drm/tegra: dp: Set channel coding on link configuration

Make use of ANSI 8B/10B channel coding if the DisplayPort sink supports
it.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dp.c

@@ -203,7 +203,7 @@ int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link)
  */
 int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link)
 {
-	u8 values[2];
+	u8 values[2], value;
 	int err;
 
 	values[0] = drm_dp_link_rate_to_bw_code(link->rate);
@@ -216,5 +216,14 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link)
 	if (err < 0)
 		return err;
 
+	if (link->caps.channel_coding)
+		value = DP_SET_ANSI_8B10B;
+	else
+		value = 0;
+
+	err = drm_dp_dpcd_writeb(aux, DP_MAIN_LINK_CHANNEL_CODING_SET, value);
+	if (err < 0)
+		return err;
+
 	return 0;
 }