2 * RTC subsystem, interface functions
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 * based on arch/arm/common/rtctime.c
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/rtc.h>
15 #include <linux/sched.h>
16 #include <linux/log2.h>
17 #include <linux/workqueue.h>
19 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
20 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
22 static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
27 else if (!rtc->ops->read_time)
30 memset(tm, 0, sizeof(struct rtc_time));
31 err = rtc->ops->read_time(rtc->dev.parent, tm);
36 int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
40 err = mutex_lock_interruptible(&rtc->ops_lock);
44 err = __rtc_read_time(rtc, tm);
45 mutex_unlock(&rtc->ops_lock);
48 EXPORT_SYMBOL_GPL(rtc_read_time);
50 int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
54 err = rtc_valid_tm(tm);
58 err = mutex_lock_interruptible(&rtc->ops_lock);
64 else if (rtc->ops->set_time)
65 err = rtc->ops->set_time(rtc->dev.parent, tm);
66 else if (rtc->ops->set_mmss) {
68 err = rtc_tm_to_time(tm, &secs);
70 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
74 mutex_unlock(&rtc->ops_lock);
77 EXPORT_SYMBOL_GPL(rtc_set_time);
79 int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
83 err = mutex_lock_interruptible(&rtc->ops_lock);
89 else if (rtc->ops->set_mmss)
90 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
91 else if (rtc->ops->read_time && rtc->ops->set_time) {
92 struct rtc_time new, old;
94 err = rtc->ops->read_time(rtc->dev.parent, &old);
96 rtc_time_to_tm(secs, &new);
99 * avoid writing when we're going to change the day of
100 * the month. We will retry in the next minute. This
101 * basically means that if the RTC must not drift
102 * by more than 1 minute in 11 minutes.
104 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
105 (new.tm_hour == 23 && new.tm_min == 59)))
106 err = rtc->ops->set_time(rtc->dev.parent,
113 mutex_unlock(&rtc->ops_lock);
117 EXPORT_SYMBOL_GPL(rtc_set_mmss);
119 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
123 err = mutex_lock_interruptible(&rtc->ops_lock);
126 if (rtc->ops == NULL)
128 else if (!rtc->ops->read_alarm)
131 memset(alarm, 0, sizeof(struct rtc_wkalrm));
132 alarm->enabled = rtc->aie_timer.enabled;
133 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
135 mutex_unlock(&rtc->ops_lock);
139 EXPORT_SYMBOL_GPL(rtc_read_alarm);
141 int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
147 err = rtc_valid_tm(&alarm->time);
150 rtc_tm_to_time(&alarm->time, &scheduled);
152 /* Make sure we're not setting alarms in the past */
153 err = __rtc_read_time(rtc, &tm);
154 rtc_tm_to_time(&tm, &now);
155 if (scheduled <= now)
158 * XXX - We just checked to make sure the alarm time is not
159 * in the past, but there is still a race window where if
160 * the is alarm set for the next second and the second ticks
161 * over right here, before we set the alarm.
166 else if (!rtc->ops->set_alarm)
169 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
174 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
178 err = rtc_valid_tm(&alarm->time);
182 err = mutex_lock_interruptible(&rtc->ops_lock);
185 if (rtc->aie_timer.enabled) {
186 rtc_timer_remove(rtc, &rtc->aie_timer);
188 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
189 rtc->aie_timer.period = ktime_set(0, 0);
190 if (alarm->enabled) {
191 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
193 mutex_unlock(&rtc->ops_lock);
196 EXPORT_SYMBOL_GPL(rtc_set_alarm);
198 int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
200 int err = mutex_lock_interruptible(&rtc->ops_lock);
204 if (rtc->aie_timer.enabled != enabled) {
206 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
208 rtc_timer_remove(rtc, &rtc->aie_timer);
216 else if (!rtc->ops->alarm_irq_enable)
219 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
221 mutex_unlock(&rtc->ops_lock);
224 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
226 int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
228 int err = mutex_lock_interruptible(&rtc->ops_lock);
232 /* make sure we're changing state */
233 if (rtc->uie_rtctimer.enabled == enabled)
240 __rtc_read_time(rtc, &tm);
241 onesec = ktime_set(1, 0);
242 now = rtc_tm_to_ktime(tm);
243 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
244 rtc->uie_rtctimer.period = ktime_set(1, 0);
245 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
247 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
250 mutex_unlock(&rtc->ops_lock);
254 EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
258 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
259 * @rtc: pointer to the rtc device
261 * This function is called when an AIE, UIE or PIE mode interrupt
262 * has occured (or been emulated).
264 * Triggers the registered irq_task function callback.
266 static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
270 /* mark one irq of the appropriate mode */
271 spin_lock_irqsave(&rtc->irq_lock, flags);
272 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
273 spin_unlock_irqrestore(&rtc->irq_lock, flags);
275 /* call the task func */
276 spin_lock_irqsave(&rtc->irq_task_lock, flags);
278 rtc->irq_task->func(rtc->irq_task->private_data);
279 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
281 wake_up_interruptible(&rtc->irq_queue);
282 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
287 * rtc_aie_update_irq - AIE mode rtctimer hook
288 * @private: pointer to the rtc_device
290 * This functions is called when the aie_timer expires.
292 void rtc_aie_update_irq(void *private)
294 struct rtc_device *rtc = (struct rtc_device *)private;
295 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
300 * rtc_uie_update_irq - UIE mode rtctimer hook
301 * @private: pointer to the rtc_device
303 * This functions is called when the uie_timer expires.
305 void rtc_uie_update_irq(void *private)
307 struct rtc_device *rtc = (struct rtc_device *)private;
308 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
313 * rtc_pie_update_irq - PIE mode hrtimer hook
314 * @timer: pointer to the pie mode hrtimer
316 * This function is used to emulate PIE mode interrupts
317 * using an hrtimer. This function is called when the periodic
320 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
322 struct rtc_device *rtc;
325 rtc = container_of(timer, struct rtc_device, pie_timer);
327 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
328 count = hrtimer_forward_now(timer, period);
330 rtc_handle_legacy_irq(rtc, count, RTC_PF);
332 return HRTIMER_RESTART;
336 * rtc_update_irq - Triggered when a RTC interrupt occurs.
337 * @rtc: the rtc device
338 * @num: how many irqs are being reported (usually one)
339 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
342 void rtc_update_irq(struct rtc_device *rtc,
343 unsigned long num, unsigned long events)
345 schedule_work(&rtc->irqwork);
347 EXPORT_SYMBOL_GPL(rtc_update_irq);
349 static int __rtc_match(struct device *dev, void *data)
351 char *name = (char *)data;
353 if (strcmp(dev_name(dev), name) == 0)
358 struct rtc_device *rtc_class_open(char *name)
361 struct rtc_device *rtc = NULL;
363 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
365 rtc = to_rtc_device(dev);
368 if (!try_module_get(rtc->owner)) {
376 EXPORT_SYMBOL_GPL(rtc_class_open);
378 void rtc_class_close(struct rtc_device *rtc)
380 module_put(rtc->owner);
381 put_device(&rtc->dev);
383 EXPORT_SYMBOL_GPL(rtc_class_close);
385 int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
389 if (task == NULL || task->func == NULL)
392 /* Cannot register while the char dev is in use */
393 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
396 spin_lock_irq(&rtc->irq_task_lock);
397 if (rtc->irq_task == NULL) {
398 rtc->irq_task = task;
401 spin_unlock_irq(&rtc->irq_task_lock);
403 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
407 EXPORT_SYMBOL_GPL(rtc_irq_register);
409 void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
411 spin_lock_irq(&rtc->irq_task_lock);
412 if (rtc->irq_task == task)
413 rtc->irq_task = NULL;
414 spin_unlock_irq(&rtc->irq_task_lock);
416 EXPORT_SYMBOL_GPL(rtc_irq_unregister);
419 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
420 * @rtc: the rtc device
421 * @task: currently registered with rtc_irq_register()
422 * @enabled: true to enable periodic IRQs
425 * Note that rtc_irq_set_freq() should previously have been used to
426 * specify the desired frequency of periodic IRQ task->func() callbacks.
428 int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
433 spin_lock_irqsave(&rtc->irq_task_lock, flags);
434 if (rtc->irq_task != NULL && task == NULL)
436 if (rtc->irq_task != task)
440 ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
441 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
443 hrtimer_cancel(&rtc->pie_timer);
445 rtc->pie_enabled = enabled;
446 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
450 EXPORT_SYMBOL_GPL(rtc_irq_set_state);
453 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
454 * @rtc: the rtc device
455 * @task: currently registered with rtc_irq_register()
456 * @freq: positive frequency with which task->func() will be called
459 * Note that rtc_irq_set_state() is used to enable or disable the
462 int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
467 spin_lock_irqsave(&rtc->irq_task_lock, flags);
468 if (rtc->irq_task != NULL && task == NULL)
470 if (rtc->irq_task != task)
473 rtc->irq_freq = freq;
474 if (rtc->pie_enabled) {
476 hrtimer_cancel(&rtc->pie_timer);
477 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
478 hrtimer_start(&rtc->pie_timer, period,
482 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
485 EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
488 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
490 * @timer timer being added.
492 * Enqueues a timer onto the rtc devices timerqueue and sets
493 * the next alarm event appropriately.
495 * Sets the enabled bit on the added timer.
497 * Must hold ops_lock for proper serialization of timerqueue
499 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
502 timerqueue_add(&rtc->timerqueue, &timer->node);
503 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
504 struct rtc_wkalrm alarm;
506 alarm.time = rtc_ktime_to_tm(timer->node.expires);
508 err = __rtc_set_alarm(rtc, &alarm);
510 schedule_work(&rtc->irqwork);
512 timerqueue_del(&rtc->timerqueue, &timer->node);
521 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
523 * @timer timer being removed.
525 * Removes a timer onto the rtc devices timerqueue and sets
526 * the next alarm event appropriately.
528 * Clears the enabled bit on the removed timer.
530 * Must hold ops_lock for proper serialization of timerqueue
532 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
534 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
535 timerqueue_del(&rtc->timerqueue, &timer->node);
537 if (next == &timer->node) {
538 struct rtc_wkalrm alarm;
540 next = timerqueue_getnext(&rtc->timerqueue);
543 alarm.time = rtc_ktime_to_tm(next->expires);
545 err = __rtc_set_alarm(rtc, &alarm);
547 schedule_work(&rtc->irqwork);
552 * rtc_timer_do_work - Expires rtc timers
554 * @timer timer being removed.
556 * Expires rtc timers. Reprograms next alarm event if needed.
557 * Called via worktask.
559 * Serializes access to timerqueue via ops_lock mutex
561 void rtc_timer_do_work(struct work_struct *work)
563 struct rtc_timer *timer;
564 struct timerqueue_node *next;
568 struct rtc_device *rtc =
569 container_of(work, struct rtc_device, irqwork);
571 mutex_lock(&rtc->ops_lock);
573 __rtc_read_time(rtc, &tm);
574 now = rtc_tm_to_ktime(tm);
575 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
576 if (next->expires.tv64 > now.tv64)
580 timer = container_of(next, struct rtc_timer, node);
581 timerqueue_del(&rtc->timerqueue, &timer->node);
583 if (timer->task.func)
584 timer->task.func(timer->task.private_data);
586 /* Re-add/fwd periodic timers */
587 if (ktime_to_ns(timer->period)) {
588 timer->node.expires = ktime_add(timer->node.expires,
591 timerqueue_add(&rtc->timerqueue, &timer->node);
597 struct rtc_wkalrm alarm;
599 alarm.time = rtc_ktime_to_tm(next->expires);
601 err = __rtc_set_alarm(rtc, &alarm);
606 mutex_unlock(&rtc->ops_lock);
610 /* rtc_timer_init - Initializes an rtc_timer
611 * @timer: timer to be intiialized
612 * @f: function pointer to be called when timer fires
613 * @data: private data passed to function pointer
615 * Kernel interface to initializing an rtc_timer.
617 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
619 timerqueue_init(&timer->node);
621 timer->task.func = f;
622 timer->task.private_data = data;
625 /* rtc_timer_start - Sets an rtc_timer to fire in the future
626 * @ rtc: rtc device to be used
627 * @ timer: timer being set
628 * @ expires: time at which to expire the timer
629 * @ period: period that the timer will recur
631 * Kernel interface to set an rtc_timer
633 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
634 ktime_t expires, ktime_t period)
637 mutex_lock(&rtc->ops_lock);
639 rtc_timer_remove(rtc, timer);
641 timer->node.expires = expires;
642 timer->period = period;
644 ret = rtc_timer_enqueue(rtc, timer);
646 mutex_unlock(&rtc->ops_lock);
650 /* rtc_timer_cancel - Stops an rtc_timer
651 * @ rtc: rtc device to be used
652 * @ timer: timer being set
654 * Kernel interface to cancel an rtc_timer
656 int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
659 mutex_lock(&rtc->ops_lock);
661 rtc_timer_remove(rtc, timer);
662 mutex_unlock(&rtc->ops_lock);