[linux.git] / drivers / rtc / class.c

/*
 * RTC subsystem, base class
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <[email protected]>
 *
 * class skeleton from drivers/hwmon/hwmon.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.
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/of.h>
#include <linux/rtc.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/workqueue.h>

#include "rtc-core.h"


static DEFINE_IDA(rtc_ida);
struct class *rtc_class;

static void rtc_device_release(struct device *dev)
{
	struct rtc_device *rtc = to_rtc_device(dev);
	ida_simple_remove(&rtc_ida, rtc->id);
	kfree(rtc);
}

#ifdef CONFIG_RTC_HCTOSYS_DEVICE
/* Result of the last RTC to system clock attempt. */
int rtc_hctosys_ret = -ENODEV;
#endif

#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
/*
 * On suspend(), measure the delta between one RTC and the
 * system's wall clock; restore it on resume().
 */

static struct timespec64 old_rtc, old_system, old_delta;


static int rtc_suspend(struct device *dev)
{
	struct rtc_device	*rtc = to_rtc_device(dev);
	struct rtc_time		tm;
	struct timespec64	delta, delta_delta;
	int err;

	if (timekeeping_rtc_skipsuspend())
		return 0;

	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
		return 0;

	/* snapshot the current RTC and system time at suspend*/
	err = rtc_read_time(rtc, &tm);
	if (err < 0) {
		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
		return 0;
	}

	getnstimeofday64(&old_system);
	old_rtc.tv_sec = rtc_tm_to_time64(&tm);


	/*
	 * To avoid drift caused by repeated suspend/resumes,
	 * which each can add ~1 second drift error,
	 * try to compensate so the difference in system time
	 * and rtc time stays close to constant.
	 */
	delta = timespec64_sub(old_system, old_rtc);
	delta_delta = timespec64_sub(delta, old_delta);
	if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) {
		/*
		 * if delta_delta is too large, assume time correction
		 * has occured and set old_delta to the current delta.
		 */
		old_delta = delta;
	} else {
		/* Otherwise try to adjust old_system to compensate */
		old_system = timespec64_sub(old_system, delta_delta);
	}

	return 0;
}

static int rtc_resume(struct device *dev)
{
	struct rtc_device	*rtc = to_rtc_device(dev);
	struct rtc_time		tm;
	struct timespec64	new_system, new_rtc;
	struct timespec64	sleep_time;
	int err;

	if (timekeeping_rtc_skipresume())
		return 0;

	rtc_hctosys_ret = -ENODEV;
	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
		return 0;

	/* snapshot the current rtc and system time at resume */
	getnstimeofday64(&new_system);
	err = rtc_read_time(rtc, &tm);
	if (err < 0) {
		pr_debug("%s:  fail to read rtc time\n", dev_name(&rtc->dev));
		return 0;
	}

	new_rtc.tv_sec = rtc_tm_to_time64(&tm);
	new_rtc.tv_nsec = 0;

	if (new_rtc.tv_sec < old_rtc.tv_sec) {
		pr_debug("%s:  time travel!\n", dev_name(&rtc->dev));
		return 0;
	}

	/* calculate the RTC time delta (sleep time)*/
	sleep_time = timespec64_sub(new_rtc, old_rtc);

	/*
	 * Since these RTC suspend/resume handlers are not called
	 * at the very end of suspend or the start of resume,
	 * some run-time may pass on either sides of the sleep time
	 * so subtract kernel run-time between rtc_suspend to rtc_resume
	 * to keep things accurate.
	 */
	sleep_time = timespec64_sub(sleep_time,
			timespec64_sub(new_system, old_system));

	if (sleep_time.tv_sec >= 0)
		timekeeping_inject_sleeptime64(&sleep_time);
	rtc_hctosys_ret = 0;
	return 0;
}

static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
#define RTC_CLASS_DEV_PM_OPS	(&rtc_class_dev_pm_ops)
#else
#define RTC_CLASS_DEV_PM_OPS	NULL
#endif

static struct rtc_device *rtc_allocate_device(void)
{
	struct rtc_device *rtc;

	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
	if (!rtc)
		return NULL;

	device_initialize(&rtc->dev);

	rtc->irq_freq = 1;
	rtc->max_user_freq = 64;
	rtc->dev.class = rtc_class;
	rtc->dev.groups = rtc_get_dev_attribute_groups();
	rtc->dev.release = rtc_device_release;

	mutex_init(&rtc->ops_lock);
	spin_lock_init(&rtc->irq_lock);
	spin_lock_init(&rtc->irq_task_lock);
	init_waitqueue_head(&rtc->irq_queue);

	/* Init timerqueue */
	timerqueue_init_head(&rtc->timerqueue);
	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
	/* Init aie timer */
	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
	/* Init uie timer */
	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
	/* Init pie timer */
	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	rtc->pie_timer.function = rtc_pie_update_irq;
	rtc->pie_enabled = 0;

	return rtc;
}

/**
 * rtc_device_register - register w/ RTC class
 * @dev: the device to register
 *
 * rtc_device_unregister() must be called when the class device is no
 * longer needed.
 *
 * Returns the pointer to the new struct class device.
 */
struct rtc_device *rtc_device_register(const char *name, struct device *dev,
					const struct rtc_class_ops *ops,
					struct module *owner)
{
	struct rtc_device *rtc;
	struct rtc_wkalrm alrm;
	int of_id = -1, id = -1, err;

	if (dev->of_node)
		of_id = of_alias_get_id(dev->of_node, "rtc");
	else if (dev->parent && dev->parent->of_node)
		of_id = of_alias_get_id(dev->parent->of_node, "rtc");

	if (of_id >= 0) {
		id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
				    GFP_KERNEL);
		if (id < 0)
			dev_warn(dev, "/aliases ID %d not available\n",
				    of_id);
	}

	if (id < 0) {
		id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
		if (id < 0) {
			err = id;
			goto exit;
		}
	}

	rtc = rtc_allocate_device();
	if (!rtc) {
		err = -ENOMEM;
		goto exit_ida;
	}

	rtc->id = id;
	rtc->ops = ops;
	rtc->owner = owner;
	rtc->dev.parent = dev;

	dev_set_name(&rtc->dev, "rtc%d", id);

	/* Check to see if there is an ALARM already set in hw */
	err = __rtc_read_alarm(rtc, &alrm);

	if (!err && !rtc_valid_tm(&alrm.time))
		rtc_initialize_alarm(rtc, &alrm);

	rtc_dev_prepare(rtc);

	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
	if (err) {
		dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",
			 name, MAJOR(rtc->dev.devt), rtc->id);

		/* This will free both memory and the ID */
		put_device(&rtc->dev);
		goto exit;
	} else {
		dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", name,
			MAJOR(rtc->dev.devt), rtc->id);
	}

	rtc_proc_add_device(rtc);

	dev_info(dev, "rtc core: registered %s as %s\n",
			name, dev_name(&rtc->dev));

	return rtc;

exit_ida:
	ida_simple_remove(&rtc_ida, id);

exit:
	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
			name, err);
	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(rtc_device_register);


/**
 * rtc_device_unregister - removes the previously registered RTC class device
 *
 * @rtc: the RTC class device to destroy
 */
void rtc_device_unregister(struct rtc_device *rtc)
{
	mutex_lock(&rtc->ops_lock);
	/*
	 * Remove innards of this RTC, then disable it, before
	 * letting any rtc_class_open() users access it again
	 */
	rtc_proc_del_device(rtc);
	cdev_device_del(&rtc->char_dev, &rtc->dev);
	rtc->ops = NULL;
	mutex_unlock(&rtc->ops_lock);
	put_device(&rtc->dev);
}
EXPORT_SYMBOL_GPL(rtc_device_unregister);

static void devm_rtc_device_release(struct device *dev, void *res)
{
	struct rtc_device *rtc = *(struct rtc_device **)res;

	rtc_device_unregister(rtc);
}

static int devm_rtc_device_match(struct device *dev, void *res, void *data)
{
	struct rtc **r = res;

	return *r == data;
}

/**
 * devm_rtc_device_register - resource managed rtc_device_register()
 * @dev: the device to register
 * @name: the name of the device
 * @ops: the rtc operations structure
 * @owner: the module owner
 *
 * @return a struct rtc on success, or an ERR_PTR on error
 *
 * Managed rtc_device_register(). The rtc_device returned from this function
 * are automatically freed on driver detach. See rtc_device_register()
 * for more information.
 */

struct rtc_device *devm_rtc_device_register(struct device *dev,
					const char *name,
					const struct rtc_class_ops *ops,
					struct module *owner)
{
	struct rtc_device **ptr, *rtc;

	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	rtc = rtc_device_register(name, dev, ops, owner);
	if (!IS_ERR(rtc)) {
		*ptr = rtc;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return rtc;
}
EXPORT_SYMBOL_GPL(devm_rtc_device_register);

/**
 * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
 * @dev: the device to unregister
 * @rtc: the RTC class device to unregister
 *
 * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
 * function will not need to be called and the resource management code will
 * ensure that the resource is freed.
 */
void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc)
{
	int rc;

	rc = devres_release(dev, devm_rtc_device_release,
				devm_rtc_device_match, rtc);
	WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);

static int __init rtc_init(void)
{
	rtc_class = class_create(THIS_MODULE, "rtc");
	if (IS_ERR(rtc_class)) {
		pr_err("couldn't create class\n");
		return PTR_ERR(rtc_class);
	}
	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
	rtc_dev_init();
	return 0;
}
subsys_initcall(rtc_init);
Commit	Line	Data
0c86edc0 AZ	1	/*
	2	* RTC subsystem, base class
	3	*
	4	* Copyright (C) 2005 Tower Technologies
	5	* Author: Alessandro Zummo <[email protected]>
	6	*
	7	* class skeleton from drivers/hwmon/hwmon.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
c100a5e0 JH	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
c100a5e0 JH	15
0c86edc0	16	#include <linux/module.h>
9d2b7e53	17	#include <linux/of.h>
0c86edc0 AZ	18	#include <linux/rtc.h>
	19	#include <linux/kdev_t.h>
	20	#include <linux/idr.h>
5a0e3ad6	21	#include <linux/slab.h>
6610e089	22	#include <linux/workqueue.h>
0c86edc0	23
5726fb20 DB	24	#include "rtc-core.h"
	25
	26
6d03d06d	27	static DEFINE_IDA(rtc_ida);
0c86edc0 AZ	28	struct class *rtc_class;
0c86edc0 AZ	29
cd966209	30	static void rtc_device_release(struct device *dev)
0c86edc0	31	{
cd966209	32	struct rtc_device *rtc = to_rtc_device(dev);
6d03d06d	33	ida_simple_remove(&rtc_ida, rtc->id);
0c86edc0 AZ	34	kfree(rtc);
	35	}
	36
4c24e29e DF	37	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
	38	/* Result of the last RTC to system clock attempt. */
	39	int rtc_hctosys_ret = -ENODEV;
	40	#endif
7ca1d488	41
92e7f04a	42	#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
7ca1d488 DB	43	/*
	44	* On suspend(), measure the delta between one RTC and the
	45	* system's wall clock; restore it on resume().
	46	*/
	47
d4bda8f8	48	static struct timespec64 old_rtc, old_system, old_delta;
3dcad5ff	49
7ca1d488	50
92e7f04a	51	static int rtc_suspend(struct device *dev)
7ca1d488 DB	52	{
	53	struct rtc_device *rtc = to_rtc_device(dev);
	54	struct rtc_time tm;
d4bda8f8	55	struct timespec64 delta, delta_delta;
e1d60093	56	int err;
9ecf37eb	57
0fa88cb4	58	if (timekeeping_rtc_skipsuspend())
9ecf37eb FT	59	return 0;
9ecf37eb FT	60
d4afc76c	61	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
7ca1d488 DB	62	return 0;
7ca1d488 DB	63
3dcad5ff	64	/* snapshot the current RTC and system time at suspend*/
e1d60093 HG	65	err = rtc_read_time(rtc, &tm);
	66	if (err < 0) {
	67	pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
	68	return 0;
	69	}
	70
d4bda8f8 JS	71	getnstimeofday64(&old_system);
d4bda8f8 JS	72	old_rtc.tv_sec = rtc_tm_to_time64(&tm);
3dcad5ff JS	73
	74
	75	/*
	76	* To avoid drift caused by repeated suspend/resumes,
	77	* which each can add ~1 second drift error,
	78	* try to compensate so the difference in system time
	79	* and rtc time stays close to constant.
	80	*/
d4bda8f8 JS	81	delta = timespec64_sub(old_system, old_rtc);
d4bda8f8 JS	82	delta_delta = timespec64_sub(delta, old_delta);
6a8943d9	83	if (delta_delta.tv_sec < -2 \|\| delta_delta.tv_sec >= 2) {
3dcad5ff JS	84	/*
	85	* if delta_delta is too large, assume time correction
	86	* has occured and set old_delta to the current delta.
	87	*/
	88	old_delta = delta;
	89	} else {
	90	/* Otherwise try to adjust old_system to compensate */
d4bda8f8	91	old_system = timespec64_sub(old_system, delta_delta);
3dcad5ff	92	}
7ca1d488	93
7ca1d488 DB	94	return 0;
	95	}
	96
	97	static int rtc_resume(struct device *dev)
	98	{
	99	struct rtc_device *rtc = to_rtc_device(dev);
	100	struct rtc_time tm;
d4bda8f8 JS	101	struct timespec64 new_system, new_rtc;
d4bda8f8 JS	102	struct timespec64 sleep_time;
e1d60093	103	int err;
7ca1d488	104
0fa88cb4	105	if (timekeeping_rtc_skipresume())
9ecf37eb FT	106	return 0;
9ecf37eb FT	107
4c24e29e	108	rtc_hctosys_ret = -ENODEV;
d4afc76c	109	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
7ca1d488 DB	110	return 0;
7ca1d488 DB	111
3dcad5ff	112	/* snapshot the current rtc and system time at resume */
d4bda8f8	113	getnstimeofday64(&new_system);
e1d60093 HG	114	err = rtc_read_time(rtc, &tm);
	115	if (err < 0) {
	116	pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
	117	return 0;
	118	}
	119
d4bda8f8	120	new_rtc.tv_sec = rtc_tm_to_time64(&tm);
3dcad5ff JS	121	new_rtc.tv_nsec = 0;
3dcad5ff JS	122
6a8943d9 AH	123	if (new_rtc.tv_sec < old_rtc.tv_sec) {
6a8943d9 AH	124	pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
7ca1d488 DB	125	return 0;
	126	}
	127
3dcad5ff	128	/* calculate the RTC time delta (sleep time)*/
d4bda8f8	129	sleep_time = timespec64_sub(new_rtc, old_rtc);
3dcad5ff JS	130
	131	/*
	132	* Since these RTC suspend/resume handlers are not called
	133	* at the very end of suspend or the start of resume,
	134	* some run-time may pass on either sides of the sleep time
	135	* so subtract kernel run-time between rtc_suspend to rtc_resume
	136	* to keep things accurate.
	137	*/
d4bda8f8 JS	138	sleep_time = timespec64_sub(sleep_time,
d4bda8f8 JS	139	timespec64_sub(new_system, old_system));
7ca1d488	140
6a8943d9	141	if (sleep_time.tv_sec >= 0)
d4bda8f8	142	timekeeping_inject_sleeptime64(&sleep_time);
4c24e29e	143	rtc_hctosys_ret = 0;
7ca1d488 DB	144	return 0;
	145	}
	146
92e7f04a SK	147	static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);
92e7f04a SK	148	#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)
7ca1d488	149	#else
92e7f04a	150	#define RTC_CLASS_DEV_PM_OPS NULL
7ca1d488 DB	151	#endif
7ca1d488 DB	152
d1bec20f AB	153	static struct rtc_device *rtc_allocate_device(void)
	154	{
	155	struct rtc_device *rtc;
	156
	157	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
	158	if (!rtc)
	159	return NULL;
	160
	161	device_initialize(&rtc->dev);
	162
	163	rtc->irq_freq = 1;
	164	rtc->max_user_freq = 64;
	165	rtc->dev.class = rtc_class;
	166	rtc->dev.groups = rtc_get_dev_attribute_groups();
	167	rtc->dev.release = rtc_device_release;
	168
	169	mutex_init(&rtc->ops_lock);
	170	spin_lock_init(&rtc->irq_lock);
	171	spin_lock_init(&rtc->irq_task_lock);
	172	init_waitqueue_head(&rtc->irq_queue);
	173
	174	/* Init timerqueue */
	175	timerqueue_init_head(&rtc->timerqueue);
	176	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
	177	/* Init aie timer */
	178	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
	179	/* Init uie timer */
	180	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
	181	/* Init pie timer */
	182	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	183	rtc->pie_timer.function = rtc_pie_update_irq;
	184	rtc->pie_enabled = 0;
	185
	186	return rtc;
	187	}
7ca1d488	188
0c86edc0 AZ	189	/**
	190	* rtc_device_register - register w/ RTC class
	191	* @dev: the device to register
	192	*
	193	* rtc_device_unregister() must be called when the class device is no
	194	* longer needed.
	195	*
	196	* Returns the pointer to the new struct class device.
	197	*/
	198	struct rtc_device rtc_device_register(const char name, struct device *dev,
ff8371ac	199	const struct rtc_class_ops *ops,
0c86edc0 AZ	200	struct module *owner)
	201	{
	202	struct rtc_device *rtc;
f44f7f96	203	struct rtc_wkalrm alrm;
9d2b7e53 SW	204	int of_id = -1, id = -1, err;
	205
	206	if (dev->of_node)
	207	of_id = of_alias_get_id(dev->of_node, "rtc");
	208	else if (dev->parent && dev->parent->of_node)
	209	of_id = of_alias_get_id(dev->parent->of_node, "rtc");
	210
	211	if (of_id >= 0) {
	212	id = ida_simple_get(&rtc_ida, of_id, of_id + 1,
	213	GFP_KERNEL);
	214	if (id < 0)
	215	dev_warn(dev, "/aliases ID %d not available\n",
	216	of_id);
	217	}
0c86edc0	218
6d03d06d	219	if (id < 0) {
9d2b7e53 SW	220	id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
	221	if (id < 0) {
	222	err = id;
	223	goto exit;
	224	}
0c86edc0 AZ	225	}
0c86edc0 AZ	226
d1bec20f AB	227	rtc = rtc_allocate_device();
d1bec20f AB	228	if (!rtc) {
0c86edc0	229	err = -ENOMEM;
6d03d06d	230	goto exit_ida;
0c86edc0 AZ	231	}
	232
	233	rtc->id = id;
	234	rtc->ops = ops;
	235	rtc->owner = owner;
cd966209	236	rtc->dev.parent = dev;
6610e089	237
182683e9 AK	238	dev_set_name(&rtc->dev, "rtc%d", id);
182683e9 AK	239
f44f7f96 JS	240	/* Check to see if there is an ALARM already set in hw */
	241	err = __rtc_read_alarm(rtc, &alrm);
	242
	243	if (!err && !rtc_valid_tm(&alrm.time))
f6d5b331	244	rtc_initialize_alarm(rtc, &alrm);
f44f7f96	245
cb3a58d2 DB	246	rtc_dev_prepare(rtc);
cb3a58d2 DB	247
d5ed9177	248	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
59cca865	249	if (err) {
d5ed9177	250	dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",
5c82a6ae	251	name, MAJOR(rtc->dev.devt), rtc->id);
d5ed9177	252
6706664d	253	/* This will free both memory and the ID */
59cca865	254	put_device(&rtc->dev);
6706664d	255	goto exit;
d5ed9177	256	} else {
5c82a6ae	257	dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", name,
d5ed9177	258	MAJOR(rtc->dev.devt), rtc->id);
59cca865	259	}
0c86edc0	260
7d9f99ec	261	rtc_proc_add_device(rtc);
5726fb20	262
0c86edc0	263	dev_info(dev, "rtc core: registered %s as %s\n",
5c82a6ae	264	name, dev_name(&rtc->dev));
0c86edc0 AZ	265
	266	return rtc;
	267
6d03d06d JC	268	exit_ida:
6d03d06d JC	269	ida_simple_remove(&rtc_ida, id);
0c86edc0 AZ	270
0c86edc0 AZ	271	exit:
d1d65b77 AZ	272	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
d1d65b77 AZ	273	name, err);
0c86edc0 AZ	274	return ERR_PTR(err);
	275	}
	276	EXPORT_SYMBOL_GPL(rtc_device_register);
	277
	278
	279	/**
	280	* rtc_device_unregister - removes the previously registered RTC class device
	281	*
	282	* @rtc: the RTC class device to destroy
	283	*/
	284	void rtc_device_unregister(struct rtc_device *rtc)
	285	{
c3b399a4 DT	286	mutex_lock(&rtc->ops_lock);
	287	/*
	288	* Remove innards of this RTC, then disable it, before
	289	* letting any rtc_class_open() users access it again
	290	*/
c3b399a4	291	rtc_proc_del_device(rtc);
d5ed9177	292	cdev_device_del(&rtc->char_dev, &rtc->dev);
c3b399a4 DT	293	rtc->ops = NULL;
	294	mutex_unlock(&rtc->ops_lock);
	295	put_device(&rtc->dev);
0c86edc0 AZ	296	}
	297	EXPORT_SYMBOL_GPL(rtc_device_unregister);
	298
3e217b66 JH	299	static void devm_rtc_device_release(struct device dev, void res)
	300	{
	301	struct rtc_device rtc = (struct rtc_device **)res;
	302
	303	rtc_device_unregister(rtc);
	304	}
	305
	306	static int devm_rtc_device_match(struct device dev, void res, void *data)
	307	{
	308	struct rtc **r = res;
	309
	310	return *r == data;
	311	}
	312
	313	/**
	314	* devm_rtc_device_register - resource managed rtc_device_register()
3e217b66	315	* @dev: the device to register
6636a994	316	* @name: the name of the device
3e217b66 JH	317	* @ops: the rtc operations structure
	318	* @owner: the module owner
	319	*
	320	* @return a struct rtc on success, or an ERR_PTR on error
	321	*
	322	* Managed rtc_device_register(). The rtc_device returned from this function
	323	* are automatically freed on driver detach. See rtc_device_register()
	324	* for more information.
	325	*/
	326
6636a994 JH	327	struct rtc_device devm_rtc_device_register(struct device dev,
6636a994 JH	328	const char *name,
3e217b66 JH	329	const struct rtc_class_ops *ops,
	330	struct module *owner)
	331	{
	332	struct rtc_device *ptr, rtc;
	333
	334	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
	335	if (!ptr)
	336	return ERR_PTR(-ENOMEM);
	337
	338	rtc = rtc_device_register(name, dev, ops, owner);
	339	if (!IS_ERR(rtc)) {
	340	*ptr = rtc;
	341	devres_add(dev, ptr);
	342	} else {
	343	devres_free(ptr);
	344	}
	345
	346	return rtc;
	347	}
	348	EXPORT_SYMBOL_GPL(devm_rtc_device_register);
	349
	350	/**
	351	* devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
	352	* @dev: the device to unregister
	353	* @rtc: the RTC class device to unregister
	354	*
	355	* Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
	356	* function will not need to be called and the resource management code will
	357	* ensure that the resource is freed.
	358	*/
	359	void devm_rtc_device_unregister(struct device dev, struct rtc_device rtc)
	360	{
	361	int rc;
	362
	363	rc = devres_release(dev, devm_rtc_device_release,
	364	devm_rtc_device_match, rtc);
	365	WARN_ON(rc);
	366	}
	367	EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
	368
0c86edc0 AZ	369	static int __init rtc_init(void)
	370	{
	371	rtc_class = class_create(THIS_MODULE, "rtc");
	372	if (IS_ERR(rtc_class)) {
c100a5e0	373	pr_err("couldn't create class\n");
0c86edc0 AZ	374	return PTR_ERR(rtc_class);
0c86edc0 AZ	375	}
92e7f04a	376	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
5726fb20	377	rtc_dev_init();
0c86edc0 AZ	378	return 0;
0c86edc0 AZ	379	}
818a8674	380	subsys_initcall(rtc_init);