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);
426 if (scheduled <= now)
429 * XXX - We just checked to make sure the alarm time is not
430 * in the past, but there is still a race window where if
431 * the is alarm set for the next second and the second ticks
432 * over right here, before we set the alarm.
435 rtc_subtract_offset(rtc, &alarm->time);
439 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
442 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
444 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
448 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
454 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
457 err = rtc_valid_tm(&alarm->time);
461 err = rtc_valid_range(rtc, &alarm->time);
465 err = mutex_lock_interruptible(&rtc->ops_lock);
468 if (rtc->aie_timer.enabled)
469 rtc_timer_remove(rtc, &rtc->aie_timer);
471 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
472 rtc->aie_timer.period = 0;
474 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
476 mutex_unlock(&rtc->ops_lock);
480 EXPORT_SYMBOL_GPL(rtc_set_alarm);
482 /* Called once per device from rtc_device_register */
483 int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
488 err = rtc_valid_tm(&alarm->time);
492 err = rtc_read_time(rtc, &now);
496 err = mutex_lock_interruptible(&rtc->ops_lock);
500 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
501 rtc->aie_timer.period = 0;
503 /* Alarm has to be enabled & in the future for us to enqueue it */
504 if (alarm->enabled && (rtc_tm_to_ktime(now) <
505 rtc->aie_timer.node.expires)) {
506 rtc->aie_timer.enabled = 1;
507 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
508 trace_rtc_timer_enqueue(&rtc->aie_timer);
510 mutex_unlock(&rtc->ops_lock);
513 EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
515 int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
519 err = mutex_lock_interruptible(&rtc->ops_lock);
523 if (rtc->aie_timer.enabled != enabled) {
525 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
527 rtc_timer_remove(rtc, &rtc->aie_timer);
534 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
537 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
539 mutex_unlock(&rtc->ops_lock);
541 trace_rtc_alarm_irq_enable(enabled, err);
544 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
546 int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
550 err = mutex_lock_interruptible(&rtc->ops_lock);
554 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
555 if (enabled == 0 && rtc->uie_irq_active) {
556 mutex_unlock(&rtc->ops_lock);
557 return rtc_dev_update_irq_enable_emul(rtc, 0);
560 /* make sure we're changing state */
561 if (rtc->uie_rtctimer.enabled == enabled)
564 if (rtc->uie_unsupported || !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
565 mutex_unlock(&rtc->ops_lock);
566 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
567 return rtc_dev_update_irq_enable_emul(rtc, enabled);
577 err = __rtc_read_time(rtc, &tm);
580 onesec = ktime_set(1, 0);
581 now = rtc_tm_to_ktime(tm);
582 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
583 rtc->uie_rtctimer.period = ktime_set(1, 0);
584 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
586 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
590 mutex_unlock(&rtc->ops_lock);
594 EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
597 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
598 * @rtc: pointer to the rtc device
599 * @num: number of occurence of the event
600 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
602 * This function is called when an AIE, UIE or PIE mode interrupt
603 * has occurred (or been emulated).
606 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
610 /* mark one irq of the appropriate mode */
611 spin_lock_irqsave(&rtc->irq_lock, flags);
612 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
613 spin_unlock_irqrestore(&rtc->irq_lock, flags);
615 wake_up_interruptible(&rtc->irq_queue);
616 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
620 * rtc_aie_update_irq - AIE mode rtctimer hook
621 * @rtc: pointer to the rtc_device
623 * This functions is called when the aie_timer expires.
625 void rtc_aie_update_irq(struct rtc_device *rtc)
627 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
631 * rtc_uie_update_irq - UIE mode rtctimer hook
632 * @rtc: pointer to the rtc_device
634 * This functions is called when the uie_timer expires.
636 void rtc_uie_update_irq(struct rtc_device *rtc)
638 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
642 * rtc_pie_update_irq - PIE mode hrtimer hook
643 * @timer: pointer to the pie mode hrtimer
645 * This function is used to emulate PIE mode interrupts
646 * using an hrtimer. This function is called when the periodic
649 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
651 struct rtc_device *rtc;
655 rtc = container_of(timer, struct rtc_device, pie_timer);
657 period = NSEC_PER_SEC / rtc->irq_freq;
658 count = hrtimer_forward_now(timer, period);
660 rtc_handle_legacy_irq(rtc, count, RTC_PF);
662 return HRTIMER_RESTART;
666 * rtc_update_irq - Triggered when a RTC interrupt occurs.
667 * @rtc: the rtc device
668 * @num: how many irqs are being reported (usually one)
669 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
672 void rtc_update_irq(struct rtc_device *rtc,
673 unsigned long num, unsigned long events)
675 if (IS_ERR_OR_NULL(rtc))
678 pm_stay_awake(rtc->dev.parent);
679 schedule_work(&rtc->irqwork);
681 EXPORT_SYMBOL_GPL(rtc_update_irq);
683 struct rtc_device *rtc_class_open(const char *name)
686 struct rtc_device *rtc = NULL;
688 dev = class_find_device_by_name(rtc_class, name);
690 rtc = to_rtc_device(dev);
693 if (!try_module_get(rtc->owner)) {
701 EXPORT_SYMBOL_GPL(rtc_class_open);
703 void rtc_class_close(struct rtc_device *rtc)
705 module_put(rtc->owner);
706 put_device(&rtc->dev);
708 EXPORT_SYMBOL_GPL(rtc_class_close);
710 static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
713 * We always cancel the timer here first, because otherwise
714 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
715 * when we manage to start the timer before the callback
716 * returns HRTIMER_RESTART.
718 * We cannot use hrtimer_cancel() here as a running callback
719 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
720 * would spin forever.
722 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
726 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
728 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
734 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
735 * @rtc: the rtc device
736 * @enabled: true to enable periodic IRQs
739 * Note that rtc_irq_set_freq() should previously have been used to
740 * specify the desired frequency of periodic IRQ.
742 int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
746 while (rtc_update_hrtimer(rtc, enabled) < 0)
749 rtc->pie_enabled = enabled;
751 trace_rtc_irq_set_state(enabled, err);
756 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
757 * @rtc: the rtc device
758 * @freq: positive frequency
761 * Note that rtc_irq_set_state() is used to enable or disable the
764 int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
768 if (freq <= 0 || freq > RTC_MAX_FREQ)
771 rtc->irq_freq = freq;
772 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
775 trace_rtc_irq_set_freq(freq, err);
780 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
782 * @timer: timer being added.
784 * Enqueues a timer onto the rtc devices timerqueue and sets
785 * the next alarm event appropriately.
787 * Sets the enabled bit on the added timer.
789 * Must hold ops_lock for proper serialization of timerqueue
791 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
793 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
798 err = __rtc_read_time(rtc, &tm);
803 now = rtc_tm_to_ktime(tm);
805 /* Skip over expired timers */
807 if (next->expires >= now)
809 next = timerqueue_iterate_next(next);
812 timerqueue_add(&rtc->timerqueue, &timer->node);
813 trace_rtc_timer_enqueue(timer);
814 if (!next || ktime_before(timer->node.expires, next->expires)) {
815 struct rtc_wkalrm alarm;
817 alarm.time = rtc_ktime_to_tm(timer->node.expires);
819 err = __rtc_set_alarm(rtc, &alarm);
821 pm_stay_awake(rtc->dev.parent);
822 schedule_work(&rtc->irqwork);
824 timerqueue_del(&rtc->timerqueue, &timer->node);
825 trace_rtc_timer_dequeue(timer);
833 static void rtc_alarm_disable(struct rtc_device *rtc)
835 if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
838 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
839 trace_rtc_alarm_irq_enable(0, 0);
843 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
845 * @timer: timer being removed.
847 * Removes a timer onto the rtc devices timerqueue and sets
848 * the next alarm event appropriately.
850 * Clears the enabled bit on the removed timer.
852 * Must hold ops_lock for proper serialization of timerqueue
854 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
856 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
858 timerqueue_del(&rtc->timerqueue, &timer->node);
859 trace_rtc_timer_dequeue(timer);
861 if (next == &timer->node) {
862 struct rtc_wkalrm alarm;
865 next = timerqueue_getnext(&rtc->timerqueue);
867 rtc_alarm_disable(rtc);
870 alarm.time = rtc_ktime_to_tm(next->expires);
872 err = __rtc_set_alarm(rtc, &alarm);
874 pm_stay_awake(rtc->dev.parent);
875 schedule_work(&rtc->irqwork);
881 * rtc_timer_do_work - Expires rtc timers
884 * Expires rtc timers. Reprograms next alarm event if needed.
885 * Called via worktask.
887 * Serializes access to timerqueue via ops_lock mutex
889 void rtc_timer_do_work(struct work_struct *work)
891 struct rtc_timer *timer;
892 struct timerqueue_node *next;
896 struct rtc_device *rtc =
897 container_of(work, struct rtc_device, irqwork);
899 mutex_lock(&rtc->ops_lock);
901 __rtc_read_time(rtc, &tm);
902 now = rtc_tm_to_ktime(tm);
903 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
904 if (next->expires > now)
908 timer = container_of(next, struct rtc_timer, node);
909 timerqueue_del(&rtc->timerqueue, &timer->node);
910 trace_rtc_timer_dequeue(timer);
913 timer->func(timer->rtc);
915 trace_rtc_timer_fired(timer);
916 /* Re-add/fwd periodic timers */
917 if (ktime_to_ns(timer->period)) {
918 timer->node.expires = ktime_add(timer->node.expires,
921 timerqueue_add(&rtc->timerqueue, &timer->node);
922 trace_rtc_timer_enqueue(timer);
928 struct rtc_wkalrm alarm;
932 alarm.time = rtc_ktime_to_tm(next->expires);
935 err = __rtc_set_alarm(rtc, &alarm);
942 timer = container_of(next, struct rtc_timer, node);
943 timerqueue_del(&rtc->timerqueue, &timer->node);
944 trace_rtc_timer_dequeue(timer);
946 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
950 rtc_alarm_disable(rtc);
953 pm_relax(rtc->dev.parent);
954 mutex_unlock(&rtc->ops_lock);
957 /* rtc_timer_init - Initializes an rtc_timer
958 * @timer: timer to be intiialized
959 * @f: function pointer to be called when timer fires
960 * @rtc: pointer to the rtc_device
962 * Kernel interface to initializing an rtc_timer.
964 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
965 struct rtc_device *rtc)
967 timerqueue_init(&timer->node);
973 /* rtc_timer_start - Sets an rtc_timer to fire in the future
974 * @ rtc: rtc device to be used
975 * @ timer: timer being set
976 * @ expires: time at which to expire the timer
977 * @ period: period that the timer will recur
979 * Kernel interface to set an rtc_timer
981 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
982 ktime_t expires, ktime_t period)
986 mutex_lock(&rtc->ops_lock);
988 rtc_timer_remove(rtc, timer);
990 timer->node.expires = expires;
991 timer->period = period;
993 ret = rtc_timer_enqueue(rtc, timer);
995 mutex_unlock(&rtc->ops_lock);
999 /* rtc_timer_cancel - Stops an rtc_timer
1000 * @ rtc: rtc device to be used
1001 * @ timer: timer being set
1003 * Kernel interface to cancel an rtc_timer
1005 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1007 mutex_lock(&rtc->ops_lock);
1009 rtc_timer_remove(rtc, timer);
1010 mutex_unlock(&rtc->ops_lock);
1014 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1015 * @rtc: rtc device to be used
1016 * @offset: the offset in parts per billion
1018 * see below for details.
1020 * Kernel interface to read rtc clock offset
1021 * Returns 0 on success, or a negative number on error.
1022 * If read_offset() is not implemented for the rtc, return -EINVAL
1024 int rtc_read_offset(struct rtc_device *rtc, long *offset)
1031 if (!rtc->ops->read_offset)
1034 mutex_lock(&rtc->ops_lock);
1035 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1036 mutex_unlock(&rtc->ops_lock);
1038 trace_rtc_read_offset(*offset, ret);
1043 * rtc_set_offset - Adjusts the duration of the average second
1044 * @rtc: rtc device to be used
1045 * @offset: the offset in parts per billion
1047 * Some rtc's allow an adjustment to the average duration of a second
1048 * to compensate for differences in the actual clock rate due to temperature,
1049 * the crystal, capacitor, etc.
1051 * The adjustment applied is as follows:
1052 * t = t0 * (1 + offset * 1e-9)
1053 * where t0 is the measured length of 1 RTC second with offset = 0
1055 * Kernel interface to adjust an rtc clock offset.
1056 * Return 0 on success, or a negative number on error.
1057 * If the rtc offset is not setable (or not implemented), return -EINVAL
1059 int rtc_set_offset(struct rtc_device *rtc, long offset)
1066 if (!rtc->ops->set_offset)
1069 mutex_lock(&rtc->ops_lock);
1070 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1071 mutex_unlock(&rtc->ops_lock);
1073 trace_rtc_set_offset(offset, ret);