To make the ds1wm driver work on a powerpc architecture (big endian, 32bit)
with a register offset multiplier of 4 i had to make some changes to

          drivers/w1/masters/ds1wm.c
and    include/linux/mfd/ds1wm.h.

I grouped theses into 4 patches of falling priority.

[PATCH 1/4] fix and simplify register access
[PATCH 2/4] Add level interrupt modes (maybe no longer needed in newer
kernels)
[PATCH 3/4] Silence interrupts on HW before claiming the interrupt
[PATCH 4/4] optional: add messages to make incorporation in  mfd drivers
easier

The patches applied cleanly against
   commit 32c1431eea4881a6b17bd7c639315010aeefa452
   Author: Linus Torvalds <torvalds@linux-foundation.org>
   Date:   Sun Jun 11 16:48:20 2017 -0700
    Linux 4.12-rc5

I could build the patched kernel (as above) with ds1wm configured in
with no errors or warnings.

I could test and verify the correct working of the patch against
kernel 3.12.15, but not against the current kernel.