On Tuesday 08 April 2008, Zhao Yakui wrote:
> Subject: ACPI: Add the support for alarm time relative to current time in sysfs
> >From : Zhao Yakui <yakui.zhao@xxxxxxxxx>
>
> In current kernel if we want to set the alarm time, the absolute time
> the seconds relative to 1970-01-01 00:00:00) should be written into
> /sys/class/rtc/rtc0/wakealarm. It is not convenient.
>
> It is more reasonable to add the support for the alarm time
> relative to current RTC time.(the unit is second)
> For example:
> If the RTC is required to generate alarm after 2 minutes, the following will
> be OK.
> echo +120 > /sys/class/rtc/rtc0/wakealarm
> or echo +0x78 > /sys/class/rtc/rtc0/wakealarm
>
>
> Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx>
> Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Makes sense.
Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
>
> ---
> drivers/rtc/rtc-sysfs.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> Index: linux-2.6/drivers/rtc/rtc-sysfs.c
> ===================================================================
> --- linux-2.6.orig/drivers/rtc/rtc-sysfs.c
> +++ linux-2.6/drivers/rtc/rtc-sysfs.c
> @@ -145,6 +145,8 @@ rtc_sysfs_set_wakealarm(struct device *d
> unsigned long now, alarm;
> struct rtc_wkalrm alm;
> struct rtc_device *rtc = to_rtc_device(dev);
> + 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.
> @@ -154,7 +156,15 @@ rtc_sysfs_set_wakealarm(struct device *d
> return retval;
> rtc_tm_to_time(&alm.time, &now);
>
> - alarm = simple_strtoul(buf, NULL, 0);
> + buf_ptr = (char *)buf;
> + if (*buf_ptr == '+') {
> + buf_ptr++;
> + adjust = 1;
> + }
> + alarm = simple_strtoul(buf_ptr, NULL, 0);
> + if (adjust) {
> + alarm += now;
> + }
> if (alarm > now) {
> /* Avoid accidentally clobbering active alarms; we can't
> * entirely prevent that here, without even the minimal
>
>
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