Thanks for the write up! Just to clarify one point, I was never proposing a 3.2 merge. The intent is definitely 3.3 as the core part hasn't yet garnered anywhere near enough review. Basically we got it into shape a few weeks too late and people have been busy.
The other big issue (possibly blocker) that has been raised is the need for in kernel interfaces. This is particularly of interest to the SoC world, where one ADC (with a multiplexer) can be used for hwmon, touchscreen (or other input) and general purpose (proposed IIO userspace user-space abi). There are two types of such interface, pull and push. There are patches for supporting both but the interaction between the two gets 'interesting'.
It's not that the in kernel interface issue directly effects the core code as proposed, but rather that we need to show that it fits well with what is in this first step (e.g. it needs to be up and running in the staging code). Always easier to answer, a 'can you do this' question if you can say 'look we did it here'!
Just to finish with the age old call for help... Anyone interested in this area, please review the code. Ideally start with the core series Jon links to and if anyone has lots of time, please join in on firstname.lastname@example.org where all the 'nasty' stuff goes first.