SPI dummy board DTS and slave device for testing

I’m pretty new in working with kernel modules and boards, and I’m struggling to emulate for HW-free testing purposes some bus interfaces. I managed to setup “virtual” devices for I2C and CAN, but I’m stopped at the moment with SPI issues.
I’ve tried different alternatives with and without spidev, also looking at samples in the linux kernel, but nothing has worked…
Any suggestion??

Thanks in advance,