Raspberry Pi Mesa 7C81

Hello,
I have a problem on how to enable SPI on my PI4. I have used the   Raspberry Pi 4 OS based on Debian Bookworm  Image and now I am stuck. I already have installed mesa flash and try to see if can see my Mesacard with mesaflash but that only gives me the message: No 7C81 board found. 
Thanks in advance.

Have you followed the instructions for the hm2_* driver that you are using?

And is it linuxcnc.org/docs/stable/html/man/man9/hm2_rpspi.9.html

or
linuxcnc.org/docs/stable/html/man/man9/hm2_spi.9.html

( I don't know which is expected to work best on the pi4)

You need to enable the SPI interface by editing config.txt

If you run menu-config using sudo there should be an option to either edit config.txt or enable interfaces, uncommercial the line that refers to spi.
Reboot and you’ll have your spi enabled.

Use the hm2_rpspi driver, the other driver will is it not suitable, if it was we could use it with the RPi5.

Hello,
Thank you for your help. I have managed to enable SPI. 
sudo mesaflash --device 7c81 --addr /dev/spidev0.0 --spi --readhmid, now shows that the card is present.
I probably will update to another Pin-configuration for the Mesacard.
How can I use the hm2_rpspi driver? I wanted to build my machine config with the  PNCconf  Wizard and then modify the .hal and .ini files for more things which are outside the capabilities of the Wizard. 
Maybe someone can give me a push in the right direction?
I a have little experience with LinuxCNC and Linux in general.
Also I have used xrdp remote client to access the PC headless and it is giving me trouble. If I install it it works fine, but when I restart the setup the screen shows some distorted mess of pixels. Maybe someone has an idea what goes wrong there?
 

pncconf in master supports the 7C81

To use older pncconf with the 7C81 you can make
a configuration with similar hardware (stepgens PWMgens etc)
 and then change the driver name in the .hal file
and card name in the .ini file.


So for example to make a simple step/dir setup
you could choose a 5I25 and prob_rxf2
 then change the:

 loadrt hm2_pci xxxxx

 line in the hal file to:

loadrt hm2_rpspi xxxxx

and the

CARD0=hm2_5i25.0

line in the .ini file

to

CARD0=hm2_7c81.0