quoted

Having so many front end drivers for a chipset should be done in a
more modular manner, so that in fact they could all coexist if
necessary.

Not sure I follow your meaning ... are you suggesting to allow the back end
driver to use run-time selectable IO accessors and other generic helper
functions, so the drivers currenlty including lib8390.c directly could use
the core code from the 8390 module instead?

Yes, David is suggesting you abstract the code so it can be built once
to support all the different interfaces and architectures.

   Andrew