diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index b1c71af88579faf4e1d2ff10ba77ef2186c83e4b..deeed73f4ed6924d92a9f66668a1249a6f144f4d 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -374,6 +374,10 @@ static bool is_edid_digital_input_dp(const struct edid *edid)
  * drm_dp_downstream_is_type() - is the downstream facing port of certain type?
  * @dpcd: DisplayPort configuration data
  * @port_cap: port capabilities
+ * @type: port type to be checked. Can be:
+ * 	  %DP_DS_PORT_TYPE_DP, %DP_DS_PORT_TYPE_VGA, %DP_DS_PORT_TYPE_DVI,
+ * 	  %DP_DS_PORT_TYPE_HDMI, %DP_DS_PORT_TYPE_NON_EDID,
+ *	  %DP_DS_PORT_TYPE_DP_DUALMODE or %DP_DS_PORT_TYPE_WIRELESS.
  *
  * Caveat: Only works with DPCD 1.1+ port caps.
  *
@@ -870,6 +874,7 @@ EXPORT_SYMBOL(drm_dp_downstream_444_to_420_conversion);
 
 /**
  * drm_dp_downstream_mode() - return a mode for downstream facing port
+ * @dev: DRM device
  * @dpcd: DisplayPort configuration data
  * @port_cap: port capabilities
  *