[PATCH] media: i2c: alvium: propagate write handshake timeouts

[Pengpeng Hou]

alvium_write_hshake() waits for the BCRM write handshake bit to become
set and then clear again, but it ignores the return value from
read_poll_timeout(). A timeout therefore leaves ret unchanged and the
caller can observe a successful register write even though the handshake
did not complete.

Assign the polling helper return value to ret for both handshake phases
so timeouts and low-level read errors are propagated to the V4L2 control
caller.

Signed-off-by: Pengpeng Hou <pengpeng@xxxxxxxxxxx>
---
 drivers/media/i2c/alvium-csi2.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/media/i2c/alvium-csi2.c b/drivers/media/i2c/alvium-csi2.c
index dd991c2ee700..9ebb2a92199a 100644
--- a/drivers/media/i2c/alvium-csi2.c
+++ b/drivers/media/i2c/alvium-csi2.c
@@ -352,11 +352,11 @@ static int alvium_write_hshake(struct alvium_dev *alvium, u32 reg, u64 val)
 	}
 
 	/* poll handshake bit since bit0 = 1 */
-	read_poll_timeout(alvium_read, hshake_bit,
-			  ((hshake_bit & BCRM_HANDSHAKE_W_DONE_EN_BIT) == 1),
-			  15000, 45000, true,
-			  alvium, REG_BCRM_WRITE_HANDSHAKE_RW,
-			  &hshake_bit, &ret);
+	ret = read_poll_timeout(alvium_read, hshake_bit,
+				((hshake_bit & BCRM_HANDSHAKE_W_DONE_EN_BIT) == 1),
+				15000, 45000, true,
+				alvium, REG_BCRM_WRITE_HANDSHAKE_RW,
+				&hshake_bit, &ret);
 	if (ret) {
 		dev_err(dev, "poll bit[0] = 1, hshake reg fail\n");
 		return ret;
@@ -370,11 +370,11 @@ static int alvium_write_hshake(struct alvium_dev *alvium, u32 reg, u64 val)
 	}
 
 	/* poll handshake bit since bit0 = 0 */
-	read_poll_timeout(alvium_read, hshake_bit,
-			  ((hshake_bit & BCRM_HANDSHAKE_W_DONE_EN_BIT) == 0),
-			  15000, 45000, true,
-			  alvium, REG_BCRM_WRITE_HANDSHAKE_RW,
-			  &hshake_bit, &ret);
+	ret = read_poll_timeout(alvium_read, hshake_bit,
+				((hshake_bit & BCRM_HANDSHAKE_W_DONE_EN_BIT) == 0),
+				15000, 45000, true,
+				alvium, REG_BCRM_WRITE_HANDSHAKE_RW,
+				&hshake_bit, &ret);
 	if (ret) {
 		dev_err(dev, "poll bit[0] = 0, hshake reg fail\n");
 		return ret;
-- 
2.50.1 (Apple Git-155)