linux/drivers/rtc/sysfs.c

// SPDX-License-Identifier: GPL-2.0
/*
 * RTC subsystem, sysfs interface
 *
 * Copyright (C) 2005 Tower Technologies
 * Author: Alessandro Zummo <[email protected]>
 */

#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)
{ … }
static DEVICE_ATTR_RO(name);

static ssize_t
date_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }
static DEVICE_ATTR_RO(date);

static ssize_t
time_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }
static DEVICE_ATTR_RO(time);

static ssize_t
since_epoch_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }
static DEVICE_ATTR_RO(since_epoch);

static ssize_t
max_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }

static ssize_t
max_user_freq_store(struct device *dev, struct device_attribute *attr,
		    const char *buf, size_t 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)
{ … }
static DEVICE_ATTR_RO(hctosys);

static ssize_t
wakealarm_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }

static ssize_t
wakealarm_store(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t n)
{ … }
static DEVICE_ATTR_RW(wakealarm);

static ssize_t
offset_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }

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

static ssize_t
range_show(struct device *dev, struct device_attribute *attr, char *buf)
{ … }
static DEVICE_ATTR_RO(range);

static struct attribute *rtc_attrs[] = …;

/* 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)
{ … }

static umode_t rtc_attr_is_visible(struct kobject *kobj,
				   struct attribute *attr, int n)
{ … }

static struct attribute_group rtc_attr_group = …;

static const struct attribute_group *rtc_attr_groups[] = …;

const struct attribute_group **rtc_get_dev_attribute_groups(void)
{ … }

int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
{ … }
EXPORT_SYMBOL(…);

int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
{ … }
EXPORT_SYMBOL(…);