[linux-2.6-block.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;
	}

	ktime_get_real_ts64(&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 */
	ktime_get_real_ts64(&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);
	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, rtc);
	/* Init uie timer */
	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, 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;
}

static void rtc_device_get_offset(struct rtc_device *rtc)
{
	time64_t range_secs;
	u32 start_year;
	int ret;

	/*
	 * If RTC driver did not implement the range of RTC hardware device,
	 * then we can not expand the RTC range by adding or subtracting one
	 * offset.
	 */
	if (rtc->range_min == rtc->range_max)
		return;

	ret = device_property_read_u32(rtc->dev.parent, "start-year",
				       &start_year);
	if (!ret) {
		rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
		rtc->set_start_time = true;
	}

	/*
	 * If user did not implement the start time for RTC driver, then no
	 * need to expand the RTC range.
	 */
	if (!rtc->set_start_time)
		return;

	range_secs = rtc->range_max - rtc->range_min + 1;

	/*
	 * If the start_secs is larger than the maximum seconds (rtc->range_max)
	 * supported by RTC hardware or the maximum seconds of new expanded
	 * range (start_secs + rtc->range_max - rtc->range_min) is less than
	 * rtc->range_min, which means the minimum seconds (rtc->range_min) of
	 * RTC hardware will be mapped to start_secs by adding one offset, so
	 * the offset seconds calculation formula should be:
	 * rtc->offset_secs = rtc->start_secs - rtc->range_min;
	 *
	 * If the start_secs is larger than the minimum seconds (rtc->range_min)
	 * supported by RTC hardware, then there is one region is overlapped
	 * between the original RTC hardware range and the new expanded range,
	 * and this overlapped region do not need to be mapped into the new
	 * expanded range due to it is valid for RTC device. So the minimum
	 * seconds of RTC hardware (rtc->range_min) should be mapped to
	 * rtc->range_max + 1, then the offset seconds formula should be:
	 * rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
	 *
	 * If the start_secs is less than the minimum seconds (rtc->range_min),
	 * which is similar to case 2. So the start_secs should be mapped to
	 * start_secs + rtc->range_max - rtc->range_min + 1, then the
	 * offset seconds formula should be:
	 * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
	 *
	 * Otherwise the offset seconds should be 0.
	 */
	if (rtc->start_secs > rtc->range_max ||
	    rtc->start_secs + range_secs - 1 < rtc->range_min)
		rtc->offset_secs = rtc->start_secs - rtc->range_min;
	else if (rtc->start_secs > rtc->range_min)
		rtc->offset_secs = range_secs;
	else if (rtc->start_secs < rtc->range_min)
		rtc->offset_secs = -range_secs;
	else
		rtc->offset_secs = 0;
}

/**
 * rtc_device_unregister - removes the previously registered RTC class device
 *
 * @rtc: the RTC class device to destroy
 */
static 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);
}

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

	rtc_nvmem_unregister(rtc);

	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;
	rtc_device_get_offset(rtc);

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

	return 0;
}
EXPORT_SYMBOL_GPL(__rtc_register_device);

/**
 * devm_rtc_device_register - resource managed rtc_device_register()
 * @dev: the device to register
 * @name: the name of the device (unused)
 * @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.
 * This function is deprecated, use devm_rtc_allocate_device and
 * rtc_register_device instead
 */
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 *rtc;
	int err;

	rtc = devm_rtc_allocate_device(dev);
	if (IS_ERR(rtc))
		return rtc;

	rtc->ops = ops;

	err = __rtc_register_device(owner, rtc);
	if (err)
		return ERR_PTR(err);

	return rtc;
}
EXPORT_SYMBOL_GPL(devm_rtc_device_register);

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
5089ea15	71	ktime_get_real_ts64(&old_system);
d4bda8f8	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 */
5089ea15	113	ktime_get_real_ts64(&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);
d1bec20f AB	175	init_waitqueue_head(&rtc->irq_queue);
	176
	177	/* Init timerqueue */
	178	timerqueue_init_head(&rtc->timerqueue);
	179	INIT_WORK(&rtc->irqwork, rtc_timer_do_work);
	180	/* Init aie timer */
9a032011	181	rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc);
d1bec20f	182	/* Init uie timer */
9a032011	183	rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc);
d1bec20f AB	184	/* Init pie timer */
	185	hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	186	rtc->pie_timer.function = rtc_pie_update_irq;
	187	rtc->pie_enabled = 0;
	188
	189	return rtc;
	190	}
7ca1d488	191
b91336df AB	192	static int rtc_device_get_id(struct device *dev)
	193	{
	194	int of_id = -1, id = -1;
	195
	196	if (dev->of_node)
	197	of_id = of_alias_get_id(dev->of_node, "rtc");
	198	else if (dev->parent && dev->parent->of_node)
	199	of_id = of_alias_get_id(dev->parent->of_node, "rtc");
	200
	201	if (of_id >= 0) {
	202	id = ida_simple_get(&rtc_ida, of_id, of_id + 1, GFP_KERNEL);
	203	if (id < 0)
	204	dev_warn(dev, "/aliases ID %d not available\n", of_id);
	205	}
	206
	207	if (id < 0)
	208	id = ida_simple_get(&rtc_ida, 0, 0, GFP_KERNEL);
	209
	210	return id;
	211	}
	212
98951564 BW	213	static void rtc_device_get_offset(struct rtc_device *rtc)
	214	{
	215	time64_t range_secs;
	216	u32 start_year;
	217	int ret;
	218
	219	/*
	220	* If RTC driver did not implement the range of RTC hardware device,
	221	* then we can not expand the RTC range by adding or subtracting one
	222	* offset.
	223	*/
	224	if (rtc->range_min == rtc->range_max)
	225	return;
	226
	227	ret = device_property_read_u32(rtc->dev.parent, "start-year",
	228	&start_year);
	229	if (!ret) {
	230	rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0);
	231	rtc->set_start_time = true;
	232	}
	233
	234	/*
	235	* If user did not implement the start time for RTC driver, then no
	236	* need to expand the RTC range.
	237	*/
	238	if (!rtc->set_start_time)
	239	return;
	240
	241	range_secs = rtc->range_max - rtc->range_min + 1;
	242
	243	/*
	244	* If the start_secs is larger than the maximum seconds (rtc->range_max)
	245	* supported by RTC hardware or the maximum seconds of new expanded
	246	* range (start_secs + rtc->range_max - rtc->range_min) is less than
	247	* rtc->range_min, which means the minimum seconds (rtc->range_min) of
	248	* RTC hardware will be mapped to start_secs by adding one offset, so
	249	* the offset seconds calculation formula should be:
	250	* rtc->offset_secs = rtc->start_secs - rtc->range_min;
	251	*
	252	* If the start_secs is larger than the minimum seconds (rtc->range_min)
	253	* supported by RTC hardware, then there is one region is overlapped
	254	* between the original RTC hardware range and the new expanded range,
	255	* and this overlapped region do not need to be mapped into the new
	256	* expanded range due to it is valid for RTC device. So the minimum
	257	* seconds of RTC hardware (rtc->range_min) should be mapped to
	258	* rtc->range_max + 1, then the offset seconds formula should be:
	259	* rtc->offset_secs = rtc->range_max - rtc->range_min + 1;
	260	*
	261	* If the start_secs is less than the minimum seconds (rtc->range_min),
	262	* which is similar to case 2. So the start_secs should be mapped to
	263	* start_secs + rtc->range_max - rtc->range_min + 1, then the
	264	* offset seconds formula should be:
	265	* rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1);
	266	*
	267	* Otherwise the offset seconds should be 0.
	268	*/
	269	if (rtc->start_secs > rtc->range_max \|\|
	270	rtc->start_secs + range_secs - 1 < rtc->range_min)
	271	rtc->offset_secs = rtc->start_secs - rtc->range_min;
	272	else if (rtc->start_secs > rtc->range_min)
	273	rtc->offset_secs = range_secs;
	274	else if (rtc->start_secs < rtc->range_min)
	275	rtc->offset_secs = -range_secs;
	276	else
277	rtc->offset_secs = 0;
278	}
279
0c86edc0 AZ	280	/**
	281	* rtc_device_unregister - removes the previously registered RTC class device
	282	*
	283	* @rtc: the RTC class device to destroy
	284	*/
1e479c61	285	static void rtc_device_unregister(struct rtc_device *rtc)
0c86edc0	286	{
c3b399a4 DT	287	mutex_lock(&rtc->ops_lock);
	288	/*
	289	* Remove innards of this RTC, then disable it, before
	290	* letting any rtc_class_open() users access it again
	291	*/
c3b399a4	292	rtc_proc_del_device(rtc);
d5ed9177	293	cdev_device_del(&rtc->char_dev, &rtc->dev);
c3b399a4 DT	294	rtc->ops = NULL;
	295	mutex_unlock(&rtc->ops_lock);
	296	put_device(&rtc->dev);
0c86edc0	297	}
0c86edc0	298
3068a254 AB	299	static void devm_rtc_release_device(struct device dev, void res)
	300	{
	301	struct rtc_device rtc = (struct rtc_device **)res;
	302
ac75779b AB	303	rtc_nvmem_unregister(rtc);
ac75779b AB	304
3068a254 AB	305	if (rtc->registered)
	306	rtc_device_unregister(rtc);
	307	else
	308	put_device(&rtc->dev);
	309	}
	310
	311	struct rtc_device devm_rtc_allocate_device(struct device dev)
	312	{
	313	struct rtc_device *ptr, rtc;
	314	int id, err;
	315
	316	id = rtc_device_get_id(dev);
	317	if (id < 0)
	318	return ERR_PTR(id);
	319
	320	ptr = devres_alloc(devm_rtc_release_device, sizeof(*ptr), GFP_KERNEL);
	321	if (!ptr) {
	322	err = -ENOMEM;
	323	goto exit_ida;
	324	}
	325
	326	rtc = rtc_allocate_device();
	327	if (!rtc) {
	328	err = -ENOMEM;
	329	goto exit_devres;
	330	}
	331
	332	*ptr = rtc;
	333	devres_add(dev, ptr);
	334
	335	rtc->id = id;
	336	rtc->dev.parent = dev;
	337	dev_set_name(&rtc->dev, "rtc%d", id);
	338
	339	return rtc;
	340
	341	exit_devres:
	342	devres_free(ptr);
	343	exit_ida:
	344	ida_simple_remove(&rtc_ida, id);
	345	return ERR_PTR(err);
	346	}
	347	EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
	348
	349	int __rtc_register_device(struct module owner, struct rtc_device rtc)
	350	{
	351	struct rtc_wkalrm alrm;
	352	int err;
	353
	354	if (!rtc->ops)
	355	return -EINVAL;
	356
	357	rtc->owner = owner;
98951564	358	rtc_device_get_offset(rtc);
3068a254 AB	359
	360	/* Check to see if there is an ALARM already set in hw */
	361	err = __rtc_read_alarm(rtc, &alrm);
	362	if (!err && !rtc_valid_tm(&alrm.time))
	363	rtc_initialize_alarm(rtc, &alrm);
	364
	365	rtc_dev_prepare(rtc);
	366
	367	err = cdev_device_add(&rtc->char_dev, &rtc->dev);
	368	if (err)
	369	dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n",
	370	MAJOR(rtc->dev.devt), rtc->id);
	371	else
	372	dev_dbg(rtc->dev.parent, "char device (%d:%d)\n",
	373	MAJOR(rtc->dev.devt), rtc->id);
	374
	375	rtc_proc_add_device(rtc);
	376
	377	rtc->registered = true;
	378	dev_info(rtc->dev.parent, "registered as %s\n",
	379	dev_name(&rtc->dev));
	380
	381	return 0;
	382	}
	383	EXPORT_SYMBOL_GPL(__rtc_register_device);
	384
a2694414 AB	385	/**
	386	* devm_rtc_device_register - resource managed rtc_device_register()
	387	* @dev: the device to register
	388	* @name: the name of the device (unused)
	389	* @ops: the rtc operations structure
	390	* @owner: the module owner
	391	*
	392	* @return a struct rtc on success, or an ERR_PTR on error
	393	*
	394	* Managed rtc_device_register(). The rtc_device returned from this function
	395	* are automatically freed on driver detach.
	396	* This function is deprecated, use devm_rtc_allocate_device and
	397	* rtc_register_device instead
	398	*/
	399	struct rtc_device devm_rtc_device_register(struct device dev,
	400	const char *name,
	401	const struct rtc_class_ops *ops,
	402	struct module *owner)
	403	{
	404	struct rtc_device *rtc;
	405	int err;
	406
	407	rtc = devm_rtc_allocate_device(dev);
	408	if (IS_ERR(rtc))
	409	return rtc;
	410
	411	rtc->ops = ops;
	412
	413	err = __rtc_register_device(owner, rtc);
	414	if (err)
	415	return ERR_PTR(err);
	416
	417	return rtc;
	418	}
	419	EXPORT_SYMBOL_GPL(devm_rtc_device_register);
	420
0c86edc0 AZ	421	static int __init rtc_init(void)
	422	{
	423	rtc_class = class_create(THIS_MODULE, "rtc");
	424	if (IS_ERR(rtc_class)) {
c100a5e0	425	pr_err("couldn't create class\n");
0c86edc0 AZ	426	return PTR_ERR(rtc_class);
0c86edc0 AZ	427	}
92e7f04a	428	rtc_class->pm = RTC_CLASS_DEV_PM_OPS;
5726fb20	429	rtc_dev_init();
0c86edc0 AZ	430	return 0;
0c86edc0 AZ	431	}
818a8674	432	subsys_initcall(rtc_init);