ah that branch brings so many headaches to my memory! It was abandoned because it was under tested and then everything else moved further, leaving it lagging behind, so that now it would be fairly convoluted to backport those changes ... Also, many i2c devices have a complicated communication protocol that is best deal with through a dedicated C++ library, than trying to do it from Pd...
Is there a Linux library available for your device? That would be the first thing to know.
In the case of our new Trill sensors, I integrated into the
default_libpd_render.cpp a way to interface to a C++ library from Pd. All the TRILL-related code is included by the
ENABLE_TRILL. That gives you an idea of the extent of work that would be required to integrate other similar features.
An alternative to integrating it in the render file as done above, would be through an OSC layer. I have done that for Trill, too (to support people who do not use Bela, or those who use something else than Pd or C++ on Bela), so it's another example of what it would take to turn an existing, working library into an OSC-compatible one (see here).