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

// SPDX-License-Identifier: GPL-2.0
/*
 * RTC subsystem, sysfs interface
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 */

#include <linux/kstrtox.h>
#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 %s\n", dev_driver_string(dev->parent),
		       dev_name(dev->parent));
}
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)
		return retval;

	return sprintf(buf, "%ptRd\n", &tm);
}
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)
		return retval;

	return sprintf(buf, "%ptRt\n", &tm);
}
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) {
		time64_t time;

		time = rtc_tm_to_time64(&tm);
		retval = sprintf(buf, "%lld\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;
	int err;

	err = kstrtoul(buf, 0, &val);
	if (err)
		return err;

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

	rtc->max_user_freq = (int)val;

	return n;
}
static DEVICE_ATTR_RW(max_user_freq);

/**
 * hctosys_show - indicate if the given RTC set the system time
 * @dev: The device that the attribute belongs to.
 * @attr: The attribute being read.
 * @buf: The result buffer.
 *
 * buf is "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");
#endif
	return sprintf(buf, "0\n");
}
static DEVICE_ATTR_RO(hctosys);

static ssize_t
wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	ssize_t retval;
	time64_t 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) {
		alarm = rtc_tm_to_time64(&alm.time);
		retval = sprintf(buf, "%lld\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;
	time64_t now, alarm;
	time64_t push = 0;
	struct rtc_wkalrm alm;
	struct rtc_device *rtc = to_rtc_device(dev);
	const 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;
	now = rtc_tm_to_time64(&alm.time);

	buf_ptr = buf;
	if (*buf_ptr == '+') {
		buf_ptr++;
		if (*buf_ptr == '=') {
			buf_ptr++;
			push = 1;
		} else {
			adjust = 1;
		}
	}
	retval = kstrtos64(buf_ptr, 0, &alarm);
	if (retval)
		return retval;
	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) {
				push = rtc_tm_to_time64(&alm.time);
				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_time64_to_tm(alarm, &alm.time);

	retval = rtc_set_alarm(rtc, &alm);
	return (retval < 0) ? retval : n;
}
static DEVICE_ATTR_RW(wakealarm);

static ssize_t
offset_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	ssize_t retval;
	long offset;

	retval = rtc_read_offset(to_rtc_device(dev), &offset);
	if (retval == 0)
		retval = sprintf(buf, "%ld\n", offset);

	return retval;
}

static ssize_t
offset_store(struct device *dev, struct device_attribute *attr,
	     const char *buf, size_t n)
{
	ssize_t retval;
	long offset;

	retval = kstrtol(buf, 10, &offset);
	if (retval == 0)
		retval = rtc_set_offset(to_rtc_device(dev), offset);

	return (retval < 0) ? retval : n;
}
static DEVICE_ATTR_RW(offset);

static ssize_t
range_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
		       to_rtc_device(dev)->range_max);
}
static DEVICE_ATTR_RO(range);

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,
	&dev_attr_wakealarm.attr,
	&dev_attr_offset.attr,
	&dev_attr_range.attr,
	NULL,
};

/* 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 !!test_bit(RTC_FEATURE_ALARM, rtc->features);
}

static umode_t rtc_attr_is_visible(struct kobject *kobj,
				   struct attribute *attr, int n)
{
	struct device *dev = kobj_to_dev(kobj);
	struct rtc_device *rtc = to_rtc_device(dev);
	umode_t mode = attr->mode;

	if (attr == &dev_attr_wakealarm.attr) {
		if (!rtc_does_wakealarm(rtc))
			mode = 0;
	} else if (attr == &dev_attr_offset.attr) {
		if (!rtc->ops->set_offset)
			mode = 0;
	} else if (attr == &dev_attr_range.attr) {
		if (!(rtc->range_max - rtc->range_min))
			mode = 0;
	}

	return mode;
}

static struct attribute_group rtc_attr_group = {
	.is_visible	= rtc_attr_is_visible,
	.attrs		= rtc_attrs,
};

static const struct attribute_group *rtc_attr_groups[] = {
	&rtc_attr_group,
	NULL
};

const struct attribute_group **rtc_get_dev_attribute_groups(void)
{
	return rtc_attr_groups;
}

int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
{
	size_t old_cnt = 0, add_cnt = 0, new_cnt;
	const struct attribute_group **groups, **old;

	if (!grps)
		return -EINVAL;

	groups = rtc->dev.groups;
	if (groups)
		for (; *groups; groups++)
			old_cnt++;

	for (groups = grps; *groups; groups++)
		add_cnt++;

	new_cnt = old_cnt + add_cnt + 1;
	groups = devm_kcalloc(&rtc->dev, new_cnt, sizeof(*groups), GFP_KERNEL);
	if (!groups)
		return -ENOMEM;
	memcpy(groups, rtc->dev.groups, old_cnt * sizeof(*groups));
	memcpy(groups + old_cnt, grps, add_cnt * sizeof(*groups));
	groups[old_cnt + add_cnt] = NULL;

	old = rtc->dev.groups;
	rtc->dev.groups = groups;
	if (old && old != rtc_attr_groups)
		devm_kfree(&rtc->dev, old);

	return 0;
}
EXPORT_SYMBOL(rtc_add_groups);

int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
{
	const struct attribute_group *groups[] = { grp, NULL };

	return rtc_add_groups(rtc, groups);
}
EXPORT_SYMBOL(rtc_add_group);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* RTC subsystem, sysfs interface
	4	*
	5	* Copyright (C) 2005 Tower Technologies
	6	* Author: Alessandro Zummo <a.zummo@towertech.it>
	7	*/
	8
	9	#include <linux/kstrtox.h>
	10	#include <linux/module.h>
	11	#include <linux/rtc.h>
	12
	13	#include "rtc-core.h"
	14
	15	/* device attributes */
	16
	17	/*
	18	* NOTE: RTC times displayed in sysfs use the RTC's timezone. That's
	19	* ideally UTC. However, PCs that also boot to MS-Windows normally use
	20	* the local time and change to match daylight savings time. That affects
	21	* attributes including date, time, since_epoch, and wakealarm.
	22	*/
	23
	24	static ssize_t
	25	name_show(struct device dev, struct device_attribute attr, char *buf)
	26	{
	27	return sprintf(buf, "%s %s\n", dev_driver_string(dev->parent),
	28	dev_name(dev->parent));
	29	}
	30	static DEVICE_ATTR_RO(name);
	31
	32	static ssize_t
	33	date_show(struct device dev, struct device_attribute attr, char *buf)
	34	{
	35	ssize_t retval;
	36	struct rtc_time tm;
	37
	38	retval = rtc_read_time(to_rtc_device(dev), &tm);
	39	if (retval)
	40	return retval;
	41
	42	return sprintf(buf, "%ptRd\n", &tm);
	43	}
	44	static DEVICE_ATTR_RO(date);
	45
	46	static ssize_t
	47	time_show(struct device dev, struct device_attribute attr, char *buf)
	48	{
	49	ssize_t retval;
	50	struct rtc_time tm;
	51
	52	retval = rtc_read_time(to_rtc_device(dev), &tm);
	53	if (retval)
	54	return retval;
	55
	56	return sprintf(buf, "%ptRt\n", &tm);
	57	}
	58	static DEVICE_ATTR_RO(time);
	59
	60	static ssize_t
	61	since_epoch_show(struct device dev, struct device_attribute attr, char *buf)
	62	{
	63	ssize_t retval;
	64	struct rtc_time tm;
	65
	66	retval = rtc_read_time(to_rtc_device(dev), &tm);
	67	if (retval == 0) {
	68	time64_t time;
	69
	70	time = rtc_tm_to_time64(&tm);
	71	retval = sprintf(buf, "%lld\n", time);
	72	}
	73
	74	return retval;
	75	}
	76	static DEVICE_ATTR_RO(since_epoch);
	77
	78	static ssize_t
	79	max_user_freq_show(struct device dev, struct device_attribute attr, char *buf)
	80	{
	81	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
	82	}
	83
	84	static ssize_t
	85	max_user_freq_store(struct device dev, struct device_attribute attr,
	86	const char *buf, size_t n)
	87	{
	88	struct rtc_device *rtc = to_rtc_device(dev);
	89	unsigned long val;
	90	int err;
	91
	92	err = kstrtoul(buf, 0, &val);
	93	if (err)
	94	return err;
	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	* hctosys_show - indicate if the given RTC set the system time
	107	* @dev: The device that the attribute belongs to.
	108	* @attr: The attribute being read.
	109	* @buf: The result buffer.
	110	*
	111	* buf is "1" if the system clock was set by this RTC at the last
	112	* boot or resume event.
	113	*/
	114	static ssize_t
	115	hctosys_show(struct device dev, struct device_attribute attr, char *buf)
	116	{
	117	#ifdef CONFIG_RTC_HCTOSYS_DEVICE
	118	if (rtc_hctosys_ret == 0 &&
	119	strcmp(dev_name(&to_rtc_device(dev)->dev),
	120	CONFIG_RTC_HCTOSYS_DEVICE) == 0)
	121	return sprintf(buf, "1\n");
	122	#endif
	123	return sprintf(buf, "0\n");
	124	}
	125	static DEVICE_ATTR_RO(hctosys);
	126
	127	static ssize_t
	128	wakealarm_show(struct device dev, struct device_attribute attr, char *buf)
	129	{
	130	ssize_t retval;
	131	time64_t alarm;
	132	struct rtc_wkalrm alm;
	133
	134	/* Don't show disabled alarms. For uniformity, RTC alarms are
	135	* conceptually one-shot, even though some common RTCs (on PCs)
	136	* don't actually work that way.
	137	*
	138	* NOTE: RTC implementations where the alarm doesn't match an
	139	* exact YYYY-MM-DD HH:MM[:SS] date must disable their RTC
	140	* alarms after they trigger, to ensure one-shot semantics.
	141	*/
	142	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
	143	if (retval == 0 && alm.enabled) {
	144	alarm = rtc_tm_to_time64(&alm.time);
	145	retval = sprintf(buf, "%lld\n", alarm);
	146	}
	147
	148	return retval;
	149	}
	150
	151	static ssize_t
	152	wakealarm_store(struct device dev, struct device_attribute attr,
	153	const char *buf, size_t n)
	154	{
	155	ssize_t retval;
	156	time64_t now, alarm;
	157	time64_t push = 0;
	158	struct rtc_wkalrm alm;
	159	struct rtc_device *rtc = to_rtc_device(dev);
	160	const char *buf_ptr;
	161	int adjust = 0;
	162
	163	/* Only request alarms that trigger in the future. Disable them
	164	* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
	165	*/
	166	retval = rtc_read_time(rtc, &alm.time);
	167	if (retval < 0)
	168	return retval;
	169	now = rtc_tm_to_time64(&alm.time);
	170
	171	buf_ptr = buf;
	172	if (*buf_ptr == '+') {
	173	buf_ptr++;
	174	if (*buf_ptr == '=') {
	175	buf_ptr++;
	176	push = 1;
	177	} else {
	178	adjust = 1;
	179	}
	180	}
	181	retval = kstrtos64(buf_ptr, 0, &alarm);
	182	if (retval)
	183	return retval;
	184	if (adjust)
	185	alarm += now;
	186	if (alarm > now \|\| push) {
	187	/* Avoid accidentally clobbering active alarms; we can't
	188	* entirely prevent that here, without even the minimal
	189	* locking from the /dev/rtcN api.
	190	*/
	191	retval = rtc_read_alarm(rtc, &alm);
	192	if (retval < 0)
	193	return retval;
	194	if (alm.enabled) {
	195	if (push) {
	196	push = rtc_tm_to_time64(&alm.time);
	197	alarm += push;
	198	} else
	199	return -EBUSY;
	200	} else if (push)
	201	return -EINVAL;
	202	alm.enabled = 1;
	203	} else {
	204	alm.enabled = 0;
	205
	206	/* Provide a valid future alarm time. Linux isn't EFI,
	207	* this time won't be ignored when disabling the alarm.
	208	*/
	209	alarm = now + 300;
	210	}
	211	rtc_time64_to_tm(alarm, &alm.time);
	212
	213	retval = rtc_set_alarm(rtc, &alm);
	214	return (retval < 0) ? retval : n;
	215	}
	216	static DEVICE_ATTR_RW(wakealarm);
	217
	218	static ssize_t
	219	offset_show(struct device dev, struct device_attribute attr, char *buf)
	220	{
	221	ssize_t retval;
	222	long offset;
	223
	224	retval = rtc_read_offset(to_rtc_device(dev), &offset);
	225	if (retval == 0)
	226	retval = sprintf(buf, "%ld\n", offset);
	227
	228	return retval;
	229	}
	230
	231	static ssize_t
	232	offset_store(struct device dev, struct device_attribute attr,
	233	const char *buf, size_t n)
	234	{
	235	ssize_t retval;
	236	long offset;
	237
	238	retval = kstrtol(buf, 10, &offset);
	239	if (retval == 0)
	240	retval = rtc_set_offset(to_rtc_device(dev), offset);
	241
	242	return (retval < 0) ? retval : n;
	243	}
	244	static DEVICE_ATTR_RW(offset);
	245
	246	static ssize_t
	247	range_show(struct device dev, struct device_attribute attr, char *buf)
	248	{
	249	return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
	250	to_rtc_device(dev)->range_max);
	251	}
	252	static DEVICE_ATTR_RO(range);
	253
	254	static struct attribute *rtc_attrs[] = {
	255	&dev_attr_name.attr,
	256	&dev_attr_date.attr,
	257	&dev_attr_time.attr,
	258	&dev_attr_since_epoch.attr,
	259	&dev_attr_max_user_freq.attr,
	260	&dev_attr_hctosys.attr,
	261	&dev_attr_wakealarm.attr,
	262	&dev_attr_offset.attr,
	263	&dev_attr_range.attr,
	264	NULL,
	265	};
	266
	267	/* The reason to trigger an alarm with no process watching it (via sysfs)
	268	* is its side effect: waking from a system state like suspend-to-RAM or
	269	* suspend-to-disk. So: no attribute unless that side effect is possible.
	270	* (Userspace may disable that mechanism later.)
	271	*/
	272	static bool rtc_does_wakealarm(struct rtc_device *rtc)
	273	{
	274	if (!device_can_wakeup(rtc->dev.parent))
	275	return false;
	276
	277	return !!test_bit(RTC_FEATURE_ALARM, rtc->features);
	278	}
	279
	280	static umode_t rtc_attr_is_visible(struct kobject *kobj,
	281	struct attribute *attr, int n)
	282	{
	283	struct device *dev = kobj_to_dev(kobj);
	284	struct rtc_device *rtc = to_rtc_device(dev);
	285	umode_t mode = attr->mode;
	286
	287	if (attr == &dev_attr_wakealarm.attr) {
	288	if (!rtc_does_wakealarm(rtc))
	289	mode = 0;
	290	} else if (attr == &dev_attr_offset.attr) {
	291	if (!rtc->ops->set_offset)
	292	mode = 0;
	293	} else if (attr == &dev_attr_range.attr) {
	294	if (!(rtc->range_max - rtc->range_min))
	295	mode = 0;
	296	}
	297
	298	return mode;
	299	}
	300
	301	static struct attribute_group rtc_attr_group = {
	302	.is_visible = rtc_attr_is_visible,
	303	.attrs = rtc_attrs,
	304	};
	305
	306	static const struct attribute_group *rtc_attr_groups[] = {
	307	&rtc_attr_group,
	308	NULL
	309	};
	310
	311	const struct attribute_group **rtc_get_dev_attribute_groups(void)
	312	{
	313	return rtc_attr_groups;
	314	}
	315
	316	int rtc_add_groups(struct rtc_device rtc, const struct attribute_group *grps)
	317	{
	318	size_t old_cnt = 0, add_cnt = 0, new_cnt;
	319	const struct attribute_group groups, old;
	320
	321	if (!grps)
	322	return -EINVAL;
	323
	324	groups = rtc->dev.groups;
	325	if (groups)
	326	for (; *groups; groups++)
	327	old_cnt++;
	328
	329	for (groups = grps; *groups; groups++)
	330	add_cnt++;
	331
	332	new_cnt = old_cnt + add_cnt + 1;
	333	groups = devm_kcalloc(&rtc->dev, new_cnt, sizeof(*groups), GFP_KERNEL);
	334	if (!groups)
	335	return -ENOMEM;
	336	memcpy(groups, rtc->dev.groups, old_cnt * sizeof(*groups));
	337	memcpy(groups + old_cnt, grps, add_cnt * sizeof(*groups));
	338	groups[old_cnt + add_cnt] = NULL;
	339
	340	old = rtc->dev.groups;
	341	rtc->dev.groups = groups;
	342	if (old && old != rtc_attr_groups)
	343	devm_kfree(&rtc->dev, old);
	344
	345	return 0;
	346	}
	347	EXPORT_SYMBOL(rtc_add_groups);
	348
	349	int rtc_add_group(struct rtc_device rtc, const struct attribute_group grp)
	350	{
	351	const struct attribute_group *groups[] = { grp, NULL };
	352
	353	return rtc_add_groups(rtc, groups);
	354	}
	355	EXPORT_SYMBOL(rtc_add_group);