drm/bridge: imx: Add LDB driver helper support

This patch adds a helper to support LDB drm bridge drivers for
i.MX SoCs.  Helper functions supported by this helper should
implement common logics for all LDB modules embedded in i.MX SoCs.

Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Colibri iMX8X, LT170410-2WHC, LP156WF1
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220611141421.718743-10-victor.liu@nxp.com

drivers/gpu/drm/bridge/imx/imx-ldb-helper.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2012 Sascha Hauer, Pengutronix
+ * Copyright 2019,2020,2022 NXP
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_print.h>
+
+#include "imx-ldb-helper.h"
+
+bool ldb_channel_is_single_link(struct ldb_channel *ldb_ch)
+{
+	return ldb_ch->link_type == LDB_CH_SINGLE_LINK;
+}
+
+bool ldb_channel_is_split_link(struct ldb_channel *ldb_ch)
+{
+	return ldb_ch->link_type == LDB_CH_DUAL_LINK_EVEN_ODD_PIXELS ||
+	       ldb_ch->link_type == LDB_CH_DUAL_LINK_ODD_EVEN_PIXELS;
+}
+
+int ldb_bridge_atomic_check_helper(struct drm_bridge *bridge,
+				   struct drm_bridge_state *bridge_state,
+				   struct drm_crtc_state *crtc_state,
+				   struct drm_connector_state *conn_state)
+{
+	struct ldb_channel *ldb_ch = bridge->driver_private;
+
+	ldb_ch->in_bus_format = bridge_state->input_bus_cfg.format;
+	ldb_ch->out_bus_format = bridge_state->output_bus_cfg.format;
+
+	return 0;
+}
+
+void ldb_bridge_mode_set_helper(struct drm_bridge *bridge,
+				const struct drm_display_mode *mode,
+				const struct drm_display_mode *adjusted_mode)
+{
+	struct ldb_channel *ldb_ch = bridge->driver_private;
+	struct ldb *ldb = ldb_ch->ldb;
+	bool is_split = ldb_channel_is_split_link(ldb_ch);
+
+	if (is_split)
+		ldb->ldb_ctrl |= LDB_SPLIT_MODE_EN;
+
+	switch (ldb_ch->out_bus_format) {
+	case MEDIA_BUS_FMT_RGB666_1X7X3_SPWG:
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+		if (ldb_ch->chno == 0 || is_split)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24;
+		if (ldb_ch->chno == 1 || is_split)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+		if (ldb_ch->chno == 0 || is_split)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH0_24 |
+					 LDB_BIT_MAP_CH0_JEIDA;
+		if (ldb_ch->chno == 1 || is_split)
+			ldb->ldb_ctrl |= LDB_DATA_WIDTH_CH1_24 |
+					 LDB_BIT_MAP_CH1_JEIDA;
+		break;
+	}
+}
+
+void ldb_bridge_enable_helper(struct drm_bridge *bridge)
+{
+	struct ldb_channel *ldb_ch = bridge->driver_private;
+	struct ldb *ldb = ldb_ch->ldb;
+
+	/*
+	 * Platform specific bridge drivers should set ldb_ctrl properly
+	 * for the enablement, so just write the ctrl_reg here.
+	 */
+	regmap_write(ldb->regmap, ldb->ctrl_reg, ldb->ldb_ctrl);
+}
+
+void ldb_bridge_disable_helper(struct drm_bridge *bridge)
+{
+	struct ldb_channel *ldb_ch = bridge->driver_private;
+	struct ldb *ldb = ldb_ch->ldb;
+	bool is_split = ldb_channel_is_split_link(ldb_ch);
+
+	if (ldb_ch->chno == 0 || is_split)
+		ldb->ldb_ctrl &= ~LDB_CH0_MODE_EN_MASK;
+	if (ldb_ch->chno == 1 || is_split)
+		ldb->ldb_ctrl &= ~LDB_CH1_MODE_EN_MASK;
+
+	regmap_write(ldb->regmap, ldb->ctrl_reg, ldb->ldb_ctrl);
+}
+
+int ldb_bridge_attach_helper(struct drm_bridge *bridge,
+			     enum drm_bridge_attach_flags flags)
+{
+	struct ldb_channel *ldb_ch = bridge->driver_private;
+	struct ldb *ldb = ldb_ch->ldb;
+
+	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
+		DRM_DEV_ERROR(ldb->dev,
+			      "do not support creating a drm_connector\n");
+		return -EINVAL;
+	}
+
+	if (!bridge->encoder) {
+		DRM_DEV_ERROR(ldb->dev, "missing encoder\n");
+		return -ENODEV;
+	}
+
+	return drm_bridge_attach(bridge->encoder,
+				ldb_ch->next_bridge, bridge,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+}
+
+int ldb_init_helper(struct ldb *ldb)
+{
+	struct device *dev = ldb->dev;
+	struct device_node *np = dev->of_node;
+	struct device_node *child;
+	int ret;
+	u32 i;
+
+	ldb->regmap = syscon_node_to_regmap(np->parent);
+	if (IS_ERR(ldb->regmap)) {
+		ret = PTR_ERR(ldb->regmap);
+		if (ret != -EPROBE_DEFER)
+			DRM_DEV_ERROR(dev, "failed to get regmap: %d\n", ret);
+		return ret;
+	}
+
+	for_each_available_child_of_node(np, child) {
+		struct ldb_channel *ldb_ch;
+
+		ret = of_property_read_u32(child, "reg", &i);
+		if (ret || i > MAX_LDB_CHAN_NUM - 1) {
+			ret = -EINVAL;
+			DRM_DEV_ERROR(dev,
+				      "invalid channel node address: %u\n", i);
+			of_node_put(child);
+			return ret;
+		}
+
+		ldb_ch = ldb->channel[i];
+		ldb_ch->ldb = ldb;
+		ldb_ch->chno = i;
+		ldb_ch->is_available = true;
+		ldb_ch->np = child;
+
+		ldb->available_ch_cnt++;
+	}
+
+	return 0;
+}
+
+int ldb_find_next_bridge_helper(struct ldb *ldb)
+{
+	struct device *dev = ldb->dev;
+	struct ldb_channel *ldb_ch;
+	int ret, i;
+
+	for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
+		ldb_ch = ldb->channel[i];
+
+		if (!ldb_ch->is_available)
+			continue;
+
+		ldb_ch->next_bridge = devm_drm_of_get_bridge(dev, ldb_ch->np,
+							     1, 0);
+		if (IS_ERR(ldb_ch->next_bridge)) {
+			ret = PTR_ERR(ldb_ch->next_bridge);
+			if (ret != -EPROBE_DEFER)
+				DRM_DEV_ERROR(dev,
+					      "failed to get next bridge: %d\n",
+					      ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+void ldb_add_bridge_helper(struct ldb *ldb,
+			   const struct drm_bridge_funcs *bridge_funcs)
+{
+	struct ldb_channel *ldb_ch;
+	int i;
+
+	for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
+		ldb_ch = ldb->channel[i];
+
+		if (!ldb_ch->is_available)
+			continue;
+
+		ldb_ch->bridge.driver_private = ldb_ch;
+		ldb_ch->bridge.funcs = bridge_funcs;
+		ldb_ch->bridge.of_node = ldb_ch->np;
+
+		drm_bridge_add(&ldb_ch->bridge);
+	}
+}
+
+void ldb_remove_bridge_helper(struct ldb *ldb)
+{
+	struct ldb_channel *ldb_ch;
+	int i;
+
+	for (i = 0; i < MAX_LDB_CHAN_NUM; i++) {
+		ldb_ch = ldb->channel[i];
+
+		if (!ldb_ch->is_available)
+			continue;
+
+		drm_bridge_remove(&ldb_ch->bridge);
+	}
+}

drivers/gpu/drm/bridge/imx/imx-ldb-helper.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+
+/*
+ * Copyright 2019,2020,2022 NXP
+ */
+
+#ifndef __IMX_LDB_HELPER__
+#define __IMX_LDB_HELPER__
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_device.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_modeset_helper_vtables.h>
+
+#define LDB_CH0_MODE_EN_TO_DI0		BIT(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		BIT(2)
+#define LDB_CH1_MODE_EN_TO_DI1		(3 << 2)
+#define LDB_CH1_MODE_EN_MASK		(3 << 2)
+#define LDB_SPLIT_MODE_EN		BIT(4)
+#define LDB_DATA_WIDTH_CH0_24		BIT(5)
+#define LDB_BIT_MAP_CH0_JEIDA		BIT(6)
+#define LDB_DATA_WIDTH_CH1_24		BIT(7)
+#define LDB_BIT_MAP_CH1_JEIDA		BIT(8)
+#define LDB_DI0_VS_POL_ACT_LOW		BIT(9)
+#define LDB_DI1_VS_POL_ACT_LOW		BIT(10)
+
+#define MAX_LDB_CHAN_NUM		2
+
+enum ldb_channel_link_type {
+	LDB_CH_SINGLE_LINK,
+	LDB_CH_DUAL_LINK_EVEN_ODD_PIXELS,
+	LDB_CH_DUAL_LINK_ODD_EVEN_PIXELS,
+};
+
+struct ldb;
+
+struct ldb_channel {
+	struct ldb *ldb;
+	struct drm_bridge bridge;
+	struct drm_bridge *next_bridge;
+	struct device_node *np;
+	u32 chno;
+	bool is_available;
+	u32 in_bus_format;
+	u32 out_bus_format;
+	enum ldb_channel_link_type link_type;
+};
+
+struct ldb {
+	struct regmap *regmap;
+	struct device *dev;
+	struct ldb_channel *channel[MAX_LDB_CHAN_NUM];
+	unsigned int ctrl_reg;
+	u32 ldb_ctrl;
+	unsigned int available_ch_cnt;
+};
+
+#define bridge_to_ldb_ch(b)	container_of(b, struct ldb_channel, bridge)
+
+bool ldb_channel_is_single_link(struct ldb_channel *ldb_ch);
+bool ldb_channel_is_split_link(struct ldb_channel *ldb_ch);
+
+int ldb_bridge_atomic_check_helper(struct drm_bridge *bridge,
+				   struct drm_bridge_state *bridge_state,
+				   struct drm_crtc_state *crtc_state,
+				   struct drm_connector_state *conn_state);
+
+void ldb_bridge_mode_set_helper(struct drm_bridge *bridge,
+				const struct drm_display_mode *mode,
+				const struct drm_display_mode *adjusted_mode);
+
+void ldb_bridge_enable_helper(struct drm_bridge *bridge);
+
+void ldb_bridge_disable_helper(struct drm_bridge *bridge);
+
+int ldb_bridge_attach_helper(struct drm_bridge *bridge,
+			     enum drm_bridge_attach_flags flags);
+
+int ldb_init_helper(struct ldb *ldb);
+
+int ldb_find_next_bridge_helper(struct ldb *ldb);
+
+void ldb_add_bridge_helper(struct ldb *ldb,
+			   const struct drm_bridge_funcs *bridge_funcs);
+
+void ldb_remove_bridge_helper(struct ldb *ldb);
+
+#endif /* __IMX_LDB_HELPER__ */