drm: bridge/dw_hdmi: add mode_valid support

some platform may not support all the display mode,
add mode_valid interface check it
Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/bridge/dw_hdmi.c

@@ -1405,6 +1405,20 @@ static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
 	return 0;
 }
 
+static enum drm_mode_status
+dw_hdmi_connector_mode_valid(struct drm_connector *connector,
+			     struct drm_display_mode *mode)
+{
+	struct dw_hdmi *hdmi = container_of(connector,
+					   struct dw_hdmi, connector);
+	enum drm_mode_status mode_status = MODE_OK;
+
+	if (hdmi->plat_data->mode_valid)
+		mode_status = hdmi->plat_data->mode_valid(connector, mode);
+
+	return mode_status;
+}
+
 static struct drm_encoder *dw_hdmi_connector_best_encoder(struct drm_connector
 							   *connector)
 {
@@ -1429,6 +1443,7 @@ static struct drm_connector_funcs dw_hdmi_connector_funcs = {
 
 static struct drm_connector_helper_funcs dw_hdmi_connector_helper_funcs = {
 	.get_modes = dw_hdmi_connector_get_modes,
+	.mode_valid = dw_hdmi_connector_mode_valid,
 	.best_encoder = dw_hdmi_connector_best_encoder,
 };