How to use GPIO triggers?

Hi,

I've tried googling again and again.

But I can't seem to find out how to use GPIO triggers with the ADC driver.

I am using a patched am335x driver and kernel version 3.11. I can use sysfs triggers to trigger and read a buffer of samples easily.

But I cannot figure out how to connect a gpio to trigger the driver. Is it some additional support to add to the driver?

Or am I missing something very obvious..

Can someone spare a few minutes and point me in the right direction?

Thank-you
Zubair Lutfullah