The Cirrus card has a 20 pin extension header and a three pin UART header that give access to RPI GPIOs, I2C and UART.
I had to scrape all this info together for my own projects so I thought I would share. As usual the info was buried in multiple documents and posts. Let me know if there are any corrections or additions.
Thanks ! I was looking for confirmed data on this CLAC expansion header.
And It seems you found and corrected the data from the schematics.
I just started a new thread to find this info, so Let me redirect that to this thread.