STM32F2 processor with STUSB4500 embedded systems

[visa]

I have made a custom board using STM32F2 processor. 
Project is to charge lithium battery. So I have used STUSB4500 and STC3115 and LTC4054 in my power supply section. I have initiated  communication to STUSB4500 through i2c.

I want to know what all registers I need to access. Any example projects available? 
attached is my power.c file where  I have developed code to initiate communication.