drm/bridge: connector: add support for HDMI codec framework

Add necessary glue code to be able to use new HDMI codec framework from
the DRM bridge drivers. The drm_bridge implements a limited set of the
hdmi_codec_ops interface, with the functions accepting both
drm_connector and drm_bridge instead of just a generic void pointer.

This framework is integrated with the DRM HDMI Connector framework, but
can also be used for DisplayPort connectors.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241224-drm-bridge-hdmi-connector-v10-4-dc89577cd438@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/display/Kconfig

@@ -15,6 +15,7 @@ if DRM_DISPLAY_HELPER
 
 config DRM_BRIDGE_CONNECTOR
 	bool
+	select DRM_DISPLAY_HDMI_AUDIO_HELPER
 	select DRM_DISPLAY_HDMI_STATE_HELPER
 	help
 	  DRM connector implementation terminating DRM bridge chains.

drivers/gpu/drm/display/drm_bridge_connector.c

@@ -18,6 +18,7 @@
 #include <drm/drm_managed.h>
 #include <drm/drm_modeset_helper_vtables.h>
 #include <drm/drm_probe_helper.h>
+#include <drm/display/drm_hdmi_audio_helper.h>
 #include <drm/display/drm_hdmi_helper.h>
 #include <drm/display/drm_hdmi_state_helper.h>
 
@@ -387,6 +388,75 @@ static const struct drm_connector_hdmi_funcs drm_bridge_connector_hdmi_funcs = {
 	.write_infoframe = drm_bridge_connector_write_infoframe,
 };
 
+static int drm_bridge_connector_audio_startup(struct drm_connector *connector)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (!bridge)
+		return -EINVAL;
+
+	if (!bridge->funcs->hdmi_audio_startup)
+		return 0;
+
+	return bridge->funcs->hdmi_audio_startup(connector, bridge);
+}
+
+static int drm_bridge_connector_audio_prepare(struct drm_connector *connector,
+					      struct hdmi_codec_daifmt *fmt,
+					      struct hdmi_codec_params *hparms)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (!bridge)
+		return -EINVAL;
+
+	return bridge->funcs->hdmi_audio_prepare(connector, bridge, fmt, hparms);
+}
+
+static void drm_bridge_connector_audio_shutdown(struct drm_connector *connector)
+{
+	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->hdmi_audio_shutdown(connector, bridge);
+}
+
+static int drm_bridge_connector_audio_mute_stream(struct drm_connector *connector,
+						  bool enable, int direction)
+{
+	struct drm_bridge_connector *bridge_connector =
+		to_drm_bridge_connector(connector);
+	struct drm_bridge *bridge;
+
+	bridge = bridge_connector->bridge_hdmi;
+	if (!bridge)
+		return -EINVAL;
+
+	if (bridge->funcs->hdmi_audio_mute_stream)
+		return bridge->funcs->hdmi_audio_mute_stream(connector, bridge,
+							     enable, direction);
+	else
+		return -ENOTSUPP;
+}
+
+static const struct drm_connector_hdmi_audio_funcs drm_bridge_connector_hdmi_audio_funcs = {
+	.startup = drm_bridge_connector_audio_startup,
+	.prepare = drm_bridge_connector_audio_prepare,
+	.shutdown = drm_bridge_connector_audio_shutdown,
+	.mute_stream = drm_bridge_connector_audio_mute_stream,
+};
+
 /* -----------------------------------------------------------------------------
  * Bridge Connector Initialisation
  */
@@ -486,7 +556,9 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	if (connector_type == DRM_MODE_CONNECTOR_Unknown)
 		return ERR_PTR(-EINVAL);
 
-	if (bridge_connector->bridge_hdmi)
+	if (bridge_connector->bridge_hdmi) {
+		bridge = bridge_connector->bridge_hdmi;
+
 		ret = drmm_connector_hdmi_init(drm, connector,
 					       bridge_connector->bridge_hdmi->vendor,
 					       bridge_connector->bridge_hdmi->product,
@@ -495,12 +567,31 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 					       connector_type, ddc,
 					       supported_formats,
 					       max_bpc);
-	else
+		if (ret)
+			return ERR_PTR(ret);
+
+		if (bridge->hdmi_audio_max_i2s_playback_channels ||
+		    bridge->hdmi_audio_spdif_playback) {
+			if (!bridge->funcs->hdmi_audio_prepare ||
+			    !bridge->funcs->hdmi_audio_shutdown)
+				return ERR_PTR(-EINVAL);
+
+			ret = drm_connector_hdmi_audio_init(connector,
+							    bridge->hdmi_audio_dev,
+							    &drm_bridge_connector_hdmi_audio_funcs,
+							    bridge->hdmi_audio_max_i2s_playback_channels,
+							    bridge->hdmi_audio_spdif_playback,
+							    bridge->hdmi_audio_dai_port);
+			if (ret)
+				return ERR_PTR(ret);
+		}
+	} else {
 		ret = drmm_connector_init(drm, connector,
 					  &drm_bridge_connector_funcs,
 					  connector_type, ddc);
-	if (ret)
+		if (ret)
-		return ERR_PTR(ret);
+			return ERR_PTR(ret);
+	}
 
 	drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs);
 

include/drm/drm_bridge.h

@@ -41,6 +41,8 @@ struct drm_display_info;
 struct drm_minor;
 struct drm_panel;
 struct edid;
+struct hdmi_codec_daifmt;
+struct hdmi_codec_params;
 struct i2c_adapter;
 
 /**
@@ -676,6 +678,57 @@ struct drm_bridge_funcs {
 				    enum hdmi_infoframe_type type,
 				    const u8 *buffer, size_t len);
 
+	/**
+	 * @hdmi_audio_startup:
+	 *
+	 * Called when ASoC starts an audio stream setup. The
+	 * @hdmi_audio_startup() is optional.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*hdmi_audio_startup)(struct drm_connector *connector,
+				  struct drm_bridge *bridge);
+
+	/**
+	 * @prepare:
+	 * Configures HDMI-encoder for audio stream. Can be called multiple
+	 * times for each setup. Mandatory if HDMI audio is enabled in the
+	 * bridge's configuration.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*hdmi_audio_prepare)(struct drm_connector *connector,
+				  struct drm_bridge *bridge,
+				  struct hdmi_codec_daifmt *fmt,
+				  struct hdmi_codec_params *hparms);
+
+	/**
+	 * @hdmi_audio_shutdown:
+	 *
+	 * Shut down the audio stream. Mandatory if HDMI audio is enabled in
+	 * the bridge's configuration.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	void (*hdmi_audio_shutdown)(struct drm_connector *connector,
+				    struct drm_bridge *bridge);
+
+	/**
+	 * @hdmi_audio_mute_stream:
+	 *
+	 * Mute/unmute HDMI audio stream. The @hdmi_audio_mute_stream callback
+	 * is optional.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*hdmi_audio_mute_stream)(struct drm_connector *connector,
+				      struct drm_bridge *bridge,
+				      bool enable, int direction);
+
 	/**
 	 * @debugfs_init:
 	 *
@@ -859,6 +912,27 @@ struct drm_bridge {
 	 * @DRM_BRIDGE_OP_HDMI is set.
 	 */
 	unsigned int max_bpc;
+
+	/**
+	 * @hdmi_audio_dev: device to be used as a parent for the HDMI Codec
+	 */
+	struct device *hdmi_audio_dev;
+
+	/**
+	 * @hdmi_audio_max_i2s_playback_channels: maximum number of playback
+	 * I2S channels for the HDMI codec
+	 */
+	int hdmi_audio_max_i2s_playback_channels;
+
+	/**
+	 * @hdmi_audio_spdif_playback: set if HDMI codec has S/PDIF playback port
+	 */
+	unsigned int hdmi_audio_spdif_playback : 1;
+
+	/**
+	 * @hdmi_audio_dai_port: sound DAI port, -1 if it is not enabled
+	 */
+	int hdmi_audio_dai_port;
 };
 
 static inline struct drm_bridge *