[PATCH, RFC] wake up from a serial port

[Scott Wood]

On Mon, Aug 13, 2007 at 12:27:30AM +0200, Guennadi Liakhovetski wrote:
> A number of Linkstation models from Buffalo Technology with PPC, ARM, and 
> also MIPS (I think) CPUs have a power-management controller connected to a 
> UART. Among other things that chip controlls power and reset buttons. 
> Working on a standby support for one of these systems (ppc mpc8241 based), 
> the only suitable wakeup source there is the power button, which means, I 
> have to configure one of the two system UARTs to not be suspendsd. Using 
> the device_*_wakeup API doesn't quite work because both serial ports share 
> one device. The below patch proposes a new port flag UPF_MAY_WAKEUP to 
> configure such UARTs. It also adds support for a new "can-wakeup" serial 
> node property to the legacy_serial driver.

Shouldn't the ability to wakeup be configured through sysfs, rather than
encoded into the device tree?  I'm assuming this is just a matter of
configuration, and not that the hardware supports waking from one and not
the other.

-Scott