drm/panel: Add and initialise an orientation field to drm_panel from OF

"rotation" is listed as a standard property of panels in panel-common.yaml,
therefore it would be logical to process that from within the core
code should a panel driver not implement the get_orientation hook.

Call of_drm_get_panel_orientation from
drm_connector_set_orientation_from_panel to get that information.

This removes the need for any boiler-plate in panel drivers for calling
drm_connector_set_orientation_from_panel or
drm_connector_set_panel_orientation.

Signed-off-by: Dave Stevenson <[email protected]>

Author: 6by9

drivers/gpu/drm/drm_connector.c

@@ -3073,10 +3073,15 @@ int drm_connector_set_orientation_from_panel(
 {
 	enum drm_panel_orientation orientation;
 
-	if (panel && panel->funcs && panel->funcs->get_orientation)
+	if (panel && panel->funcs && panel->funcs->get_orientation) {
 		orientation = panel->funcs->get_orientation(panel);
-	else
+	} else {
 		orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
+		if (panel) {
+			of_drm_get_panel_orientation(panel->dev->of_node,
+						     &orientation);
+		}
+	}
 
 	return drm_connector_set_panel_orientation(connector, orientation);
 }