mfp —
X68K Multi-function Peripherals
mfp0 at intio0 addr 0xe88000 size 0x2000 intr 64
mfp drives Motorola MC68901 MFP (Multi-function
  Peripheral). mfp driver is always required to run the
  NetBSD/x68k kernel, because it is connected to
  important devices such as the display controller, and provides fundamental
  functions like the system clock tick and interrupt controller. Since
  mfp provides many functions, most of the jobs as a
  device driver is done by its child drivers such as
  kbd(4) and
  clock(4).
  mfp driver itself only provides the common way to
  access its registers and a few utility functions for other non-child drivers.
Machine-dependent part and machine-independent part should be split.