drm/bridge: panel: Implement bridge connector operations

Implement the newly added bridge connector operations, allowing the
usage of drm_bridge_panel with drm_bridge_connector.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200226112514.12455-18-laurent.pinchart@ideasonboard.com

drivers/gpu/drm/bridge/panel.c

@@ -60,10 +60,8 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
 	struct drm_connector *connector = &panel_bridge->connector;
 	int ret;
 
-	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
-		DRM_ERROR("Fix bridge driver to make connector optional!");
-		return -EINVAL;
-	}
+	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
+		return 0;
 
 	if (!bridge->encoder) {
 		DRM_ERROR("Missing encoder\n");
@@ -126,6 +124,14 @@ static void panel_bridge_post_disable(struct drm_bridge *bridge)
 	drm_panel_unprepare(panel_bridge->panel);
 }
 
+static int panel_bridge_get_modes(struct drm_bridge *bridge,
+				  struct drm_connector *connector)
+{
+	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+
+	return drm_panel_get_modes(panel_bridge->panel, connector);
+}
+
 static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
 	.attach = panel_bridge_attach,
 	.detach = panel_bridge_detach,
@@ -133,6 +139,7 @@ static const struct drm_bridge_funcs panel_bridge_bridge_funcs = {
 	.enable = panel_bridge_enable,
 	.disable = panel_bridge_disable,
 	.post_disable = panel_bridge_post_disable,
+	.get_modes = panel_bridge_get_modes,
 	.atomic_reset = drm_atomic_helper_bridge_reset,
 	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
@@ -206,6 +213,8 @@ struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
 #ifdef CONFIG_OF
 	panel_bridge->bridge.of_node = panel->dev->of_node;
 #endif
+	panel_bridge->bridge.ops = DRM_BRIDGE_OP_MODES;
+	panel_bridge->bridge.type = connector_type;
 
 	drm_bridge_add(&panel_bridge->bridge);