It is better to use Cypress CY4532 to begin to customize it. Since CY4532 can be brought from Cypress websites and details hardware schematic can be found from the link:
firmware source code can be download from link:
With the CY4532 kit, you can use Type-C and Type-A port to test/demonstrate QC3.0 class A or Class B as per your requirements.
If you opened the schematic, you will found that Type-A VBUS power is supplied by SC8701 and it is PWM controlled.
And then, you can open the firmware code (project name: CYPD3171-24LQXQ_pb under example code). You can get a tap of TypeA in TopDesign.cysch.
You can use the name of those signals/components on the TypeA page and search it in the firmware project to see the relates code of those parts, You will found that all of operations is under a Marco define #if (CCG_TYPE_A_PORT_ENABLE == 1). And almost of them is under file type_a.c.
You can clear the project at first and then add I2C component into the project to complete your project. It is very easy to start.
Thank you. That is excellent information and we will proceed to source the suggested reference kit for our development.