Thanks to Federico Grau (for going back and forth with Vernier) for
finding a calibration mechanism, but also for noting that Greg Kroah
Hartman's tutorial and example code (in particular, the user-space
get_temp wrapper) actually multiplies by the cryptic-looking
value 0.0078125 to get Celsius values.
Thanks also to johnl for pointing out that his device was
calibrated in units of 128ths of a degree, instead of 100ths; when he
pointed that out, I went back and looked at the cryptic-looking
number, and realized that my "computational numerology" skills had
failed me - 0.0078125 is 1/128 (my original 1/100 was an entirely
unjustified guess.)
(Also, thanks to Dave Vernier for his feedback, which hasn't yet been incorporated into the code - that's right, Vernier isn't just a clever name for a measurement company, it's an actual person :-)
Footnotes: