[PATCH] rtc: ds1307: fix RX8130 wakeup alarm WADA bit for day-of-month mode

[Robert Leussler]

The RX8130 wakeup alarm never fired when set via
/sys/class/rtc/rtc0/wakealarm. The root cause is that the WADA bit
(bit 3) in the Extension register (0x1c) was never set before
programming the alarm registers.

Per the RX8130 datasheet:
WADA=0 - Week alarm: register 0x19 is compared against day-of-week
WADA=1 - Day alarm:  register 0x19 is compared against day-of-month

rx8130_set_alarm() always writes a BCD day-of-month value to alarm
register 0x19, so WADA must be 1. With WADA=0 the hardware matched the
day-of-month value (e.g. 15) as a day-of-week index, which is always
out of range (valid weekdays are 0-6), so the alarm interrupt was never
asserted.

Fix by setting the WADA bit in rx8130_set_alarm() before writing the
Extension register back to the device.

This is consistent with rx8130_read_alarm(), which decodes the same
register under the same assumption (24-hour and day-of-month mode).


Signed-off-by: Robert Leussler <robert.leussler@xxxxxxxxxxxxxxxxxxxx>
---
 drivers/rtc/rtc-ds1307.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 1960d1bd851c..3631f0894d55 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -656,7 +656,7 @@ static int rx8130_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	if (ret < 0)
 		return ret;
 
-	ctl[0] &= RX8130_REG_EXTENSION_WADA;
+	ctl[0] |= RX8130_REG_EXTENSION_WADA;
 	ctl[1] &= ~RX8130_REG_FLAG_AF;
 	ctl[2] &= ~RX8130_REG_CONTROL0_AIE;
 
-- 
2.43.0