Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
driver_unregister - remove driver from system.
SYNOPSIS
void driver_unregister (struct device_driver * drv);
ARGUMENTS
drv driver.
DESCRIPTION
Again, we pass off most of the work to the bus-level call.
Though, once that is done, we wait until drv->unloaded is completed.
This will block until the driver refcount reaches 0, and it is
released. Only modular drivers will call this function, and we have to
guarantee that it won’t complete, letting the driver unload until all
references are gone.