drm/tegra: output: hdmi: Support bridge/connector

Some Tegra device-trees may specify a video output graph, which involves
MHL bridge/simple bridge and/or connector framework. This patch adds
support for the bridge/connector attached to the HDMI output, allowing
us to model the hardware properly.

Inspired by: 29efdc29 ("drm/tegra: output: rgb: Support LVDS encoder bridge")

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS TF T30
Tested-by: Maxim Schwalm <maxim.schwalm@gmail.com> # ASUS P1801-T T30
Tested-by: Robert Eckelmann <longnoserob@gmail.com> # ASUS TF101 T20
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # ASUS TF201 T30
Signed-off-by: Maxim Schwalm <maxim.schwalm@gmail.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230618085046.10081-2-clamor95@gmail.com

drivers/gpu/drm/tegra/hdmi.c

@@ -20,6 +20,7 @@
 #include <soc/tegra/common.h>
 #include <sound/hdmi-codec.h>
 
+#include <drm/drm_bridge_connector.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_debugfs.h>
@@ -1545,26 +1546,47 @@ static int tegra_hdmi_init(struct host1x_client *client)
 {
 	struct tegra_hdmi *hdmi = host1x_client_to_hdmi(client);
 	struct drm_device *drm = dev_get_drvdata(client->host);
+	struct drm_connector *connector;
 	int err;
 
 	hdmi->output.dev = client->dev;
 
-	drm_connector_init_with_ddc(drm, &hdmi->output.connector,
-				    &tegra_hdmi_connector_funcs,
-				    DRM_MODE_CONNECTOR_HDMIA,
-				    hdmi->output.ddc);
-	drm_connector_helper_add(&hdmi->output.connector,
-				 &tegra_hdmi_connector_helper_funcs);
-	hdmi->output.connector.dpms = DRM_MODE_DPMS_OFF;
-
 	drm_simple_encoder_init(drm, &hdmi->output.encoder,
 				DRM_MODE_ENCODER_TMDS);
 	drm_encoder_helper_add(&hdmi->output.encoder,
 			       &tegra_hdmi_encoder_helper_funcs);
 
-	drm_connector_attach_encoder(&hdmi->output.connector,
-					  &hdmi->output.encoder);
-	drm_connector_register(&hdmi->output.connector);
+	if (hdmi->output.bridge) {
+		err = drm_bridge_attach(&hdmi->output.encoder, hdmi->output.bridge,
+					NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+		if (err) {
+			dev_err(client->dev, "failed to attach bridge: %d\n",
+				err);
+			return err;
+		}
+
+		connector = drm_bridge_connector_init(drm, &hdmi->output.encoder);
+		if (IS_ERR(connector)) {
+			dev_err(client->dev,
+				"failed to initialize bridge connector: %pe\n",
+				connector);
+			return PTR_ERR(connector);
+		}
+
+		drm_connector_attach_encoder(connector, &hdmi->output.encoder);
+	} else {
+		drm_connector_init_with_ddc(drm, &hdmi->output.connector,
+					    &tegra_hdmi_connector_funcs,
+					    DRM_MODE_CONNECTOR_HDMIA,
+					    hdmi->output.ddc);
+		drm_connector_helper_add(&hdmi->output.connector,
+					 &tegra_hdmi_connector_helper_funcs);
+		hdmi->output.connector.dpms = DRM_MODE_DPMS_OFF;
+
+		drm_connector_attach_encoder(&hdmi->output.connector,
+					     &hdmi->output.encoder);
+		drm_connector_register(&hdmi->output.connector);
+	}
 
 	err = tegra_output_init(drm, &hdmi->output);
 	if (err < 0) {