alarmtimer: Implement remaining callback

Preparatory change to utilize the common posix timer mechanisms.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.592676753@linutronix.de

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 6082cf1af876ada09329ad8bf16adb4c34b640f0..02ddc40f19fe9ef59c839ed84214c6de6364be85 100644 (file)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -560,6 +560,18 @@ static int alarm_timer_forward(struct k_itimer *timr, ktime_t now)
        return (int) alarm_forward(alarm, timr->it_interval, now);
 }
 
+/**
+ * alarm_timer_remaining - Posix timer callback to retrieve remaining time
+ * @timr:      Pointer to the posixtimer data struct
+ * @now:       Current time to calculate against
+ */
+static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
+{
+       struct alarm *alarm = &timr->it.alarm.alarmtimer;
+
+       return ktime_sub(now, alarm->node.expires);
+}
+
 /**
  * alarm_clock_getres - posix getres interface
  * @which_clock: clockid
@@ -881,15 +893,16 @@ out:
 }
 
 const struct k_clock alarm_clock = {
-       .clock_getres   = alarm_clock_getres,
-       .clock_get      = alarm_clock_get,
-       .timer_create   = alarm_timer_create,
-       .timer_set      = alarm_timer_set,
-       .timer_del      = alarm_timer_del,
-       .timer_get      = alarm_timer_get,
-       .timer_rearm    = alarm_timer_rearm,
-       .timer_forward  = alarm_timer_forward,
-       .nsleep         = alarm_timer_nsleep,
+       .clock_getres           = alarm_clock_getres,
+       .clock_get              = alarm_clock_get,
+       .timer_create           = alarm_timer_create,
+       .timer_set              = alarm_timer_set,
+       .timer_del              = alarm_timer_del,
+       .timer_get              = alarm_timer_get,
+       .timer_rearm            = alarm_timer_rearm,
+       .timer_forward          = alarm_timer_forward,
+       .timer_remaining        = alarm_timer_remaining,
+       .nsleep                 = alarm_timer_nsleep,
 };
 #endif /* CONFIG_POSIX_TIMERS */