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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352// 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_tname_show(struct device *dev, struct device_attribute *attr, char *buf){ return sysfs_emit(buf, "%s %s\n", dev_driver_string(dev->parent), dev_name(dev->parent));}static DEVICE_ATTR_RO(name);
static ssize_tdate_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 sysfs_emit(buf, "%ptRd\n", &tm);}static DEVICE_ATTR_RO(date);
static ssize_ttime_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 sysfs_emit(buf, "%ptRt\n", &tm);}static DEVICE_ATTR_RO(time);
static ssize_tsince_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) return retval;
return sysfs_emit(buf, "%lld\n", rtc_tm_to_time64(&tm));}static DEVICE_ATTR_RO(since_epoch);
static ssize_tmax_user_freq_show(struct device *dev, struct device_attribute *attr, char *buf){ return sysfs_emit(buf, "%d\n", to_rtc_device(dev)->max_user_freq);}
static ssize_tmax_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_thctosys_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 sysfs_emit(buf, "1\n");#endif return sysfs_emit(buf, "0\n");}static DEVICE_ATTR_RO(hctosys);
static ssize_twakealarm_show(struct device *dev, struct device_attribute *attr, char *buf){ ssize_t retval; 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) return retval;
if (alm.enabled) return sysfs_emit(buf, "%lld\n", rtc_tm_to_time64(&alm.time));
return 0;}
static ssize_twakealarm_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_toffset_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) return retval;
return sysfs_emit(buf, "%ld\n", offset);}
static ssize_toffset_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_trange_show(struct device *dev, struct device_attribute *attr, char *buf){ return sysfs_emit(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,};__ATTRIBUTE_GROUPS(rtc_attr);
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) { for (groups = grps; *groups; groups++) add_cnt++; /* No need to modify current groups if nothing new is provided */ if (add_cnt == 0) return 0; } else { return -EINVAL; }
groups = rtc->dev.groups; if (groups) for (; *groups; groups++) old_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);