drm/tilcdc: Add drm bridge support for attaching drm bridge drivers

Adds drm bride support for attaching drm bridge drivers to tilcdc. The
decision whether a video port leads to an external encoder or bridge
is made simply based on remote device's compatible string. The code
has been tested with BeagleBone-Black with and without BeagleBone
DVI-D Cape Rev A3 using ti-tfp410 driver.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Tested-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index 3d2cea0..7f4d3bc 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -209,7 +209,7 @@ static void tilcdc_fini(struct drm_device *dev)
 
 	drm_irq_uninstall(dev);
 	drm_mode_config_cleanup(dev);
-	tilcdc_remove_external_encoders(dev);
+	tilcdc_remove_external_device(dev);
 
 #ifdef CONFIG_CPU_FREQ
 	if (priv->freq_transition.notifier_call)
@@ -381,12 +381,17 @@ static int tilcdc_init(struct drm_driver *ddrv, struct device *dev)
 		if (ret < 0)
 			goto init_failed;
 
-		ret = tilcdc_add_external_encoders(ddev);
+		ret = tilcdc_add_component_encoder(ddev);
 		if (ret < 0)
 			goto init_failed;
+	} else {
+		ret = tilcdc_attach_external_device(ddev);
+		if (ret)
+			goto init_failed;
 	}
 
-	if ((priv->num_encoders == 0) || (priv->num_connectors == 0)) {
+	if (!priv->external_connector &&
+	    ((priv->num_encoders == 0) || (priv->num_connectors == 0))) {
 		dev_err(dev, "no encoders/connectors found\n");
 		ret = -ENXIO;
 		goto init_failed;