linux-kernel - [PATCH 1/2] rtc-cmos: Clear expired alarm after resume

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Message-Id: <1464795615-7748-1-git-send-email-gabriele.mzt@gmail.com>
Date:	Wed,  1 Jun 2016 17:40:14 +0200
From:	Gabriele Mazzotta <gabriele.mzt@...il.com>
To:	a.zummo@...ertech.it, alexandre.belloni@...e-electrons.com
Cc:	rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org,
	matthew.garrett@...ula.com,
	Gabriele Mazzotta <gabriele.mzt@...il.com>
Subject: [PATCH 1/2] rtc-cmos: Clear expired alarm after resume

If the system wakes up because of a wake alarm, the internal state
of the alarm is not updated. As consequence, the state no longer
reflects the actual state of the hardware and setting a new alarm
is not possible until the expired alarm is cleared.

Signed-off-by: Gabriele Mazzotta <gabriele.mzt@...il.com>
---
 drivers/rtc/rtc-cmos.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index fbe9c72..fd121e3 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -900,11 +900,33 @@ static inline int cmos_poweroff(struct device *dev)
 
 #ifdef	CONFIG_PM_SLEEP
 
+static void cmos_check_alarm(struct device *dev)
+{
+	struct cmos_rtc *cmos = dev_get_drvdata(dev);
+	struct rtc_wkalrm alarm;
+	struct rtc_time now;
+	time64_t t_now;
+	time64_t t_expires;
+
+	cmos_read_time(dev, &now);
+	rtc_read_alarm(cmos->rtc, &alarm);
+	t_now = rtc_tm_to_time64(&now);
+	t_expires = rtc_tm_to_time64(&alarm.time);
+
+	if (t_expires <= t_now && alarm.enabled) {
+		alarm.enabled = 0;
+		cmos->suspend_ctrl &= ~RTC_AIE;
+		rtc_set_alarm(cmos->rtc, &alarm);
+	}
+}
+
 static int cmos_resume(struct device *dev)
 {
 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 	unsigned char tmp;
 
+	cmos_check_alarm(dev);
+
 	if (cmos->enabled_wake) {
 		if (cmos->wake_off)
 			cmos->wake_off(dev);
-- 
2.8.1