[PATCH v6 2/9] rtc: abx80x: fix error check after i2c_smbus_read in read_alarm()

[Antoni Pokusinski]

i2c_smbus_read_i2c_block_data() returns the number of bytes read on
success and a negative error code on failure. The existing code treated
any non-zero return value as an error.

Fix the error handling by checking only for negative return values.

Fixes: 718a820a303c ("rtc: abx80x: add alarm support")
Signed-off-by: Antoni Pokusinski <apokusinski01@xxxxxxxxx>
---
 drivers/rtc/rtc-abx80x.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 5486d9d0b1e5..e4fd7b5d4b11 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -294,8 +294,10 @@ static int abx80x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 
 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_ASC,
 					    sizeof(buf), buf);
-	if (err)
+	if (err < 0)
 		return err;
+	if (err < ARRAY_SIZE(buf))
+		return -EIO;
 
 	irq_mask = i2c_smbus_read_byte_data(client, ABX8XX_REG_IRQ);
 	if (irq_mask < 0)
@@ -311,7 +313,7 @@ static int abx80x_read_alarm(struct device *dev, struct rtc_wkalrm *t)
 	t->enabled = !!(irq_mask & ABX8XX_IRQ_AIE);
 	t->pending = (buf[6] & ABX8XX_STATUS_AF) && t->enabled;
 
-	return err;
+	return 0;
 }
 
 static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
-- 
2.55.0