[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/log2.h>

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

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

	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);
	}

	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 -EBUSY;

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

	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 -EBUSY;

	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);

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

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

	if (rtc->ops == NULL)
		err = -ENODEV;
	else if (!rtc->ops->read_alarm)
		err = -EINVAL;
	else {
		memset(alarm, 0, sizeof(struct rtc_wkalrm));
		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
	}

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

int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
	int err;
	struct rtc_time before, now;
	int first_time = 1;

	/* The lower level RTC driver may not be capable of filling
	 * in all fields of the rtc_time struct (eg. rtc-cmos),
	 * and so might instead return -1 in some fields.
	 * We deal with that here by grabbing a current RTC timestamp
	 * and using values from that for any missing (-1) values.
	 *
	 * But this can be racey, because some fields of the RTC timestamp
	 * may have wrapped in the interval since we read the RTC alarm,
	 * which would lead to us inserting inconsistent values in place
	 * of the -1 fields.
	 *
	 * Reading the alarm and timestamp in the reverse sequence
	 * would have the same race condition, and not solve the issue.
	 *
	 * So, we must first read the RTC timestamp,
	 * then read the RTC alarm value,
	 * and then read a second RTC timestamp.
	 *
	 * If any fields of the second timestamp have changed
	 * when compared with the first timestamp, then we know
	 * our timestamp may be inconsistent with that used by
	 * the low-level rtc_read_alarm_internal() function.
	 *
	 * So, when the two timestamps disagree, we just loop and do
	 * the process again to get a fully consistent set of values.
	 *
	 * This could all instead be done in the lower level driver,
	 * but since more than one lower level RTC implementation needs it,
	 * then it's probably best best to do it here instead of there..
	 */

	/* Get the "before" timestamp */
	err = rtc_read_time(rtc, &before);
	if (err < 0)
		return err;
	do {
		if (!first_time)
			memcpy(&before, &now, sizeof(struct rtc_time));
		first_time = 0;

		/* get the RTC alarm values, which may be incomplete */
		err = rtc_read_alarm_internal(rtc, alarm);
		if (err)
			return err;
		if (!alarm->enabled)
			return 0;

		/* get the "after" timestamp, to detect wrapped fields */
		err = rtc_read_time(rtc, &now);
		if (err < 0)
			return err;

		/* note that tm_sec is a "don't care" value here: */
	} while (   before.tm_min   != now.tm_min
		 || before.tm_hour  != now.tm_hour
		 || before.tm_mon   != now.tm_mon
		 || before.tm_year  != now.tm_year
		 || before.tm_isdst != now.tm_isdst);

	/* Fill in any missing alarm fields using the timestamp */
	if (alarm->time.tm_sec == -1)
		alarm->time.tm_sec = now.tm_sec;
	if (alarm->time.tm_min == -1)
		alarm->time.tm_min = now.tm_min;
	if (alarm->time.tm_hour == -1)
		alarm->time.tm_hour = now.tm_hour;
	if (alarm->time.tm_mday == -1)
		alarm->time.tm_mday = now.tm_mday;
	if (alarm->time.tm_mon == -1)
		alarm->time.tm_mon = now.tm_mon;
	if (alarm->time.tm_year == -1)
		alarm->time.tm_year = now.tm_year;
	return 0;
}
EXPORT_SYMBOL_GPL(rtc_read_alarm);

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 -EBUSY;

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

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

/**
 * rtc_update_irq - report RTC periodic, alarm, and/or update irqs
 * @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: in_interrupt(), irqs blocked
 */
void rtc_update_irq(struct rtc_device *rtc,
		unsigned long num, unsigned long events)
{
	spin_lock(&rtc->irq_lock);
	rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
	spin_unlock(&rtc->irq_lock);

	spin_lock(&rtc->irq_task_lock);
	if (rtc->irq_task)
		rtc->irq_task->func(rtc->irq_task->private_data);
	spin_unlock(&rtc->irq_task_lock);

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

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

	down(&rtc_class->sem);
	list_for_each_entry(dev, &rtc_class->devices, node) {
		if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) {
			dev = get_device(dev);
			if (dev)
				rtc = to_rtc_device(dev);
			break;
		}
	}

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

	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(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(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;

	if (rtc->ops->irq_set_state == NULL)
		return -ENXIO;

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

	if (err == 0)
		err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);

	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;

	if (rtc->ops->irq_set_freq == NULL)
		return -ENXIO;

	if (!is_power_of_2(freq))
		return -EINVAL;

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

	if (err == 0) {
		err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
		if (err == 0)
			rtc->irq_freq = freq;
	}
	return err;
}
EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
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>
97144c67	15	#include <linux/log2.h>
0c86edc0	16
ab6a2d70	17	int rtc_read_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	18	{
0c86edc0 AZ	19	int err;
0c86edc0 AZ	20
	21	err = mutex_lock_interruptible(&rtc->ops_lock);
	22	if (err)
	23	return -EBUSY;
	24
	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 AZ	32	}
	33
	34	mutex_unlock(&rtc->ops_lock);
	35	return err;
	36	}
	37	EXPORT_SYMBOL_GPL(rtc_read_time);
	38
ab6a2d70	39	int rtc_set_time(struct rtc_device rtc, struct rtc_time tm)
0c86edc0 AZ	40	{
0c86edc0 AZ	41	int err;
0c86edc0 AZ	42
	43	err = rtc_valid_tm(tm);
	44	if (err != 0)
	45	return err;
	46
	47	err = mutex_lock_interruptible(&rtc->ops_lock);
	48	if (err)
	49	return -EBUSY;
	50
	51	if (!rtc->ops)
	52	err = -ENODEV;
	53	else if (!rtc->ops->set_time)
	54	err = -EINVAL;
	55	else
cd966209	56	err = rtc->ops->set_time(rtc->dev.parent, tm);
0c86edc0 AZ	57
	58	mutex_unlock(&rtc->ops_lock);
	59	return err;
	60	}
	61	EXPORT_SYMBOL_GPL(rtc_set_time);
	62
ab6a2d70	63	int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
0c86edc0 AZ	64	{
0c86edc0 AZ	65	int err;
0c86edc0 AZ	66
	67	err = mutex_lock_interruptible(&rtc->ops_lock);
	68	if (err)
	69	return -EBUSY;
	70
	71	if (!rtc->ops)
	72	err = -ENODEV;
	73	else if (rtc->ops->set_mmss)
cd966209	74	err = rtc->ops->set_mmss(rtc->dev.parent, secs);
0c86edc0 AZ	75	else if (rtc->ops->read_time && rtc->ops->set_time) {
	76	struct rtc_time new, old;
	77
cd966209	78	err = rtc->ops->read_time(rtc->dev.parent, &old);
0c86edc0 AZ	79	if (err == 0) {
	80	rtc_time_to_tm(secs, &new);
	81
	82	/*
	83	* avoid writing when we're going to change the day of
	84	* the month. We will retry in the next minute. This
	85	* basically means that if the RTC must not drift
	86	* by more than 1 minute in 11 minutes.
	87	*/
	88	if (!((old.tm_hour == 23 && old.tm_min == 59) \|\|
	89	(new.tm_hour == 23 && new.tm_min == 59)))
cd966209	90	err = rtc->ops->set_time(rtc->dev.parent,
ab6a2d70	91	&new);
0c86edc0 AZ	92	}
	93	}
	94	else
	95	err = -EINVAL;
	96
	97	mutex_unlock(&rtc->ops_lock);
	98
	99	return err;
	100	}
	101	EXPORT_SYMBOL_GPL(rtc_set_mmss);
	102
0e36a9a4	103	static int rtc_read_alarm_internal(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	104	{
0c86edc0 AZ	105	int err;
0c86edc0 AZ	106
	107	err = mutex_lock_interruptible(&rtc->ops_lock);
	108	if (err)
	109	return -EBUSY;
	110
	111	if (rtc->ops == NULL)
	112	err = -ENODEV;
	113	else if (!rtc->ops->read_alarm)
	114	err = -EINVAL;
	115	else {
	116	memset(alarm, 0, sizeof(struct rtc_wkalrm));
cd966209	117	err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
0c86edc0 AZ	118	}
	119
	120	mutex_unlock(&rtc->ops_lock);
	121	return err;
	122	}
0e36a9a4 ML	123
	124	int rtc_read_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
	125	{
	126	int err;
	127	struct rtc_time before, now;
	128	int first_time = 1;
	129
	130	/* The lower level RTC driver may not be capable of filling
	131	* in all fields of the rtc_time struct (eg. rtc-cmos),
	132	* and so might instead return -1 in some fields.
	133	* We deal with that here by grabbing a current RTC timestamp
	134	* and using values from that for any missing (-1) values.
	135	*
	136	* But this can be racey, because some fields of the RTC timestamp
	137	* may have wrapped in the interval since we read the RTC alarm,
	138	* which would lead to us inserting inconsistent values in place
	139	* of the -1 fields.
	140	*
	141	* Reading the alarm and timestamp in the reverse sequence
	142	* would have the same race condition, and not solve the issue.
	143	*
	144	* So, we must first read the RTC timestamp,
	145	* then read the RTC alarm value,
	146	* and then read a second RTC timestamp.
	147	*
	148	* If any fields of the second timestamp have changed
	149	* when compared with the first timestamp, then we know
	150	* our timestamp may be inconsistent with that used by
	151	* the low-level rtc_read_alarm_internal() function.
	152	*
	153	* So, when the two timestamps disagree, we just loop and do
	154	* the process again to get a fully consistent set of values.
	155	*
	156	* This could all instead be done in the lower level driver,
	157	* but since more than one lower level RTC implementation needs it,
	158	* then it's probably best best to do it here instead of there..
	159	*/
	160
	161	/* Get the "before" timestamp */
	162	err = rtc_read_time(rtc, &before);
	163	if (err < 0)
	164	return err;
	165	do {
	166	if (!first_time)
	167	memcpy(&before, &now, sizeof(struct rtc_time));
	168	first_time = 0;
	169
	170	/* get the RTC alarm values, which may be incomplete */
	171	err = rtc_read_alarm_internal(rtc, alarm);
	172	if (err)
	173	return err;
	174	if (!alarm->enabled)
	175	return 0;
	176
	177	/* get the "after" timestamp, to detect wrapped fields */
	178	err = rtc_read_time(rtc, &now);
	179	if (err < 0)
	180	return err;
	181
	182	/* note that tm_sec is a "don't care" value here: */
	183	} while ( before.tm_min != now.tm_min
	184	\|\| before.tm_hour != now.tm_hour
	185	\|\| before.tm_mon != now.tm_mon
	186	\|\| before.tm_year != now.tm_year
187	\|\| before.tm_isdst != now.tm_isdst);
188
189	/* Fill in any missing alarm fields using the timestamp */
190	if (alarm->time.tm_sec == -1)
191	alarm->time.tm_sec = now.tm_sec;
192	if (alarm->time.tm_min == -1)
193	alarm->time.tm_min = now.tm_min;
194	if (alarm->time.tm_hour == -1)
195	alarm->time.tm_hour = now.tm_hour;
196	if (alarm->time.tm_mday == -1)
197	alarm->time.tm_mday = now.tm_mday;
198	if (alarm->time.tm_mon == -1)
199	alarm->time.tm_mon = now.tm_mon;
200	if (alarm->time.tm_year == -1)
201	alarm->time.tm_year = now.tm_year;
202	return 0;
203	}
0c86edc0 AZ	204	EXPORT_SYMBOL_GPL(rtc_read_alarm);
0c86edc0 AZ	205
ab6a2d70	206	int rtc_set_alarm(struct rtc_device rtc, struct rtc_wkalrm alarm)
0c86edc0 AZ	207	{
0c86edc0 AZ	208	int err;
0c86edc0	209
f8245c26 DB	210	err = rtc_valid_tm(&alarm->time);
	211	if (err != 0)
	212	return err;
	213
0c86edc0 AZ	214	err = mutex_lock_interruptible(&rtc->ops_lock);
	215	if (err)
	216	return -EBUSY;
	217
	218	if (!rtc->ops)
	219	err = -ENODEV;
	220	else if (!rtc->ops->set_alarm)
	221	err = -EINVAL;
	222	else
cd966209	223	err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
0c86edc0 AZ	224
	225	mutex_unlock(&rtc->ops_lock);
	226	return err;
	227	}
	228	EXPORT_SYMBOL_GPL(rtc_set_alarm);
	229
d728b1e6 DB	230	/**
d728b1e6 DB	231	* rtc_update_irq - report RTC periodic, alarm, and/or update irqs
ab6a2d70	232	* @rtc: the rtc device
d728b1e6 DB	233	* @num: how many irqs are being reported (usually one)
	234	* @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
	235	* Context: in_interrupt(), irqs blocked
	236	*/
ab6a2d70	237	void rtc_update_irq(struct rtc_device *rtc,
0c86edc0 AZ	238	unsigned long num, unsigned long events)
0c86edc0 AZ	239	{
0c86edc0 AZ	240	spin_lock(&rtc->irq_lock);
	241	rtc->irq_data = (rtc->irq_data + (num << 8)) \| events;
	242	spin_unlock(&rtc->irq_lock);
	243
	244	spin_lock(&rtc->irq_task_lock);
	245	if (rtc->irq_task)
	246	rtc->irq_task->func(rtc->irq_task->private_data);
	247	spin_unlock(&rtc->irq_task_lock);
	248
	249	wake_up_interruptible(&rtc->irq_queue);
	250	kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
	251	}
	252	EXPORT_SYMBOL_GPL(rtc_update_irq);
	253
ab6a2d70	254	struct rtc_device rtc_class_open(char name)
0c86edc0	255	{
cd966209	256	struct device *dev;
ab6a2d70	257	struct rtc_device *rtc = NULL;
0c86edc0 AZ	258
0c86edc0 AZ	259	down(&rtc_class->sem);
cd966209 DB	260	list_for_each_entry(dev, &rtc_class->devices, node) {
	261	if (strncmp(dev->bus_id, name, BUS_ID_SIZE) == 0) {
	262	dev = get_device(dev);
	263	if (dev)
	264	rtc = to_rtc_device(dev);
0c86edc0 AZ	265	break;
	266	}
	267	}
	268
ab6a2d70 DB	269	if (rtc) {
ab6a2d70 DB	270	if (!try_module_get(rtc->owner)) {
cd966209	271	put_device(dev);
ab6a2d70 DB	272	rtc = NULL;
ab6a2d70 DB	273	}
0c86edc0 AZ	274	}
	275	up(&rtc_class->sem);
	276
ab6a2d70	277	return rtc;
0c86edc0 AZ	278	}
	279	EXPORT_SYMBOL_GPL(rtc_class_open);
	280
ab6a2d70	281	void rtc_class_close(struct rtc_device *rtc)
0c86edc0	282	{
ab6a2d70	283	module_put(rtc->owner);
cd966209	284	put_device(&rtc->dev);
0c86edc0 AZ	285	}
	286	EXPORT_SYMBOL_GPL(rtc_class_close);
	287
ab6a2d70	288	int rtc_irq_register(struct rtc_device rtc, struct rtc_task task)
0c86edc0 AZ	289	{
0c86edc0 AZ	290	int retval = -EBUSY;
0c86edc0 AZ	291
	292	if (task == NULL \|\| task->func == NULL)
	293	return -EINVAL;
	294
d691eb90	295	/* Cannot register while the char dev is in use */
8853c202	296	if (test_and_set_bit(RTC_DEV_BUSY, &rtc->flags))
d691eb90 AZ	297	return -EBUSY;
d691eb90 AZ	298
d728b1e6	299	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	300	if (rtc->irq_task == NULL) {
	301	rtc->irq_task = task;
	302	retval = 0;
	303	}
d728b1e6	304	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0	305
8853c202	306	clear_bit(RTC_DEV_BUSY, &rtc->flags);
d691eb90	307
0c86edc0 AZ	308	return retval;
	309	}
	310	EXPORT_SYMBOL_GPL(rtc_irq_register);
	311
ab6a2d70	312	void rtc_irq_unregister(struct rtc_device rtc, struct rtc_task task)
0c86edc0	313	{
d728b1e6	314	spin_lock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	315	if (rtc->irq_task == task)
0c86edc0 AZ	316	rtc->irq_task = NULL;
d728b1e6	317	spin_unlock_irq(&rtc->irq_task_lock);
0c86edc0 AZ	318	}
	319	EXPORT_SYMBOL_GPL(rtc_irq_unregister);
	320
97144c67 DB	321	/**
	322	* rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
	323	* @rtc: the rtc device
	324	* @task: currently registered with rtc_irq_register()
	325	* @enabled: true to enable periodic IRQs
	326	* Context: any
	327	*
	328	* Note that rtc_irq_set_freq() should previously have been used to
	329	* specify the desired frequency of periodic IRQ task->func() callbacks.
	330	*/
ab6a2d70	331	int rtc_irq_set_state(struct rtc_device rtc, struct rtc_task task, int enabled)
0c86edc0 AZ	332	{
	333	int err = 0;
	334	unsigned long flags;
0c86edc0	335
56f10c63 AZ	336	if (rtc->ops->irq_set_state == NULL)
	337	return -ENXIO;
	338
0c86edc0	339	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	340	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	341	err = -EBUSY;
0c86edc0	342	if (rtc->irq_task != task)
d691eb90	343	err = -EACCES;
0c86edc0 AZ	344	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
	345
	346	if (err == 0)
cd966209	347	err = rtc->ops->irq_set_state(rtc->dev.parent, enabled);
0c86edc0 AZ	348
	349	return err;
	350	}
	351	EXPORT_SYMBOL_GPL(rtc_irq_set_state);
	352
97144c67 DB	353	/**
	354	* rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
	355	* @rtc: the rtc device
	356	* @task: currently registered with rtc_irq_register()
	357	* @freq: positive frequency with which task->func() will be called
	358	* Context: any
	359	*
	360	* Note that rtc_irq_set_state() is used to enable or disable the
	361	* periodic IRQs.
	362	*/
ab6a2d70	363	int rtc_irq_set_freq(struct rtc_device rtc, struct rtc_task task, int freq)
0c86edc0	364	{
56f10c63	365	int err = 0;
0c86edc0	366	unsigned long flags;
0c86edc0	367
56f10c63 AZ	368	if (rtc->ops->irq_set_freq == NULL)
56f10c63 AZ	369	return -ENXIO;
0c86edc0	370
97144c67 DB	371	if (!is_power_of_2(freq))
	372	return -EINVAL;
	373
0c86edc0	374	spin_lock_irqsave(&rtc->irq_task_lock, flags);
d691eb90 AZ	375	if (rtc->irq_task != NULL && task == NULL)
d691eb90 AZ	376	err = -EBUSY;
0c86edc0	377	if (rtc->irq_task != task)
d691eb90	378	err = -EACCES;
0c86edc0 AZ	379	spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
	380
	381	if (err == 0) {
cd966209	382	err = rtc->ops->irq_set_freq(rtc->dev.parent, freq);
0c86edc0 AZ	383	if (err == 0)
	384	rtc->irq_freq = freq;
	385	}
	386	return err;
	387	}
2601a464	388	EXPORT_SYMBOL_GPL(rtc_irq_set_freq);