[PATCH 5.19 0359/1157] drm/bridge: anx7625: Zero error variable when panel bridge not present

[Greg Kroah-Hartman]

From: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>

[ Upstream commit 3f49f7591e7150c502aa8d04354941ec2394153f ]

While parsing the DT, the anx7625 driver checks for the presence of a
panel bridge on endpoint 1. If it is missing, pdata->panel_bridge stores
the error pointer and the function returns successfully without first
cleaning that variable. This is an issue since other functions later
check for the presence of a panel bridge by testing the trueness of that
variable.

In order to ensure proper behavior, zero out pdata->panel_bridge before
returning when no panel bridge is found.

Fixes: 9e82ea0fb1df ("drm/bridge: anx7625: switch to devm_drm_of_get_bridge")
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220613163705.1531721-1-nfraprado@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 01f46d9189c1..0117fd8c62ae 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1657,8 +1657,10 @@ static int anx7625_parse_dt(struct device *dev,
 
 	pdata->panel_bridge = devm_drm_of_get_bridge(dev, np, 1, 0);
 	if (IS_ERR(pdata->panel_bridge)) {
-		if (PTR_ERR(pdata->panel_bridge) == -ENODEV)
+		if (PTR_ERR(pdata->panel_bridge) == -ENODEV) {
+			pdata->panel_bridge = NULL;
 			return 0;
+		}
 
 		return PTR_ERR(pdata->panel_bridge);
 	}
-- 
2.35.1