drm/bridge-connector: implement glue code for HDMI connector

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.

Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240607-bridge-hdmi-connector-v5-3-ab384e6021af@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 5cf41f92d1f0..75019d16be64 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -631,6 +631,52 @@ struct drm_bridge_funcs {
 	void (*hpd_disable)(struct drm_bridge *bridge);
 
 	/**
+	 * @hdmi_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 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
+	(*hdmi_tmds_char_rate_valid)(const struct drm_bridge *bridge,
+				     const struct drm_display_mode *mode,
+				     unsigned long long tmds_rate);
+
+	/**
+	 * @hdmi_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 but it must be implemented by bridges that
+	 * set the DRM_BRIDGE_OP_HDMI flag in their &drm_bridge->ops.
+	 */
+	int (*hdmi_clear_infoframe)(struct drm_bridge *bridge,
+				    enum hdmi_infoframe_type type);
+	/**
+	 * @hdmi_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 (*hdmi_write_infoframe)(struct drm_bridge *bridge,
+				    enum hdmi_infoframe_type type,
+				    const u8 *buffer, size_t len);
+
+	/**
 	 * @debugfs_init:
 	 *
 	 * Allows bridges to create bridge-specific debugfs files.
@@ -705,6 +751,16 @@ 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 +829,31 @@ struct drm_bridge {
 	 * @hpd_cb.
 	 */
 	void *hpd_data;
+
+	/**
+	 * @vendor: Vendor of the product to be used for the SPD InfoFrame
+	 * generation. This is required if @DRM_BRIDGE_OP_HDMI is set.
+	 */
+	const char *vendor;
+
+	/**
+	 * @product: Name of the product to be used for the SPD InfoFrame
+	 * generation. This is required if @DRM_BRIDGE_OP_HDMI is set.
+	 */
+	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. Allowed
+	 * values are 8, 10 and 12. This is only relevant if
+	 * @DRM_BRIDGE_OP_HDMI is set.
+	 */
+	unsigned int max_bpc;
 };
 
 static inline struct drm_bridge *