4 * This interface provides a timer which is similarto hrtimers,
5 * but triggers a RTC alarm if the box is suspend.
7 * This interface is influenced by the Android RTC Alarm timer
10 * Copyright (C) 2010 IBM Corperation
12 * Author: John Stultz <john.stultz@linaro.org>
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
18 #include <linux/time.h>
19 #include <linux/hrtimer.h>
20 #include <linux/timerqueue.h>
21 #include <linux/rtc.h>
22 #include <linux/sched/signal.h>
23 #include <linux/sched/debug.h>
24 #include <linux/alarmtimer.h>
25 #include <linux/mutex.h>
26 #include <linux/platform_device.h>
27 #include <linux/posix-timers.h>
28 #include <linux/workqueue.h>
29 #include <linux/freezer.h>
30 #include <linux/compat.h>
31 #include <linux/module.h>
33 #include "posix-timers.h"
35 #define CREATE_TRACE_POINTS
36 #include <trace/events/alarmtimer.h>
39 * struct alarm_base - Alarm timer bases
40 * @lock: Lock for syncrhonized access to the base
41 * @timerqueue: Timerqueue head managing the list of events
42 * @gettime: Function to read the time correlating to the base
43 * @base_clockid: clockid for the base
45 static struct alarm_base {
47 struct timerqueue_head timerqueue;
48 ktime_t (*gettime)(void);
49 clockid_t base_clockid;
50 } alarm_bases[ALARM_NUMTYPE];
52 #if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
53 /* freezer information to handle clock_nanosleep triggered wakeups */
54 static enum alarmtimer_type freezer_alarmtype;
55 static ktime_t freezer_expires;
56 static ktime_t freezer_delta;
57 static DEFINE_SPINLOCK(freezer_delta_lock);
60 #ifdef CONFIG_RTC_CLASS
61 static struct wakeup_source *ws;
63 /* rtc timer and device for setting alarm wakeups at suspend */
64 static struct rtc_timer rtctimer;
65 static struct rtc_device *rtcdev;
66 static DEFINE_SPINLOCK(rtcdev_lock);
69 * alarmtimer_get_rtcdev - Return selected rtcdevice
71 * This function returns the rtc device to use for wakealarms.
72 * If one has not already been chosen, it checks to see if a
73 * functional rtc device is available.
75 struct rtc_device *alarmtimer_get_rtcdev(void)
78 struct rtc_device *ret;
80 spin_lock_irqsave(&rtcdev_lock, flags);
82 spin_unlock_irqrestore(&rtcdev_lock, flags);
86 EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
88 static int alarmtimer_rtc_add_device(struct device *dev,
89 struct class_interface *class_intf)
92 struct rtc_device *rtc = to_rtc_device(dev);
93 struct wakeup_source *__ws;
98 if (!rtc->ops->set_alarm)
100 if (!device_may_wakeup(rtc->dev.parent))
103 __ws = wakeup_source_register("alarmtimer");
105 spin_lock_irqsave(&rtcdev_lock, flags);
107 if (!try_module_get(rtc->owner)) {
108 spin_unlock_irqrestore(&rtcdev_lock, flags);
113 /* hold a reference so it doesn't go away */
118 spin_unlock_irqrestore(&rtcdev_lock, flags);
120 wakeup_source_unregister(__ws);
125 static inline void alarmtimer_rtc_timer_init(void)
127 rtc_timer_init(&rtctimer, NULL, NULL);
130 static struct class_interface alarmtimer_rtc_interface = {
131 .add_dev = &alarmtimer_rtc_add_device,
134 static int alarmtimer_rtc_interface_setup(void)
136 alarmtimer_rtc_interface.class = rtc_class;
137 return class_interface_register(&alarmtimer_rtc_interface);
139 static void alarmtimer_rtc_interface_remove(void)
141 class_interface_unregister(&alarmtimer_rtc_interface);
144 struct rtc_device *alarmtimer_get_rtcdev(void)
148 #define rtcdev (NULL)
149 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
150 static inline void alarmtimer_rtc_interface_remove(void) { }
151 static inline void alarmtimer_rtc_timer_init(void) { }
155 * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
156 * @base: pointer to the base where the timer is being run
157 * @alarm: pointer to alarm being enqueued.
159 * Adds alarm to a alarm_base timerqueue
161 * Must hold base->lock when calling.
163 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
165 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
166 timerqueue_del(&base->timerqueue, &alarm->node);
168 timerqueue_add(&base->timerqueue, &alarm->node);
169 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
173 * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
174 * @base: pointer to the base where the timer is running
175 * @alarm: pointer to alarm being removed
177 * Removes alarm to a alarm_base timerqueue
179 * Must hold base->lock when calling.
181 static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
183 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
186 timerqueue_del(&base->timerqueue, &alarm->node);
187 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
192 * alarmtimer_fired - Handles alarm hrtimer being fired.
193 * @timer: pointer to hrtimer being run
195 * When a alarm timer fires, this runs through the timerqueue to
196 * see which alarms expired, and runs those. If there are more alarm
197 * timers queued for the future, we set the hrtimer to fire when
198 * when the next future alarm timer expires.
200 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
202 struct alarm *alarm = container_of(timer, struct alarm, timer);
203 struct alarm_base *base = &alarm_bases[alarm->type];
205 int ret = HRTIMER_NORESTART;
206 int restart = ALARMTIMER_NORESTART;
208 spin_lock_irqsave(&base->lock, flags);
209 alarmtimer_dequeue(base, alarm);
210 spin_unlock_irqrestore(&base->lock, flags);
213 restart = alarm->function(alarm, base->gettime());
215 spin_lock_irqsave(&base->lock, flags);
216 if (restart != ALARMTIMER_NORESTART) {
217 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
218 alarmtimer_enqueue(base, alarm);
219 ret = HRTIMER_RESTART;
221 spin_unlock_irqrestore(&base->lock, flags);
223 trace_alarmtimer_fired(alarm, base->gettime());
228 ktime_t alarm_expires_remaining(const struct alarm *alarm)
230 struct alarm_base *base = &alarm_bases[alarm->type];
231 return ktime_sub(alarm->node.expires, base->gettime());
233 EXPORT_SYMBOL_GPL(alarm_expires_remaining);
235 #ifdef CONFIG_RTC_CLASS
237 * alarmtimer_suspend - Suspend time callback
241 * When we are going into suspend, we look through the bases
242 * to see which is the soonest timer to expire. We then
243 * set an rtc timer to fire that far into the future, which
244 * will wake us from suspend.
246 static int alarmtimer_suspend(struct device *dev)
248 ktime_t min, now, expires;
250 struct rtc_device *rtc;
254 spin_lock_irqsave(&freezer_delta_lock, flags);
256 expires = freezer_expires;
257 type = freezer_alarmtype;
259 spin_unlock_irqrestore(&freezer_delta_lock, flags);
261 rtc = alarmtimer_get_rtcdev();
262 /* If we have no rtcdev, just return */
266 /* Find the soonest timer to expire*/
267 for (i = 0; i < ALARM_NUMTYPE; i++) {
268 struct alarm_base *base = &alarm_bases[i];
269 struct timerqueue_node *next;
272 spin_lock_irqsave(&base->lock, flags);
273 next = timerqueue_getnext(&base->timerqueue);
274 spin_unlock_irqrestore(&base->lock, flags);
277 delta = ktime_sub(next->expires, base->gettime());
278 if (!min || (delta < min)) {
279 expires = next->expires;
287 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
288 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
292 trace_alarmtimer_suspend(expires, type);
294 /* Setup an rtc timer to fire that far in the future */
295 rtc_timer_cancel(rtc, &rtctimer);
296 rtc_read_time(rtc, &tm);
297 now = rtc_tm_to_ktime(tm);
298 now = ktime_add(now, min);
300 /* Set alarm, if in the past reject suspend briefly to handle */
301 ret = rtc_timer_start(rtc, &rtctimer, now, 0);
303 __pm_wakeup_event(ws, MSEC_PER_SEC);
307 static int alarmtimer_resume(struct device *dev)
309 struct rtc_device *rtc;
311 rtc = alarmtimer_get_rtcdev();
313 rtc_timer_cancel(rtc, &rtctimer);
318 static int alarmtimer_suspend(struct device *dev)
323 static int alarmtimer_resume(struct device *dev)
330 * alarm_init - Initialize an alarm structure
331 * @alarm: ptr to alarm to be initialized
332 * @type: the type of the alarm
333 * @function: callback that is run when the alarm fires
335 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
336 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
338 timerqueue_init(&alarm->node);
339 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
341 alarm->timer.function = alarmtimer_fired;
342 alarm->function = function;
344 alarm->state = ALARMTIMER_STATE_INACTIVE;
346 EXPORT_SYMBOL_GPL(alarm_init);
349 * alarm_start - Sets an absolute alarm to fire
350 * @alarm: ptr to alarm to set
351 * @start: time to run the alarm
353 void alarm_start(struct alarm *alarm, ktime_t start)
355 struct alarm_base *base = &alarm_bases[alarm->type];
358 spin_lock_irqsave(&base->lock, flags);
359 alarm->node.expires = start;
360 alarmtimer_enqueue(base, alarm);
361 hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
362 spin_unlock_irqrestore(&base->lock, flags);
364 trace_alarmtimer_start(alarm, base->gettime());
366 EXPORT_SYMBOL_GPL(alarm_start);
369 * alarm_start_relative - Sets a relative alarm to fire
370 * @alarm: ptr to alarm to set
371 * @start: time relative to now to run the alarm
373 void alarm_start_relative(struct alarm *alarm, ktime_t start)
375 struct alarm_base *base = &alarm_bases[alarm->type];
377 start = ktime_add_safe(start, base->gettime());
378 alarm_start(alarm, start);
380 EXPORT_SYMBOL_GPL(alarm_start_relative);
382 void alarm_restart(struct alarm *alarm)
384 struct alarm_base *base = &alarm_bases[alarm->type];
387 spin_lock_irqsave(&base->lock, flags);
388 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
389 hrtimer_restart(&alarm->timer);
390 alarmtimer_enqueue(base, alarm);
391 spin_unlock_irqrestore(&base->lock, flags);
393 EXPORT_SYMBOL_GPL(alarm_restart);
396 * alarm_try_to_cancel - Tries to cancel an alarm timer
397 * @alarm: ptr to alarm to be canceled
399 * Returns 1 if the timer was canceled, 0 if it was not running,
400 * and -1 if the callback was running
402 int alarm_try_to_cancel(struct alarm *alarm)
404 struct alarm_base *base = &alarm_bases[alarm->type];
408 spin_lock_irqsave(&base->lock, flags);
409 ret = hrtimer_try_to_cancel(&alarm->timer);
411 alarmtimer_dequeue(base, alarm);
412 spin_unlock_irqrestore(&base->lock, flags);
414 trace_alarmtimer_cancel(alarm, base->gettime());
417 EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
421 * alarm_cancel - Spins trying to cancel an alarm timer until it is done
422 * @alarm: ptr to alarm to be canceled
424 * Returns 1 if the timer was canceled, 0 if it was not active.
426 int alarm_cancel(struct alarm *alarm)
429 int ret = alarm_try_to_cancel(alarm);
435 EXPORT_SYMBOL_GPL(alarm_cancel);
438 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
443 delta = ktime_sub(now, alarm->node.expires);
448 if (unlikely(delta >= interval)) {
449 s64 incr = ktime_to_ns(interval);
451 overrun = ktime_divns(delta, incr);
453 alarm->node.expires = ktime_add_ns(alarm->node.expires,
456 if (alarm->node.expires > now)
459 * This (and the ktime_add() below) is the
460 * correction for exact:
465 alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
468 EXPORT_SYMBOL_GPL(alarm_forward);
470 u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
472 struct alarm_base *base = &alarm_bases[alarm->type];
474 return alarm_forward(alarm, base->gettime(), interval);
476 EXPORT_SYMBOL_GPL(alarm_forward_now);
478 #ifdef CONFIG_POSIX_TIMERS
480 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
482 struct alarm_base *base;
488 base = &alarm_bases[ALARM_REALTIME];
489 type = ALARM_REALTIME_FREEZER;
492 base = &alarm_bases[ALARM_BOOTTIME];
493 type = ALARM_BOOTTIME_FREEZER;
496 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
500 delta = ktime_sub(absexp, base->gettime());
502 spin_lock_irqsave(&freezer_delta_lock, flags);
503 if (!freezer_delta || (delta < freezer_delta)) {
504 freezer_delta = delta;
505 freezer_expires = absexp;
506 freezer_alarmtype = type;
508 spin_unlock_irqrestore(&freezer_delta_lock, flags);
512 * clock2alarm - helper that converts from clockid to alarmtypes
515 static enum alarmtimer_type clock2alarm(clockid_t clockid)
517 if (clockid == CLOCK_REALTIME_ALARM)
518 return ALARM_REALTIME;
519 if (clockid == CLOCK_BOOTTIME_ALARM)
520 return ALARM_BOOTTIME;
525 * alarm_handle_timer - Callback for posix timers
526 * @alarm: alarm that fired
528 * Posix timer callback for expired alarm timers.
530 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
533 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
534 it.alarm.alarmtimer);
535 enum alarmtimer_restart result = ALARMTIMER_NORESTART;
539 spin_lock_irqsave(&ptr->it_lock, flags);
542 if (ptr->it_interval)
543 si_private = ++ptr->it_requeue_pending;
545 if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
547 * Handle ignored signals and rearm the timer. This will go
548 * away once we handle ignored signals proper.
550 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
551 ++ptr->it_requeue_pending;
553 result = ALARMTIMER_RESTART;
555 spin_unlock_irqrestore(&ptr->it_lock, flags);
561 * alarm_timer_rearm - Posix timer callback for rearming timer
562 * @timr: Pointer to the posixtimer data struct
564 static void alarm_timer_rearm(struct k_itimer *timr)
566 struct alarm *alarm = &timr->it.alarm.alarmtimer;
568 timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
569 alarm_start(alarm, alarm->node.expires);
573 * alarm_timer_forward - Posix timer callback for forwarding timer
574 * @timr: Pointer to the posixtimer data struct
575 * @now: Current time to forward the timer against
577 static int alarm_timer_forward(struct k_itimer *timr, ktime_t now)
579 struct alarm *alarm = &timr->it.alarm.alarmtimer;
581 return (int) alarm_forward(alarm, timr->it_interval, now);
585 * alarm_timer_remaining - Posix timer callback to retrieve remaining time
586 * @timr: Pointer to the posixtimer data struct
587 * @now: Current time to calculate against
589 static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
591 struct alarm *alarm = &timr->it.alarm.alarmtimer;
593 return ktime_sub(now, alarm->node.expires);
597 * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
598 * @timr: Pointer to the posixtimer data struct
600 static int alarm_timer_try_to_cancel(struct k_itimer *timr)
602 return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
606 * alarm_timer_arm - Posix timer callback to arm a timer
607 * @timr: Pointer to the posixtimer data struct
608 * @expires: The new expiry time
609 * @absolute: Expiry value is absolute time
610 * @sigev_none: Posix timer does not deliver signals
612 static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
613 bool absolute, bool sigev_none)
615 struct alarm *alarm = &timr->it.alarm.alarmtimer;
616 struct alarm_base *base = &alarm_bases[alarm->type];
619 expires = ktime_add_safe(expires, base->gettime());
621 alarm->node.expires = expires;
623 alarm_start(&timr->it.alarm.alarmtimer, expires);
627 * alarm_clock_getres - posix getres interface
628 * @which_clock: clockid
629 * @tp: timespec to fill
631 * Returns the granularity of underlying alarm base clock
633 static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
635 if (!alarmtimer_get_rtcdev())
639 tp->tv_nsec = hrtimer_resolution;
644 * alarm_clock_get - posix clock_get interface
645 * @which_clock: clockid
646 * @tp: timespec to fill.
648 * Provides the underlying alarm base time.
650 static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
652 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
654 if (!alarmtimer_get_rtcdev())
657 *tp = ktime_to_timespec64(base->gettime());
662 * alarm_timer_create - posix timer_create interface
663 * @new_timer: k_itimer pointer to manage
665 * Initializes the k_itimer structure.
667 static int alarm_timer_create(struct k_itimer *new_timer)
669 enum alarmtimer_type type;
671 if (!alarmtimer_get_rtcdev())
674 if (!capable(CAP_WAKE_ALARM))
677 type = clock2alarm(new_timer->it_clock);
678 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
683 * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
684 * @alarm: ptr to alarm that fired
686 * Wakes up the task that set the alarmtimer
688 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
691 struct task_struct *task = (struct task_struct *)alarm->data;
695 wake_up_process(task);
696 return ALARMTIMER_NORESTART;
700 * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
701 * @alarm: ptr to alarmtimer
702 * @absexp: absolute expiration time
704 * Sets the alarm timer and sleeps until it is fired or interrupted.
706 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
707 enum alarmtimer_type type)
709 struct restart_block *restart;
710 alarm->data = (void *)current;
712 set_current_state(TASK_INTERRUPTIBLE);
713 alarm_start(alarm, absexp);
714 if (likely(alarm->data))
718 } while (alarm->data && !signal_pending(current));
720 __set_current_state(TASK_RUNNING);
725 if (freezing(current))
726 alarmtimer_freezerset(absexp, type);
727 restart = ¤t->restart_block;
728 if (restart->nanosleep.type != TT_NONE) {
729 struct timespec64 rmt;
732 rem = ktime_sub(absexp, alarm_bases[type].gettime());
736 rmt = ktime_to_timespec64(rem);
738 return nanosleep_copyout(restart, &rmt);
740 return -ERESTART_RESTARTBLOCK;
744 * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
745 * @restart: ptr to restart block
747 * Handles restarted clock_nanosleep calls
749 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
751 enum alarmtimer_type type = restart->nanosleep.clockid;
752 ktime_t exp = restart->nanosleep.expires;
755 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
757 return alarmtimer_do_nsleep(&alarm, exp, type);
761 * alarm_timer_nsleep - alarmtimer nanosleep
762 * @which_clock: clockid
763 * @flags: determins abstime or relative
764 * @tsreq: requested sleep time (abs or rel)
765 * @rmtp: remaining sleep time saved
767 * Handles clock_nanosleep calls against _ALARM clockids
769 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
770 const struct timespec64 *tsreq)
772 enum alarmtimer_type type = clock2alarm(which_clock);
773 struct restart_block *restart = ¤t->restart_block;
778 if (!alarmtimer_get_rtcdev())
781 if (flags & ~TIMER_ABSTIME)
784 if (!capable(CAP_WAKE_ALARM))
787 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
789 exp = timespec64_to_ktime(*tsreq);
790 /* Convert (if necessary) to absolute time */
791 if (flags != TIMER_ABSTIME) {
792 ktime_t now = alarm_bases[type].gettime();
793 exp = ktime_add(now, exp);
796 ret = alarmtimer_do_nsleep(&alarm, exp, type);
797 if (ret != -ERESTART_RESTARTBLOCK)
800 /* abs timers don't set remaining time or restart */
801 if (flags == TIMER_ABSTIME)
802 return -ERESTARTNOHAND;
804 restart->fn = alarm_timer_nsleep_restart;
805 restart->nanosleep.clockid = type;
806 restart->nanosleep.expires = exp;
810 const struct k_clock alarm_clock = {
811 .clock_getres = alarm_clock_getres,
812 .clock_get = alarm_clock_get,
813 .timer_create = alarm_timer_create,
814 .timer_set = common_timer_set,
815 .timer_del = common_timer_del,
816 .timer_get = common_timer_get,
817 .timer_arm = alarm_timer_arm,
818 .timer_rearm = alarm_timer_rearm,
819 .timer_forward = alarm_timer_forward,
820 .timer_remaining = alarm_timer_remaining,
821 .timer_try_to_cancel = alarm_timer_try_to_cancel,
822 .nsleep = alarm_timer_nsleep,
824 #endif /* CONFIG_POSIX_TIMERS */
827 /* Suspend hook structures */
828 static const struct dev_pm_ops alarmtimer_pm_ops = {
829 .suspend = alarmtimer_suspend,
830 .resume = alarmtimer_resume,
833 static struct platform_driver alarmtimer_driver = {
835 .name = "alarmtimer",
836 .pm = &alarmtimer_pm_ops,
841 * alarmtimer_init - Initialize alarm timer code
843 * This function initializes the alarm bases and registers
844 * the posix clock ids.
846 static int __init alarmtimer_init(void)
848 struct platform_device *pdev;
852 alarmtimer_rtc_timer_init();
854 /* Initialize alarm bases */
855 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
856 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
857 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
858 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
859 for (i = 0; i < ALARM_NUMTYPE; i++) {
860 timerqueue_init_head(&alarm_bases[i].timerqueue);
861 spin_lock_init(&alarm_bases[i].lock);
864 error = alarmtimer_rtc_interface_setup();
868 error = platform_driver_register(&alarmtimer_driver);
872 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
874 error = PTR_ERR(pdev);
880 platform_driver_unregister(&alarmtimer_driver);
882 alarmtimer_rtc_interface_remove();
885 device_initcall(alarmtimer_init);