[i2c,cw340] Getting I2C working on CW340

I'm trying to use OpenTitan as an I2C device. I have an implementation of an I2C host in a breadboarded generic microcontroller, and intend to connect the I2C bus to my CW340 FPGA.

I need some guidance on getting this set up correctly on the CW340. It's unclear to me which pins should be used for I2C0 on the CW340 board, and I didn't find anything in the CW340 schematic for the I2C0 peripheral. I assume there will need to be some calls in my OpenTitan software to `dif_pinmux_input_select` and `dif_pinmux_output_select`, but I don't know which MIO input/outputs should be used for I2C0. I've tried a few different random pins that are broken out on the CW340 board without any success.

I would really appreciate some guidance on this. Thanks for your help in advance.

Start with the CW340 schematic and the OpenTitan I2C0 pinmux configuration, including dif_pinmux_input_select and dif_pinmux_output_select. Identify which MIO signals reach the board's broken-out pins, then document the required pin choices and setup; done means an external I2C host can communicate with I2C0 through the CW340.

Written by the indexing model from the issue text.