how enable/disable internal pull-up gpio?

[artone]

i use a external pull-up to read a gpio pin with my code in c .
to test if it is possible use a pin with internal pull-up (without external), how  can i enable and set internal pull-up?
Thanks

[swahren]

At First

disclaimer: i never tested pull-up configuration on my Olimex board.

To your question, it depends on the Kernel version

Freescale downstream kernel 2.6.35: look at the board config code

Mainline kernel > 3.x: look at the devicetree source and binding doc

Looking at the i.MX23 reference manual shows only a few pins on Olimex boards have configurable pull-ups like GPMI_CE0N and GPMI_CE1N (10 k).