I have created project for managing I2C-bus low power LED drivers build at PCA9632 chip. (with possible modification for PCA9624,PCA9635PW,PCA9685,PCA9955B,PCA9956B).
You are able to manage chip from Raspberry. (It was tested at version 3 +). Github project contains documentation, sources and binaries. Who is interested in he is also welcome for testing of functionality and cooperative feed back.
Code is written at (python3 & adafruit library) as backend and free pascal as frontend.