[PATCH 5.15 241/277] drm/panel: ili9341: fix optional regulator handling

[Greg Kroah-Hartman]

From: Daniel Mack <daniel@xxxxxxxxxx>

commit d14eb80e27795b7b20060f7b151cdfe39722a813 upstream.

If the optional regulator lookup fails, reset the pointer to NULL.
Other functions such as mipi_dbi_poweron_reset_conditional() only do
a NULL pointer check and will otherwise dereference the error pointer.

Fixes: 5a04227326b04c15 ("drm/panel: Add ilitek ili9341 panel driver")
Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220317225537.826302-1-daniel@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/panel/panel-ilitek-ili9341.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
@@ -612,8 +612,10 @@ static int ili9341_dbi_probe(struct spi_
 	int ret;
 
 	vcc = devm_regulator_get_optional(dev, "vcc");
-	if (IS_ERR(vcc))
+	if (IS_ERR(vcc)) {
 		dev_err(dev, "get optional vcc failed\n");
+		vcc = NULL;
+	}
 
 	dbidev = devm_drm_dev_alloc(dev, &ili9341_dbi_driver,
 				    struct mipi_dbi_dev, drm);