[tip:timers/core] alarmtimer: Implement remaining callback

[tip-bot for Thomas Gleixner]

Commit-ID:  d653d8457c76da11f047af1f66256ac9b8421b69
Gitweb:     http://git.kernel.org/tip/d653d8457c76da11f047af1f66256ac9b8421b69
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Tue, 30 May 2017 23:15:56 +0200
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sun, 4 Jun 2017 15:40:31 +0200

alarmtimer: Implement remaining callback

Preparatory change to utilize the common posix timer mechanisms.

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

---
 kernel/time/alarmtimer.c | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 6082cf1..02ddc40 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -561,6 +561,18 @@ static int alarm_timer_forward(struct k_itimer *timr, ktime_t 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
  * @tp: timespec to fill
@@ -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 */