[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/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) && 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 timespec old_rtc, old_system, old_delta;


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

	if (has_persistent_clock())
		return 0;

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

	/* snapshot the current RTC and system time at suspend*/
	rtc_read_time(rtc, &tm);
	getnstimeofday(&old_system);
	rtc_tm_to_time(&tm, &old_rtc.tv_sec);


	/*
	 * 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 = timespec_sub(old_system, old_rtc);
	delta_delta = timespec_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 = timespec_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 timespec		new_system, new_rtc;
	struct timespec		sleep_time;

	if (has_persistent_clock())
		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 */
	getnstimeofday(&new_system);
	rtc_read_time(rtc, &tm);
	if (rtc_valid_tm(&tm) != 0) {
		pr_debug("%s:  bogus resume time\n", dev_name(&rtc->dev));
		return 0;
	}
	rtc_tm_to_time(&tm, &new_rtc.tv_sec);
	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 = timespec_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 = timespec_sub(sleep_time,
			timespec_sub(new_system, old_system));

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

#else
#define rtc_suspend	NULL
#define rtc_resume	NULL
#endif


/**
 * 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 id, err;

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

	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
	if (rtc == NULL) {
		err = -ENOMEM;
		goto exit_ida;
	}

	rtc->id = id;
	rtc->ops = ops;
	rtc->owner = owner;
	rtc->irq_freq = 1;
	rtc->max_user_freq = 64;
	rtc->dev.parent = dev;
	rtc->dev.class = rtc_class;
	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;

	/* 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);

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

	rtc_dev_prepare(rtc);

	err = device_register(&rtc->dev);
	if (err) {
		put_device(&rtc->dev);
		goto exit_kfree;
	}

	rtc_dev_add_device(rtc);
	rtc_sysfs_add_device(rtc);
	rtc_proc_add_device(rtc);

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

	return rtc;

exit_kfree:
	kfree(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)
{
	if (get_device(&rtc->dev) != NULL) {
		mutex_lock(&rtc->ops_lock);
		/* remove innards of this RTC, then disable it, before
		 * letting any rtc_class_open() users access it again
		 */
		rtc_sysfs_del_device(rtc);
		rtc_dev_del_device(rtc);
		rtc_proc_del_device(rtc);
		device_unregister(&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->suspend = rtc_suspend;
	rtc_class->resume = rtc_resume;
	rtc_dev_init();
	rtc_sysfs_init(rtc_class);
	return 0;
}

static void __exit rtc_exit(void)
{
	rtc_dev_exit();
	class_destroy(rtc_class);
	ida_destroy(&rtc_ida);
}

subsys_initcall(rtc_init);
module_exit(rtc_exit);

MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
MODULE_DESCRIPTION("RTC class support");
MODULE_LICENSE("GPL");
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 AZ	16	#include <linux/module.h>
	17	#include <linux/rtc.h>
	18	#include <linux/kdev_t.h>
	19	#include <linux/idr.h>
5a0e3ad6	20	#include <linux/slab.h>
6610e089	21	#include <linux/workqueue.h>
0c86edc0	22
5726fb20 DB	23	#include "rtc-core.h"
	24
	25
6d03d06d	26	static DEFINE_IDA(rtc_ida);
0c86edc0 AZ	27	struct class *rtc_class;
0c86edc0 AZ	28
cd966209	29	static void rtc_device_release(struct device *dev)
0c86edc0	30	{
cd966209	31	struct rtc_device *rtc = to_rtc_device(dev);
6d03d06d	32	ida_simple_remove(&rtc_ida, rtc->id);
0c86edc0 AZ	33	kfree(rtc);
	34	}
	35
4c24e29e DF	36	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
	37	/* Result of the last RTC to system clock attempt. */
	38	int rtc_hctosys_ret = -ENODEV;
	39	#endif
7ca1d488	40
4c24e29e	41	#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
7ca1d488 DB	42	/*
	43	* On suspend(), measure the delta between one RTC and the
	44	* system's wall clock; restore it on resume().
	45	*/
	46
3dcad5ff JS	47	static struct timespec old_rtc, old_system, old_delta;
3dcad5ff JS	48
7ca1d488 DB	49
	50	static int rtc_suspend(struct device *dev, pm_message_t mesg)
	51	{
	52	struct rtc_device *rtc = to_rtc_device(dev);
	53	struct rtc_time tm;
3dcad5ff	54	struct timespec delta, delta_delta;
9ecf37eb FT	55
	56	if (has_persistent_clock())
	57	return 0;
	58
d4afc76c	59	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
7ca1d488 DB	60	return 0;
7ca1d488 DB	61
3dcad5ff	62	/* snapshot the current RTC and system time at suspend*/
7ca1d488	63	rtc_read_time(rtc, &tm);
3dcad5ff JS	64	getnstimeofday(&old_system);
	65	rtc_tm_to_time(&tm, &old_rtc.tv_sec);
	66
	67
	68	/*
	69	* To avoid drift caused by repeated suspend/resumes,
	70	* which each can add ~1 second drift error,
	71	* try to compensate so the difference in system time
	72	* and rtc time stays close to constant.
	73	*/
	74	delta = timespec_sub(old_system, old_rtc);
	75	delta_delta = timespec_sub(delta, old_delta);
6a8943d9	76	if (delta_delta.tv_sec < -2 \|\| delta_delta.tv_sec >= 2) {
3dcad5ff JS	77	/*
	78	* if delta_delta is too large, assume time correction
	79	* has occured and set old_delta to the current delta.
	80	*/
	81	old_delta = delta;
	82	} else {
	83	/* Otherwise try to adjust old_system to compensate */
	84	old_system = timespec_sub(old_system, delta_delta);
	85	}
7ca1d488	86
7ca1d488 DB	87	return 0;
	88	}
	89
	90	static int rtc_resume(struct device *dev)
	91	{
	92	struct rtc_device *rtc = to_rtc_device(dev);
	93	struct rtc_time tm;
3dcad5ff JS	94	struct timespec new_system, new_rtc;
3dcad5ff JS	95	struct timespec sleep_time;
7ca1d488	96
9ecf37eb FT	97	if (has_persistent_clock())
	98	return 0;
	99
4c24e29e	100	rtc_hctosys_ret = -ENODEV;
d4afc76c	101	if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0)
7ca1d488 DB	102	return 0;
7ca1d488 DB	103
3dcad5ff JS	104	/* snapshot the current rtc and system time at resume */
3dcad5ff JS	105	getnstimeofday(&new_system);
7ca1d488 DB	106	rtc_read_time(rtc, &tm);
7ca1d488 DB	107	if (rtc_valid_tm(&tm) != 0) {
d4afc76c	108	pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
7ca1d488 DB	109	return 0;
7ca1d488 DB	110	}
3dcad5ff JS	111	rtc_tm_to_time(&tm, &new_rtc.tv_sec);
	112	new_rtc.tv_nsec = 0;
	113
6a8943d9 AH	114	if (new_rtc.tv_sec < old_rtc.tv_sec) {
6a8943d9 AH	115	pr_debug("%s: time travel!\n", dev_name(&rtc->dev));
7ca1d488 DB	116	return 0;
	117	}
	118
3dcad5ff JS	119	/* calculate the RTC time delta (sleep time)*/
	120	sleep_time = timespec_sub(new_rtc, old_rtc);
	121
	122	/*
	123	* Since these RTC suspend/resume handlers are not called
	124	* at the very end of suspend or the start of resume,
	125	* some run-time may pass on either sides of the sleep time
	126	* so subtract kernel run-time between rtc_suspend to rtc_resume
	127	* to keep things accurate.
	128	*/
	129	sleep_time = timespec_sub(sleep_time,
	130	timespec_sub(new_system, old_system));
7ca1d488	131
6a8943d9 AH	132	if (sleep_time.tv_sec >= 0)
6a8943d9 AH	133	timekeeping_inject_sleeptime(&sleep_time);
4c24e29e	134	rtc_hctosys_ret = 0;
7ca1d488 DB	135	return 0;
	136	}
	137
	138	#else
	139	#define rtc_suspend NULL
	140	#define rtc_resume NULL
	141	#endif
	142
	143
0c86edc0 AZ	144	/**
	145	* rtc_device_register - register w/ RTC class
	146	* @dev: the device to register
	147	*
	148	* rtc_device_unregister() must be called when the class device is no
	149	* longer needed.
	150	*
	151	* Returns the pointer to the new struct class device.
	152	*/
	153	struct rtc_device rtc_device_register(const char name, struct device *dev,
ff8371ac	154	const struct rtc_class_ops *ops,
0c86edc0 AZ	155	struct module *owner)
	156	{
	157	struct rtc_device *rtc;
f44f7f96	158	struct rtc_wkalrm alrm;
0c86edc0 AZ	159	int id, err;
0c86edc0 AZ	160
6d03d06d JC	161	id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
	162	if (id < 0) {
	163	err = id;
0c86edc0 AZ	164	goto exit;
	165	}
	166
0c86edc0 AZ	167	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
	168	if (rtc == NULL) {
	169	err = -ENOMEM;
6d03d06d	170	goto exit_ida;
0c86edc0 AZ	171	}
	172
	173	rtc->id = id;
	174	rtc->ops = ops;
	175	rtc->owner = owner;
83a06bf5	176	rtc->irq_freq = 1;
110d693d	177	rtc->max_user_freq = 64;
cd966209 DB	178	rtc->dev.parent = dev;
	179	rtc->dev.class = rtc_class;
	180	rtc->dev.release = rtc_device_release;
0c86edc0 AZ	181
	182	mutex_init(&rtc->ops_lock);
	183	spin_lock_init(&rtc->irq_lock);
	184	spin_lock_init(&rtc->irq_task_lock);
d691eb90	185	init_waitqueue_head(&rtc->irq_queue);
0c86edc0	186
6610e089 JS	187	/* Init timerqueue */
6610e089 JS	188	timerqueue_init_head(&rtc->timerqueue);
96c8f06a	189	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
6610e089	190	/* Init aie timer */
96c8f06a	191	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
6610e089	192	/* Init uie timer */
96c8f06a	193	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
6610e089 JS	194	/* Init pie timer */
	195	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	196	rtc->pie_timer.function = rtc_pie_update_irq;
	197	rtc->pie_enabled = 0;
	198
f44f7f96 JS	199	/* Check to see if there is an ALARM already set in hw */
	200	err = __rtc_read_alarm(rtc, &alrm);
	201
	202	if (!err && !rtc_valid_tm(&alrm.time))
f6d5b331	203	rtc_initialize_alarm(rtc, &alrm);
f44f7f96	204
0c86edc0	205	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
d4afc76c	206	dev_set_name(&rtc->dev, "rtc%d", id);
0c86edc0	207
cb3a58d2 DB	208	rtc_dev_prepare(rtc);
cb3a58d2 DB	209
cd966209	210	err = device_register(&rtc->dev);
59cca865 VK	211	if (err) {
59cca865 VK	212	put_device(&rtc->dev);
0c86edc0	213	goto exit_kfree;
59cca865	214	}
0c86edc0	215
5726fb20	216	rtc_dev_add_device(rtc);
446ecbd9	217	rtc_sysfs_add_device(rtc);
7d9f99ec	218	rtc_proc_add_device(rtc);
5726fb20	219
0c86edc0	220	dev_info(dev, "rtc core: registered %s as %s\n",
d4afc76c	221	rtc->name, dev_name(&rtc->dev));
0c86edc0 AZ	222
	223	return rtc;
	224
	225	exit_kfree:
	226	kfree(rtc);
	227
6d03d06d JC	228	exit_ida:
6d03d06d JC	229	ida_simple_remove(&rtc_ida, id);
0c86edc0 AZ	230
0c86edc0 AZ	231	exit:
d1d65b77 AZ	232	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
d1d65b77 AZ	233	name, err);
0c86edc0 AZ	234	return ERR_PTR(err);
	235	}
	236	EXPORT_SYMBOL_GPL(rtc_device_register);
	237
	238
	239	/**
	240	* rtc_device_unregister - removes the previously registered RTC class device
	241	*
	242	* @rtc: the RTC class device to destroy
	243	*/
	244	void rtc_device_unregister(struct rtc_device *rtc)
	245	{
cd966209	246	if (get_device(&rtc->dev) != NULL) {
e109ebd1 DB	247	mutex_lock(&rtc->ops_lock);
	248	/* remove innards of this RTC, then disable it, before
	249	* letting any rtc_class_open() users access it again
	250	*/
446ecbd9	251	rtc_sysfs_del_device(rtc);
5726fb20	252	rtc_dev_del_device(rtc);
7d9f99ec	253	rtc_proc_del_device(rtc);
cd966209	254	device_unregister(&rtc->dev);
e109ebd1 DB	255	rtc->ops = NULL;
e109ebd1 DB	256	mutex_unlock(&rtc->ops_lock);
cd966209	257	put_device(&rtc->dev);
e109ebd1	258	}
0c86edc0 AZ	259	}
	260	EXPORT_SYMBOL_GPL(rtc_device_unregister);
	261
3e217b66 JH	262	static void devm_rtc_device_release(struct device dev, void res)
	263	{
	264	struct rtc_device rtc = (struct rtc_device **)res;
	265
	266	rtc_device_unregister(rtc);
	267	}
	268
	269	static int devm_rtc_device_match(struct device dev, void res, void *data)
	270	{
	271	struct rtc **r = res;
	272
	273	return *r == data;
	274	}
	275
	276	/**
	277	* devm_rtc_device_register - resource managed rtc_device_register()
3e217b66	278	* @dev: the device to register
6636a994	279	* @name: the name of the device
3e217b66 JH	280	* @ops: the rtc operations structure
	281	* @owner: the module owner
	282	*
	283	* @return a struct rtc on success, or an ERR_PTR on error
	284	*
	285	* Managed rtc_device_register(). The rtc_device returned from this function
	286	* are automatically freed on driver detach. See rtc_device_register()
	287	* for more information.
	288	*/
	289
6636a994 JH	290	struct rtc_device devm_rtc_device_register(struct device dev,
6636a994 JH	291	const char *name,
3e217b66 JH	292	const struct rtc_class_ops *ops,
	293	struct module *owner)
	294	{
	295	struct rtc_device *ptr, rtc;
	296
	297	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
	298	if (!ptr)
	299	return ERR_PTR(-ENOMEM);
	300
	301	rtc = rtc_device_register(name, dev, ops, owner);
	302	if (!IS_ERR(rtc)) {
	303	*ptr = rtc;
	304	devres_add(dev, ptr);
	305	} else {
	306	devres_free(ptr);
	307	}
	308
	309	return rtc;
	310	}
	311	EXPORT_SYMBOL_GPL(devm_rtc_device_register);
	312
	313	/**
	314	* devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
	315	* @dev: the device to unregister
	316	* @rtc: the RTC class device to unregister
	317	*
	318	* Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
	319	* function will not need to be called and the resource management code will
	320	* ensure that the resource is freed.
	321	*/
	322	void devm_rtc_device_unregister(struct device dev, struct rtc_device rtc)
	323	{
	324	int rc;
	325
	326	rc = devres_release(dev, devm_rtc_device_release,
	327	devm_rtc_device_match, rtc);
	328	WARN_ON(rc);
	329	}
	330	EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
	331
0c86edc0 AZ	332	static int __init rtc_init(void)
	333	{
	334	rtc_class = class_create(THIS_MODULE, "rtc");
	335	if (IS_ERR(rtc_class)) {
c100a5e0	336	pr_err("couldn't create class\n");
0c86edc0 AZ	337	return PTR_ERR(rtc_class);
0c86edc0 AZ	338	}
7ca1d488 DB	339	rtc_class->suspend = rtc_suspend;
7ca1d488 DB	340	rtc_class->resume = rtc_resume;
5726fb20	341	rtc_dev_init();
446ecbd9	342	rtc_sysfs_init(rtc_class);
0c86edc0 AZ	343	return 0;
	344	}
	345
	346	static void __exit rtc_exit(void)
	347	{
5726fb20	348	rtc_dev_exit();
0c86edc0	349	class_destroy(rtc_class);
6d03d06d	350	ida_destroy(&rtc_ida);
0c86edc0 AZ	351	}
0c86edc0 AZ	352
818a8674	353	subsys_initcall(rtc_init);
0c86edc0 AZ	354	module_exit(rtc_exit);
0c86edc0 AZ	355
818a8674	356	MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
0c86edc0 AZ	357	MODULE_DESCRIPTION("RTC class support");
0c86edc0 AZ	358	MODULE_LICENSE("GPL");