rtc: Disable the alarm in the hardware

Currently, the RTC code does not disable the alarm in the hardware.

This means that after a sequence such as the one below (the files are in the
RTC sysfs), the box will boot up after 2 minutes even though we've
asked for the alarm to be turned off.

	# echo $((`cat since_epoch`)+120) > wakealarm
	# echo 0 > wakealarm
	# poweroff

Fix this by disabling the alarm when there are no timers to run.

Cc: stable@kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 34 insertions, 10 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index 3195dbd3ec34..e3cf2f54221f 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -318,6 +318,20 @@ int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 }
 EXPORT_SYMBOL_GPL(rtc_read_alarm);
 
+static int ___rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
+{
+        int err;
+
+        if (!rtc->ops)
+                err = -ENODEV;
+        else if (!rtc->ops->set_alarm)
+                err = -EINVAL;
+        else
+                err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
+
+        return err;
+}
+
 static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 {
         struct rtc_time tm;
@@ -341,14 +355,7 @@ static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
          * over right here, before we set the alarm.
          */
 
-        if (!rtc->ops)
-                err = -ENODEV;
-        else if (!rtc->ops->set_alarm)
-                err = -EINVAL;
-        else
-                err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
-
-        return err;
+        return ___rtc_set_alarm(rtc, alarm);
 }
 
 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
@@ -762,6 +769,20 @@ static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
         return 0;
 }
 
+static void rtc_alarm_disable(struct rtc_device *rtc)
+{
+        struct rtc_wkalrm alarm;
+        struct rtc_time tm;
+
+        __rtc_read_time(rtc, &tm);
+
+        alarm.time = rtc_ktime_to_tm(ktime_add(rtc_tm_to_ktime(tm),
+                                     ktime_set(300, 0)));
+        alarm.enabled = 0;
+
+        ___rtc_set_alarm(rtc, &alarm);
+}
+
 /**
  * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
  * @rtc rtc device
@@ -783,8 +804,10 @@ static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
                 struct rtc_wkalrm alarm;
                 int err;
                 next = timerqueue_getnext(&rtc->timerqueue);
-                if (!next)
+                if (!next) {
+                        rtc_alarm_disable(rtc);
                         return;
+                }
                 alarm.time = rtc_ktime_to_tm(next->expires);
                 alarm.enabled = 1;
                 err = __rtc_set_alarm(rtc, &alarm);
@@ -846,7 +869,8 @@ again:
                 err = __rtc_set_alarm(rtc, &alarm);
                 if (err == -ETIME)
                         goto again;
-        }
+        } else
+                rtc_alarm_disable(rtc);
 
         mutex_unlock(&rtc->ops_lock);
 }