Recently bought a Micro Dot pHAT to go on a Raspberry Pi. Onboard are three smt IS31FL3730 chips and three pairs of matrix displays all driven over I2C. It comes as a kit so you have to solder on the GPIO connector and all the DIL displays (The IS31FL3730 have already been installed). This took me about half an hour.
I couldn’t find any C programs to get the board going (everyone seems to love python these days!) In the end I grabbed fragments of code I found on the Internet and wrote a small set of C functions that I think are useful. Help yourself if you were looking for a simple solution.