z8530_init -- Initialise a Z8530 device
(struct z8530_dev * dev);
Z8530 device to initialise.
Configure up a Z8530/Z85C30 or Z85230 chip. We check the device
is present, identify the type and then program it to hopefully
keep quite and behave. This matters a lot, a Z8530 in the wrong
state will sometimes get into stupid modes generating 10Khz
interrupt streams and the like.
We set the interrupt handler up to discard any events, in case
we get them during reset or setp.
Return 0 for success, or a negative value indicating the problem
in errno form.