int dual = ldb->ldb_ctrl & LDB_SPLIT_MODE_EN;
+	int mux, ret;
+
+	drm_panel_disable(imx_ldb_ch->panel);
+
+	if (imx_ldb_ch == &ldb->channel[0] || dual)
+		ldb->ldb_ctrl &= ~LDB_CH0_MODE_EN_MASK;
+	if (imx_ldb_ch == &ldb->channel[1] || dual)
+		ldb->ldb_ctrl &= ~LDB_CH1_MODE_EN_MASK;
+
+	regmap_write(ldb->regmap, IOMUXC_GPR2, ldb->ldb_ctrl);
+
+	if (dual) {
+		clk_disable_unprepare(ldb->clk[0]);
+		clk_disable_unprepare(ldb->clk[1]);
+	}
+
+	if (ldb->lvds_mux) {
+		const struct bus_mux *lvds_mux = NULL;
+
+		if (imx_ldb_ch == &ldb->channel[0])
+			lvds_mux = &ldb->lvds_mux[0];
+		else if (imx_ldb_ch == &ldb->channel[1])
+			lvds_mux = &ldb->lvds_mux[1];
+
+		regmap_read(ldb->regmap, lvds_mux->reg, &mux);
+		mux &= lvds_mux->mask;
+		mux >>= lvds_mux->shift;
+	} else {
+		mux = (imx_ldb_ch == &ldb->channel[0]) ? 0 : 1;
+	}
+
+	/* set display clock mux back to original input clock */
+	ret = clk_set_parent(ldb->clk_sel[mux], ldb->clk_parent[mux]);
+	if (ret)
+		dev_err(ldb->dev,
+			"unable to set di%d parent clock to original parent\n",
+			mux);
+
+	drm_panel_unprepare(imx_ldb_ch->panel);
+}
+
+static int imx_ldb_encoder_atomic_check(struct drm_encoder *encoder,
+					struct drm_crtc_state *crtc_state,
+					struct drm_connector_state *conn_state)
+{
+	struct imx_crtc_state *imx_crtc_state = to_imx_crtc_state(crtc_state);
+	struct imx_ldb_channel *imx_ldb_ch = enc_to_imx_ldb_ch(encoder);
+	struct drm_display_info *di = &conn_state->connector->display_info;
+	u32 bus_format = imx_ldb_ch->bus_format;
+
+	/* Bus format description in DT overrides connector display info. */
+	if (!bus_format && di->num_bus_formats) {
+		bus_format = di->bus_formats[0];
+		imx_crtc_state->bus_flags = di->bus_flags;
+	} else {
+		bus_format = imx_ldb_ch->bus_format;
+		imx_crtc_state->bus_flags = imx_ldb_ch->bus_flags;
+	}
+	switch (bus_format) {
+	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+		imx_crtc_state->bus_format = MEDIA_BUS_FMT_RGB666_1X18;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+		imx_crtc_state->bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	imx_crtc_state->di_hsync_pin = 2;
+	imx_crtc_state->di_vsync_pin = 3;
+
+	return 0;
+}
+
+
+static const struct drm_connector_funcs imx_ldb_connector_funcs = {
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = imx_drm_connector_destroy,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static const struct drm_connector_helper_funcs imx_ldb_connector_helper_funcs = {
+	.get_modes = imx_ldb_connector_get_modes,
+	.best_encoder = imx_ldb_connector_best_encoder,
+};
+
+static const struct drm_encoder_funcs imx_ldb_encoder_funcs = {
+	.destroy = imx_drm_encoder_destroy,
+};
+
+static const struct drm_encoder_helper_funcs imx_ldb_encoder_helper_funcs = {
+	.atomic_mode_set = imx_ldb_encoder_atomic_mode_set,
+	.enable = imx_ldb_encoder_enable,
+	.disable = imx_ldb_encoder_disable,
+	.atomic_check = imx_ldb_encoder_atomic_check,
+};
+
+static int imx_ldb_get_clk(struct imx_ldb *ldb, int chno)
+{
+	char clkname[16];
+
+	snprintf(clkname, sizeof(clkname), "di%d", chno);
+	ldb->clk[chno] = devm_clk_get(ldb->dev, clkname);
+	if (IS_ERR(ldb->clk[chno]))
+		return PTR_ERR(ldb->clk[chno]);
+
+	snprintf(clkname, sizeof(clkname), "di%d_pll", chno);
+	ldb->clk_pll[chno] = devm_clk_get(ldb->dev, clkname);
+
+	return PTR_ERR_OR_ZERO(ldb->clk_pll[chno]);
+}
+
+static int imx_ldb_register(struct drm_device *drm,
+	struct imx_ldb_channel *imx_ldb_ch)
+{
+	struct imx_ldb *ldb = imx_ldb_ch->ldb;
+	struct drm_encoder *encoder = &imx_ldb_ch->encoder;
+	int ret;
+
+	ret = imx_drm_encoder_parse_of(drm, encoder, imx_ldb_ch->child);
+	if (ret)
+		return ret;
+
+	ret = imx_ldb_get_clk(ldb, imx_ldb_ch->chno);
+	if (ret)
+		return ret;
+
+	if (ldb->ldb_ctrl & LDB_SPLIT_MODE_EN) {
+		ret = imx_ldb_get_clk(ldb, 1);
+		if (ret)
+			return ret;
+	}
+
+	drm_encoder_helper_add(encoder, &imx_ldb_encoder_helper_funcs);
+	drm_encoder_init(drm, encoder, &imx_ldb_encoder_funcs,
+			 DRM_MODE_ENCODER_LVDS, NULL);
+
+	if (imx_ldb_ch->bridge) {
+		ret = drm_bridge_attach(&imx_ldb_ch->encoder,
+					imx_ldb_ch->bridge, NULL);
+		if (ret) {
+			DRM_ERROR("Failed to initialize bridge with drm\n");
+			return ret;
+		}
+	} else {
+		/*
+		 * We want to add the connector whenever there is no bridge
+		 * that brings its own, not only when there is a panel. For
+		 * historical reasons, the ldb driver can also work without
+		 * a panel.
+		 */
+		drm_connector_helper_add(&imx_ldb_ch->connector,
+				&imx_ldb_connector_helper_funcs);
+		drm_connector_init(drm, &imx_ldb_ch->connector,
+				&imx_ldb_connector_funcs,
+				DRM_MODE_CONNECTOR_LVDS);
+		drm_connector_attach_encoder(&imx_ldb_ch->connector, encoder);
+	}
+
+	if (imx_ldb_ch->panel) {
+		ret = drm_panel_attach(imx_ldb_ch->panel,
+				       &imx_ldb_ch->connector);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+enum {
+	LVDS_BIT_MAP_SPWG,
+	LVDS_BIT_MAP_JEIDA
+};
+
+struct imx_ldb_bit_mapping {
+	u32 bus_format;
+	u32 datawidth;
+	const char * const mapping;
+};
+
+static const struct imx_ldb_bit_mapping imx_ldb_bit_mappings[] = {
+	{ MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,  18, "spwg" },
+	{ MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,  24, "spwg" },
+	{ MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA, 24, "jeida" },
+};
+
+static u32 of_get_bus_format(struct device *dev, struct device_node *np)
+{
+	const char *bm;
+	u32 datawidth = 0;
+	int ret, i;
+
+	ret = of_property_read_string(np, "fsl,data-mapping", &bm);
+	if (ret < 0)
+		return ret;
+
+	of_property_read_u32(np, "fsl,data-width", &datawidth);
+
+	for (i = 0; i < ARRAY_SIZE(imx_ldb_bit_mappings); i++) {
+		if (!strcasecmp(bm, imx_ldb_bit_mappings[i].mapping) &&
+		    datawidth == imx_ldb_bit_mappings[i].datawidth)
+			return imx_ldb_bit_mappings[i].bus_format;
+	}
+
+	dev_err(dev, "invalid data mapping: %d-bit \"%s\"\n", datawidth, bm);
+
+	return -ENOENT;
+}
+
+static struct bus_mux imx6q_lvds_mux[2] = {
+	{
+		.reg = IOMUXC_GPR3,
+		.shift = 6,
+		.mask = IMX6Q_GPR3_LVDS0_MUX_CTL_MASK,
+	}, {
+		.reg = IOMUXC_GPR3,
+		.shift = 8,
+		.mask = IMX6Q_GPR3_LVDS1_MUX_CTL_MASK,
+	}
+};
+
+/*
+ * For a device declaring compatible = "fsl,imx6q-ldb", "fsl,imx53-ldb",
+ * of_match_device will walk through this list and take the first entry
+ * matching any of its compatible values. Therefore, the more generic
+ * entries (in this case fsl,imx53-ldb) need to be ordered last.
+ */
+static const struct of_device_id imx_ldb_dt_ids[] = {
+	{ .compatible = "fsl,imx6q-ldb", .data = imx6q_lvds_mux, },
+	{ .compatible = "fsl,imx53-ldb", .data = NULL, },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, imx_ldb_dt_ids);
+
+static int imx_ldb_panel_ddc(struct device *dev,
+		struct imx_ldb_channel *channel, struct device_node *child)
+{
+	struct device_node *ddc_node;
+	const u8 *edidp;
+	int ret;
+
+	ddc_node = of_parse_phandle(child, "ddc-i2c-bus", 0);
+	if (ddc_node) {
+		channel->ddc = of_find_i2c_adapter_by_node(ddc_node);
+		of_node_put(ddc_node);
+		if (!channel->ddc) {
+			dev_warn(dev, "failed to get ddc i2c adapter\n");
+			return -EPROBE_DEFER;
+		}
+	}
+
+	if (!channel->ddc) {
+		/* if no DDC available, fallback to hardcoded EDID */
+		dev_dbg(dev, "no ddc available\n");
+
+		edidp = of_get_property(child, "edid",
+					&channel->edid_len);
+		if (edidp) {
+			channel->edid = kmemdup(edidp,
+						channel->edid_len,
+						GFP_KERNEL);
+		} else if (!channel->panel) {
+			/* fallback to display-timings node */
+			ret = of_get_drm_display_mode(child,
+						      &channel->mode,
+						      &channel->bus_flags,
+						      OF_USE_NATIVE_MODE);
+			if (!ret)
+				channel->mode_valid = 1;
+		}
+	}
+	return 0;
+}
+
+static int imx_ldb_bind(struct device *dev, struct device *master, void *data)
+{
+	struct drm_device *drm = data;
+	struct device_node *np = dev->of_node;
+	const struct of_device_id *of_id =
+			of_match_device(imx_ldb_dt_ids, dev);
+	struct device_node *child;
+	struct imx_ldb *imx_ldb;
+	int dual;
+	int ret;
+	int i;
+
+	imx_ldb = devm_kzalloc(dev, sizeof(*imx_ldb), GFP_KERNEL);
+	if (!imx_ldb)
+		return -ENOMEM;
+
+	imx_ldb->regmap = syscon_regmap_lookup_by_phandle(np, "gpr");
+	if (IS_ERR(imx_ldb->regmap)) {
+		dev_err(dev, "failed to get parent regmap\n");
+		return PTR_ERR(imx_ldb->regmap);
+	}
+
+	/* disable LDB by resetting the control register to POR default */
+	regmap_write(imx_ldb->regmap, IOMUXC_GPR2, 0);
+
+	imx_ldb->dev = dev;
+
+	if (of_id)
+		imx_ldb->lvds_mux = of_id->data;
+
+	dual = of_property_read_bool(np, "fsl,dual-channel");
+	if (dual)
+		imx_ldb->ldb_ctrl |= LDB_SPLIT_MODE_EN;
+
+	/*
+	 * There are three different possible clock mux configurations:
+	 * i.MX53:  ipu1_di0_sel, ipu1_di1_sel
+	 * i.MX6q:  ipu1_di0_sel, ipu1_di1_sel, ipu2_di0_sel, ipu2_di1_sel
+	 * i.MX6dl: ipu1_di0_sel, ipu1_di1_sel, lcdif_sel
+	 * Map them all to di0_sel...di3_sel.
+	 */
+	for (i = 0; i < 4; i++) {
+		char clkname[16];
+
+		sprintf(clkname, "di%d_sel", i);
+		imx_ldb->clk_sel[i] = devm_clk_get(imx_ldb->dev, clkname);
+		if (IS_ERR(imx_ldb->clk_sel[i])) {
+			ret = PTR_ERR(imx_ldb->clk_sel[i]);
+			imx_ldb->clk_sel[i] = NULL;
+			break;
+		}
+
+		imx_ldb->clk_parent[i] = clk_get_parent(imx_ldb->clk_sel[i]);
+	}
+	if (i == 0)
+		return ret;
+
+	for_each_child_of_node(np, child) {
+		struct imx_ldb_channel *channel;
+		int bus_format;
+
+		ret = of_property_read_u32(child, "reg", &i);
+		if (ret || i < 0 || i > 1) {
+			ret = -EINVAL;
+			goto free_child;
+		}
+
+		if (!of_device_is_available(child))
+			continue;
+
+		if (dual && i > 0) {
+			dev_warn(dev, "dual-channel mode, ignoring second output\n");
+			continue;
+		}
+
+		channel = &imx_ldb->channel[i];
+		channel->ldb = imx_ldb;
+		channel->chno = i;
+
+		/*
+		 * The output port is port@4 with an external 4-port mux or
+		 * port@2 with the internal 2-port mux.
+		 */
+		ret = drm_of_find_panel_or_bridge(child,
+						  imx_ldb->lvds_mux ? 4 : 2, 0,
+						  &channel->panel, &channel->bridge);
+		if (ret && ret != -ENODEV)
+			goto free_child;
+
+		/* panel ddc only if there is no bridge */
+		if (!channel->bridge) {
+			ret = imx_ldb_panel_ddc(dev, channel, child);
+			if (ret)
+				goto free_child;
+		}
+
+		bus_format = of_get_bus_format(dev, child);
+		if (bus_format == -EINVAL) {
+			/*
+			 * If no bus format was specified in the device tree,
+			 * we can still get it from the connected panel later.
+			 */
+			if (channel->panel && channel->panel->funcs &&
+			    channel->panel->funcs->get_modes)
+				bus_format = 0;
+		}
+		if (bus_format < 0) {
+			dev_err(dev, "could not determine data mapping: %d\n",
+				bus_format);
+			ret = bus_format;
+			goto free_child;
+		}
+		channel->bus_format = bus_format;
+		channel->child = child;
+
+		ret = imx_ldb_register(drm, channel);
+		if (ret) {
+			channel->child = NULL;
+			goto free_child;
+		}
+	}
+
+	dev_set_drvdata(dev, imx_ldb);
+
+	return 0;
+
+free_child:
+	of_node_put(child);
+	return ret;
+}
+
+static void imx_ldb_unbind(struct device *dev, struct device *master,
+	void *data)
+{
+	struct imx_ldb *imx_ldb = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		struct imx_ldb_channel *channel = &imx_ldb->channel[i];
+
+		if (channel->panel)
+			drm_panel_detach(channel->panel);
+
+		kfree(channel->edid);
+		i2c_put_adapter(channel->ddc);
+	}
+}
+
+static const struct component_ops imx_ldb_ops = {
+	.bind	= imx_ldb_bind,
+	.unbind	= imx_ldb_unbind,
+};
+
+static int imx_ldb_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &imx_ldb_ops);
+}
+
+static int imx_ldb_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &imx_ldb_ops);
+	return 0;
+}
+
+static struct platform_driver imx_ldb_driver = {
+	.probe		= imx_ldb_probe,
+	.remove		= imx_ldb_remove,
+	.driver		= {
+		.of_match_table = imx_ldb_dt_ids,
+		.name	= DRIVER_NAME,
+	},
+};
+
+module_platform_driver(imx_ldb_driver);
+
+MODULE_DESCRIPTION("i.MX LVDS driver");
+MODULE_AUTHOR("Sascha Hauer, Pengutronix");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);