Hello all, I have AT91SAM9260 custom board. I want to develop an application to control the devices connected to the GPIO of the board.

Linux-2.6.20.1 kernel is already ported on the board. I want to add GPIO support in this running kernel. I checked the source code, but could not found generic GPIO driver.

Can you please give me some direction on how to add GPIO support in this kernel version and any other way to control GPIO.

With ARM CPUs, the GPIO are regular registers.
I suggest you to study the AT91SAM9260 datasheet.
If you want to play with registers from userspace you can use the devmem2 tool
ftp://ftp.koansoftware.com/public/linux ... /devmem2.c