[linux.git] / drivers / rtc / rtc-sysfs.c

/*
 * RTC subsystem, sysfs interface
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <[email protected]>
 *
 * 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 "rtc-core.h"


/* device attributes */

/*
 * NOTE:  RTC times displayed in sysfs use the RTC's timezone.  That's
 * ideally UTC.  However, PCs that also boot to MS-Windows normally use
 * the local time and change to match daylight savings time.  That affects
 * attributes including date, time, since_epoch, and wakealarm.
 */

static ssize_t
rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
}

static ssize_t
rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	ssize_t retval;
	struct rtc_time tm;

	retval = rtc_read_time(to_rtc_device(dev), &tm);
	if (retval == 0) {
		retval = sprintf(buf, "%04d-%02d-%02d\n",
			tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
	}

	return retval;
}

static ssize_t
rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	ssize_t retval;
	struct rtc_time tm;

	retval = rtc_read_time(to_rtc_device(dev), &tm);
	if (retval == 0) {
		retval = sprintf(buf, "%02d:%02d:%02d\n",
			tm.tm_hour, tm.tm_min, tm.tm_sec);
	}

	return retval;
}

static ssize_t
rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	ssize_t retval;
	struct rtc_time tm;

	retval = rtc_read_time(to_rtc_device(dev), &tm);
	if (retval == 0) {
		unsigned long time;
		rtc_tm_to_time(&tm, &time);
		retval = sprintf(buf, "%lu\n", time);
	}

	return retval;
}

static ssize_t
rtc_sysfs_show_max_user_freq(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
}

static ssize_t
rtc_sysfs_set_max_user_freq(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t n)
{
	struct rtc_device *rtc = to_rtc_device(dev);
	unsigned long val = simple_strtoul(buf, NULL, 0);

	if (val >= 4096 || val == 0)
		return -EINVAL;

	rtc->max_user_freq = (int)val;

	return n;
}

/**
 * rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
 *
 * Returns 1 if the system clock was set by this RTC at the last
 * boot or resume event.
 */
static ssize_t
rtc_sysfs_show_hctosys(struct device *dev, struct device_attribute *attr,
		char *buf)
{
#ifdef CONFIG_RTC_HCTOSYS_DEVICE
	if (rtc_hctosys_ret == 0 &&
			strcmp(dev_name(&to_rtc_device(dev)->dev),
				CONFIG_RTC_HCTOSYS_DEVICE) == 0)
		return sprintf(buf, "1\n");
	else
#endif
		return sprintf(buf, "0\n");
}

static struct device_attribute rtc_attrs[] = {
	__ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
	__ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
	__ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),
	__ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
	__ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,
			rtc_sysfs_set_max_user_freq),
	__ATTR(hctosys, S_IRUGO, rtc_sysfs_show_hctosys, NULL),
	{ },
};

static ssize_t
rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
		char *buf)
{
	ssize_t retval;
	unsigned long alarm;
	struct rtc_wkalrm alm;

	/* Don't show disabled alarms.  For uniformity, RTC alarms are
	 * conceptually one-shot, even though some common RTCs (on PCs)
	 * don't actually work that way.
	 *
	 * NOTE: RTC implementations where the alarm doesn't match an
	 * exact YYYY-MM-DD HH:MM[:SS] date *must* disable their RTC
	 * alarms after they trigger, to ensure one-shot semantics.
	 */
	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
	if (retval == 0 && alm.enabled) {
		rtc_tm_to_time(&alm.time, &alarm);
		retval = sprintf(buf, "%lu\n", alarm);
	}

	return retval;
}

static ssize_t
rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t n)
{
	ssize_t retval;
	unsigned long now, alarm;
	struct rtc_wkalrm alm;
	struct rtc_device *rtc = to_rtc_device(dev);
	char *buf_ptr;
	int adjust = 0;

	/* Only request alarms that trigger in the future.  Disable them
	 * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
	 */
	retval = rtc_read_time(rtc, &alm.time);
	if (retval < 0)
		return retval;
	rtc_tm_to_time(&alm.time, &now);

	buf_ptr = (char *)buf;
	if (*buf_ptr == '+') {
		buf_ptr++;
		adjust = 1;
	}
	alarm = simple_strtoul(buf_ptr, NULL, 0);
	if (adjust) {
		alarm += now;
	}
	if (alarm > now) {
		/* Avoid accidentally clobbering active alarms; we can't
		 * entirely prevent that here, without even the minimal
		 * locking from the /dev/rtcN api.
		 */
		retval = rtc_read_alarm(rtc, &alm);
		if (retval < 0)
			return retval;
		if (alm.enabled)
			return -EBUSY;

		alm.enabled = 1;
	} else {
		alm.enabled = 0;

		/* Provide a valid future alarm time.  Linux isn't EFI,
		 * this time won't be ignored when disabling the alarm.
		 */
		alarm = now + 300;
	}
	rtc_time_to_tm(alarm, &alm.time);

	retval = rtc_set_alarm(rtc, &alm);
	return (retval < 0) ? retval : n;
}
static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
		rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);


/* The reason to trigger an alarm with no process watching it (via sysfs)
 * is its side effect:  waking from a system state like suspend-to-RAM or
 * suspend-to-disk.  So: no attribute unless that side effect is possible.
 * (Userspace may disable that mechanism later.)
 */
static inline int rtc_does_wakealarm(struct rtc_device *rtc)
{
	if (!device_can_wakeup(rtc->dev.parent))
		return 0;
	return rtc->ops->set_alarm != NULL;
}


void rtc_sysfs_add_device(struct rtc_device *rtc)
{
	int err;

	/* not all RTCs support both alarms and wakeup */
	if (!rtc_does_wakealarm(rtc))
		return;

	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
	if (err)
		dev_err(rtc->dev.parent,
			"failed to create alarm attribute, %d\n", err);
}

void rtc_sysfs_del_device(struct rtc_device *rtc)
{
	/* REVISIT did we add it successfully? */
	if (rtc_does_wakealarm(rtc))
		device_remove_file(&rtc->dev, &dev_attr_wakealarm);
}

void __init rtc_sysfs_init(struct class *rtc_class)
{
	rtc_class->dev_attrs = rtc_attrs;
}
Commit	Line	Data
c5c3e192 AZ	1	/*
	2	* RTC subsystem, sysfs interface
	3	*
	4	* Copyright (C) 2005 Tower Technologies
	5	* Author: Alessandro Zummo <[email protected]>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/rtc.h>
	14
ab6a2d70 DB	15	#include "rtc-core.h"
	16
	17
c5c3e192 AZ	18	/* device attributes */
c5c3e192 AZ	19
8a0bdfd7 DB	20	/*
	21	* NOTE: RTC times displayed in sysfs use the RTC's timezone. That's
	22	* ideally UTC. However, PCs that also boot to MS-Windows normally use
	23	* the local time and change to match daylight savings time. That affects
	24	* attributes including date, time, since_epoch, and wakealarm.
	25	*/
	26
cd966209 DB	27	static ssize_t
	28	rtc_sysfs_show_name(struct device dev, struct device_attribute attr,
	29	char *buf)
c5c3e192 AZ	30	{
	31	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
	32	}
c5c3e192	33
cd966209 DB	34	static ssize_t
	35	rtc_sysfs_show_date(struct device dev, struct device_attribute attr,
	36	char *buf)
c5c3e192 AZ	37	{
	38	ssize_t retval;
	39	struct rtc_time tm;
	40
ab6a2d70	41	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	42	if (retval == 0) {
	43	retval = sprintf(buf, "%04d-%02d-%02d\n",
	44	tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
	45	}
	46
	47	return retval;
	48	}
c5c3e192	49
cd966209 DB	50	static ssize_t
	51	rtc_sysfs_show_time(struct device dev, struct device_attribute attr,
	52	char *buf)
c5c3e192 AZ	53	{
	54	ssize_t retval;
	55	struct rtc_time tm;
	56
ab6a2d70	57	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	58	if (retval == 0) {
	59	retval = sprintf(buf, "%02d:%02d:%02d\n",
	60	tm.tm_hour, tm.tm_min, tm.tm_sec);
	61	}
	62
	63	return retval;
	64	}
c5c3e192	65
cd966209 DB	66	static ssize_t
	67	rtc_sysfs_show_since_epoch(struct device dev, struct device_attribute attr,
	68	char *buf)
c5c3e192 AZ	69	{
	70	ssize_t retval;
	71	struct rtc_time tm;
	72
ab6a2d70	73	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	74	if (retval == 0) {
	75	unsigned long time;
	76	rtc_tm_to_time(&tm, &time);
	77	retval = sprintf(buf, "%lu\n", time);
	78	}
	79
	80	return retval;
	81	}
c5c3e192	82
06c65eb4 BK	83	static ssize_t
	84	rtc_sysfs_show_max_user_freq(struct device dev, struct device_attribute attr,
	85	char *buf)
	86	{
	87	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
	88	}
	89
	90	static ssize_t
	91	rtc_sysfs_set_max_user_freq(struct device dev, struct device_attribute attr,
	92	const char *buf, size_t n)
	93	{
	94	struct rtc_device *rtc = to_rtc_device(dev);
	95	unsigned long val = simple_strtoul(buf, NULL, 0);
	96
	97	if (val >= 4096 \|\| val == 0)
	98	return -EINVAL;
	99
	100	rtc->max_user_freq = (int)val;
	101
	102	return n;
	103	}
	104
4c24e29e DF	105	/**
	106	* rtc_sysfs_show_hctosys - indicate if the given RTC set the system time
	107	*
	108	* Returns 1 if the system clock was set by this RTC at the last
	109	* boot or resume event.
	110	*/
d8c1acb1 MG	111	static ssize_t
	112	rtc_sysfs_show_hctosys(struct device dev, struct device_attribute attr,
	113	char *buf)
	114	{
	115	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
d0ab4a4d UKK	116	if (rtc_hctosys_ret == 0 &&
	117	strcmp(dev_name(&to_rtc_device(dev)->dev),
	118	CONFIG_RTC_HCTOSYS_DEVICE) == 0)
d8c1acb1 MG	119	return sprintf(buf, "1\n");
	120	else
	121	#endif
	122	return sprintf(buf, "0\n");
	123	}
	124
cd966209	125	static struct device_attribute rtc_attrs[] = {
446ecbd9 DB	126	__ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
	127	__ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
	128	__ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),
	129	__ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
06c65eb4 BK	130	__ATTR(max_user_freq, S_IRUGO \| S_IWUSR, rtc_sysfs_show_max_user_freq,
06c65eb4 BK	131	rtc_sysfs_set_max_user_freq),
d8c1acb1	132	__ATTR(hctosys, S_IRUGO, rtc_sysfs_show_hctosys, NULL),
446ecbd9	133	{ },
c5c3e192 AZ	134	};
c5c3e192 AZ	135
3925a5ce	136	static ssize_t
cd966209 DB	137	rtc_sysfs_show_wakealarm(struct device dev, struct device_attribute attr,
cd966209 DB	138	char *buf)
3925a5ce DB	139	{
	140	ssize_t retval;
	141	unsigned long alarm;
	142	struct rtc_wkalrm alm;
	143
8a0bdfd7 DB	144	/* Don't show disabled alarms. For uniformity, RTC alarms are
	145	* conceptually one-shot, even though some common RTCs (on PCs)
	146	* don't actually work that way.
3925a5ce	147	*
8a0bdfd7 DB	148	* NOTE: RTC implementations where the alarm doesn't match an
	149	* exact YYYY-MM-DD HH:MM[:SS] date must disable their RTC
	150	* alarms after they trigger, to ensure one-shot semantics.
3925a5ce	151	*/
ab6a2d70	152	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
3925a5ce DB	153	if (retval == 0 && alm.enabled) {
	154	rtc_tm_to_time(&alm.time, &alarm);
	155	retval = sprintf(buf, "%lu\n", alarm);
	156	}
	157
	158	return retval;
	159	}
	160
	161	static ssize_t
cd966209 DB	162	rtc_sysfs_set_wakealarm(struct device dev, struct device_attribute attr,
cd966209 DB	163	const char *buf, size_t n)
3925a5ce DB	164	{
	165	ssize_t retval;
	166	unsigned long now, alarm;
	167	struct rtc_wkalrm alm;
ab6a2d70	168	struct rtc_device *rtc = to_rtc_device(dev);
c116bc2a ZY	169	char *buf_ptr;
c116bc2a ZY	170	int adjust = 0;
3925a5ce DB	171
	172	/* Only request alarms that trigger in the future. Disable them
	173	* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
	174	*/
ab6a2d70	175	retval = rtc_read_time(rtc, &alm.time);
3925a5ce DB	176	if (retval < 0)
	177	return retval;
	178	rtc_tm_to_time(&alm.time, &now);
	179
c116bc2a ZY	180	buf_ptr = (char *)buf;
	181	if (*buf_ptr == '+') {
	182	buf_ptr++;
	183	adjust = 1;
	184	}
	185	alarm = simple_strtoul(buf_ptr, NULL, 0);
	186	if (adjust) {
	187	alarm += now;
	188	}
3925a5ce DB	189	if (alarm > now) {
	190	/* Avoid accidentally clobbering active alarms; we can't
	191	* entirely prevent that here, without even the minimal
	192	* locking from the /dev/rtcN api.
	193	*/
ab6a2d70	194	retval = rtc_read_alarm(rtc, &alm);
3925a5ce DB	195	if (retval < 0)
	196	return retval;
	197	if (alm.enabled)
	198	return -EBUSY;
	199
	200	alm.enabled = 1;
	201	} else {
	202	alm.enabled = 0;
	203
	204	/* Provide a valid future alarm time. Linux isn't EFI,
	205	* this time won't be ignored when disabling the alarm.
	206	*/
	207	alarm = now + 300;
	208	}
	209	rtc_time_to_tm(alarm, &alm.time);
	210
ab6a2d70	211	retval = rtc_set_alarm(rtc, &alm);
3925a5ce DB	212	return (retval < 0) ? retval : n;
3925a5ce DB	213	}
cd966209	214	static DEVICE_ATTR(wakealarm, S_IRUGO \| S_IWUSR,
3925a5ce DB	215	rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
	216
	217
	218	/* The reason to trigger an alarm with no process watching it (via sysfs)
	219	* is its side effect: waking from a system state like suspend-to-RAM or
	220	* suspend-to-disk. So: no attribute unless that side effect is possible.
	221	* (Userspace may disable that mechanism later.)
	222	*/
446ecbd9	223	static inline int rtc_does_wakealarm(struct rtc_device *rtc)
3925a5ce	224	{
cd966209	225	if (!device_can_wakeup(rtc->dev.parent))
3925a5ce	226	return 0;
3925a5ce DB	227	return rtc->ops->set_alarm != NULL;
	228	}
	229
	230
446ecbd9	231	void rtc_sysfs_add_device(struct rtc_device *rtc)
c5c3e192 AZ	232	{
	233	int err;
	234
446ecbd9 DB	235	/* not all RTCs support both alarms and wakeup */
	236	if (!rtc_does_wakealarm(rtc))
	237	return;
c5c3e192	238
cd966209	239	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
c5c3e192	240	if (err)
898eb71c JP	241	dev_err(rtc->dev.parent,
898eb71c JP	242	"failed to create alarm attribute, %d\n", err);
c5c3e192 AZ	243	}
c5c3e192 AZ	244
446ecbd9	245	void rtc_sysfs_del_device(struct rtc_device *rtc)
c5c3e192	246	{
446ecbd9 DB	247	/* REVISIT did we add it successfully? */
446ecbd9 DB	248	if (rtc_does_wakealarm(rtc))
cd966209	249	device_remove_file(&rtc->dev, &dev_attr_wakealarm);
c5c3e192 AZ	250	}
c5c3e192 AZ	251
446ecbd9	252	void __init rtc_sysfs_init(struct class *rtc_class)
c5c3e192	253	{
cd966209	254	rtc_class->dev_attrs = rtc_attrs;
c5c3e192	255	}