Our engineers have made initial progress in developing a driver for the W55RP20, but we've encountered a few difficulties that we would like to address with your team. Below is a brief overview of the situation:

The W55RP20 is a SiP project that integrates the RP2040 and W5500 in one chip. Internally, the dies are connected via general GPIO pins, not the typical SPI pins. As a result, a PIO program is needed to configure these pins for SPI communication.

Our engineers then decided to start from scratch, writing a PIO program and general code to initialize the W5500 through registers. They were able to create a basic loopback server in standalone mode. While this solution works as an alternative, we thought about the possibility of creating a new CHIP_VARIANT for rp2 CHIP_FAMILY. Given our limited resources, we thought of collaboration with Adafruit to further develop the driver.

The link below is to a WIZNet PIO example we created.
https://github.com/WIZnet-ioNIC/WIZnet-ioNIC-Circuitpython