[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;
	struct timespec		ts = current_kernel_time();

	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,
				ts.tv_sec - oldtime,
				ts.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;
2c6b47de	49	struct timespec ts = current_kernel_time();
7ca1d488 DB	50
	51	if (strncmp(rtc->dev.bus_id,
	52	CONFIG_RTC_HCTOSYS_DEVICE,
	53	BUS_ID_SIZE) != 0)
	54	return 0;
	55
	56	rtc_read_time(rtc, &tm);
	57	rtc_tm_to_time(&tm, &oldtime);
	58
	59	/* RTC precision is 1 second; adjust delta for avg 1/2 sec err */
	60	set_normalized_timespec(&delta,
2c6b47de	61	ts.tv_sec - oldtime,
2c6b47de	62	ts.tv_nsec - (NSEC_PER_SEC >> 1));
7ca1d488 DB	63
	64	return 0;
	65	}
	66
	67	static int rtc_resume(struct device *dev)
	68	{
	69	struct rtc_device *rtc = to_rtc_device(dev);
	70	struct rtc_time tm;
	71	time_t newtime;
	72	struct timespec time;
	73
	74	if (strncmp(rtc->dev.bus_id,
	75	CONFIG_RTC_HCTOSYS_DEVICE,
	76	BUS_ID_SIZE) != 0)
	77	return 0;
	78
	79	rtc_read_time(rtc, &tm);
	80	if (rtc_valid_tm(&tm) != 0) {
	81	pr_debug("%s: bogus resume time\n", rtc->dev.bus_id);
	82	return 0;
	83	}
	84	rtc_tm_to_time(&tm, &newtime);
	85	if (newtime <= oldtime) {
	86	if (newtime < oldtime)
	87	pr_debug("%s: time travel!\n", rtc->dev.bus_id);
	88	return 0;
	89	}
	90
	91	/* restore wall clock using delta against this RTC;
	92	* adjust again for avg 1/2 second RTC sampling error
	93	*/
	94	set_normalized_timespec(&time,
	95	newtime + delta.tv_sec,
	96	(NSEC_PER_SEC >> 1) + delta.tv_nsec);
	97	do_settimeofday(&time);
	98
	99	return 0;
	100	}
	101
	102	#else
	103	#define rtc_suspend NULL
	104	#define rtc_resume NULL
	105	#endif
	106
	107
0c86edc0 AZ	108	/**
	109	* rtc_device_register - register w/ RTC class
	110	* @dev: the device to register
	111	*
	112	* rtc_device_unregister() must be called when the class device is no
	113	* longer needed.
	114	*
	115	* Returns the pointer to the new struct class device.
	116	*/
	117	struct rtc_device rtc_device_register(const char name, struct device *dev,
ff8371ac	118	const struct rtc_class_ops *ops,
0c86edc0 AZ	119	struct module *owner)
	120	{
	121	struct rtc_device *rtc;
	122	int id, err;
	123
	124	if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
	125	err = -ENOMEM;
	126	goto exit;
	127	}
	128
	129
	130	mutex_lock(&idr_lock);
	131	err = idr_get_new(&rtc_idr, NULL, &id);
	132	mutex_unlock(&idr_lock);
	133
	134	if (err < 0)
	135	goto exit;
	136
	137	id = id & MAX_ID_MASK;
	138
	139	rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
	140	if (rtc == NULL) {
	141	err = -ENOMEM;
	142	goto exit_idr;
	143	}
	144
	145	rtc->id = id;
	146	rtc->ops = ops;
	147	rtc->owner = owner;
110d693d	148	rtc->max_user_freq = 64;
cd966209 DB	149	rtc->dev.parent = dev;
	150	rtc->dev.class = rtc_class;
	151	rtc->dev.release = rtc_device_release;
0c86edc0 AZ	152
	153	mutex_init(&rtc->ops_lock);
	154	spin_lock_init(&rtc->irq_lock);
	155	spin_lock_init(&rtc->irq_task_lock);
	156
	157	strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
cd966209	158	snprintf(rtc->dev.bus_id, BUS_ID_SIZE, "rtc%d", id);
0c86edc0	159
cb3a58d2 DB	160	rtc_dev_prepare(rtc);
cb3a58d2 DB	161
cd966209	162	err = device_register(&rtc->dev);
0c86edc0 AZ	163	if (err)
	164	goto exit_kfree;
	165
5726fb20	166	rtc_dev_add_device(rtc);
446ecbd9	167	rtc_sysfs_add_device(rtc);
7d9f99ec	168	rtc_proc_add_device(rtc);
5726fb20	169
0c86edc0	170	dev_info(dev, "rtc core: registered %s as %s\n",
cd966209	171	rtc->name, rtc->dev.bus_id);
0c86edc0 AZ	172
	173	return rtc;
	174
	175	exit_kfree:
	176	kfree(rtc);
	177
	178	exit_idr:
6ac12dfe	179	mutex_lock(&idr_lock);
0c86edc0	180	idr_remove(&rtc_idr, id);
6ac12dfe	181	mutex_unlock(&idr_lock);
0c86edc0 AZ	182
0c86edc0 AZ	183	exit:
d1d65b77 AZ	184	dev_err(dev, "rtc core: unable to register %s, err = %d\n",
d1d65b77 AZ	185	name, err);
0c86edc0 AZ	186	return ERR_PTR(err);
	187	}
	188	EXPORT_SYMBOL_GPL(rtc_device_register);
	189
	190
	191	/**
	192	* rtc_device_unregister - removes the previously registered RTC class device
	193	*
	194	* @rtc: the RTC class device to destroy
	195	*/
	196	void rtc_device_unregister(struct rtc_device *rtc)
	197	{
cd966209	198	if (get_device(&rtc->dev) != NULL) {
e109ebd1 DB	199	mutex_lock(&rtc->ops_lock);
	200	/* remove innards of this RTC, then disable it, before
	201	* letting any rtc_class_open() users access it again
	202	*/
446ecbd9	203	rtc_sysfs_del_device(rtc);
5726fb20	204	rtc_dev_del_device(rtc);
7d9f99ec	205	rtc_proc_del_device(rtc);
cd966209	206	device_unregister(&rtc->dev);
e109ebd1 DB	207	rtc->ops = NULL;
e109ebd1 DB	208	mutex_unlock(&rtc->ops_lock);
cd966209	209	put_device(&rtc->dev);
e109ebd1	210	}
0c86edc0 AZ	211	}
	212	EXPORT_SYMBOL_GPL(rtc_device_unregister);
	213
0c86edc0 AZ	214	static int __init rtc_init(void)
	215	{
	216	rtc_class = class_create(THIS_MODULE, "rtc");
	217	if (IS_ERR(rtc_class)) {
	218	printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
	219	return PTR_ERR(rtc_class);
	220	}
7ca1d488 DB	221	rtc_class->suspend = rtc_suspend;
7ca1d488 DB	222	rtc_class->resume = rtc_resume;
5726fb20	223	rtc_dev_init();
446ecbd9	224	rtc_sysfs_init(rtc_class);
0c86edc0 AZ	225	return 0;
	226	}
	227
	228	static void __exit rtc_exit(void)
	229	{
5726fb20	230	rtc_dev_exit();
0c86edc0 AZ	231	class_destroy(rtc_class);
	232	}
	233
818a8674	234	subsys_initcall(rtc_init);
0c86edc0 AZ	235	module_exit(rtc_exit);
0c86edc0 AZ	236
818a8674	237	MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
0c86edc0 AZ	238	MODULE_DESCRIPTION("RTC class support");
0c86edc0 AZ	239	MODULE_LICENSE("GPL");