diff --git a/drivers/rtc/rtc-ds1390.c b/drivers/rtc/rtc-ds1390.c
index f46428ca77cc..f7afd6bdeb4a 100644
--- a/drivers/rtc/rtc-ds1390.c
+++ b/drivers/rtc/rtc-ds1390.c
@@ -134,7 +134,7 @@ static int ds1390_read_time(struct device *dev, struct rtc_time *dt)
 	chip->txrx_buf[0] = DS1390_REG_SECONDS;
 
 	/* do the i/o */
-	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 8);
+	status = spi_write_then_read(spi, chip->txrx_buf, 1, chip->txrx_buf, 7);
 	if (status != 0)
 		return status;