| SMbus standardizes that -- in approx. the same way (IIRC, one's
| apprximately a subset of the other, but I forget which) -- plus a

This is a framework for I2C, *NOT* SMbus.  SMBus may standardize
some of these issues.  But that's immaterial for I2C devices.  The
three I2C bus devices I've written drivers for have nothing at all
in common in their command protocols.

It may be possible to come up with a much simpler, cleaner 
interface for SMbus, but this is not a for SMbus.  This is for
I2C.

Eduardo