There's probably an example of this in the tree, but I didn't find
it. Sorry for bugging the list.

I'm writing a device driver for a device that has i/o on both the
ISA bus and on a GPIO pin. Obviously I need to map handles for both
busses so I can do I/O for the device, but I don't know how to write
the CONFIG file entry for the device. (Or if config is the wrong way,
how to find the second bus's tag so that I can use it to map.)

Any pointer to a similar example or advice would be greatly
appreciated.