[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / rtc / interface.c

/*
 * RTC subsystem, interface functions
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * based on arch/arm/common/rtctime.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/rtc.h>
#include <linux/sched.h>
#include <linux/log2.h>
#include <linux/workqueue.h>

static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);

static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;
	if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->read_time)
		err = -EINVAL;
	else {
		memset(tm, 0, sizeof(struct rtc_time));
		err = rtc->ops->read_time(rtc->dev.parent, tm);
	}
	return err;
}

int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	err = __rtc_read_time(rtc, tm);
	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_read_time);

int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
{
	int err;

	err = rtc_valid_tm(tm);
	if (err != 0)
		return err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (!rtc->ops)
		err = -ENODEV;
	else if (rtc->ops->set_time)
		err = rtc->ops->set_time(rtc->dev.parent, tm);
	else if (rtc->ops->set_mmss) {
		unsigned long secs;
		err = rtc_tm_to_time(tm, &secs);
		if (err == 0)
			err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	} else
		err = -EINVAL;

	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_time);

int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (!rtc->ops)
		err = -ENODEV;
	else if (rtc->ops->set_mmss)
		err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	else if (rtc->ops->read_time && rtc->ops->set_time) {
		struct rtc_time new, old;

		err = rtc->ops->read_time(rtc->dev.parent, &old);
		if (err == 0) {
			rtc_time_to_tm(secs, &new);

			/*
			 * avoid writing when we're going to change the day of
			 * the month. We will retry in the next minute. This
			 * basically means that if the RTC must not drift
			 * by more than 1 minute in 11 minutes.
			 */
			if (!((old.tm_hour == 23 && old.tm_min == 59) ||
				(new.tm_hour == 23 && new.tm_min == 59)))
				err = rtc->ops->set_time(rtc->dev.parent,
						&new);
		}
	}
	else
		err = -EINVAL;

	mutex_unlock(&rtc->ops_lock);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_mmss);

int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	int err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;
	if (rtc->ops == NULL)
		err = -ENODEV;
	else if (!rtc->ops->read_alarm)
		err = -EINVAL;
	else {
		memset(alarm, 0, sizeof(struct rtc_wkalrm));
		alarm->enabled = rtc->aie_timer.enabled;
		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
	}
	mutex_unlock(&rtc->ops_lock);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_read_alarm);

int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	struct rtc_time tm;
	long now, scheduled;
	int err;

	err = rtc_valid_tm(&alarm->time);
	if (err)
		return err;
	rtc_tm_to_time(&alarm->time, &scheduled);

	/* Make sure we're not setting alarms in the past */
	err = __rtc_read_time(rtc, &tm);
	rtc_tm_to_time(&tm, &now);
	if (scheduled <= now)
		return -ETIME;
	/*
	 * XXX - We just checked to make sure the alarm time is not
	 * in the past, but there is still a race window where if
	 * the is alarm set for the next second and the second ticks
	 * over right here, before we set the alarm.
	 */

	if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->set_alarm)
		err = -EINVAL;
	else
		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);

	return err;
}

int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	int err;

	err = rtc_valid_tm(&alarm->time);
	if (err != 0)
		return err;

	err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;
	if (rtc->aie_timer.enabled) {
		rtc_timer_remove(rtc, &rtc->aie_timer);
	}
	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
	rtc->aie_timer.period = ktime_set(0, 0);
	if (alarm->enabled) {
		err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
	}
	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_set_alarm);

int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
{
	int err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	if (rtc->aie_timer.enabled != enabled) {
		if (enabled)
			err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
		else
			rtc_timer_remove(rtc, &rtc->aie_timer);
	}

	if (err)
		return err;

	if (!rtc->ops)
		err = -ENODEV;
	else if (!rtc->ops->alarm_irq_enable)
		err = -EINVAL;
	else
		err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);

	mutex_unlock(&rtc->ops_lock);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);

int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
{
	int err = mutex_lock_interruptible(&rtc->ops_lock);
	if (err)
		return err;

	/* make sure we're changing state */
	if (rtc->uie_rtctimer.enabled == enabled)
		goto out;

	if (enabled) {
		struct rtc_time tm;
		ktime_t now, onesec;

		__rtc_read_time(rtc, &tm);
		onesec = ktime_set(1, 0);
		now = rtc_tm_to_ktime(tm);
		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
		rtc->uie_rtctimer.period = ktime_set(1, 0);
		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
	} else
		rtc_timer_remove(rtc, &rtc->uie_rtctimer);

out:
	mutex_unlock(&rtc->ops_lock);
	return err;

}
EXPORT_SYMBOL_GPL(rtc_update_irq_enable);


/**
 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
 * @rtc: pointer to the rtc device
 *
 * This function is called when an AIE, UIE or PIE mode interrupt
 * has occured (or been emulated).
 *
 * Triggers the registered irq_task function callback.
 */
static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
{
	unsigned long flags;

	/* mark one irq of the appropriate mode */
	spin_lock_irqsave(&rtc->irq_lock, flags);
	rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
	spin_unlock_irqrestore(&rtc->irq_lock, flags);

	/* call the task func */
	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task)
		rtc->irq_task->func(rtc->irq_task->private_data);
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	wake_up_interruptible(&rtc->irq_queue);
	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
}


/**
 * rtc_aie_update_irq - AIE mode rtctimer hook
 * @private: pointer to the rtc_device
 *
 * This functions is called when the aie_timer expires.
 */
void rtc_aie_update_irq(void *private)
{
	struct rtc_device *rtc = (struct rtc_device *)private;
	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
}


/**
 * rtc_uie_update_irq - UIE mode rtctimer hook
 * @private: pointer to the rtc_device
 *
 * This functions is called when the uie_timer expires.
 */
void rtc_uie_update_irq(void *private)
{
	struct rtc_device *rtc = (struct rtc_device *)private;
	rtc_handle_legacy_irq(rtc, 1,  RTC_UF);
}


/**
 * rtc_pie_update_irq - PIE mode hrtimer hook
 * @timer: pointer to the pie mode hrtimer
 *
 * This function is used to emulate PIE mode interrupts
 * using an hrtimer. This function is called when the periodic
 * hrtimer expires.
 */
enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
{
	struct rtc_device *rtc;
	ktime_t period;
	int count;
	rtc = container_of(timer, struct rtc_device, pie_timer);

	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	count = hrtimer_forward_now(timer, period);

	rtc_handle_legacy_irq(rtc, count, RTC_PF);

	return HRTIMER_RESTART;
}

/**
 * rtc_update_irq - Triggered when a RTC interrupt occurs.
 * @rtc: the rtc device
 * @num: how many irqs are being reported (usually one)
 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
 * Context: any
 */
void rtc_update_irq(struct rtc_device *rtc,
		unsigned long num, unsigned long events)
{
	schedule_work(&rtc->irqwork);
}
EXPORT_SYMBOL_GPL(rtc_update_irq);

static int __rtc_match(struct device *dev, void *data)
{
	char *name = (char *)data;

	if (strcmp(dev_name(dev), name) == 0)
		return 1;
	return 0;
}

struct rtc_device *rtc_class_open(char *name)
{
	struct device *dev;
	struct rtc_device *rtc = NULL;

	dev = class_find_device(rtc_class, NULL, name, __rtc_match);
	if (dev)
		rtc = to_rtc_device(dev);

	if (rtc) {
		if (!try_module_get(rtc->owner)) {
			put_device(dev);
			rtc = NULL;
		}
	}

	return rtc;
}
EXPORT_SYMBOL_GPL(rtc_class_open);

void rtc_class_close(struct rtc_device *rtc)
{
	module_put(rtc->owner);
	put_device(&rtc->dev);
}
EXPORT_SYMBOL_GPL(rtc_class_close);

int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
{
	int retval = -EBUSY;

	if (task == NULL || task->func == NULL)
		return -EINVAL;

	/* Cannot register while the char dev is in use */
	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
		return -EBUSY;

	spin_lock_irq(&rtc->irq_task_lock);
	if (rtc->irq_task == NULL) {
		rtc->irq_task = task;
		retval = 0;
	}
	spin_unlock_irq(&rtc->irq_task_lock);

	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);

	return retval;
}
EXPORT_SYMBOL_GPL(rtc_irq_register);

void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
{
	spin_lock_irq(&rtc->irq_task_lock);
	if (rtc->irq_task == task)
		rtc->irq_task = NULL;
	spin_unlock_irq(&rtc->irq_task_lock);
}
EXPORT_SYMBOL_GPL(rtc_irq_unregister);

/**
 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
 * @rtc: the rtc device
 * @task: currently registered with rtc_irq_register()
 * @enabled: true to enable periodic IRQs
 * Context: any
 *
 * Note that rtc_irq_set_freq() should previously have been used to
 * specify the desired frequency of periodic IRQ task->func() callbacks.
 */
int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
{
	int err = 0;
	unsigned long flags;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task != NULL && task == NULL)
		err = -EBUSY;
	if (rtc->irq_task != task)
		err = -EACCES;

	if (enabled) {
		ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
		hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
	} else {
		hrtimer_cancel(&rtc->pie_timer);
	}
	rtc->pie_enabled = enabled;
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);

	return err;
}
EXPORT_SYMBOL_GPL(rtc_irq_set_state);

/**
 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
 * @rtc: the rtc device
 * @task: currently registered with rtc_irq_register()
 * @freq: positive frequency with which task->func() will be called
 * Context: any
 *
 * Note that rtc_irq_set_state() is used to enable or disable the
 * periodic IRQs.
 */
int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
{
	int err = 0;
	unsigned long flags;

	spin_lock_irqsave(&rtc->irq_task_lock, flags);
	if (rtc->irq_task != NULL && task == NULL)
		err = -EBUSY;
	if (rtc->irq_task != task)
		err = -EACCES;
	if (err == 0) {
		rtc->irq_freq = freq;
		if (rtc->pie_enabled) {
			ktime_t period;
			hrtimer_cancel(&rtc->pie_timer);
			period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
			hrtimer_start(&rtc->pie_timer, period,
					HRTIMER_MODE_REL);
		}
	}
	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
	return err;
}
EXPORT_SYMBOL_GPL(rtc_irq_set_freq);

/**
 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
 * @rtc rtc device
 * @timer timer being added.
 *
 * Enqueues a timer onto the rtc devices timerqueue and sets
 * the next alarm event appropriately.
 *
 * Sets the enabled bit on the added timer.
 *
 * Must hold ops_lock for proper serialization of timerqueue
 */
static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
{
	timer->enabled = 1;
	timerqueue_add(&rtc->timerqueue, &timer->node);
	if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
		struct rtc_wkalrm alarm;
		int err;
		alarm.time = rtc_ktime_to_tm(timer->node.expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			schedule_work(&rtc->irqwork);
		else if (err) {
			timerqueue_del(&rtc->timerqueue, &timer->node);
			timer->enabled = 0;
			return err;
		}
	}
	return 0;
}

/**
 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
 * @rtc rtc device
 * @timer timer being removed.
 *
 * Removes a timer onto the rtc devices timerqueue and sets
 * the next alarm event appropriately.
 *
 * Clears the enabled bit on the removed timer.
 *
 * Must hold ops_lock for proper serialization of timerqueue
 */
static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
{
	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
	timerqueue_del(&rtc->timerqueue, &timer->node);
	timer->enabled = 0;
	if (next == &timer->node) {
		struct rtc_wkalrm alarm;
		int err;
		next = timerqueue_getnext(&rtc->timerqueue);
		if (!next)
			return;
		alarm.time = rtc_ktime_to_tm(next->expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			schedule_work(&rtc->irqwork);
	}
}

/**
 * rtc_timer_do_work - Expires rtc timers
 * @rtc rtc device
 * @timer timer being removed.
 *
 * Expires rtc timers. Reprograms next alarm event if needed.
 * Called via worktask.
 *
 * Serializes access to timerqueue via ops_lock mutex
 */
void rtc_timer_do_work(struct work_struct *work)
{
	struct rtc_timer *timer;
	struct timerqueue_node *next;
	ktime_t now;
	struct rtc_time tm;

	struct rtc_device *rtc =
		container_of(work, struct rtc_device, irqwork);

	mutex_lock(&rtc->ops_lock);
again:
	__rtc_read_time(rtc, &tm);
	now = rtc_tm_to_ktime(tm);
	while ((next = timerqueue_getnext(&rtc->timerqueue))) {
		if (next->expires.tv64 > now.tv64)
			break;

		/* expire timer */
		timer = container_of(next, struct rtc_timer, node);
		timerqueue_del(&rtc->timerqueue, &timer->node);
		timer->enabled = 0;
		if (timer->task.func)
			timer->task.func(timer->task.private_data);

		/* Re-add/fwd periodic timers */
		if (ktime_to_ns(timer->period)) {
			timer->node.expires = ktime_add(timer->node.expires,
							timer->period);
			timer->enabled = 1;
			timerqueue_add(&rtc->timerqueue, &timer->node);
		}
	}

	/* Set next alarm */
	if (next) {
		struct rtc_wkalrm alarm;
		int err;
		alarm.time = rtc_ktime_to_tm(next->expires);
		alarm.enabled = 1;
		err = __rtc_set_alarm(rtc, &alarm);
		if (err == -ETIME)
			goto again;
	}

	mutex_unlock(&rtc->ops_lock);
}


/* rtc_timer_init - Initializes an rtc_timer
 * @timer: timer to be intiialized
 * @f: function pointer to be called when timer fires
 * @data: private data passed to function pointer
 *
 * Kernel interface to initializing an rtc_timer.
 */
void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
{
	timerqueue_init(&timer->node);
	timer->enabled = 0;
	timer->task.func = f;
	timer->task.private_data = data;
}

/* rtc_timer_start - Sets an rtc_timer to fire in the future
 * @ rtc: rtc device to be used
 * @ timer: timer being set
 * @ expires: time at which to expire the timer
 * @ period: period that the timer will recur
 *
 * Kernel interface to set an rtc_timer
 */
int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
			ktime_t expires, ktime_t period)
{
	int ret = 0;
	mutex_lock(&rtc->ops_lock);
	if (timer->enabled)
		rtc_timer_remove(rtc, timer);

	timer->node.expires = expires;
	timer->period = period;

	ret = rtc_timer_enqueue(rtc, timer);

	mutex_unlock(&rtc->ops_lock);
	return ret;
}

/* rtc_timer_cancel - Stops an rtc_timer
 * @ rtc: rtc device to be used
 * @ timer: timer being set
 *
 * Kernel interface to cancel an rtc_timer
 */
int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
{
	int ret = 0;
	mutex_lock(&rtc->ops_lock);
	if (timer->enabled)
		rtc_timer_remove(rtc, timer);
	mutex_unlock(&rtc->ops_lock);
	return ret;
}
Commit	Line	Data
0c86edc0 AZ	1	/*
	2	* RTC subsystem, interface functions
	3	*
	4	* Copyright (C) 2005 Tower Technologies
	5	* Author: Alessandro Zummo <a.zummo@towertech.it>
	6	*
	7	* based on arch/arm/common/rtctime.c
	8	*
	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.
	12	*/
	13
	14	#include <linux/rtc.h>
d43c36dc	15	#include <linux/sched.h>
97144c67	16	#include <linux/log2.h>
6610e089	17	#include <linux/workqueue.h>
0c86edc0	18
aa0be0f4 JS	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);
	21
6610e089	22	static int __rtc_read_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	23	{
0c86edc0 AZ	24	int err;
0c86edc0 AZ	25	if (!rtc->ops)
	26	err = -ENODEV;
	27	else if (!rtc->ops->read_time)
	28	err = -EINVAL;
	29	else {
	30	memset(tm, 0, sizeof(struct rtc_time));
cd966209	31	err = rtc->ops->read_time(rtc->dev.parent, tm);
0c86edc0	32	}
6610e089 JS	33	return err;
	34	}
	35
	36	int rtc_read_time(struct rtc_device rtc, struct rtc_time tm)
	37	{
	38	int err;
0c86edc0	39
6610e089 JS	40	err = mutex_lock_interruptible(&rtc->ops_lock);
	41	if (err)
	42	return err;
	43
	44	err = __rtc_read_time(rtc, tm);
0c86edc0 AZ	45	mutex_unlock(&rtc->ops_lock);
	46	return err;
	47	}
	48	EXPORT_SYMBOL_GPL(rtc_read_time);
	49
ab6a2d70	50	int rtc_set_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	51	{
0c86edc0 AZ	52	int err;
0c86edc0 AZ	53
	54	err = rtc_valid_tm(tm);
	55	if (err != 0)
	56	return err;
	57
	58	err = mutex_lock_interruptible(&rtc->ops_lock);
	59	if (err)
b68bb263	60	return err;
0c86edc0 AZ	61
	62	if (!rtc->ops)
	63	err = -ENODEV;
bbccf83f	64	else if (rtc->ops->set_time)
cd966209	65	err = rtc->ops->set_time(rtc->dev.parent, tm);
bbccf83f AZ	66	else if (rtc->ops->set_mmss) {
	67	unsigned long secs;
	68	err = rtc_tm_to_time(tm, &secs);
	69	if (err == 0)
	70	err = rtc->ops->set_mmss(rtc->dev.parent, secs);
	71	} else
	72	err = -EINVAL;
0c86edc0 AZ	73
	74	mutex_unlock(&rtc->ops_lock);
	75	return err;
	76	}
	77	EXPORT_SYMBOL_GPL(rtc_set_time);
	78
ab6a2d70	79	int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
0c86edc0 AZ	80	{
0c86edc0 AZ	81	int err;
0c86edc0 AZ	82
	83	err = mutex_lock_interruptible(&rtc->ops_lock);
	84	if (err)
b68bb263	85	return err;
0c86edc0 AZ	86
	87	if (!rtc->ops)
	88	err = -ENODEV;
	89	else if (rtc->ops->set_mmss)
cd966209	90	err = rtc->ops->set_mmss(rtc->dev.parent, secs);
0c86edc0 AZ	91	else if (rtc->ops->read_time && rtc->ops->set_time) {
	92	struct rtc_time new, old;
	93
cd966209	94	err = rtc->ops->read_time(rtc->dev.parent, &old);
0c86edc0 AZ	95	if (err == 0) {
	96	rtc_time_to_tm(secs, &new);
	97
	98	/*
	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.
	103	*/
	104	if (!((old.tm_hour == 23 && old.tm_min == 59) \|\|
	105	(new.tm_hour == 23 && new.tm_min == 59)))
cd966209	106	err = rtc->ops->set_time(rtc->dev.parent,
ab6a2d70	107	&new);
0c86edc0 AZ	108	}
	109	}
	110	else
	111	err = -EINVAL;
	112
	113	mutex_unlock(&rtc->ops_lock);
	114
	115	return err;
	116	}
	117	EXPORT_SYMBOL_GPL(rtc_set_mmss);
	118
6610e089	119	int rtc_read_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	120	{
0c86edc0 AZ	121	int err;
0c86edc0 AZ	122
	123	err = mutex_lock_interruptible(&rtc->ops_lock);
	124	if (err)
b68bb263	125	return err;
d5553a55 JS	126	if (rtc->ops == NULL)
	127	err = -ENODEV;
	128	else if (!rtc->ops->read_alarm)
	129	err = -EINVAL;
	130	else {
	131	memset(alarm, 0, sizeof(struct rtc_wkalrm));
	132	alarm->enabled = rtc->aie_timer.enabled;
6610e089	133	alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
d5553a55	134	}
0c86edc0	135	mutex_unlock(&rtc->ops_lock);
6610e089	136
d5553a55	137	return err;
0c86edc0	138	}
6610e089	139	EXPORT_SYMBOL_GPL(rtc_read_alarm);
0e36a9a4	140
6610e089	141	int __rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0e36a9a4	142	{
6610e089 JS	143	struct rtc_time tm;
6610e089 JS	144	long now, scheduled;
0e36a9a4	145	int err;
0e36a9a4	146
6610e089 JS	147	err = rtc_valid_tm(&alarm->time);
6610e089 JS	148	if (err)
0e36a9a4	149	return err;
6610e089	150	rtc_tm_to_time(&alarm->time, &scheduled);
a01cc657	151
6610e089 JS	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)
	156	return -ETIME;
	157	/*
	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.
a01cc657	162	*/
a01cc657	163
6610e089 JS	164	if (!rtc->ops)
	165	err = -ENODEV;
	166	else if (!rtc->ops->set_alarm)
	167	err = -EINVAL;
	168	else
	169	err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
	170
	171	return err;
0e36a9a4	172	}
0c86edc0	173
ab6a2d70	174	int rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	175	{
0c86edc0 AZ	176	int err;
0c86edc0	177
f8245c26 DB	178	err = rtc_valid_tm(&alarm->time);
	179	if (err != 0)
	180	return err;
	181
0c86edc0 AZ	182	err = mutex_lock_interruptible(&rtc->ops_lock);
0c86edc0 AZ	183	if (err)
b68bb263	184	return err;
6610e089	185	if (rtc->aie_timer.enabled) {
96c8f06a	186	rtc_timer_remove(rtc, &rtc->aie_timer);
6610e089 JS	187	}
	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) {
aa0be0f4	191	err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
6610e089	192	}
0c86edc0	193	mutex_unlock(&rtc->ops_lock);
aa0be0f4	194	return err;
0c86edc0 AZ	195	}
	196	EXPORT_SYMBOL_GPL(rtc_set_alarm);
	197
099e6576 AZ	198	int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
	199	{
	200	int err = mutex_lock_interruptible(&rtc->ops_lock);
	201	if (err)
	202	return err;
	203
6610e089	204	if (rtc->aie_timer.enabled != enabled) {
aa0be0f4 JS	205	if (enabled)
	206	err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
	207	else
96c8f06a	208	rtc_timer_remove(rtc, &rtc->aie_timer);
6610e089 JS	209	}
6610e089 JS	210
aa0be0f4 JS	211	if (err)
	212	return err;
	213
099e6576 AZ	214	if (!rtc->ops)
	215	err = -ENODEV;
	216	else if (!rtc->ops->alarm_irq_enable)
	217	err = -EINVAL;
	218	else
	219	err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
	220
	221	mutex_unlock(&rtc->ops_lock);
	222	return err;
	223	}
	224	EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
	225
	226	int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
	227	{
	228	int err = mutex_lock_interruptible(&rtc->ops_lock);
	229	if (err)
	230	return err;
	231
6610e089 JS	232	/* make sure we're changing state */
	233	if (rtc->uie_rtctimer.enabled == enabled)
	234	goto out;
	235
	236	if (enabled) {
	237	struct rtc_time tm;
	238	ktime_t now, onesec;
	239
	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);
aa0be0f4 JS	245	err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
aa0be0f4 JS	246	} else
96c8f06a	247	rtc_timer_remove(rtc, &rtc->uie_rtctimer);
099e6576	248
6610e089	249	out:
099e6576	250	mutex_unlock(&rtc->ops_lock);
099e6576	251	return err;
6610e089	252
099e6576 AZ	253	}
	254	EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
	255
6610e089	256
d728b1e6	257	/**
6610e089 JS	258	* rtc_handle_legacy_irq - AIE, UIE and PIE event hook
	259	* @rtc: pointer to the rtc device
	260	*
	261	* This function is called when an AIE, UIE or PIE mode interrupt
	262	* has occured (or been emulated).
	263	*
	264	* Triggers the registered irq_task function callback.
d728b1e6	265	*/
6610e089	266	static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
0c86edc0	267	{
e6229bec AN	268	unsigned long flags;
e6229bec AN	269
6610e089	270	/* mark one irq of the appropriate mode */
e6229bec	271	spin_lock_irqsave(&rtc->irq_lock, flags);
6610e089	272	rtc->irq_data = (rtc->irq_data + (num << 8)) \| (RTC_IRQF\|mode);
e6229bec	273	spin_unlock_irqrestore(&rtc->irq_lock, flags);
0c86edc0	274
6610e089	275	/* call the task func */
e6229bec	276	spin_lock_irqsave(&rtc->irq_task_lock, flags);
0c86edc0 AZ	277	if (rtc->irq_task)
0c86edc0 AZ	278	rtc->irq_task->func(rtc->irq_task->private_data);
e6229bec	279	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	280
	281	wake_up_interruptible(&rtc->irq_queue);
	282	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
	283	}
6610e089 JS	284
	285
	286	/**
	287	* rtc_aie_update_irq - AIE mode rtctimer hook
	288	* @private: pointer to the rtc_device
	289	*
	290	* This functions is called when the aie_timer expires.
	291	*/
	292	void rtc_aie_update_irq(void *private)
	293	{
	294	struct rtc_device rtc = (struct rtc_device )private;
	295	rtc_handle_legacy_irq(rtc, 1, RTC_AF);
	296	}
	297
	298
	299	/**
	300	* rtc_uie_update_irq - UIE mode rtctimer hook
	301	* @private: pointer to the rtc_device
	302	*
	303	* This functions is called when the uie_timer expires.
	304	*/
	305	void rtc_uie_update_irq(void *private)
	306	{
	307	struct rtc_device rtc = (struct rtc_device )private;
	308	rtc_handle_legacy_irq(rtc, 1, RTC_UF);
	309	}
	310
	311
	312	/**
	313	* rtc_pie_update_irq - PIE mode hrtimer hook
	314	* @timer: pointer to the pie mode hrtimer
	315	*
	316	* This function is used to emulate PIE mode interrupts
	317	* using an hrtimer. This function is called when the periodic
	318	* hrtimer expires.
	319	*/
	320	enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
	321	{
	322	struct rtc_device *rtc;
	323	ktime_t period;
	324	int count;
	325	rtc = container_of(timer, struct rtc_device, pie_timer);
	326
	327	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	328	count = hrtimer_forward_now(timer, period);
	329
	330	rtc_handle_legacy_irq(rtc, count, RTC_PF);
	331
	332	return HRTIMER_RESTART;
	333	}
	334
	335	/**
	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
	340	* Context: any
	341	*/
	342	void rtc_update_irq(struct rtc_device *rtc,
	343	unsigned long num, unsigned long events)
	344	{
	345	schedule_work(&rtc->irqwork);
	346	}
0c86edc0 AZ	347	EXPORT_SYMBOL_GPL(rtc_update_irq);
0c86edc0 AZ	348
71da8905 DY	349	static int __rtc_match(struct device dev, void data)
	350	{
	351	char name = (char )data;
	352
d4afc76c	353	if (strcmp(dev_name(dev), name) == 0)
71da8905 DY	354	return 1;
	355	return 0;
	356	}
	357
ab6a2d70	358	struct rtc_device rtc_class_open(char name)
0c86edc0	359	{
cd966209	360	struct device *dev;
ab6a2d70	361	struct rtc_device *rtc = NULL;
0c86edc0	362
695794ae	363	dev = class_find_device(rtc_class, NULL, name, __rtc_match);
71da8905 DY	364	if (dev)
71da8905 DY	365	rtc = to_rtc_device(dev);
0c86edc0	366
ab6a2d70 DB	367	if (rtc) {
ab6a2d70 DB	368	if (!try_module_get(rtc->owner)) {
cd966209	369	put_device(dev);
ab6a2d70 DB	370	rtc = NULL;
ab6a2d70 DB	371	}
0c86edc0	372	}
0c86edc0	373
ab6a2d70	374	return rtc;
0c86edc0 AZ	375	}
	376	EXPORT_SYMBOL_GPL(rtc_class_open);
	377
ab6a2d70	378	void rtc_class_close(struct rtc_device *rtc)
0c86edc0	379	{
ab6a2d70	380	module_put(rtc->owner);
cd966209	381	put_device(&rtc->dev);
0c86edc0 AZ	382	}
	383	EXPORT_SYMBOL_GPL(rtc_class_close);
	384
ab6a2d70	385	int rtc_irq_register(struct rtc_device rtc, struct rtc_task task)
0c86edc0 AZ	386	{
0c86edc0 AZ	387	int retval = -EBUSY;
0c86edc0 AZ	388
	389	if (task == NULL \|\| task->func == NULL)
	390	return -EINVAL;
	391
d691eb90	392	/* Cannot register while the char dev is in use */
372a302e	393	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
d691eb90 AZ	394	return -EBUSY;
d691eb90 AZ	395
d728b1e6	396	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	397	if (rtc->irq_task == NULL) {
	398	rtc->irq_task = task;
	399	retval = 0;
	400	}
d728b1e6	401	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0	402
372a302e	403	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
d691eb90	404
0c86edc0 AZ	405	return retval;
	406	}
	407	EXPORT_SYMBOL_GPL(rtc_irq_register);
	408
ab6a2d70	409	void rtc_irq_unregister(struct rtc_device rtc, struct rtc_task task)
0c86edc0	410	{
d728b1e6	411	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	412	if (rtc->irq_task == task)
0c86edc0 AZ	413	rtc->irq_task = NULL;
d728b1e6	414	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	415	}
	416	EXPORT_SYMBOL_GPL(rtc_irq_unregister);
	417
97144c67 DB	418	/**
	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
	423	* Context: any
	424	*
	425	* Note that rtc_irq_set_freq() should previously have been used to
	426	* specify the desired frequency of periodic IRQ task->func() callbacks.
	427	*/
ab6a2d70	428	int rtc_irq_set_state(struct rtc_device rtc, struct rtc_task task, int enabled)
0c86edc0 AZ	429	{
	430	int err = 0;
	431	unsigned long flags;
0c86edc0 AZ	432
0c86edc0 AZ	433	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	434	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	435	err = -EBUSY;
0c86edc0	436	if (rtc->irq_task != task)
d691eb90	437	err = -EACCES;
0c86edc0	438
6610e089 JS	439	if (enabled) {
	440	ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	441	hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
	442	} else {
	443	hrtimer_cancel(&rtc->pie_timer);
	444	}
	445	rtc->pie_enabled = enabled;
	446	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	447
	448	return err;
	449	}
	450	EXPORT_SYMBOL_GPL(rtc_irq_set_state);
	451
97144c67 DB	452	/**
	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
	457	* Context: any
	458	*
	459	* Note that rtc_irq_set_state() is used to enable or disable the
	460	* periodic IRQs.
	461	*/
ab6a2d70	462	int rtc_irq_set_freq(struct rtc_device rtc, struct rtc_task task, int freq)
0c86edc0	463	{
56f10c63	464	int err = 0;
0c86edc0	465	unsigned long flags;
0c86edc0	466
0c86edc0	467	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	468	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	469	err = -EBUSY;
0c86edc0	470	if (rtc->irq_task != task)
d691eb90	471	err = -EACCES;
0c86edc0	472	if (err == 0) {
6610e089 JS	473	rtc->irq_freq = freq;
	474	if (rtc->pie_enabled) {
	475	ktime_t period;
	476	hrtimer_cancel(&rtc->pie_timer);
	477	period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
	478	hrtimer_start(&rtc->pie_timer, period,
	479	HRTIMER_MODE_REL);
	480	}
0c86edc0	481	}
6610e089	482	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
0c86edc0 AZ	483	return err;
0c86edc0 AZ	484	}
2601a464	485	EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
6610e089 JS	486
6610e089 JS	487	/**
96c8f06a	488	* rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
6610e089 JS	489	* @rtc rtc device
	490	* @timer timer being added.
	491	*
	492	* Enqueues a timer onto the rtc devices timerqueue and sets
	493	* the next alarm event appropriately.
	494	*
aa0be0f4 JS	495	* Sets the enabled bit on the added timer.
aa0be0f4 JS	496	*
6610e089 JS	497	* Must hold ops_lock for proper serialization of timerqueue
6610e089 JS	498	*/
aa0be0f4	499	static int rtc_timer_enqueue(struct rtc_device rtc, struct rtc_timer timer)
6610e089	500	{
aa0be0f4	501	timer->enabled = 1;
6610e089 JS	502	timerqueue_add(&rtc->timerqueue, &timer->node);
	503	if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
	504	struct rtc_wkalrm alarm;
	505	int err;
	506	alarm.time = rtc_ktime_to_tm(timer->node.expires);
	507	alarm.enabled = 1;
	508	err = __rtc_set_alarm(rtc, &alarm);
	509	if (err == -ETIME)
	510	schedule_work(&rtc->irqwork);
aa0be0f4 JS	511	else if (err) {
	512	timerqueue_del(&rtc->timerqueue, &timer->node);
	513	timer->enabled = 0;
	514	return err;
	515	}
6610e089	516	}
aa0be0f4	517	return 0;
6610e089 JS	518	}
	519
	520	/**
96c8f06a	521	* rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
6610e089 JS	522	* @rtc rtc device
	523	* @timer timer being removed.
	524	*
	525	* Removes a timer onto the rtc devices timerqueue and sets
	526	* the next alarm event appropriately.
	527	*
aa0be0f4 JS	528	* Clears the enabled bit on the removed timer.
aa0be0f4 JS	529	*
6610e089 JS	530	* Must hold ops_lock for proper serialization of timerqueue
6610e089 JS	531	*/
aa0be0f4	532	static void rtc_timer_remove(struct rtc_device rtc, struct rtc_timer timer)
6610e089 JS	533	{
	534	struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
	535	timerqueue_del(&rtc->timerqueue, &timer->node);
aa0be0f4	536	timer->enabled = 0;
6610e089 JS	537	if (next == &timer->node) {
	538	struct rtc_wkalrm alarm;
	539	int err;
	540	next = timerqueue_getnext(&rtc->timerqueue);
	541	if (!next)
	542	return;
	543	alarm.time = rtc_ktime_to_tm(next->expires);
	544	alarm.enabled = 1;
	545	err = __rtc_set_alarm(rtc, &alarm);
	546	if (err == -ETIME)
	547	schedule_work(&rtc->irqwork);
	548	}
	549	}
	550
	551	/**
96c8f06a	552	* rtc_timer_do_work - Expires rtc timers
6610e089 JS	553	* @rtc rtc device
	554	* @timer timer being removed.
	555	*
	556	* Expires rtc timers. Reprograms next alarm event if needed.
	557	* Called via worktask.
	558	*
	559	* Serializes access to timerqueue via ops_lock mutex
	560	*/
96c8f06a	561	void rtc_timer_do_work(struct work_struct *work)
6610e089 JS	562	{
	563	struct rtc_timer *timer;
	564	struct timerqueue_node *next;
	565	ktime_t now;
	566	struct rtc_time tm;
	567
	568	struct rtc_device *rtc =
	569	container_of(work, struct rtc_device, irqwork);
	570
	571	mutex_lock(&rtc->ops_lock);
	572	again:
	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)
	577	break;
	578
	579	/* expire timer */
	580	timer = container_of(next, struct rtc_timer, node);
	581	timerqueue_del(&rtc->timerqueue, &timer->node);
	582	timer->enabled = 0;
	583	if (timer->task.func)
	584	timer->task.func(timer->task.private_data);
	585
	586	/* Re-add/fwd periodic timers */
	587	if (ktime_to_ns(timer->period)) {
	588	timer->node.expires = ktime_add(timer->node.expires,
	589	timer->period);
	590	timer->enabled = 1;
	591	timerqueue_add(&rtc->timerqueue, &timer->node);
	592	}
	593	}
	594
	595	/* Set next alarm */
	596	if (next) {
	597	struct rtc_wkalrm alarm;
	598	int err;
	599	alarm.time = rtc_ktime_to_tm(next->expires);
	600	alarm.enabled = 1;
	601	err = __rtc_set_alarm(rtc, &alarm);
	602	if (err == -ETIME)
	603	goto again;
	604	}
	605
	606	mutex_unlock(&rtc->ops_lock);
	607	}
	608
	609
96c8f06a	610	/* rtc_timer_init - Initializes an rtc_timer
6610e089 JS	611	* @timer: timer to be intiialized
	612	* @f: function pointer to be called when timer fires
	613	* @data: private data passed to function pointer
	614	*
	615	* Kernel interface to initializing an rtc_timer.
	616	*/
96c8f06a	617	void rtc_timer_init(struct rtc_timer timer, void (f)(void* p), void* data)
6610e089 JS	618	{
	619	timerqueue_init(&timer->node);
	620	timer->enabled = 0;
	621	timer->task.func = f;
	622	timer->task.private_data = data;
	623	}
	624
96c8f06a	625	/* rtc_timer_start - Sets an rtc_timer to fire in the future
6610e089 JS	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
	630	*
	631	* Kernel interface to set an rtc_timer
	632	*/
96c8f06a	633	int rtc_timer_start(struct rtc_device rtc, struct rtc_timer timer,
6610e089 JS	634	ktime_t expires, ktime_t period)
	635	{
	636	int ret = 0;
	637	mutex_lock(&rtc->ops_lock);
	638	if (timer->enabled)
96c8f06a	639	rtc_timer_remove(rtc, timer);
6610e089 JS	640
	641	timer->node.expires = expires;
	642	timer->period = period;
	643
aa0be0f4	644	ret = rtc_timer_enqueue(rtc, timer);
6610e089 JS	645
	646	mutex_unlock(&rtc->ops_lock);
	647	return ret;
	648	}
	649
96c8f06a	650	/* rtc_timer_cancel - Stops an rtc_timer
6610e089 JS	651	* @ rtc: rtc device to be used
	652	* @ timer: timer being set
	653	*
	654	* Kernel interface to cancel an rtc_timer
	655	*/
96c8f06a	656	int rtc_timer_cancel(struct rtc_device rtc, struct rtc_timer timer)
6610e089 JS	657	{
	658	int ret = 0;
	659	mutex_lock(&rtc->ops_lock);
	660	if (timer->enabled)
96c8f06a	661	rtc_timer_remove(rtc, timer);
6610e089 JS	662	mutex_unlock(&rtc->ops_lock);
	663	return ret;
	664	}
	665
	666