[deliverable/linux.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.
*/

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

#include "rtc-core.h"


static DEFINE_IDR(rtc_idr);
static DEFINE_MUTEX(idr_lock);
struct class *rtc_class;

static void rtc_device_release(struct device *dev)
{
	struct rtc_device *rtc = to_rtc_device(dev);
	mutex_lock(&idr_lock);
	idr_remove(&rtc_idr, rtc->id);
	mutex_unlock(&idr_lock);
	kfree(rtc);
}

#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	delta;
static time_t		oldtime;

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

	if (strncmp(rtc->dev.bus_id,
				CONFIG_RTC_HCTOSYS_DEVICE,
				BUS_ID_SIZE) != 0)
		return 0;

	rtc_read_time(rtc, &tm);
	rtc_tm_to_time(&tm, &oldtime);

	/* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
	set_normalized_timespec(&delta,
				xtime.tv_sec - oldtime,
				xtime.tv_nsec - (NSEC_PER_SEC >> 1));

	return 0;
}

static int rtc_resume(struct device *dev)
{
	struct rtc_device	*rtc = to_rtc_device(dev);
	struct rtc_time		tm;
	time_t			newtime;
	struct timespec		time;

	if (strncmp(rtc->dev.bus_id,
				CONFIG_RTC_HCTOSYS_DEVICE,
				BUS_ID_SIZE) != 0)
		return 0;

	rtc_read_time(rtc, &tm);
	if (rtc_valid_tm(&tm) != 0) {
		pr_debug("%s:  bogus resume time\n", rtc->dev.bus_id);
		return 0;
	}
	rtc_tm_to_time(&tm, &newtime);
	if (newtime <= oldtime) {
		if (newtime < oldtime)
			pr_debug("%s:  time travel!\n", rtc->dev.bus_id);
		return 0;
	}

	/* restore wall clock using delta against this RTC;
	 * adjust again for avg 1/2 second RTC sampling error
	 */
	set_normalized_timespec(&time,
				newtime + delta.tv_sec,
				(NSEC_PER_SEC >> 1) + delta.tv_nsec);
	do_settimeofday(&time);

	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;
	int id, err;

	if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
		err = -ENOMEM;
		goto exit;
	}


	mutex_lock(&idr_lock);
	err = idr_get_new(&rtc_idr, NULL, &id);
	mutex_unlock(&idr_lock);

	if (err < 0)
		goto exit;

	id = id & MAX_ID_MASK;

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

	rtc->id = id;
	rtc->ops = ops;
	rtc->owner = owner;
	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);

	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
	snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id);

	rtc_dev_prepare(rtc);

	err = device_register(&rtc->dev);
	if (err)
		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, rtc->dev.bus_id);

	return rtc;

exit_kfree:
	kfree(rtc);

exit_idr:
	mutex_lock(&idr_lock);
	idr_remove(&rtc_idr, id);
	mutex_unlock(&idr_lock);

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 int __init rtc_init(void)
{
	rtc_class = class_create(THIS_MODULE, "rtc");
	if (IS_ERR(rtc_class)) {
		printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
		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);
}

subsys_initcall(rtc_init);
module_exit(rtc_exit);

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
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 <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
	14	#include <linux/module.h>
	15	#include <linux/rtc.h>
	16	#include <linux/kdev_t.h>
	17	#include <linux/idr.h>
	18
5726fb20 DB	19	#include "rtc-core.h"
	20
	21
0c86edc0 AZ	22	static DEFINE_IDR(rtc_idr);
	23	static DEFINE_MUTEX(idr_lock);
	24	struct class *rtc_class;
	25
cd966209	26	static void rtc_device_release(struct device *dev)
0c86edc0	27	{
cd966209	28	struct rtc_device *rtc = to_rtc_device(dev);
0c86edc0 AZ	29	mutex_lock(&idr_lock);
	30	idr_remove(&rtc_idr, rtc->id);
	31	mutex_unlock(&idr_lock);
	32	kfree(rtc);
	33	}
	34
7ca1d488 DB	35	#if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
	36
	37	/*
	38	* On suspend(), measure the delta between one RTC and the
	39	* system's wall clock; restore it on resume().
	40	*/
	41
	42	static struct timespec delta;
	43	static time_t oldtime;
	44
	45	static int rtc_suspend(struct device *dev, pm_message_t mesg)
	46	{
	47	struct rtc_device *rtc = to_rtc_device(dev);
	48	struct rtc_time tm;
	49
	50	if (strncmp(rtc->dev.bus_id,
	51	CONFIG_RTC_HCTOSYS_DEVICE,
	52	BUS_ID_SIZE) != 0)
	53	return 0;
	54
	55	rtc_read_time(rtc, &tm);
	56	rtc_tm_to_time(&tm, &oldtime);
	57
	58	/* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
	59	set_normalized_timespec(&delta,
	60	xtime.tv_sec - oldtime,
	61	xtime.tv_nsec - (NSEC_PER_SEC >> 1));
	62
	63	return 0;
	64	}
	65
	66	static int rtc_resume(struct device *dev)
	67	{
	68	struct rtc_device *rtc = to_rtc_device(dev);
	69	struct rtc_time tm;
	70	time_t newtime;
	71	struct timespec time;
	72
	73	if (strncmp(rtc->dev.bus_id,
	74	CONFIG_RTC_HCTOSYS_DEVICE,
	75	BUS_ID_SIZE) != 0)
	76	return 0;
	77
	78	rtc_read_time(rtc, &tm);
	79	if (rtc_valid_tm(&tm) != 0) {
	80	pr_debug("%s: bogus resume time\n", rtc->dev.bus_id);
	81	return 0;
	82	}
	83	rtc_tm_to_time(&tm, &newtime);
	84	if (newtime <= oldtime) {
	85	if (newtime < oldtime)
	86	pr_debug("%s: time travel!\n", rtc->dev.bus_id);
	87	return 0;
	88	}
	89
	90	/* restore wall clock using delta against this RTC;
	91	* adjust again for avg 1/2 second RTC sampling error
	92	*/
	93	set_normalized_timespec(&time,
	94	newtime + delta.tv_sec,
	95	(NSEC_PER_SEC >> 1) + delta.tv_nsec);
	96	do_settimeofday(&time);
	97
	98	return 0;
99	}
100
101	#else
102	#define rtc_suspend NULL
103	#define rtc_resume NULL
104	#endif
105
106
0c86edc0 AZ	107	/**
	108	* rtc_device_register - register w/ RTC class
	109	* @dev: the device to register
	110	*
	111	* rtc_device_unregister() must be called when the class device is no
	112	* longer needed.
	113	*
	114	* Returns the pointer to the new struct class device.
	115	*/
	116	struct rtc_device rtc_device_register(const char name, struct device *dev,
ff8371ac	117	const struct rtc_class_ops *ops,
0c86edc0 AZ	118	struct module *owner)
	119	{
	120	struct rtc_device *rtc;
	121	int id, err;
	122
	123	if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
	124	err = -ENOMEM;
	125	goto exit;
	126	}
	127
	128
	129	mutex_lock(&idr_lock);
	130	err = idr_get_new(&rtc_idr, NULL, &id);
	131	mutex_unlock(&idr_lock);
	132
	133	if (err < 0)
	134	goto exit;
	135
	136	id = id & MAX_ID_MASK;
	137
	138	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
	139	if (rtc == NULL) {
	140	err = -ENOMEM;
	141	goto exit_idr;
	142	}
	143
	144	rtc->id = id;
	145	rtc->ops = ops;
	146	rtc->owner = owner;
110d693d	147	rtc->max_user_freq = 64;
cd966209 DB	148	rtc->dev.parent = dev;
	149	rtc->dev.class = rtc_class;
	150	rtc->dev.release = rtc_device_release;
0c86edc0 AZ	151
	152	mutex_init(&rtc->ops_lock);
	153	spin_lock_init(&rtc->irq_lock);
	154	spin_lock_init(&rtc->irq_task_lock);
	155
	156	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
cd966209	157	snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id);
0c86edc0	158
cb3a58d2 DB	159	rtc_dev_prepare(rtc);
cb3a58d2 DB	160
cd966209	161	err = device_register(&rtc->dev);
0c86edc0 AZ	162	if (err)
	163	goto exit_kfree;
	164
5726fb20	165	rtc_dev_add_device(rtc);
446ecbd9	166	rtc_sysfs_add_device(rtc);
7d9f99ec	167	rtc_proc_add_device(rtc);
5726fb20	168
0c86edc0	169	dev_info(dev, "rtc core: registered %s as %s\n",
cd966209	170	rtc->name, rtc->dev.bus_id);
0c86edc0 AZ	171
	172	return rtc;
	173
	174	exit_kfree:
	175	kfree(rtc);
	176
	177	exit_idr:
6ac12dfe	178	mutex_lock(&idr_lock);
0c86edc0	179	idr_remove(&rtc_idr, id);
6ac12dfe	180	mutex_unlock(&idr_lock);
0c86edc0 AZ	181
0c86edc0 AZ	182	exit:
d1d65b77 AZ	183	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
d1d65b77 AZ	184	name, err);
0c86edc0 AZ	185	return ERR_PTR(err);
	186	}
	187	EXPORT_SYMBOL_GPL(rtc_device_register);
	188
	189
	190	/**
	191	* rtc_device_unregister - removes the previously registered RTC class device
	192	*
	193	* @rtc: the RTC class device to destroy
	194	*/
	195	void rtc_device_unregister(struct rtc_device *rtc)
	196	{
cd966209	197	if (get_device(&rtc->dev) != NULL) {
e109ebd1 DB	198	mutex_lock(&rtc->ops_lock);
	199	/* remove innards of this RTC, then disable it, before
	200	* letting any rtc_class_open() users access it again
	201	*/
446ecbd9	202	rtc_sysfs_del_device(rtc);
5726fb20	203	rtc_dev_del_device(rtc);
7d9f99ec	204	rtc_proc_del_device(rtc);
cd966209	205	device_unregister(&rtc->dev);
e109ebd1 DB	206	rtc->ops = NULL;
e109ebd1 DB	207	mutex_unlock(&rtc->ops_lock);
cd966209	208	put_device(&rtc->dev);
e109ebd1	209	}
0c86edc0 AZ	210	}
	211	EXPORT_SYMBOL_GPL(rtc_device_unregister);
	212
0c86edc0 AZ	213	static int __init rtc_init(void)
	214	{
	215	rtc_class = class_create(THIS_MODULE, "rtc");
	216	if (IS_ERR(rtc_class)) {
	217	printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
	218	return PTR_ERR(rtc_class);
	219	}
7ca1d488 DB	220	rtc_class->suspend = rtc_suspend;
7ca1d488 DB	221	rtc_class->resume = rtc_resume;
5726fb20	222	rtc_dev_init();
446ecbd9	223	rtc_sysfs_init(rtc_class);
0c86edc0 AZ	224	return 0;
	225	}
	226
	227	static void __exit rtc_exit(void)
	228	{
5726fb20	229	rtc_dev_exit();
0c86edc0 AZ	230	class_destroy(rtc_class);
	231	}
	232
818a8674	233	subsys_initcall(rtc_init);
0c86edc0 AZ	234	module_exit(rtc_exit);
0c86edc0 AZ	235
818a8674	236	MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
0c86edc0 AZ	237	MODULE_DESCRIPTION("RTC class support");
0c86edc0 AZ	238	MODULE_LICENSE("GPL");