[Uninteresting specific case]
Ok, so the situation is following: we have a kind of multi-layered
driver here. Lowest level is a w1_slave bus driver, talking to a
specific chip and providing low-level API for accessing data in terms
of this chip (or chip class) notions. Above it, we have higher-level
driver which interprets data from the low-level one, converting it to
a standard device-independent form, plus possibly does some other
minor things, like providing feedback indication on these data.
(Forgot to say that this is battery driver.)
So, just in case if some reader of this has quick suggestion of
merging these drivers into one, thanks, but they do different things,
and we want to keep them nicely decoupled. But now issue of how these
drivers talk between themselves raises, and that's exactly the grief
point.