SLLA565 September 2021 TUSB1044
The TPS6598x and TPS6599x both allow either I2C1 or I2C3 to be I2C master for controlling and configuring the slave devices.
The Using I2C Master in TPS65987D and TPS65988 PD Controllers application note introduces the method to initiate a I2C master control through the PD controller configuration GUI.