GPIO from userspace

[Sergey Manucharian]

Hello,

I need help to start working with CS5536 GPIOs.

I've installed Archlinux (2.6.28.1) on Geode LX800/CS5536 box.
The driver - cs5535_gpio is loaded and I can see the
devices /dev/cs5355_gpioX. I can read GPIOs and get strings
like "0IoabTPdnxL". I've looked into the driver's code to
understand how to set I/O, Open drain etc. Trying to do something
simple, like changing from "input" to "output" with e.g. "1iOabtpdnxH"
has no effect (subsequent reading as well as direct measurement show no
difference). 
I do not have much experience with such things and probably I'm missing
something. Could somebody give me the direction?

Thanks,
Sergey