from memory, the calibration code is not compiled into any of the MI modules we added into 1.0.12.
BUT the code can still be found in firmware/mutable instruments.
MI uses a pretty simple approach, taking to voltages as at known points in the scale (eg. C1 C4) , this then let means you can calculate a scaling factor, (3 oct in this can for the diff between v4-v1)...
from memory I think c1 is lowest, so this given you the base offset
as I say, its not really very complex, so probably easier to code yourself, as make it specific to axo code from the outset.
( I don't remember any quantisation code, but perhaps I just didn't spot it... but again we have quantizers in axo anyway)