[mirror_ubuntu-bionic-kernel.git] / drivers / rtc / class.c

/*
 * RTC subsystem, base class
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * 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

/* Ensure the caller will set the id before releasing the device */
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);

	/* Drivers can revise this default after allocating the device. */
	rtc->set_offset_nsec =  NSEC_PER_SEC / 2;

	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;
}

static int rtc_device_get_id(struct device *dev)
{
	int of_id = -1, id = -1;

	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);

	return id;
}

/**
 * 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 = rtc_device_get_id(dev);
	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)
{
	rtc_nvmem_unregister(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 void devm_rtc_release_device(struct device *dev, void *res)
{
	struct rtc_device *rtc = *(struct rtc_device **)res;

	if (rtc->registered)
		rtc_device_unregister(rtc);
	else
		put_device(&rtc->dev);
}

struct rtc_device *devm_rtc_allocate_device(struct device *dev)
{
	struct rtc_device **ptr, *rtc;
	int id, err;

	id = rtc_device_get_id(dev);
	if (id < 0)
		return ERR_PTR(id);

	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
	if (!ptr) {
		err = -ENOMEM;
		goto exit_ida;
	}

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

	*ptr = rtc;
	devres_add(dev, ptr);

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

	return rtc;

exit_devres:
	devres_free(ptr);
exit_ida:
	ida_simple_remove(&rtc_ida, id);
	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);

int __rtc_register_device(struct module *owner, struct rtc_device *rtc)
{
	struct rtc_wkalrm alrm;
	int err;

	if (!rtc->ops)
		return -EINVAL;

	rtc->owner = owner;

	/* 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.parent, "failed to add char device %d:%d\n",
			 MAJOR(rtc->dev.devt), rtc->id);
	else
		dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
			MAJOR(rtc->dev.devt), rtc->id);

	rtc_proc_add_device(rtc);

	rtc_nvmem_register(rtc);

	rtc->registered = true;
	dev_info(rtc->dev.parent, "registered as %s\n",
		 dev_name(&rtc->dev));

	return 0;
}
EXPORT_SYMBOL_GPL(__rtc_register_device);

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 <a.zummo@towertech.it>
	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
3068a254	153	/* Ensure the caller will set the id before releasing the device */
d1bec20f AB	154	static struct rtc_device *rtc_allocate_device(void)
	155	{
	156	struct rtc_device *rtc;
	157
	158	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
	159	if (!rtc)
	160	return NULL;
	161
	162	device_initialize(&rtc->dev);
	163
0f295b06 JG	164	/* Drivers can revise this default after allocating the device. */
	165	rtc->set_offset_nsec = NSEC_PER_SEC / 2;
	166
d1bec20f AB	167	rtc->irq_freq = 1;
	168	rtc->max_user_freq = 64;
	169	rtc->dev.class = rtc_class;
	170	rtc->dev.groups = rtc_get_dev_attribute_groups();
	171	rtc->dev.release = rtc_device_release;
	172
	173	mutex_init(&rtc->ops_lock);
	174	spin_lock_init(&rtc->irq_lock);
	175	spin_lock_init(&rtc->irq_task_lock);
	176	init_waitqueue_head(&rtc->irq_queue);
	177
	178	/* Init timerqueue */
	179	timerqueue_init_head(&rtc->timerqueue);
	180	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
	181	/* Init aie timer */
	182	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc);
	183	/* Init uie timer */
	184	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc);
	185	/* Init pie timer */
	186	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	187	rtc->pie_timer.function = rtc_pie_update_irq;
	188	rtc->pie_enabled = 0;
	189
	190	return rtc;
	191	}
7ca1d488	192
b91336df AB	193	static int rtc_device_get_id(struct device *dev)
	194	{
	195	int of_id = -1, id = -1;
	196
	197	if (dev->of_node)
	198	of_id = of_alias_get_id(dev->of_node, "rtc");
	199	else if (dev->parent && dev->parent->of_node)
	200	of_id = of_alias_get_id(dev->parent->of_node, "rtc");
	201
	202	if (of_id >= 0) {
	203	id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
	204	if (id < 0)
	205	dev_warn(dev, "/aliases ID %d not available\n", of_id);
	206	}
	207
	208	if (id < 0)
	209	id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
	210
	211	return id;
	212	}
	213
0c86edc0 AZ	214	/**
	215	* rtc_device_register - register w/ RTC class
	216	* @dev: the device to register
	217	*
	218	* rtc_device_unregister() must be called when the class device is no
	219	* longer needed.
	220	*
	221	* Returns the pointer to the new struct class device.
	222	*/
	223	struct rtc_device rtc_device_register(const char name, struct device *dev,
ff8371ac	224	const struct rtc_class_ops *ops,
0c86edc0 AZ	225	struct module *owner)
	226	{
	227	struct rtc_device *rtc;
f44f7f96	228	struct rtc_wkalrm alrm;
b91336df	229	int id, err;
0c86edc0	230
b91336df	231	id = rtc_device_get_id(dev);
6d03d06d	232	if (id < 0) {
b91336df AB	233	err = id;
b91336df AB	234	goto exit;
0c86edc0 AZ	235	}
0c86edc0 AZ	236
d1bec20f AB	237	rtc = rtc_allocate_device();
d1bec20f AB	238	if (!rtc) {
0c86edc0	239	err = -ENOMEM;
6d03d06d	240	goto exit_ida;
0c86edc0 AZ	241	}
	242
	243	rtc->id = id;
	244	rtc->ops = ops;
	245	rtc->owner = owner;
cd966209	246	rtc->dev.parent = dev;
6610e089	247
182683e9 AK	248	dev_set_name(&rtc->dev, "rtc%d", id);
182683e9 AK	249
f44f7f96 JS	250	/* Check to see if there is an ALARM already set in hw */
	251	err = __rtc_read_alarm(rtc, &alrm);
	252
	253	if (!err && !rtc_valid_tm(&alrm.time))
f6d5b331	254	rtc_initialize_alarm(rtc, &alrm);
f44f7f96	255
cb3a58d2 DB	256	rtc_dev_prepare(rtc);
cb3a58d2 DB	257
d5ed9177	258	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
59cca865	259	if (err) {
d5ed9177	260	dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n",
5c82a6ae	261	name, MAJOR(rtc->dev.devt), rtc->id);
d5ed9177	262
6706664d	263	/* This will free both memory and the ID */
59cca865	264	put_device(&rtc->dev);
6706664d	265	goto exit;
d5ed9177	266	} else {
5c82a6ae	267	dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", name,
d5ed9177	268	MAJOR(rtc->dev.devt), rtc->id);
59cca865	269	}
0c86edc0	270
7d9f99ec	271	rtc_proc_add_device(rtc);
5726fb20	272
0c86edc0	273	dev_info(dev, "rtc core: registered %s as %s\n",
5c82a6ae	274	name, dev_name(&rtc->dev));
0c86edc0 AZ	275
	276	return rtc;
	277
6d03d06d JC	278	exit_ida:
6d03d06d JC	279	ida_simple_remove(&rtc_ida, id);
0c86edc0 AZ	280
0c86edc0 AZ	281	exit:
d1d65b77 AZ	282	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
d1d65b77 AZ	283	name, err);
0c86edc0 AZ	284	return ERR_PTR(err);
	285	}
	286	EXPORT_SYMBOL_GPL(rtc_device_register);
	287
	288
	289	/**
	290	* rtc_device_unregister - removes the previously registered RTC class device
	291	*
	292	* @rtc: the RTC class device to destroy
	293	*/
	294	void rtc_device_unregister(struct rtc_device *rtc)
	295	{
697e5a47 AB	296	rtc_nvmem_unregister(rtc);
697e5a47 AB	297
c3b399a4 DT	298	mutex_lock(&rtc->ops_lock);
	299	/*
	300	* Remove innards of this RTC, then disable it, before
	301	* letting any rtc_class_open() users access it again
	302	*/
c3b399a4	303	rtc_proc_del_device(rtc);
d5ed9177	304	cdev_device_del(&rtc->char_dev, &rtc->dev);
c3b399a4 DT	305	rtc->ops = NULL;
	306	mutex_unlock(&rtc->ops_lock);
	307	put_device(&rtc->dev);
0c86edc0 AZ	308	}
	309	EXPORT_SYMBOL_GPL(rtc_device_unregister);
	310
3e217b66 JH	311	static void devm_rtc_device_release(struct device dev, void res)
	312	{
	313	struct rtc_device rtc = (struct rtc_device **)res;
	314
	315	rtc_device_unregister(rtc);
	316	}
	317
	318	static int devm_rtc_device_match(struct device dev, void res, void *data)
	319	{
	320	struct rtc **r = res;
	321
	322	return *r == data;
	323	}
	324
	325	/**
	326	* devm_rtc_device_register - resource managed rtc_device_register()
3e217b66	327	* @dev: the device to register
6636a994	328	* @name: the name of the device
3e217b66 JH	329	* @ops: the rtc operations structure
	330	* @owner: the module owner
	331	*
	332	* @return a struct rtc on success, or an ERR_PTR on error
	333	*
	334	* Managed rtc_device_register(). The rtc_device returned from this function
	335	* are automatically freed on driver detach. See rtc_device_register()
	336	* for more information.
	337	*/
	338
6636a994 JH	339	struct rtc_device devm_rtc_device_register(struct device dev,
6636a994 JH	340	const char *name,
3e217b66 JH	341	const struct rtc_class_ops *ops,
	342	struct module *owner)
	343	{
	344	struct rtc_device *ptr, rtc;
	345
	346	ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL);
	347	if (!ptr)
	348	return ERR_PTR(-ENOMEM);
	349
	350	rtc = rtc_device_register(name, dev, ops, owner);
	351	if (!IS_ERR(rtc)) {
	352	*ptr = rtc;
	353	devres_add(dev, ptr);
	354	} else {
	355	devres_free(ptr);
	356	}
	357
	358	return rtc;
	359	}
	360	EXPORT_SYMBOL_GPL(devm_rtc_device_register);
	361
	362	/**
	363	* devm_rtc_device_unregister - resource managed devm_rtc_device_unregister()
	364	* @dev: the device to unregister
	365	* @rtc: the RTC class device to unregister
	366	*
	367	* Deallocated a rtc allocated with devm_rtc_device_register(). Normally this
	368	* function will not need to be called and the resource management code will
	369	* ensure that the resource is freed.
	370	*/
	371	void devm_rtc_device_unregister(struct device dev, struct rtc_device rtc)
	372	{
	373	int rc;
	374
	375	rc = devres_release(dev, devm_rtc_device_release,
	376	devm_rtc_device_match, rtc);
	377	WARN_ON(rc);
	378	}
	379	EXPORT_SYMBOL_GPL(devm_rtc_device_unregister);
	380
3068a254 AB	381	static void devm_rtc_release_device(struct device dev, void res)
	382	{
	383	struct rtc_device rtc = (struct rtc_device **)res;
	384
	385	if (rtc->registered)
	386	rtc_device_unregister(rtc);
	387	else
	388	put_device(&rtc->dev);
	389	}
	390
	391	struct rtc_device devm_rtc_allocate_device(struct device dev)
	392	{
	393	struct rtc_device *ptr, rtc;
	394	int id, err;
	395
	396	id = rtc_device_get_id(dev);
	397	if (id < 0)
	398	return ERR_PTR(id);
	399
	400	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
	401	if (!ptr) {
	402	err = -ENOMEM;
	403	goto exit_ida;
	404	}
	405
	406	rtc = rtc_allocate_device();
	407	if (!rtc) {
	408	err = -ENOMEM;
	409	goto exit_devres;
	410	}
	411
	412	*ptr = rtc;
	413	devres_add(dev, ptr);
	414
	415	rtc->id = id;
	416	rtc->dev.parent = dev;
	417	dev_set_name(&rtc->dev, "rtc%d", id);
	418
	419	return rtc;
	420
	421	exit_devres:
	422	devres_free(ptr);
	423	exit_ida:
	424	ida_simple_remove(&rtc_ida, id);
	425	return ERR_PTR(err);
	426	}
	427	EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
	428
	429	int __rtc_register_device(struct module owner, struct rtc_device rtc)
	430	{
	431	struct rtc_wkalrm alrm;
	432	int err;
	433
	434	if (!rtc->ops)
	435	return -EINVAL;
	436
	437	rtc->owner = owner;
	438
	439	/* Check to see if there is an ALARM already set in hw */
	440	err = __rtc_read_alarm(rtc, &alrm);
	441	if (!err && !rtc_valid_tm(&alrm.time))
	442	rtc_initialize_alarm(rtc, &alrm);
	443
	444	rtc_dev_prepare(rtc);
445
446	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
447	if (err)
448	dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
449	MAJOR(rtc->dev.devt), rtc->id);
450	else
451	dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
452	MAJOR(rtc->dev.devt), rtc->id);
453
454	rtc_proc_add_device(rtc);
455
697e5a47 AB	456	rtc_nvmem_register(rtc);
697e5a47 AB	457
3068a254 AB	458	rtc->registered = true;
	459	dev_info(rtc->dev.parent, "registered as %s\n",
	460	dev_name(&rtc->dev));
	461
	462	return 0;
	463	}
	464	EXPORT_SYMBOL_GPL(__rtc_register_device);
	465
0c86edc0 AZ	466	static int __init rtc_init(void)
	467	{
	468	rtc_class = class_create(THIS_MODULE, "rtc");
	469	if (IS_ERR(rtc_class)) {
c100a5e0	470	pr_err("couldn't create class\n");
0c86edc0 AZ	471	return PTR_ERR(rtc_class);
0c86edc0 AZ	472	}
92e7f04a	473	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
5726fb20	474	rtc_dev_init();
0c86edc0 AZ	475	return 0;
0c86edc0 AZ	476	}
818a8674	477	subsys_initcall(rtc_init);