[PATCH RFC v2 3/5] drm/bridge-connector: implement glue code for HDMI connector

Dmitry Baryshkov dmitry.baryshkov at linaro.org
Sat Mar 9 10:31:30 UTC 2024


In order to let bridge chains implement HDMI connector infrastructure,
add necessary glue code to the drm_bridge_connector. In case there is a
bridge that sets DRM_BRIDGE_OP_HDMI, drm_bridge_connector will register
itself as a HDMI connector and provide proxy drm_connector_hdmi_funcs
implementation.

Note, to simplify implementation, there can be only one bridge in a
chain that sets DRM_BRIDGE_OP_HDMI. Setting more than one is considered
an error. This limitation can be lifted later, if the need arises.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
---
 drivers/gpu/drm/drm_bridge_connector.c | 118 ++++++++++++++++++++++++++++++++-
 include/drm/drm_bridge.h               |  82 +++++++++++++++++++++++
 2 files changed, 197 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge_connector.c b/drivers/gpu/drm/drm_bridge_connector.c
index 982552c9f92c..514dbb38dfed 100644
--- a/drivers/gpu/drm/drm_bridge_connector.c
+++ b/drivers/gpu/drm/drm_bridge_connector.c
@@ -86,6 +86,13 @@ struct drm_bridge_connector {
 	 * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES).
 	 */
 	struct drm_bridge *bridge_modes;
+	/**
+	 * @bridge_hdmi:
+	 *
+	 * The bridge in the chain that implements necessary support for the
+	 * HDMI connector infrastructure, if any (see &DRM_BRIDGE_OP_HDMI).
+	 */
+	struct drm_bridge *bridge_hdmi;
 };
 
 #define to_drm_bridge_connector(x) \
@@ -293,11 +300,86 @@ static int drm_bridge_connector_get_modes(struct drm_connector *connector)
 	return 0;
 }
 
+static int drm_bridge_connector_atomic_check(struct drm_connector *connector,
+					     struct drm_atomic_state *state)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+	int ret;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (bridge) {
+		ret = drm_atomic_helper_connector_hdmi_check(connector, state);
+
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = {
 	.get_modes = drm_bridge_connector_get_modes,
 	/* No need for .mode_valid(), the bridges are checked by the core. */
 	.enable_hpd = drm_bridge_connector_enable_hpd,
 	.disable_hpd = drm_bridge_connector_disable_hpd,
+	.atomic_check = drm_bridge_connector_atomic_check,
+};
+
+static enum drm_mode_status
+drm_bridge_connector_tmds_char_rate_valid(const struct drm_connector *connector,
+					  const struct drm_display_mode *mode,
+					  unsigned long long tmds_rate)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (bridge)
+		return bridge->funcs->tmds_char_rate_valid ?
+			bridge->funcs->tmds_char_rate_valid(bridge, mode, tmds_rate) :
+			MODE_OK;
+
+	return MODE_ERROR;
+}
+
+static int drm_bridge_connector_clear_infoframe(struct drm_connector *connector,
+						enum hdmi_infoframe_type type)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (bridge)
+		return bridge->funcs->clear_infoframe ?
+			bridge->funcs->clear_infoframe(bridge, type) :
+			0;
+
+	return -EINVAL;
+}
+
+static int drm_bridge_connector_write_infoframe(struct drm_connector *connector,
+						enum hdmi_infoframe_type type,
+						const u8 *buffer, size_t len)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (bridge)
+		return bridge->funcs->write_infoframe(bridge, type, buffer, len);
+
+	return -EINVAL;
+}
+
+static const struct drm_connector_hdmi_funcs drm_bridge_connector_hdmi_funcs = {
+	.tmds_char_rate_valid = drm_bridge_connector_tmds_char_rate_valid,
+	.clear_infoframe = drm_bridge_connector_clear_infoframe,
+	.write_infoframe = drm_bridge_connector_write_infoframe,
 };
 
 /* -----------------------------------------------------------------------------
@@ -325,6 +407,10 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	struct drm_connector *connector;
 	struct i2c_adapter *ddc = NULL;
 	struct drm_bridge *bridge, *panel_bridge = NULL;
+	const char *vendor = "Unknown";
+	const char *product = "Unknown";
+	unsigned int supported_formats = BIT(HDMI_COLORSPACE_RGB);
+	unsigned int max_bpc = 8;
 	int connector_type;
 	int ret;
 
@@ -361,6 +447,23 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 			bridge_connector->bridge_detect = bridge;
 		if (bridge->ops & DRM_BRIDGE_OP_MODES)
 			bridge_connector->bridge_modes = bridge;
+		if (bridge->ops & DRM_BRIDGE_OP_HDMI) {
+			if (bridge_connector->bridge_hdmi)
+				return ERR_PTR(-EBUSY);
+
+			bridge_connector->bridge_hdmi = bridge;
+
+			if (bridge->supported_formats)
+				supported_formats = bridge->supported_formats;
+			if (bridge->max_bpc)
+				max_bpc = bridge->max_bpc;
+		}
+
+		if (bridge->vendor)
+			vendor = bridge->vendor;
+
+		if (bridge->product)
+			product = bridge->product;
 
 		if (!drm_bridge_get_next_bridge(bridge))
 			connector_type = bridge->type;
@@ -383,9 +486,18 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 		return ERR_PTR(-EINVAL);
 	}
 
-	ret = drm_connector_init_with_ddc(drm, connector,
-					  &drm_bridge_connector_funcs,
-					  connector_type, ddc);
+	if (bridge_connector->bridge_hdmi)
+		ret = drm_connector_hdmi_init(drm, connector,
+					      vendor, product,
+					      &drm_bridge_connector_funcs,
+					      &drm_bridge_connector_hdmi_funcs,
+					      connector_type, ddc,
+					      supported_formats,
+					      max_bpc);
+	else
+		ret = drm_connector_init_with_ddc(drm, connector,
+						  &drm_bridge_connector_funcs,
+						  connector_type, ddc);
 	if (ret) {
 		kfree(bridge_connector);
 		return ERR_PTR(ret);
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 3606e1a7f965..f44f32b182b8 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -630,6 +630,54 @@ struct drm_bridge_funcs {
 	 */
 	void (*hpd_disable)(struct drm_bridge *bridge);
 
+	/**
+	 * @tmds_char_rate_valid:
+	 *
+	 * Check whether a particular TMDS character rate is supported by the
+	 * driver.
+	 *
+	 * This callback is optional and should only be implemented by the
+	 * bridges that take part in the HDMI connector implementation. Bridges
+	 * that implement it shall set set the DRM_BRIDGE_OP_HDMI flag in their
+	 * &drm_bridge->ops.
+	 *
+	 * Returns:
+	 *
+	 * Either &drm_mode_status.MODE_OK or one of the failure reasons
+	 * in &enum drm_mode_status.
+	 */
+	enum drm_mode_status
+	(*tmds_char_rate_valid)(const struct drm_bridge *bridge,
+				const struct drm_display_mode *mode,
+				unsigned long long tmds_rate);
+
+	/**
+	 * @clear_infoframe:
+	 *
+	 * This callback clears the infoframes in the hardware during commit.
+	 * It will be called multiple times, once for every disabled infoframe
+	 * type.
+	 *
+	 * This callback is optional and should only be implemented by the
+	 * bridges that take part in the HDMI connector implementation. Bridges
+	 * that implement it shall set set the DRM_BRIDGE_OP_HDMI flag in their
+	 * &drm_bridge->ops.
+	 */
+	int (*clear_infoframe)(struct drm_bridge *bridge,
+			       enum hdmi_infoframe_type type);
+	/**
+	 * @write_infoframe:
+	 *
+	 * Program the infoframe into the hardware. It will be called multiple
+	 * times, once for every updated infoframe type.
+	 *
+	 * This callback is optional but it must be implemented by bridges that
+	 * set the DRM_BRIDGE_OP_HDMI flag in their &drm_bridge->ops.
+	 */
+	int (*write_infoframe)(struct drm_bridge *bridge,
+			       enum hdmi_infoframe_type type,
+			       const u8 *buffer, size_t len);
+
 	/**
 	 * @debugfs_init:
 	 *
@@ -705,6 +753,16 @@ enum drm_bridge_ops {
 	 * this flag shall implement the &drm_bridge_funcs->get_modes callback.
 	 */
 	DRM_BRIDGE_OP_MODES = BIT(3),
+	/**
+	 * @DRM_BRIDGE_OP_HDMI: The bridge provides HDMI connector operations,
+	 * including infoframes support. Bridges that set this flag must
+	 * implement the &drm_bridge_funcs->write_infoframe callback.
+	 *
+	 * Note: currently there can be at most one bridge in a chain that sets
+	 * this bit. This is to simplify corresponding glue code in connector
+	 * drivers.
+	 */
+	DRM_BRIDGE_OP_HDMI = BIT(4),
 };
 
 /**
@@ -773,6 +831,30 @@ struct drm_bridge {
 	 * @hpd_cb.
 	 */
 	void *hpd_data;
+
+	/**
+	 * @vendor: Vendor of the product to be used for the SPD InfoFrame
+	 * generation.
+	 */
+	const char *vendor;
+
+	/**
+	 * @product: Name of the product to be used for the SPD InfoFrame
+	 * generation.
+	 */
+	const char *product;
+
+	/**
+	 * @supported_formats: Bitmask of @hdmi_colorspace listing supported
+	 * output formats. This is only relevant if @DRM_BRIDGE_OP_HDMI is set.
+	 */
+	unsigned int supported_formats;
+
+	/**
+	 * @max_bpc: Maximum bits per char the HDMI bridge supports. This is
+	 * only relevant if @DRM_BRIDGE_OP_HDMI is set.
+	 */
+	unsigned int max_bpc;
 };
 
 static inline struct drm_bridge *

-- 
2.39.2



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