[PATCH] drm/bridge: ite-it66121: Add drm_connector support

[Miguel Gazquez <miguel.gazquez@bootlin.com>]

From: Aradhya Bhatia <a-bhatia1@ti.com>

Add support for DRM connector and make the driver support the older
format of attaching connectors onto the encoder->bridge->connector
chain.
This makes the driver compatible with display controller that only
supports the old format.

[Miguel Gazquez: Rebased + made driver work with or without
DRM_BRIDGE_ATTACH_NO_CONNECTOR]

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Miguel Gazquez <miguel.gazquez@bootlin.com>
---
 drivers/gpu/drm/bridge/ite-it66121.c | 121 ++++++++++++++++++++++++++++++++---
 1 file changed, 112 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index aa7b1dcc5d70e5d15199e071e4cd96e08b4bda1b..cd1d926fed8560fb5f8e1ab585b9bf72a70ee8e3 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -284,6 +284,10 @@
 
 #define IT66121_AFE_CLK_HIGH			80000 /* Khz */
 
+#define IT66121_MAX_CLOCK_12BIT 74250  /* Khz */
+#define IT66121_MAX_CLOCK_24BIT 148500 /* Khz */
+#define IT66121_MIN_CLOCK 25000        /* Khz */
+
 enum chip_id {
 	ID_IT6610,
 	ID_IT66121,
@@ -299,6 +303,7 @@ struct it66121_ctx {
 	struct drm_bridge bridge;
 	struct drm_bridge *next_bridge;
 	struct drm_connector *connector;
+	struct drm_connector conn;
 	struct device *dev;
 	struct gpio_desc *gpio_reset;
 	struct i2c_client *client;
@@ -315,6 +320,11 @@ struct it66121_ctx {
 	const struct it66121_chip_info *info;
 };
 
+static inline struct it66121_ctx *connector_to_it66121(struct drm_connector *con)
+{
+	return container_of(con, struct it66121_ctx, conn);
+}
+
 static const struct regmap_range_cfg it66121_regmap_banks[] = {
 	{
 		.name = "it66121",
@@ -585,19 +595,112 @@ static bool it66121_is_hpd_detect(struct it66121_ctx *ctx)
 	return val & IT66121_SYS_STATUS_HPDETECT;
 }
 
+static enum drm_mode_status it66121_mode_valid(struct drm_connector *connector,
+					       const struct drm_display_mode *mode)
+{
+	struct it66121_ctx *ctx = connector_to_it66121(connector);
+	unsigned long max_clock;
+
+	max_clock = (ctx->bus_width == 12) ? IT66121_MAX_CLOCK_12BIT : IT66121_MAX_CLOCK_24BIT;
+
+	if (mode->clock > max_clock)
+		return MODE_CLOCK_HIGH;
+
+	if (mode->clock < 25000)
+		return MODE_CLOCK_LOW;
+
+	return MODE_OK;
+}
+
+static const struct drm_edid *it66121_get_edid(struct it66121_ctx *ctx,
+					       struct drm_connector *connector)
+{
+	const struct drm_edid *drm_edid;
+
+	mutex_lock(&ctx->lock);
+	drm_edid = drm_edid_read_custom(connector, it66121_get_edid_block, ctx);
+	mutex_unlock(&ctx->lock);
+
+	return drm_edid;
+}
+
+static int it66121_get_modes(struct drm_connector *connector)
+{
+	struct it66121_ctx *ctx = connector_to_it66121(connector);
+	const struct drm_edid *drm_edid;
+	int num = 0;
+
+	drm_edid = it66121_get_edid(ctx, connector);
+	drm_edid_connector_update(connector, drm_edid);
+	if (drm_edid) {
+		num = drm_edid_connector_add_modes(connector);
+		drm_edid_free(drm_edid);
+	}
+
+	return num;
+}
+
+static const struct drm_connector_helper_funcs it66121_connector_helper_funcs = {
+	.get_modes = it66121_get_modes,
+	.mode_valid = it66121_mode_valid,
+};
+
+static enum drm_connector_status
+it66121_connector_detect(struct drm_connector *connector, bool force)
+{
+	struct it66121_ctx *ctx = connector_to_it66121(connector);
+
+	return it66121_is_hpd_detect(ctx) ? connector_status_connected
+					  : connector_status_disconnected;
+}
+
+static const struct drm_connector_funcs it66121_connector_funcs = {
+	.detect = it66121_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = drm_connector_cleanup,
+	.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 int it66121_bridge_attach(struct drm_bridge *bridge,
 				 struct drm_encoder *encoder,
 				 enum drm_bridge_attach_flags flags)
 {
 	struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
+	u32 bus_format;
 	int ret;
 
-	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
-		return -EINVAL;
+	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
+		ret = drm_bridge_attach(encoder, ctx->next_bridge, bridge, flags);
+		if (ret)
+			return ret;
+	} else {
+		if (ctx->bus_width == 12) {
+			bus_format = MEDIA_BUS_FMT_RGB888_2X12_LE;
+		} else if (ctx->bus_width == 24) {
+			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+		} else {
+			dev_err(ctx->dev, "Invalid bus width\n");
+			return -EINVAL;
+		}
 
-	ret = drm_bridge_attach(encoder, ctx->next_bridge, bridge, flags);
-	if (ret)
-		return ret;
+		drm_connector_helper_add(&ctx->conn,
+					 &it66121_connector_helper_funcs);
+
+		ret = drm_connector_init(bridge->dev, &ctx->conn,
+					 &it66121_connector_funcs,
+					 DRM_MODE_CONNECTOR_HDMIA);
+		if (ret)
+			return ret;
+
+		ret = drm_display_info_set_bus_formats(&ctx->conn.display_info,
+						       &bus_format, 1);
+		if (ret)
+			return ret;
+
+		drm_connector_attach_encoder(&ctx->conn, bridge->encoder);
+	}
 
 	if (ctx->info->id == ID_IT66121) {
 		ret = regmap_write_bits(ctx->regmap, IT66121_CLK_BANK_REG,
@@ -830,14 +933,14 @@ static enum drm_mode_status it66121_bridge_mode_valid(struct drm_bridge *bridge,
 						      const struct drm_display_mode *mode)
 {
 	struct it66121_ctx *ctx = container_of(bridge, struct it66121_ctx, bridge);
-	unsigned long max_clock;
+	unsigned long max_clock_khz;
 
-	max_clock = (ctx->bus_width == 12) ? 74250 : 148500;
+	max_clock_khz = (ctx->bus_width == 12) ? IT66121_MAX_CLOCK_12BIT : IT66121_MAX_CLOCK_24BIT;
 
-	if (mode->clock > max_clock)
+	if (mode->clock > max_clock_khz)
 		return MODE_CLOCK_HIGH;
 
-	if (mode->clock < 25000)
+	if (mode->clock < IT66121_MIN_CLOCK)
 		return MODE_CLOCK_LOW;
 
 	return MODE_OK;

---
base-commit: 9e05c8dc4e8bb14bdb86eccff1d07169cfd69df8
change-id: 20250905-it66121-fix-1bd3888759b1

Best regards,
-- 
Miguel Gazquez <miguel.gazquez@bootlin.com>