Use SPI port for Telemtry Radio

I have a Pixhawk 4
I’m trying to use my custom own made Radio Controller that uses SPI port (THIS IS IMPORTANT) but i didn’t find any example for this.

In PX4 user guide has been written: SPI is synchronous serial communication interface used for connecting faster sensors and devices. This protocol is commonly use is for connecting optical flow sensors or “special telemetry modems”
see this:

Does anybody have a solution for me?