linux-kernel - [PATCH v2] rtc: interface: Add RTC offset to alarm after fix-up

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Date: Wed, 19 Jun 2024 16:04:52 +0200
From: Csókás, Bence <csokas.bence@...lan.hu>
To: Alexandre Belloni <alexandre.belloni@...tlin.com>,
	<linux-rtc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: Csókás, Bence <csokas.bence@...lan.hu>
Subject: [PATCH v2] rtc: interface: Add RTC offset to alarm after fix-up

`rtc_add_offset()` is called by `__rtc_read_time()`
and `__rtc_read_alarm()` to add the RTC's offset to
the raw read-outs from the device drivers. However,
in the latter case, a fix-up algorithm is run if
the RTC device does not report a full `struct rtc_time`
alarm value. In that case, the offset was forgot to be
added.

Fixes: fd6792bb022e ("rtc: fix alarm read and set offset")

Signed-off-by: Csókás, Bence <csokas.bence@...lan.hu>
---

Notes:
    Changes in v2:
    * don't try to add offset to an invalid tm

 drivers/rtc/interface.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 1b63111cdda2..0b23706d9fd3 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -272,14 +272,13 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 		err = rtc_read_alarm_internal(rtc, alarm);
 		if (err)
 			return err;
 
 		/* full-function RTCs won't have such missing fields */
-		if (rtc_valid_tm(&alarm->time) == 0) {
-			rtc_add_offset(rtc, &alarm->time);
-			return 0;
-		}
+		err = rtc_valid_tm(&alarm->time);
+		if (!err)
+			goto done;
 
 		/* get the "after" timestamp, to detect wrapped fields */
 		err = rtc_read_time(rtc, &now);
 		if (err < 0)
 			return err;
@@ -377,10 +376,12 @@ int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 
 done:
 	if (err && alarm->enabled)
 		dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
 			 &alarm->time);
+	else
+		rtc_add_offset(rtc, &alarm->time);
 
 	return err;
 }
 
 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
-- 
2.34.1