[mirror_ubuntu-jammy-kernel.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/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);

/**
 * 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 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 rtc->ops->set_alarm != NULL;
}

static umode_t rtc_attr_is_visible(struct kobject *kobj,
				   struct attribute *attr, int n)
{
	struct device *dev = container_of(kobj, struct device, 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 (rtc->registered)
		return -EINVAL;
	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
cdf7545a	1	// SPDX-License-Identifier: GPL-2.0
c5c3e192 AZ	2	/*
	3	* RTC subsystem, sysfs interface
	4	*
	5	* Copyright (C) 2005 Tower Technologies
	6	* Author: Alessandro Zummo <a.zummo@towertech.it>
cdf7545a	7	*/
c5c3e192 AZ	8
	9	#include <linux/module.h>
	10	#include <linux/rtc.h>
	11
ab6a2d70 DB	12	#include "rtc-core.h"
	13
	14
c5c3e192 AZ	15	/* device attributes */
c5c3e192 AZ	16
8a0bdfd7 DB	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
cd966209	24	static ssize_t
f21e6835	25	name_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192	26	{
77a73f3c AB	27	return sprintf(buf, "%s %s\n", dev_driver_string(dev->parent),
77a73f3c AB	28	dev_name(dev->parent));
c5c3e192	29	}
f21e6835	30	static DEVICE_ATTR_RO(name);
c5c3e192	31
cd966209	32	static ssize_t
f21e6835	33	date_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	34	{
	35	ssize_t retval;
	36	struct rtc_time tm;
	37
ab6a2d70	38	retval = rtc_read_time(to_rtc_device(dev), &tm);
5548cbf7 AS	39	if (retval)
5548cbf7 AS	40	return retval;
c5c3e192	41
5548cbf7	42	return sprintf(buf, "%ptRd\n", &tm);
c5c3e192	43	}
f21e6835	44	static DEVICE_ATTR_RO(date);
c5c3e192	45
cd966209	46	static ssize_t
f21e6835	47	time_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	48	{
	49	ssize_t retval;
	50	struct rtc_time tm;
	51
ab6a2d70	52	retval = rtc_read_time(to_rtc_device(dev), &tm);
5548cbf7 AS	53	if (retval)
5548cbf7 AS	54	return retval;
c5c3e192	55
5548cbf7	56	return sprintf(buf, "%ptRt\n", &tm);
c5c3e192	57	}
f21e6835	58	static DEVICE_ATTR_RO(time);
c5c3e192	59
cd966209	60	static ssize_t
f21e6835	61	since_epoch_show(struct device dev, struct device_attribute attr, char *buf)
c5c3e192 AZ	62	{
	63	ssize_t retval;
	64	struct rtc_time tm;
	65
ab6a2d70	66	retval = rtc_read_time(to_rtc_device(dev), &tm);
c5c3e192	67	if (retval == 0) {
9a06da2e BW	68	time64_t time;
	69
	70	time = rtc_tm_to_time64(&tm);
	71	retval = sprintf(buf, "%lld\n", time);
c5c3e192 AZ	72	}
	73
	74	return retval;
	75	}
f21e6835	76	static DEVICE_ATTR_RO(since_epoch);
c5c3e192	77
06c65eb4	78	static ssize_t
f21e6835	79	max_user_freq_show(struct device dev, struct device_attribute attr, char *buf)
06c65eb4 BK	80	{
	81	return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
	82	}
	83
	84	static ssize_t
f21e6835	85	max_user_freq_store(struct device dev, struct device_attribute attr,
06c65eb4 BK	86	const char *buf, size_t n)
	87	{
	88	struct rtc_device *rtc = to_rtc_device(dev);
f571287b LC	89	unsigned long val;
	90	int err;
	91
	92	err = kstrtoul(buf, 0, &val);
	93	if (err)
	94	return err;
06c65eb4 BK	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);
f21e6835 GKH	124
3925a5ce	125	static ssize_t
a17ccd1c	126	wakealarm_show(struct device dev, struct device_attribute attr, char *buf)
3925a5ce DB	127	{
3925a5ce DB	128	ssize_t retval;
9a06da2e	129	time64_t alarm;
3925a5ce DB	130	struct rtc_wkalrm alm;
3925a5ce DB	131
8a0bdfd7 DB	132	/* Don't show disabled alarms. For uniformity, RTC alarms are
	133	* conceptually one-shot, even though some common RTCs (on PCs)
	134	* don't actually work that way.
3925a5ce	135	*
8a0bdfd7 DB	136	* NOTE: RTC implementations where the alarm doesn't match an
	137	* exact YYYY-MM-DD HH:MM[:SS] date must disable their RTC
	138	* alarms after they trigger, to ensure one-shot semantics.
3925a5ce	139	*/
ab6a2d70	140	retval = rtc_read_alarm(to_rtc_device(dev), &alm);
3925a5ce	141	if (retval == 0 && alm.enabled) {
9a06da2e BW	142	alarm = rtc_tm_to_time64(&alm.time);
9a06da2e BW	143	retval = sprintf(buf, "%lld\n", alarm);
3925a5ce DB	144	}
	145
	146	return retval;
	147	}
	148
	149	static ssize_t
a17ccd1c	150	wakealarm_store(struct device dev, struct device_attribute attr,
cd966209	151	const char *buf, size_t n)
3925a5ce DB	152	{
3925a5ce DB	153	ssize_t retval;
9a06da2e BW	154	time64_t now, alarm;
9a06da2e BW	155	time64_t push = 0;
3925a5ce	156	struct rtc_wkalrm alm;
ab6a2d70	157	struct rtc_device *rtc = to_rtc_device(dev);
84281c2d	158	const char *buf_ptr;
c116bc2a	159	int adjust = 0;
3925a5ce DB	160
	161	/* Only request alarms that trigger in the future. Disable them
	162	* by writing another time, e.g. 0 meaning Jan 1 1970 UTC.
	163	*/
ab6a2d70	164	retval = rtc_read_time(rtc, &alm.time);
3925a5ce DB	165	if (retval < 0)
3925a5ce DB	166	return retval;
9a06da2e	167	now = rtc_tm_to_time64(&alm.time);
3925a5ce	168
84281c2d	169	buf_ptr = buf;
c116bc2a ZY	170	if (*buf_ptr == '+') {
c116bc2a ZY	171	buf_ptr++;
1df0a471 BT	172	if (*buf_ptr == '=') {
	173	buf_ptr++;
	174	push = 1;
	175	} else
	176	adjust = 1;
c116bc2a	177	}
9a06da2e	178	retval = kstrtos64(buf_ptr, 0, &alarm);
f571287b LC	179	if (retval)
f571287b LC	180	return retval;
c116bc2a ZY	181	if (adjust) {
	182	alarm += now;
	183	}
1df0a471	184	if (alarm > now \|\| push) {
3925a5ce DB	185	/* Avoid accidentally clobbering active alarms; we can't
	186	* entirely prevent that here, without even the minimal
	187	* locking from the /dev/rtcN api.
	188	*/
ab6a2d70	189	retval = rtc_read_alarm(rtc, &alm);
3925a5ce DB	190	if (retval < 0)
3925a5ce DB	191	return retval;
1df0a471 BT	192	if (alm.enabled) {
1df0a471 BT	193	if (push) {
9a06da2e	194	push = rtc_tm_to_time64(&alm.time);
1df0a471 BT	195	alarm += push;
	196	} else
	197	return -EBUSY;
	198	} else if (push)
	199	return -EINVAL;
3925a5ce DB	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	}
9a06da2e	209	rtc_time64_to_tm(alarm, &alm.time);
3925a5ce	210
ab6a2d70	211	retval = rtc_set_alarm(rtc, &alm);
3925a5ce DB	212	return (retval < 0) ? retval : n;
3925a5ce DB	213	}
a17ccd1c	214	static DEVICE_ATTR_RW(wakealarm);
3925a5ce	215
5495a415 JC	216	static ssize_t
	217	offset_show(struct device dev, struct device_attribute attr, char *buf)
	218	{
	219	ssize_t retval;
	220	long offset;
	221
	222	retval = rtc_read_offset(to_rtc_device(dev), &offset);
	223	if (retval == 0)
	224	retval = sprintf(buf, "%ld\n", offset);
	225
	226	return retval;
	227	}
	228
	229	static ssize_t
	230	offset_store(struct device dev, struct device_attribute attr,
	231	const char *buf, size_t n)
	232	{
	233	ssize_t retval;
	234	long offset;
	235
	236	retval = kstrtol(buf, 10, &offset);
	237	if (retval == 0)
	238	retval = rtc_set_offset(to_rtc_device(dev), offset);
	239
	240	return (retval < 0) ? retval : n;
	241	}
	242	static DEVICE_ATTR_RW(offset);
	243
71db049e AB	244	static ssize_t
	245	range_show(struct device dev, struct device_attribute attr, char *buf)
	246	{
	247	return sprintf(buf, "[%lld,%llu]\n", to_rtc_device(dev)->range_min,
	248	to_rtc_device(dev)->range_max);
	249	}
	250	static DEVICE_ATTR_RO(range);
	251
3ee2c40b DT	252	static struct attribute *rtc_attrs[] = {
	253	&dev_attr_name.attr,
	254	&dev_attr_date.attr,
	255	&dev_attr_time.attr,
	256	&dev_attr_since_epoch.attr,
	257	&dev_attr_max_user_freq.attr,
	258	&dev_attr_hctosys.attr,
	259	&dev_attr_wakealarm.attr,
5495a415	260	&dev_attr_offset.attr,
71db049e	261	&dev_attr_range.attr,
3ee2c40b DT	262	NULL,
3ee2c40b DT	263	};
3925a5ce DB	264
	265	/* The reason to trigger an alarm with no process watching it (via sysfs)
	266	* is its side effect: waking from a system state like suspend-to-RAM or
	267	* suspend-to-disk. So: no attribute unless that side effect is possible.
	268	* (Userspace may disable that mechanism later.)
	269	*/
df100c01	270	static bool rtc_does_wakealarm(struct rtc_device *rtc)
3925a5ce	271	{
cd966209	272	if (!device_can_wakeup(rtc->dev.parent))
df100c01 DT	273	return false;
df100c01 DT	274
3925a5ce DB	275	return rtc->ops->set_alarm != NULL;
	276	}
	277
3ee2c40b DT	278	static umode_t rtc_attr_is_visible(struct kobject *kobj,
3ee2c40b DT	279	struct attribute *attr, int n)
c5c3e192	280	{
3ee2c40b DT	281	struct device *dev = container_of(kobj, struct device, kobj);
	282	struct rtc_device *rtc = to_rtc_device(dev);
	283	umode_t mode = attr->mode;
c5c3e192	284
5495a415	285	if (attr == &dev_attr_wakealarm.attr) {
3ee2c40b DT	286	if (!rtc_does_wakealarm(rtc))
3ee2c40b DT	287	mode = 0;
5495a415 JC	288	} else if (attr == &dev_attr_offset.attr) {
	289	if (!rtc->ops->set_offset)
	290	mode = 0;
71db049e AB	291	} else if (attr == &dev_attr_range.attr) {
	292	if (!(rtc->range_max - rtc->range_min))
	293	mode = 0;
5495a415	294	}
c5c3e192	295
3ee2c40b	296	return mode;
c5c3e192 AZ	297	}
c5c3e192 AZ	298
3ee2c40b DT	299	static struct attribute_group rtc_attr_group = {
	300	.is_visible = rtc_attr_is_visible,
	301	.attrs = rtc_attrs,
	302	};
	303
	304	static const struct attribute_group *rtc_attr_groups[] = {
	305	&rtc_attr_group,
	306	NULL
	307	};
c5c3e192	308
3ee2c40b	309	const struct attribute_group **rtc_get_dev_attribute_groups(void)
c5c3e192	310	{
3ee2c40b	311	return rtc_attr_groups;
c5c3e192	312	}
a0a1a1ba DO	313
	314	int rtc_add_groups(struct rtc_device rtc, const struct attribute_group *grps)
	315	{
	316	size_t old_cnt = 0, add_cnt = 0, new_cnt;
	317	const struct attribute_group groups, old;
	318
	319	if (rtc->registered)
	320	return -EINVAL;
	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);
777d8ae5 DC	334	if (!groups)
777d8ae5 DC	335	return -ENOMEM;
a0a1a1ba DO	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);