EPROTO stands for protocol error and a lot of driver already use it
to designate errors in the sent or received data from a peripheral.

So use it in the qnap-mcu as well for checksum errors.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/mfd/qnap-mcu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/qnap-mcu.c b/drivers/mfd/qnap-mcu.c
index e3210541ec56..b4b630f7d413 100644
--- a/drivers/mfd/qnap-mcu.c
+++ b/drivers/mfd/qnap-mcu.c
@@ -178,7 +178,7 @@ int qnap_mcu_exec(struct qnap_mcu *mcu,
 	crc = qnap_mcu_csum(rx, reply->received - QNAP_MCU_CHECKSUM_SIZE);
 	if (crc != rx[reply->received - QNAP_MCU_CHECKSUM_SIZE]) {
 		dev_err(&mcu->serdev->dev, "Invalid Checksum received\n");
-		return -EIO;
+		return -EPROTO;
 	}
 
 	memcpy(reply_data, rx, reply_data_size);
-- 
2.47.2