Hi again,
The datasheet that you share with us is the one that mentions that it is not compatible with I2C.
I must admit that your question is difficult to answer because we do not have something similar developed. And you will need to develop your own driver, which will not me a trivial task.
But for that you can refer to the 4.3.2.1 General purpose I/O (GPIO) AC parameters section of the datasheet.
Hope it helps you.
Have a nice day!