[mirror_ubuntu-jammy-kernel.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
wakealarm_show(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
wakealarm_store(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_RW(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 bool rtc_does_wakealarm(struct rtc_device *rtc)
{
	if (!device_can_wakeup(rtc->dev.parent))
		return false;

	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
c5c3e192 AZ	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
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	27	static ssize_t
f21e6835	28	name_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	29	{
	30	return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
	31	}
f21e6835	32	static DEVICE_ATTR_RO(name);
c5c3e192	33
cd966209	34	static ssize_t
f21e6835	35	date_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	36	{
	37	ssize_t retval;
	38	struct rtc_time tm;
	39
ab6a2d70	40	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	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	}
f21e6835	48	static DEVICE_ATTR_RO(date);
c5c3e192	49
cd966209	50	static ssize_t
f21e6835	51	time_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	52	{
	53	ssize_t retval;
	54	struct rtc_time tm;
	55
ab6a2d70	56	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	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	}
f21e6835	64	static DEVICE_ATTR_RO(time);
c5c3e192	65
cd966209	66	static ssize_t
f21e6835	67	since_epoch_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	68	{
	69	ssize_t retval;
	70	struct rtc_time tm;
	71
ab6a2d70	72	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192 AZ	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	}
f21e6835	81	static DEVICE_ATTR_RO(since_epoch);
c5c3e192	82
06c65eb4	83	static ssize_t
f21e6835	84	max_user_freq_show(struct device dev, struct device_attribute attr, char *buf)
06c65eb4 BK	85	{
	86	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
	87	}
	88
	89	static ssize_t
f21e6835	90	max_user_freq_store(struct device dev, struct device_attribute attr,
06c65eb4 BK	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	}
f21e6835	103	static DEVICE_ATTR_RW(max_user_freq);
06c65eb4	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	111	static ssize_t
f21e6835	112	hctosys_show(struct device dev, struct device_attribute attr, char *buf)
d8c1acb1 MG	113	{
d8c1acb1 MG	114	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
d0ab4a4d UKK	115	if (rtc_hctosys_ret == 0 &&
	116	strcmp(dev_name(&to_rtc_device(dev)->dev),
	117	CONFIG_RTC_HCTOSYS_DEVICE) == 0)
d8c1acb1 MG	118	return sprintf(buf, "1\n");
	119	else
	120	#endif
	121	return sprintf(buf, "0\n");
	122	}
f21e6835 GKH	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,
c5c3e192	133	};
f21e6835	134	ATTRIBUTE_GROUPS(rtc);
c5c3e192	135
3925a5ce	136	static ssize_t
a17ccd1c	137	wakealarm_show(struct device dev, struct device_attribute attr, char *buf)
3925a5ce DB	138	{
	139	ssize_t retval;
	140	unsigned long alarm;
	141	struct rtc_wkalrm alm;
	142
8a0bdfd7 DB	143	/* Don't show disabled alarms. For uniformity, RTC alarms are
	144	* conceptually one-shot, even though some common RTCs (on PCs)
	145	* don't actually work that way.
3925a5ce	146	*
8a0bdfd7 DB	147	* NOTE: RTC implementations where the alarm doesn't match an
	148	* exact YYYY-MM-DD HH:MM[:SS] date must disable their RTC
	149	* alarms after they trigger, to ensure one-shot semantics.
3925a5ce	150	*/
ab6a2d70	151	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
3925a5ce DB	152	if (retval == 0 && alm.enabled) {
	153	rtc_tm_to_time(&alm.time, &alarm);
	154	retval = sprintf(buf, "%lu\n", alarm);
	155	}
	156
	157	return retval;
	158	}
	159
	160	static ssize_t
a17ccd1c	161	wakealarm_store(struct device dev, struct device_attribute attr,
cd966209	162	const char *buf, size_t n)
3925a5ce DB	163	{
	164	ssize_t retval;
	165	unsigned long now, alarm;
1df0a471	166	unsigned long push = 0;
3925a5ce	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++;
1df0a471 BT	183	if (*buf_ptr == '=') {
	184	buf_ptr++;
	185	push = 1;
	186	} else
	187	adjust = 1;
c116bc2a ZY	188	}
	189	alarm = simple_strtoul(buf_ptr, NULL, 0);
	190	if (adjust) {
	191	alarm += now;
	192	}
1df0a471	193	if (alarm > now \|\| push) {
3925a5ce DB	194	/* Avoid accidentally clobbering active alarms; we can't
	195	* entirely prevent that here, without even the minimal
	196	* locking from the /dev/rtcN api.
	197	*/
ab6a2d70	198	retval = rtc_read_alarm(rtc, &alm);
3925a5ce DB	199	if (retval < 0)
3925a5ce DB	200	return retval;
1df0a471 BT	201	if (alm.enabled) {
	202	if (push) {
	203	rtc_tm_to_time(&alm.time, &push);
	204	alarm += push;
	205	} else
	206	return -EBUSY;
	207	} else if (push)
	208	return -EINVAL;
3925a5ce DB	209	alm.enabled = 1;
	210	} else {
	211	alm.enabled = 0;
	212
	213	/* Provide a valid future alarm time. Linux isn't EFI,
	214	* this time won't be ignored when disabling the alarm.
	215	*/
	216	alarm = now + 300;
	217	}
	218	rtc_time_to_tm(alarm, &alm.time);
	219
ab6a2d70	220	retval = rtc_set_alarm(rtc, &alm);
3925a5ce DB	221	return (retval < 0) ? retval : n;
3925a5ce DB	222	}
a17ccd1c	223	static DEVICE_ATTR_RW(wakealarm);
3925a5ce DB	224
	225
	226	/* The reason to trigger an alarm with no process watching it (via sysfs)
	227	* is its side effect: waking from a system state like suspend-to-RAM or
	228	* suspend-to-disk. So: no attribute unless that side effect is possible.
	229	* (Userspace may disable that mechanism later.)
	230	*/
df100c01	231	static bool rtc_does_wakealarm(struct rtc_device *rtc)
3925a5ce	232	{
cd966209	233	if (!device_can_wakeup(rtc->dev.parent))
df100c01 DT	234	return false;
df100c01 DT	235
3925a5ce DB	236	return rtc->ops->set_alarm != NULL;
	237	}
	238
	239
446ecbd9	240	void rtc_sysfs_add_device(struct rtc_device *rtc)
c5c3e192 AZ	241	{
	242	int err;
	243
446ecbd9 DB	244	/* not all RTCs support both alarms and wakeup */
	245	if (!rtc_does_wakealarm(rtc))
	246	return;
c5c3e192	247
cd966209	248	err = device_create_file(&rtc->dev, &dev_attr_wakealarm);
c5c3e192	249	if (err)
898eb71c JP	250	dev_err(rtc->dev.parent,
898eb71c JP	251	"failed to create alarm attribute, %d\n", err);
c5c3e192 AZ	252	}
c5c3e192 AZ	253
446ecbd9	254	void rtc_sysfs_del_device(struct rtc_device *rtc)
c5c3e192	255	{
446ecbd9 DB	256	/* REVISIT did we add it successfully? */
446ecbd9 DB	257	if (rtc_does_wakealarm(rtc))
cd966209	258	device_remove_file(&rtc->dev, &dev_attr_wakealarm);
c5c3e192 AZ	259	}
c5c3e192 AZ	260
446ecbd9	261	void __init rtc_sysfs_init(struct class *rtc_class)
c5c3e192	262	{
f21e6835	263	rtc_class->dev_groups = rtc_groups;
c5c3e192	264	}