rtc: allow rtc_read_alarm without read_alarm callback

[ Upstream commit a783c962619271a8b905efad1d89adfec11ae0c8 ]

.read_alarm is not necessary to read the current alarm because it is
recorded in the aie_timer and so rtc_read_alarm() will never call
rtc_read_alarm_internal() which is the only function calling the callback.

Reported-by: Zhipeng Wang <zhipeng.wang_1@nxp.com>
Reported-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Fixes: 7ae41220ef58 ("rtc: introduce features bitfield")
Tested-by: Philippe Schenker <philippe.schenker@toradex.com>
Link: https://lore.kernel.org/r/20230214222754.582582-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 9edd662..3d0fbc6 100644 (file)
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -392,7 +392,7 @@ int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
                return err;
        if (!rtc->ops) {
                err = -ENODEV;
-       } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
+       } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) {
                err = -EINVAL;
        } else {
                memset(alarm, 0, sizeof(struct rtc_wkalrm));