SLLA565 September 2021 TUSB1044
The DIR0 and DIR1 set the data path direction format. The DIR0 chooses between source side (DFP) Alt mode or sink side (UFP) Alt mode. The DIR1 choose between the DP Alt Mode and Custom Alt Mode.
In the I2C mode, DIR[1:0] can be controlled through I2C register 0x0C. For this reason, DIR[1:0] can be left unconnected.