Linux to ESP32 SDIO slave

[fasthands]

Hi,

Are there any skeleton linux driver examples to allow data transfer from Linux, acting as a SDIO host, to ESP32, acting as the SDIO slave?
The ESP32 is been detected by the linux core SDIO drivers (mmc1: new SDIO card at address 0001) but I can't write to a ESP32 register or raise an interrupt from the host.

I'm using the slave example from esp-idf/examples/peripherals/sdio/slave and a home brew linux driver.

Any pointers?

Regards
Scott