drm/atomic: Add a function to reset connector TV properties

During the connector reset, if that connector has a TV property, it needs
to be reset to the value provided on the command line.

Provide a helper to do that.
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/84a7b657f09303a2850e1cc79e68f623547f3fdd.1560783090.git-series.maxime.ripard@bootlin.com

drivers/gpu/drm/drm_atomic_state_helper.c

@@ -379,6 +379,24 @@ void drm_atomic_helper_connector_reset(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_atomic_helper_connector_reset);
 
+/**
+ * drm_atomic_helper_connector_tv_reset - Resets TV connector properties
+ * @connector: DRM connector
+ *
+ * Resets the TV-related properties attached to a connector.
+ */
+void drm_atomic_helper_connector_tv_reset(struct drm_connector *connector)
+{
+	struct drm_cmdline_mode *cmdline = &connector->cmdline_mode;
+	struct drm_connector_state *state = connector->state;
+
+	state->tv.margins.left = cmdline->tv_margins.left;
+	state->tv.margins.right = cmdline->tv_margins.right;
+	state->tv.margins.top = cmdline->tv_margins.top;
+	state->tv.margins.bottom = cmdline->tv_margins.bottom;
+}
+EXPORT_SYMBOL(drm_atomic_helper_connector_tv_reset);
+
 /**
  * __drm_atomic_helper_connector_duplicate_state - copy atomic connector state
  * @connector: connector object

include/drm/drm_atomic_state_helper.h

@@ -62,6 +62,7 @@ void drm_atomic_helper_plane_destroy_state(struct drm_plane *plane,
 void __drm_atomic_helper_connector_reset(struct drm_connector *connector,
 					 struct drm_connector_state *conn_state);
 void drm_atomic_helper_connector_reset(struct drm_connector *connector);
+void drm_atomic_helper_connector_tv_reset(struct drm_connector *connector);
 void
 __drm_atomic_helper_connector_duplicate_state(struct drm_connector *connector,
 					   struct drm_connector_state *state);