Hey Tobias,
Indeed there aren't many examples but to point you in the right direction:
TI offers a web tool that you can also download called Sysconfig that lets you generate DTS files so you can find the right pin files (you'll need to match your config parameters with EVM schematic)
https://www.ti.com/tool/SYSCONFIG
You'll want to select Device (not Software Product) and click start....
Then you can add a SPI node and match your pins etc, and you'll see it generates a device tree.dtsi files with the right pins for you. Something like this -
From there, to enable Spidev itself I would look at examples from BeagleBoard like this and adjust for your needs, this should give you the spidev node-
https://openbeagle.org/beagleboard/BeagleBoard-DeviceTrees/-/blob/v6.12.x-Beagle/src/arm64/overlays/k3-am67a-beagley-ai-spidev0.dtso?ref_type=heads
Note - you might notice some oddity with "compatible = "rohm,dh2228fv";" - That's one of those weird things about embedded Linux, my understanding is that the Spidev maintainers don't really want you to just attach "any" device, they want you to specify the exact device that SPI will be connected to but if you'r developing you can use some of those older drivers to kind of force it to be have generically.
Let me know if that helps
