kernel-ark/drivers/rtc/rtc-sysfs.c

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/*
* 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
rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%s\n", to_rtc_device(dev)->name);
}
static ssize_t
rtc_sysfs_show_date(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 ssize_t
rtc_sysfs_show_time(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 ssize_t
rtc_sysfs_show_since_epoch(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 ssize_t
rtc_sysfs_show_max_user_freq(struct device *dev, struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);
}
static ssize_t
rtc_sysfs_set_max_user_freq(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 struct device_attribute rtc_attrs[] = {
__ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),
__ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),
__ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),
__ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),
__ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,
rtc_sysfs_set_max_user_freq),
{ },
};
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
static ssize_t
rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,
char *buf)
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
{
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.
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
*
* 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.
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
*/
retval = rtc_read_alarm(to_rtc_device(dev), &alm);
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
if (retval == 0 && alm.enabled) {
rtc_tm_to_time(&alm.time, &alarm);
retval = sprintf(buf, "%lu\n", alarm);
}
return retval;
}
static ssize_t
rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,
const char *buf, size_t n)
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
{
ssize_t retval;
unsigned long now, alarm;
struct rtc_wkalrm alm;
struct rtc_device *rtc = to_rtc_device(dev);
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
/* 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);
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
if (retval < 0)
return retval;
rtc_tm_to_time(&alm.time, &now);
alarm = simple_strtoul(buf, NULL, 0);
if (alarm > now) {
/* 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);
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
if (retval < 0)
return retval;
if (alm.enabled)
return -EBUSY;
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);
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
return (retval < 0) ? retval : n;
}
static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
rtc_sysfs_show_wakealarm, rtc_sysfs_set_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 inline int rtc_does_wakealarm(struct rtc_device *rtc)
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
{
if (!device_can_wakeup(rtc->dev.parent))
[PATCH] RTC gets sysfs wakealarm attribute This adds a new "wakealarm" sysfs attribute to RTC class devices which support alarm operations and are wakeup-capable: - It reads as either empty, or the scheduled alarm time as seconds since the POSIX epoch. (That time may already have passed, since nothing currently enforces one-shot alarm semantics.) - It can be written with an alarm time in the future, again seconds since the POSIX epoch, which enables the alarm. - It can be written with an alarm time not in the future (such as 0, the start of the POSIX epoch) to disable the alarm. Usage examples (some need GNU date) after "cd /sys/class/rtc/rtcN": alarm after 10 minutes: # echo $(( $(cat since_epoch) + 10 * 60 )) > wakealarm alarm tuesday evening 10pm: # date -d '10pm tuesday' "+%s" > wakealarm disable alarm: # echo 0 > wakealarm This resembles the /proc/acpi/alarm file in that nothing happens when the alarm triggers ... except possibly waking the system from sleep. It's also like that in a nasty way: not much can be done to prevent one task from clobbering another task's alarm settings. It differs from that file in that there's no in-kernel date parser. Note that a few RTCs ignore rtc_wkalrm.enabled when setting alarms, or aren't set up correctly, so they won't yet behave with this attribute. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 08:52:47 +00:00
return 0;
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_attrs = rtc_attrs;
}