Using RTC for wake up

Sven Klomp sven at
Wed Jul 30 15:44:06 CEST 2008

On Wednesday 30 July 2008 13:57:29 Holger Freyther wrote:
> On Wednesday 30 July 2008 11:22:44 Sven Klomp wrote:
> > some time ago I heard that the realtime clock can be used to wake up the
> > CPU from supend:
> >
> >
> > However, I couldn't find an further information. How can I set PMU to
> > wake up the CPU based on the clock? Is there any sysfs file?
> with ASU atd is running and you can schedule execution of programs by
> placing files in a certain directory (take a look at the code), otherwise
> use the plain linux rtc ioctl interface directly.

And atd can also wake up from suspend? I couldn't find where the RTC is set...

I had a look in ioctl calls in Python. However it looks hard to get the 
parameters for fcntl.ioctl() corresponding to e.g. RTC_ALM_SET. Someone 
already used Python ioctl on the Freerunner?


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