Using xgpio

Hi,
 
Can anyone give me an example of using the xgpio on an ML403 using
Montavista Linux. 
 
I can see the driver uses ioctl but this only seems to be able to set
the io direction, and I am not clear how to use this, for instance how
do I turn one of the led's on/off or read the GPIO_SW's.
 
Many thanks.
 
Tom Johnson