[PATCH v2 1/3] drm/display: bridge-connector: add DisplayPort bridges

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

DRM HDMI Codec framework is useful not only for the HDMI bridges, but
also for the DisplayPort bridges. Add new DRM_BRIDGE_OP_DisplayPort
define in order to distinguish DP bridges. Create HDMI codec device
automatically for DP bridges which have declared audio support.

Note, unlike HDMI devices, which already have a framework to handle HPD
notifications in a standard way, DP drivers don't (yet?) have such a
framework. As such it is necessary to manually call
drm_connector_hdmi_audio_plugged_notify(). This requirement hopefully
can be lifted later on, if/when DRM framework gets better DisplayPort
ports support in the core layer.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 66 ++++++++++++++++++++------
 include/drm/drm_bridge.h                       | 14 +++++-
 2 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 30c736fc0067e31a97db242e5b16ea8a5b4cf359..5e031395b801f9a1371dcb4ac09f3da23e4615dd 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -98,6 +98,13 @@ struct drm_bridge_connector {
 	 * HDMI connector infrastructure, if any (see &DRM_BRIDGE_OP_HDMI).
 	 */
 	struct drm_bridge *bridge_hdmi;
+	/**
+	 * @bridge_dp:
+	 *
+	 * The bridge in the chain that implements necessary support for the
+	 * DisplayPort connector infrastructure, if any (see &DRM_BRIDGE_OP_DisplayPort).
+	 */
+	struct drm_bridge *bridge_dp;
 };
 
 #define to_drm_bridge_connector(x) \
@@ -496,6 +503,25 @@ static const struct drm_connector_hdmi_audio_funcs drm_bridge_connector_hdmi_aud
 	.mute_stream = drm_bridge_connector_audio_mute_stream,
 };
 
+static int drm_bridge_connector_hdmi_audio_init(struct drm_connector *connector,
+						struct drm_bridge *bridge)
+{
+	if (!bridge->hdmi_audio_max_i2s_playback_channels &&
+	    !bridge->hdmi_audio_spdif_playback)
+		return 0;
+
+	if (!bridge->funcs->hdmi_audio_prepare ||
+	    !bridge->funcs->hdmi_audio_shutdown)
+		return -EINVAL;
+
+	return 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);
+}
+
 /* -----------------------------------------------------------------------------
  * Bridge Connector Initialisation
  */
@@ -564,6 +590,8 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 		if (bridge->ops & DRM_BRIDGE_OP_HDMI) {
 			if (bridge_connector->bridge_hdmi)
 				return ERR_PTR(-EBUSY);
+			if (bridge_connector->bridge_dp)
+				return ERR_PTR(-EINVAL);
 			if (!bridge->funcs->hdmi_write_infoframe ||
 			    !bridge->funcs->hdmi_clear_infoframe)
 				return ERR_PTR(-EINVAL);
@@ -576,6 +604,16 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 				max_bpc = bridge->max_bpc;
 		}
 
+		if (bridge->ops & DRM_BRIDGE_OP_DisplayPort) {
+			if (bridge_connector->bridge_dp)
+				return ERR_PTR(-EBUSY);
+			if (bridge_connector->bridge_hdmi)
+				return ERR_PTR(-EINVAL);
+
+			bridge_connector->bridge_dp = bridge;
+
+		}
+
 		if (!drm_bridge_get_next_bridge(bridge))
 			connector_type = bridge->type;
 
@@ -612,21 +650,21 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 		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_bridge_connector_hdmi_audio_init(connector, bridge);
+		if (ret)
+			return ERR_PTR(ret);
+	} else if (bridge_connector->bridge_dp) {
+		bridge = bridge_connector->bridge_dp;
 
-			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);
-		}
+		ret = drmm_connector_init(drm, connector,
+					  &drm_bridge_connector_funcs,
+					  connector_type, ddc);
+		if (ret)
+			return ERR_PTR(ret);
+
+		ret = drm_bridge_connector_hdmi_audio_init(connector, bridge);
+		if (ret)
+			return ERR_PTR(ret);
 	} else {
 		ret = drmm_connector_init(drm, connector,
 					  &drm_bridge_connector_funcs,
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 496dbbd2ad7edff7f091adfbe62de1e33ef0cf07..40f37444426b1b8ded25da9ba9e2963f18ad6267 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -811,9 +811,21 @@ enum drm_bridge_ops {
 	 *
 	 * 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.
+	 * drivers. Having both HDMI and DisplayPort bridges in the same bridge
+	 * chain is also not allowed.
 	 */
 	DRM_BRIDGE_OP_HDMI = BIT(4),
+	/**
+	 * @DRM_BRIDGE_OP_DisplayPort: The bridge provides DisplayPort connector
+	 * operations. Currently this is limited to the optional HDMI codec
+	 * support.
+	 *
+	 * 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. Having both HDMI and DisplayPort bridges in the same bridge
+	 * chain is also not allowed.
+	 */
+	DRM_BRIDGE_OP_DisplayPort = BIT(5),
 };
 
 /**

-- 
2.39.5