Device Driver issues on 4.7

[Joe Kelsey]

I have taken several existing device driver sources and used them to
create a new device driver.  However, I cannot seem to get the system to
probe for my device.

I created a device driver named vsbc which can get configured at either
0x0e0 or 0x1e0 depending on BIOS settings in a PC-104 mobo.  Therefore,
I need to use a kernel configuration line like:

device vsbc0 at isa? port 0x0e0

to configure it.  I added the lines to files.i386 and this part of the
configuration seems to work correctly, up to a point.  The problem
occurs somewhere in the actual device probing, in that isa_common.c
prints the following during boot -v:

vsbc0 failed to probe at port 0xe0 on isa0

I do not understand which important piece of linkage I have missed in
order to get the system to call my probe and attach subroutines in order
to make the device connect properly.

I have read all of the existing web resources I can find, and they all
seem hopelessly out-of-date or ones that apply only to -CURRENT.  I have
an isa_driver structure in my code which includes the probe and attach
linkages, so I guess the problem comes in linking this structure into
some sort of global list so the system can find it.

So, can anyone tell me which important piece of the configuration I have
missed?

Thanks in advance.
/Joe