drm: Config orientation property if panel provides it

Panel orientation property should be set before drm_dev_register().
Some drm driver calls drm_dev_register() in .bind(). However, most
panels sets orientation property relatively late, mostly in .get_modes()
callback, since this is when they are able to get the connector and
binds the orientation property to it, though the value should be known
when the panel is probed.

In drm_bridge_connector_init(), if a bridge is a panel bridge, use it to
set the connector's panel orientation property.

Suggested-by: Douglas Anderson <[e-mail]>
Signed-off-by: Hsin-Yi Wang <[e-mail]>
Reviewed-by: Douglas Anderson <[e-mail]>
Reviewed-by: Stephen Boyd <[e-mail]>
[dianders: fixed space vs. tab indentation]
Signed-off-by: Douglas Anderson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/bridge/panel.c

···
 };
 
 /**
+ * drm_bridge_is_panel - Checks if a drm_bridge is a panel_bridge.
+ *
+ * @bridge: The drm_bridge to be checked.
+ *
+ * Returns true if the bridge is a panel bridge, or false otherwise.
+ */
+bool drm_bridge_is_panel(const struct drm_bridge *bridge)
+{
+	return bridge->funcs == &panel_bridge_bridge_funcs;
+}
+EXPORT_SYMBOL(drm_bridge_is_panel);
+
+/**
  * drm_panel_bridge_add - Creates a &drm_bridge and &drm_connector that
  * just calls the appropriate functions from &drm_panel.
  *
···
 	devm_kfree(panel_bridge->panel->dev, bridge);
 }
 EXPORT_SYMBOL(drm_panel_bridge_remove);
+
+/**
+ * drm_panel_bridge_set_orientation - Set the connector's panel orientation
+ * from the bridge that can be transformed to panel bridge.
+ *
+ * @connector: The connector to be set panel orientation.
+ * @bridge: The drm_bridge to be transformed to panel bridge.
+ *
+ * Returns 0 on success, negative errno on failure.
+ */
+int drm_panel_bridge_set_orientation(struct drm_connector *connector,
+				     struct drm_bridge *bridge)
+{
+	struct panel_bridge *panel_bridge;
+
+	panel_bridge = drm_bridge_to_panel_bridge(bridge);
+
+	return drm_connector_set_orientation_from_panel(connector,
+							panel_bridge->panel);
+}
+EXPORT_SYMBOL(drm_panel_bridge_set_orientation);
 
 static void devm_drm_panel_bridge_release(struct device *dev, void *res)
 {

drivers/gpu/drm/drm_bridge_connector.c

···
 	struct drm_bridge_connector *bridge_connector;
 	struct drm_connector *connector;
 	struct i2c_adapter *ddc = NULL;
-	struct drm_bridge *bridge;
+	struct drm_bridge *bridge, *panel_bridge = NULL;
 	int connector_type;
 
 	bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL);
···
 
 		if (bridge->ddc)
 			ddc = bridge->ddc;
+
+		if (drm_bridge_is_panel(bridge))
+			panel_bridge = bridge;
 	}
 
 	if (connector_type == DRM_MODE_CONNECTOR_Unknown) {
···
 	else if (bridge_connector->bridge_detect)
 		connector->polled = DRM_CONNECTOR_POLL_CONNECT
 				  | DRM_CONNECTOR_POLL_DISCONNECT;
+
+	if (panel_bridge)
+		drm_panel_bridge_set_orientation(connector, panel_bridge);
 
 	return connector;
 }

include/drm/drm_bridge.h

···
 			   enum drm_connector_status status);
 
 #ifdef CONFIG_DRM_PANEL_BRIDGE
+bool drm_bridge_is_panel(const struct drm_bridge *bridge);
 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
 struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
 					      u32 connector_type);
 void drm_panel_bridge_remove(struct drm_bridge *bridge);
+int drm_panel_bridge_set_orientation(struct drm_connector *connector,
+				     struct drm_bridge *bridge);
 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
 					     struct drm_panel *panel);
 struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
 						   struct drm_panel *panel,
 						   u32 connector_type);
 struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge);
+#else
+static inline bool drm_bridge_is_panel(const struct drm_bridge *bridge)
+{
+	return false;
+}
+
+static inline int drm_panel_bridge_set_orientation(struct drm_connector *connector,
+						   struct drm_bridge *bridge)
+{
+	return -EINVAL;
+}
 #endif
 
 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)