# Exclusive acces to a chipset



## cedric (Sep 20, 2010)

Hi, 

I'm pretty novice writing FreeBSD driver, but I've succeeded writing my first one : a LED driver to handle additional LEDs plugged to the NAS7800 (VIA) GPIO.
And it works !  :e

My question is : Is the same chipset can be accessing at the same time by another driver ? Because to control the GPIO, I need to send some byte sequence to the chip Control and Data ports. How can I be certain that the kernel, or any other driver doesn't use the same ports exactly at the same time ?

A driver can be interrupted during a callback execution ? In particular, I'm using the standard led driver, and all GPIO R/W are done inside the callback passed to led_create() function.

Thank you for your help.


----------

