[PATCH v4 2/3] drm/bridge: analogix_dp: Add validation for samsung,lane-count property

[Damon Ding]

Add range check for samsung,lane-count to avoid invalid values.
Validation is only applied when the property exists to maintain
backward compatibility.

Suggested-by: Luca Ceresoli <luca.ceresoli at bootlin.com>
Signed-off-by: Damon Ding <damon.ding at rock-chips.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 8cf6b73bceac..699a7f380c56 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1238,6 +1238,7 @@ static int analogix_dp_dt_parse_pdata(struct analogix_dp_device *dp)
 {
 	struct device_node *dp_node = dp->dev->of_node;
 	struct video_info *video_info = &dp->video_info;
+	int ret;
 
 	switch (dp->plat_data->dev_type) {
 	case RK3288_DP:
@@ -1260,8 +1261,16 @@ static int analogix_dp_dt_parse_pdata(struct analogix_dp_device *dp)
 		 */
 		of_property_read_u32(dp_node, "samsung,link-rate",
 				     &video_info->max_link_rate);
-		of_property_read_u32(dp_node, "samsung,lane-count",
-				     &video_info->max_lane_count);
+		ret = of_property_read_u32(dp_node, "samsung,lane-count",
+					   &video_info->max_lane_count);
+		if (!ret) {
+			if (video_info->max_lane_count == 0 ||
+			    video_info->max_lane_count > LANE_COUNT4) {
+				dev_err(dp->dev, "samsung,lane-count = %d is out of range\n",
+					video_info->max_lane_count);
+				return -EINVAL;
+			}
+		}
 		break;
 	}
 
-- 
2.34.1