A breakout board for the Semtech's i2c GPIO expander
Arduino driver is complete except for the PLD features. I will have to define an API for them that makes sense, or at least expose the relevant registers as a binary blob. In any case, the Arduino example is complete, tested on a Teensy3.2, and listed on Tindie.
I am still evaluating this part. Pictures, libraries, and OSHPark links are forthcoming.