[linux-2.6-block.git] / drivers / rtc / rtc-sysfs.c

/*
 * RTC subsystem, sysfs interface
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 *
 * 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
name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
}
static DEVICE_ATTR_RO(name);

static ssize_t
date_show(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 DEVICE_ATTR_RO(date);

static ssize_t
time_show(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 DEVICE_ATTR_RO(time);

static ssize_t
since_epoch_show(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 DEVICE_ATTR_RO(since_epoch);

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

static ssize_t
max_user_freq_store(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;
}
static DEVICE_ATTR_RW(max_user_freq);

/**
 * 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
hctosys_show(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 DEVICE_ATTR_RO(hctosys);

static struct attribute *rtc_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_date.attr,
	&dev_attr_time.attr,
	&dev_attr_since_epoch.attr,
	&dev_attr_max_user_freq.attr,
	&dev_attr_hctosys.attr,
	NULL,
};
ATTRIBUTE_GROUPS(rtc);

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;
	unsigned long push = 0;
	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++;
		if (*buf_ptr == '=') {
			buf_ptr++;
			push = 1;
		} else
			adjust = 1;
	}
	alarm = simple_strtoul(buf_ptr, NULL, 0);
	if (adjust) {
		alarm += now;
	}
	if (alarm > now || push) {
		/* 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) {
			if (push) {
				rtc_tm_to_time(&alm.time, &push);
				alarm += push;
			} else
				return -EBUSY;
		} else if (push)
			return -EINVAL;
		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_groups = rtc_groups;
}
Commit	Line	Data
	1	/*
	2	* RTC subsystem, sysfs interface
	3	*
	4	* Copyright (C) 2005 Tower Technologies
	5	* Author: Alessandro Zummo <a.zummo@towertech.it>
	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
	15	#include "rtc-core.h"
	16
	17
	18	/* device attributes */
	19
	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
	27	static ssize_t
	28	name_show(struct device dev, struct device_attribute attr, char *buf)
	29	{
	30	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
	31	}
	32	static DEVICE_ATTR_RO(name);
	33
	34	static ssize_t
	35	date_show(struct device dev, struct device_attribute attr, char *buf)
	36	{
	37	ssize_t retval;
	38	struct rtc_time tm;
	39
	40	retval = rtc_read_time(to_rtc_device(dev), &tm);
	41	if (retval == 0) {
	42	retval = sprintf(buf, "%04d-%02d-%02d\n",
	43	tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
	44	}
	45
	46	return retval;
	47	}
	48	static DEVICE_ATTR_RO(date);
	49
	50	static ssize_t
	51	time_show(struct device dev, struct device_attribute attr, char *buf)
	52	{
	53	ssize_t retval;
	54	struct rtc_time tm;
	55
	56	retval = rtc_read_time(to_rtc_device(dev), &tm);
	57	if (retval == 0) {
	58	retval = sprintf(buf, "%02d:%02d:%02d\n",
	59	tm.tm_hour, tm.tm_min, tm.tm_sec);
	60	}
	61
	62	return retval;
	63	}
	64	static DEVICE_ATTR_RO(time);
	65
	66	static ssize_t
	67	since_epoch_show(struct device dev, struct device_attribute attr, char *buf)
	68	{
	69	ssize_t retval;
	70	struct rtc_time tm;
	71
	72	retval = rtc_read_time(to_rtc_device(dev), &tm);
	73	if (retval == 0) {
	74	unsigned long time;
	75	rtc_tm_to_time(&tm, &time);
	76	retval = sprintf(buf, "%lu\n", time);
	77	}
	78
	79	return retval;
	80	}
	81	static DEVICE_ATTR_RO(since_epoch);
	82
	83	static ssize_t
	84	max_user_freq_show(struct device dev, struct device_attribute attr, char *buf)
	85	{
	86	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
	87	}
	88
	89	static ssize_t
	90	max_user_freq_store(struct device dev, struct device_attribute attr,
	91	const char *buf, size_t n)
	92	{
	93	struct rtc_device *rtc = to_rtc_device(dev);
	94	unsigned long val = simple_strtoul(buf, NULL, 0);
	95
	96	if (val >= 4096 \|\| val == 0)
	97	return -EINVAL;
	98
	99	rtc->max_user_freq = (int)val;
	100
	101	return n;
	102	}
	103	static DEVICE_ATTR_RW(max_user_freq);
	104
	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	*/
	111	static ssize_t
	112	hctosys_show(struct device dev, struct device_attribute attr, char *buf)
	113	{
	114	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
	115	if (rtc_hctosys_ret == 0 &&
	116	strcmp(dev_name(&to_rtc_device(dev)->dev),
	117	CONFIG_RTC_HCTOSYS_DEVICE) == 0)
	118	return sprintf(buf, "1\n");
	119	else
	120	#endif
	121	return sprintf(buf, "0\n");
	122	}
	123	static DEVICE_ATTR_RO(hctosys);
	124
	125	static struct attribute *rtc_attrs[] = {
	126	&dev_attr_name.attr,
	127	&dev_attr_date.attr,
	128	&dev_attr_time.attr,
	129	&dev_attr_since_epoch.attr,
	130	&dev_attr_max_user_freq.attr,
	131	&dev_attr_hctosys.attr,
	132	NULL,
	133	};
	134	ATTRIBUTE_GROUPS(rtc);
	135
	136	static ssize_t
	137	rtc_sysfs_show_wakealarm(struct device dev, struct device_attribute attr,
	138	char *buf)
	139	{
	140	ssize_t retval;
	141	unsigned long alarm;
	142	struct rtc_wkalrm alm;
	143
	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.
	147	*
	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.
	151	*/
	152	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
	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
	162	rtc_sysfs_set_wakealarm(struct device dev, struct device_attribute attr,
	163	const char *buf, size_t n)
	164	{
	165	ssize_t retval;
	166	unsigned long now, alarm;
	167	unsigned long push = 0;
	168	struct rtc_wkalrm alm;
	169	struct rtc_device *rtc = to_rtc_device(dev);
	170	char *buf_ptr;
	171	int adjust = 0;
	172
	173	/* Only request alarms that trigger in the future. Disable them
	174	* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
	175	*/
	176	retval = rtc_read_time(rtc, &alm.time);
	177	if (retval < 0)
	178	return retval;
	179	rtc_tm_to_time(&alm.time, &now);
	180
	181	buf_ptr = (char *)buf;
	182	if (*buf_ptr == '+') {
	183	buf_ptr++;
	184	if (*buf_ptr == '=') {
	185	buf_ptr++;
	186	push = 1;
	187	} else
	188	adjust = 1;
	189	}
	190	alarm = simple_strtoul(buf_ptr, NULL, 0);
	191	if (adjust) {
	192	alarm += now;
	193	}
	194	if (alarm > now \|\| push) {
	195	/* Avoid accidentally clobbering active alarms; we can't
	196	* entirely prevent that here, without even the minimal
	197	* locking from the /dev/rtcN api.
	198	*/
	199	retval = rtc_read_alarm(rtc, &alm);
	200	if (retval < 0)
	201	return retval;
	202	if (alm.enabled) {
	203	if (push) {
	204	rtc_tm_to_time(&alm.time, &push);
	205	alarm += push;
	206	} else
	207	return -EBUSY;
	208	} else if (push)
	209	return -EINVAL;
	210	alm.enabled = 1;
	211	} else {
	212	alm.enabled = 0;
	213
	214	/* Provide a valid future alarm time. Linux isn't EFI,
	215	* this time won't be ignored when disabling the alarm.
	216	*/
	217	alarm = now + 300;
	218	}
	219	rtc_time_to_tm(alarm, &alm.time);
	220
	221	retval = rtc_set_alarm(rtc, &alm);
	222	return (retval < 0) ? retval : n;
	223	}
	224	static DEVICE_ATTR(wakealarm, S_IRUGO \| S_IWUSR,
	225	rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);
	226
	227
	228	/* The reason to trigger an alarm with no process watching it (via sysfs)
	229	* is its side effect: waking from a system state like suspend-to-RAM or
	230	* suspend-to-disk. So: no attribute unless that side effect is possible.
	231	* (Userspace may disable that mechanism later.)
	232	*/
	233	static inline int rtc_does_wakealarm(struct rtc_device *rtc)
	234	{
	235	if (!device_can_wakeup(rtc->dev.parent))
	236	return 0;
	237	return rtc->ops->set_alarm != NULL;
	238	}
	239
	240
	241	void rtc_sysfs_add_device(struct rtc_device *rtc)
	242	{
	243	int err;
	244
	245	/* not all RTCs support both alarms and wakeup */
	246	if (!rtc_does_wakealarm(rtc))
	247	return;
	248
	249	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
	250	if (err)
	251	dev_err(rtc->dev.parent,
	252	"failed to create alarm attribute, %d\n", err);
	253	}
	254
	255	void rtc_sysfs_del_device(struct rtc_device *rtc)
	256	{
	257	/* REVISIT did we add it successfully? */
	258	if (rtc_does_wakealarm(rtc))
	259	device_remove_file(&rtc->dev, &dev_attr_wakealarm);
	260	}
	261
	262	void __init rtc_sysfs_init(struct class *rtc_class)
	263	{
	264	rtc_class->dev_groups = rtc_groups;
	265	}