1 // SPDX-License-Identifier: GPL-2.0
3 * RTC subsystem, interface functions
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
8 * based on arch/arm/common/rtctime.c
11 #include <linux/rtc.h>
12 #include <linux/sched.h>
13 #include <linux/module.h>
14 #include <linux/log2.h>
15 #include <linux/workqueue.h>
17 #define CREATE_TRACE_POINTS
18 #include <trace/events/rtc.h>
20 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
21 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
23 static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
27 if (!rtc->offset_secs)
30 secs = rtc_tm_to_time64(tm);
33 * Since the reading time values from RTC device are always in the RTC
34 * original valid range, but we need to skip the overlapped region
35 * between expanded range and original range, which is no need to add
38 if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
39 (rtc->start_secs < rtc->range_min &&
40 secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
43 rtc_time64_to_tm(secs + rtc->offset_secs, tm);
46 static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
50 if (!rtc->offset_secs)
53 secs = rtc_tm_to_time64(tm);
56 * If the setting time values are in the valid range of RTC hardware
57 * device, then no need to subtract the offset when setting time to RTC
58 * device. Otherwise we need to subtract the offset to make the time
59 * values are valid for RTC hardware device.
61 if (secs >= rtc->range_min && secs <= rtc->range_max)
64 rtc_time64_to_tm(secs - rtc->offset_secs, tm);
67 static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
69 if (rtc->range_min != rtc->range_max) {
70 time64_t time = rtc_tm_to_time64(tm);
71 time64_t range_min = rtc->set_start_time ? rtc->start_secs :
73 timeu64_t range_max = rtc->set_start_time ?
74 (rtc->start_secs + rtc->range_max - rtc->range_min) :
77 if (time < range_min || time > range_max)
84 static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
90 } else if (!rtc->ops->read_time) {
93 memset(tm, 0, sizeof(struct rtc_time));
94 err = rtc->ops->read_time(rtc->dev.parent, tm);
96 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
101 rtc_add_offset(rtc, tm);
103 err = rtc_valid_tm(tm);
105 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
110 int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
114 err = mutex_lock_interruptible(&rtc->ops_lock);
118 err = __rtc_read_time(rtc, tm);
119 mutex_unlock(&rtc->ops_lock);
121 trace_rtc_read_time(rtc_tm_to_time64(tm), err);
124 EXPORT_SYMBOL_GPL(rtc_read_time);
126 int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
130 err = rtc_valid_tm(tm);
134 err = rtc_valid_range(rtc, tm);
138 rtc_subtract_offset(rtc, tm);
140 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
141 uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
143 uie = rtc->uie_rtctimer.enabled;
146 err = rtc_update_irq_enable(rtc, 0);
151 err = mutex_lock_interruptible(&rtc->ops_lock);
157 else if (rtc->ops->set_time)
158 err = rtc->ops->set_time(rtc->dev.parent, tm);
162 pm_stay_awake(rtc->dev.parent);
163 mutex_unlock(&rtc->ops_lock);
164 /* A timer might have just expired */
165 schedule_work(&rtc->irqwork);
168 err = rtc_update_irq_enable(rtc, 1);
173 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
176 EXPORT_SYMBOL_GPL(rtc_set_time);
178 static int rtc_read_alarm_internal(struct rtc_device *rtc,
179 struct rtc_wkalrm *alarm)
183 err = mutex_lock_interruptible(&rtc->ops_lock);
189 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
194 alarm->time.tm_sec = -1;
195 alarm->time.tm_min = -1;
196 alarm->time.tm_hour = -1;
197 alarm->time.tm_mday = -1;
198 alarm->time.tm_mon = -1;
199 alarm->time.tm_year = -1;
200 alarm->time.tm_wday = -1;
201 alarm->time.tm_yday = -1;
202 alarm->time.tm_isdst = -1;
203 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
206 mutex_unlock(&rtc->ops_lock);
208 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
212 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
215 struct rtc_time before, now;
217 time64_t t_now, t_alm;
218 enum { none, day, month, year } missing = none;
221 /* The lower level RTC driver may return -1 in some fields,
222 * creating invalid alarm->time values, for reasons like:
224 * - The hardware may not be capable of filling them in;
225 * many alarms match only on time-of-day fields, not
226 * day/month/year calendar data.
228 * - Some hardware uses illegal values as "wildcard" match
229 * values, which non-Linux firmware (like a BIOS) may try
230 * to set up as e.g. "alarm 15 minutes after each hour".
231 * Linux uses only oneshot alarms.
233 * When we see that here, we deal with it by using values from
234 * a current RTC timestamp for any missing (-1) values. The
235 * RTC driver prevents "periodic alarm" modes.
237 * But this can be racey, because some fields of the RTC timestamp
238 * may have wrapped in the interval since we read the RTC alarm,
239 * which would lead to us inserting inconsistent values in place
242 * Reading the alarm and timestamp in the reverse sequence
243 * would have the same race condition, and not solve the issue.
245 * So, we must first read the RTC timestamp,
246 * then read the RTC alarm value,
247 * and then read a second RTC timestamp.
249 * If any fields of the second timestamp have changed
250 * when compared with the first timestamp, then we know
251 * our timestamp may be inconsistent with that used by
252 * the low-level rtc_read_alarm_internal() function.
254 * So, when the two timestamps disagree, we just loop and do
255 * the process again to get a fully consistent set of values.
257 * This could all instead be done in the lower level driver,
258 * but since more than one lower level RTC implementation needs it,
259 * then it's probably best best to do it here instead of there..
262 /* Get the "before" timestamp */
263 err = rtc_read_time(rtc, &before);
268 memcpy(&before, &now, sizeof(struct rtc_time));
271 /* get the RTC alarm values, which may be incomplete */
272 err = rtc_read_alarm_internal(rtc, alarm);
276 /* full-function RTCs won't have such missing fields */
277 if (rtc_valid_tm(&alarm->time) == 0) {
278 rtc_add_offset(rtc, &alarm->time);
282 /* get the "after" timestamp, to detect wrapped fields */
283 err = rtc_read_time(rtc, &now);
287 /* note that tm_sec is a "don't care" value here: */
288 } while (before.tm_min != now.tm_min ||
289 before.tm_hour != now.tm_hour ||
290 before.tm_mon != now.tm_mon ||
291 before.tm_year != now.tm_year);
293 /* Fill in the missing alarm fields using the timestamp; we
294 * know there's at least one since alarm->time is invalid.
296 if (alarm->time.tm_sec == -1)
297 alarm->time.tm_sec = now.tm_sec;
298 if (alarm->time.tm_min == -1)
299 alarm->time.tm_min = now.tm_min;
300 if (alarm->time.tm_hour == -1)
301 alarm->time.tm_hour = now.tm_hour;
303 /* For simplicity, only support date rollover for now */
304 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
305 alarm->time.tm_mday = now.tm_mday;
308 if ((unsigned int)alarm->time.tm_mon >= 12) {
309 alarm->time.tm_mon = now.tm_mon;
313 if (alarm->time.tm_year == -1) {
314 alarm->time.tm_year = now.tm_year;
319 /* Can't proceed if alarm is still invalid after replacing
322 err = rtc_valid_tm(&alarm->time);
326 /* with luck, no rollover is needed */
327 t_now = rtc_tm_to_time64(&now);
328 t_alm = rtc_tm_to_time64(&alarm->time);
333 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
334 * that will trigger at 5am will do so at 5am Tuesday, which
335 * could also be in the next month or year. This is a common
336 * case, especially for PCs.
339 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
340 t_alm += 24 * 60 * 60;
341 rtc_time64_to_tm(t_alm, &alarm->time);
344 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
345 * be next month. An alarm matching on the 30th, 29th, or 28th
346 * may end up in the month after that! Many newer PCs support
347 * this type of alarm.
350 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
352 if (alarm->time.tm_mon < 11) {
353 alarm->time.tm_mon++;
355 alarm->time.tm_mon = 0;
356 alarm->time.tm_year++;
358 days = rtc_month_days(alarm->time.tm_mon,
359 alarm->time.tm_year);
360 } while (days < alarm->time.tm_mday);
363 /* Year rollover ... easy except for leap years! */
365 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
367 alarm->time.tm_year++;
368 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
369 rtc_valid_tm(&alarm->time) != 0);
373 dev_warn(&rtc->dev, "alarm rollover not handled\n");
376 err = rtc_valid_tm(&alarm->time);
380 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
386 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
390 err = mutex_lock_interruptible(&rtc->ops_lock);
395 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
398 memset(alarm, 0, sizeof(struct rtc_wkalrm));
399 alarm->enabled = rtc->aie_timer.enabled;
400 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
402 mutex_unlock(&rtc->ops_lock);
404 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
407 EXPORT_SYMBOL_GPL(rtc_read_alarm);
409 static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
412 time64_t now, scheduled;
415 err = rtc_valid_tm(&alarm->time);
419 scheduled = rtc_tm_to_time64(&alarm->time);
421 /* Make sure we're not setting alarms in the past */
422 err = __rtc_read_time(rtc, &tm);
425 now = rtc_tm_to_time64(&tm);
427 if (scheduled <= now)
430 * XXX - We just checked to make sure the alarm time is not
431 * in the past, but there is still a race window where if
432 * the is alarm set for the next second and the second ticks
433 * over right here, before we set the alarm.
436 rtc_subtract_offset(rtc, &alarm->time);
440 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
443 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
445 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
449 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
456 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
459 err = rtc_valid_tm(&alarm->time);
463 err = rtc_valid_range(rtc, &alarm->time);
467 err = mutex_lock_interruptible(&rtc->ops_lock);
470 if (rtc->aie_timer.enabled)
471 rtc_timer_remove(rtc, &rtc->aie_timer);
473 alarm_time = rtc_tm_to_ktime(alarm->time);
475 * Round down so we never miss a deadline, checking for past deadline is
476 * done in __rtc_set_alarm
478 if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
479 alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
481 rtc->aie_timer.node.expires = alarm_time;
482 rtc->aie_timer.period = 0;
484 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
486 mutex_unlock(&rtc->ops_lock);
490 EXPORT_SYMBOL_GPL(rtc_set_alarm);
492 /* Called once per device from rtc_device_register */
493 int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
498 err = rtc_valid_tm(&alarm->time);
502 err = rtc_read_time(rtc, &now);
506 err = mutex_lock_interruptible(&rtc->ops_lock);
510 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
511 rtc->aie_timer.period = 0;
513 /* Alarm has to be enabled & in the future for us to enqueue it */
514 if (alarm->enabled && (rtc_tm_to_ktime(now) <
515 rtc->aie_timer.node.expires)) {
516 rtc->aie_timer.enabled = 1;
517 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
518 trace_rtc_timer_enqueue(&rtc->aie_timer);
520 mutex_unlock(&rtc->ops_lock);
523 EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
525 int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
529 err = mutex_lock_interruptible(&rtc->ops_lock);
533 if (rtc->aie_timer.enabled != enabled) {
535 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
537 rtc_timer_remove(rtc, &rtc->aie_timer);
544 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
547 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
549 mutex_unlock(&rtc->ops_lock);
551 trace_rtc_alarm_irq_enable(enabled, err);
554 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
556 int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
560 err = mutex_lock_interruptible(&rtc->ops_lock);
564 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
565 if (enabled == 0 && rtc->uie_irq_active) {
566 mutex_unlock(&rtc->ops_lock);
567 return rtc_dev_update_irq_enable_emul(rtc, 0);
570 /* make sure we're changing state */
571 if (rtc->uie_rtctimer.enabled == enabled)
574 if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) ||
575 !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
576 mutex_unlock(&rtc->ops_lock);
577 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
578 return rtc_dev_update_irq_enable_emul(rtc, enabled);
588 err = __rtc_read_time(rtc, &tm);
591 onesec = ktime_set(1, 0);
592 now = rtc_tm_to_ktime(tm);
593 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
594 rtc->uie_rtctimer.period = ktime_set(1, 0);
595 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
597 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
601 mutex_unlock(&rtc->ops_lock);
605 EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
608 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
609 * @rtc: pointer to the rtc device
610 * @num: number of occurence of the event
611 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
613 * This function is called when an AIE, UIE or PIE mode interrupt
614 * has occurred (or been emulated).
617 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
621 /* mark one irq of the appropriate mode */
622 spin_lock_irqsave(&rtc->irq_lock, flags);
623 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
624 spin_unlock_irqrestore(&rtc->irq_lock, flags);
626 wake_up_interruptible(&rtc->irq_queue);
627 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
631 * rtc_aie_update_irq - AIE mode rtctimer hook
632 * @rtc: pointer to the rtc_device
634 * This functions is called when the aie_timer expires.
636 void rtc_aie_update_irq(struct rtc_device *rtc)
638 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
642 * rtc_uie_update_irq - UIE mode rtctimer hook
643 * @rtc: pointer to the rtc_device
645 * This functions is called when the uie_timer expires.
647 void rtc_uie_update_irq(struct rtc_device *rtc)
649 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
653 * rtc_pie_update_irq - PIE mode hrtimer hook
654 * @timer: pointer to the pie mode hrtimer
656 * This function is used to emulate PIE mode interrupts
657 * using an hrtimer. This function is called when the periodic
660 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
662 struct rtc_device *rtc;
666 rtc = container_of(timer, struct rtc_device, pie_timer);
668 period = NSEC_PER_SEC / rtc->irq_freq;
669 count = hrtimer_forward_now(timer, period);
671 rtc_handle_legacy_irq(rtc, count, RTC_PF);
673 return HRTIMER_RESTART;
677 * rtc_update_irq - Triggered when a RTC interrupt occurs.
678 * @rtc: the rtc device
679 * @num: how many irqs are being reported (usually one)
680 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
683 void rtc_update_irq(struct rtc_device *rtc,
684 unsigned long num, unsigned long events)
686 if (IS_ERR_OR_NULL(rtc))
689 pm_stay_awake(rtc->dev.parent);
690 schedule_work(&rtc->irqwork);
692 EXPORT_SYMBOL_GPL(rtc_update_irq);
694 struct rtc_device *rtc_class_open(const char *name)
697 struct rtc_device *rtc = NULL;
699 dev = class_find_device_by_name(rtc_class, name);
701 rtc = to_rtc_device(dev);
704 if (!try_module_get(rtc->owner)) {
712 EXPORT_SYMBOL_GPL(rtc_class_open);
714 void rtc_class_close(struct rtc_device *rtc)
716 module_put(rtc->owner);
717 put_device(&rtc->dev);
719 EXPORT_SYMBOL_GPL(rtc_class_close);
721 static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
724 * We always cancel the timer here first, because otherwise
725 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
726 * when we manage to start the timer before the callback
727 * returns HRTIMER_RESTART.
729 * We cannot use hrtimer_cancel() here as a running callback
730 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
731 * would spin forever.
733 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
737 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
739 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
745 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
746 * @rtc: the rtc device
747 * @enabled: true to enable periodic IRQs
750 * Note that rtc_irq_set_freq() should previously have been used to
751 * specify the desired frequency of periodic IRQ.
753 int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
757 while (rtc_update_hrtimer(rtc, enabled) < 0)
760 rtc->pie_enabled = enabled;
762 trace_rtc_irq_set_state(enabled, err);
767 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
768 * @rtc: the rtc device
769 * @freq: positive frequency
772 * Note that rtc_irq_set_state() is used to enable or disable the
775 int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
779 if (freq <= 0 || freq > RTC_MAX_FREQ)
782 rtc->irq_freq = freq;
783 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
786 trace_rtc_irq_set_freq(freq, err);
791 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
793 * @timer: timer being added.
795 * Enqueues a timer onto the rtc devices timerqueue and sets
796 * the next alarm event appropriately.
798 * Sets the enabled bit on the added timer.
800 * Must hold ops_lock for proper serialization of timerqueue
802 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
804 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
809 __rtc_read_time(rtc, &tm);
810 now = rtc_tm_to_ktime(tm);
812 /* Skip over expired timers */
814 if (next->expires >= now)
816 next = timerqueue_iterate_next(next);
819 timerqueue_add(&rtc->timerqueue, &timer->node);
820 trace_rtc_timer_enqueue(timer);
821 if (!next || ktime_before(timer->node.expires, next->expires)) {
822 struct rtc_wkalrm alarm;
825 alarm.time = rtc_ktime_to_tm(timer->node.expires);
827 err = __rtc_set_alarm(rtc, &alarm);
829 pm_stay_awake(rtc->dev.parent);
830 schedule_work(&rtc->irqwork);
832 timerqueue_del(&rtc->timerqueue, &timer->node);
833 trace_rtc_timer_dequeue(timer);
841 static void rtc_alarm_disable(struct rtc_device *rtc)
843 if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
846 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
847 trace_rtc_alarm_irq_enable(0, 0);
851 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
853 * @timer: timer being removed.
855 * Removes a timer onto the rtc devices timerqueue and sets
856 * the next alarm event appropriately.
858 * Clears the enabled bit on the removed timer.
860 * Must hold ops_lock for proper serialization of timerqueue
862 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
864 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
866 timerqueue_del(&rtc->timerqueue, &timer->node);
867 trace_rtc_timer_dequeue(timer);
869 if (next == &timer->node) {
870 struct rtc_wkalrm alarm;
873 next = timerqueue_getnext(&rtc->timerqueue);
875 rtc_alarm_disable(rtc);
878 alarm.time = rtc_ktime_to_tm(next->expires);
880 err = __rtc_set_alarm(rtc, &alarm);
882 pm_stay_awake(rtc->dev.parent);
883 schedule_work(&rtc->irqwork);
889 * rtc_timer_do_work - Expires rtc timers
892 * Expires rtc timers. Reprograms next alarm event if needed.
893 * Called via worktask.
895 * Serializes access to timerqueue via ops_lock mutex
897 void rtc_timer_do_work(struct work_struct *work)
899 struct rtc_timer *timer;
900 struct timerqueue_node *next;
904 struct rtc_device *rtc =
905 container_of(work, struct rtc_device, irqwork);
907 mutex_lock(&rtc->ops_lock);
909 __rtc_read_time(rtc, &tm);
910 now = rtc_tm_to_ktime(tm);
911 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
912 if (next->expires > now)
916 timer = container_of(next, struct rtc_timer, node);
917 timerqueue_del(&rtc->timerqueue, &timer->node);
918 trace_rtc_timer_dequeue(timer);
921 timer->func(timer->rtc);
923 trace_rtc_timer_fired(timer);
924 /* Re-add/fwd periodic timers */
925 if (ktime_to_ns(timer->period)) {
926 timer->node.expires = ktime_add(timer->node.expires,
929 timerqueue_add(&rtc->timerqueue, &timer->node);
930 trace_rtc_timer_enqueue(timer);
936 struct rtc_wkalrm alarm;
940 alarm.time = rtc_ktime_to_tm(next->expires);
943 err = __rtc_set_alarm(rtc, &alarm);
950 timer = container_of(next, struct rtc_timer, node);
951 timerqueue_del(&rtc->timerqueue, &timer->node);
952 trace_rtc_timer_dequeue(timer);
954 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
958 rtc_alarm_disable(rtc);
961 pm_relax(rtc->dev.parent);
962 mutex_unlock(&rtc->ops_lock);
965 /* rtc_timer_init - Initializes an rtc_timer
966 * @timer: timer to be intiialized
967 * @f: function pointer to be called when timer fires
968 * @rtc: pointer to the rtc_device
970 * Kernel interface to initializing an rtc_timer.
972 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
973 struct rtc_device *rtc)
975 timerqueue_init(&timer->node);
981 /* rtc_timer_start - Sets an rtc_timer to fire in the future
982 * @ rtc: rtc device to be used
983 * @ timer: timer being set
984 * @ expires: time at which to expire the timer
985 * @ period: period that the timer will recur
987 * Kernel interface to set an rtc_timer
989 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
990 ktime_t expires, ktime_t period)
994 mutex_lock(&rtc->ops_lock);
996 rtc_timer_remove(rtc, timer);
998 timer->node.expires = expires;
999 timer->period = period;
1001 ret = rtc_timer_enqueue(rtc, timer);
1003 mutex_unlock(&rtc->ops_lock);
1007 /* rtc_timer_cancel - Stops an rtc_timer
1008 * @ rtc: rtc device to be used
1009 * @ timer: timer being set
1011 * Kernel interface to cancel an rtc_timer
1013 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1015 mutex_lock(&rtc->ops_lock);
1017 rtc_timer_remove(rtc, timer);
1018 mutex_unlock(&rtc->ops_lock);
1022 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1023 * @rtc: rtc device to be used
1024 * @offset: the offset in parts per billion
1026 * see below for details.
1028 * Kernel interface to read rtc clock offset
1029 * Returns 0 on success, or a negative number on error.
1030 * If read_offset() is not implemented for the rtc, return -EINVAL
1032 int rtc_read_offset(struct rtc_device *rtc, long *offset)
1039 if (!rtc->ops->read_offset)
1042 mutex_lock(&rtc->ops_lock);
1043 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1044 mutex_unlock(&rtc->ops_lock);
1046 trace_rtc_read_offset(*offset, ret);
1051 * rtc_set_offset - Adjusts the duration of the average second
1052 * @rtc: rtc device to be used
1053 * @offset: the offset in parts per billion
1055 * Some rtc's allow an adjustment to the average duration of a second
1056 * to compensate for differences in the actual clock rate due to temperature,
1057 * the crystal, capacitor, etc.
1059 * The adjustment applied is as follows:
1060 * t = t0 * (1 + offset * 1e-9)
1061 * where t0 is the measured length of 1 RTC second with offset = 0
1063 * Kernel interface to adjust an rtc clock offset.
1064 * Return 0 on success, or a negative number on error.
1065 * If the rtc offset is not setable (or not implemented), return -EINVAL
1067 int rtc_set_offset(struct rtc_device *rtc, long offset)
1074 if (!rtc->ops->set_offset)
1077 mutex_lock(&rtc->ops_lock);
1078 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1079 mutex_unlock(&rtc->ops_lock);
1081 trace_rtc_set_offset(offset, ret);