The include/linux/watchdog.h is, well, a little hard to read and 
understand.  I have attached a patch that documents this as best as I 
can understand it.  It also add a few small things.  It would be nice to 
get all the watchdogs to conform to one interface for things like 
setting the timeout, they all seem to have their own unique ways of 
doing a lot of things.

-Corey