diff --git a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
index 813b5db4e98b..7d1327d67a4c 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi-rockchip.c
@@ -68,6 +68,7 @@
 /**
  * struct rockchip_hdmi_chip_data - splite the grf setting of kind of chips
  * @lcdsel_grf_reg: grf register offset of lcdc select
+ * @ddc_en_reg: grf register offset of hdmi ddc enable
  * @lcdsel_big: reg value of selecting vop big for HDMI
  * @lcdsel_lit: reg value of selecting vop little for HDMI
  */