[PATCH] media: i2c: imx471: Fix uninitialized error value in imx471_set_ctrl()

[David Carlier <devnexen@gmail.com>]

The exposure control write passes the address of the local ret variable
to cci_write() as its error pointer while ret is still uninitialized.
cci_write() returns early without touching the hardware when the error
value it is handed is already non-zero, so a non-zero garbage value on
the stack silently skips programming the exposure register and makes the
control write return a bogus, possibly positive, status.

This path runs on every stream start and on every exposure update from
userspace. Initialize ret to zero so the exposure register is always
written and a correct status is returned.

Fixes: be1589e567ae ("media: i2c: imx471: Add Sony IMX471 image sensor driver")
Signed-off-by: David Carlier <devnexen@gmail.com>
---
 drivers/media/i2c/imx471.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/i2c/imx471.c b/drivers/media/i2c/imx471.c
index 6d358b11e96d..5aca5f2355d6 100644
--- a/drivers/media/i2c/imx471.c
+++ b/drivers/media/i2c/imx471.c
@@ -306,7 +306,7 @@ static int imx471_set_ctrl(struct v4l2_ctrl *ctrl)
 			v4l2_subdev_get_locked_active_state(&sensor->sd);
 	const struct v4l2_mbus_framefmt *format =
 			v4l2_subdev_state_get_format(state, 0);
-	int ret;
+	int ret = 0;
 
 	if (ctrl->id == V4L2_CID_VBLANK) {
 		s64 exposure_max = format->height + ctrl->val -
-- 
2.53.0