quoted

I had a look at other drivers, and /sys/devices/platform/ts/ seems to be
a good place to hold those entries (one per options as you suggested).
Do you agree with that?

No, this is not a platform device, is it?  Only platform devices go
there, and I really doubt you have many of them for this board.

It seems analogous to some of the laptop helpers so I don't think it is
that unreasonable to make the board config a platform device of its own -
we don't really have a general solution to the board as a device, so if
you look at equivalents on laptops and the like we have assorted platform
control interfaces that are platform devices.

Alan