Can't find how to activate SPI

#1

I am trying to move from raspberry 3B + SPI HAT to rock 3C + SPI HAT.
My HAT uses what is know as SPI0 on a raspberry board, on pins 19, 21 & 23.
It looks like it’s called SPI1 on a rock3 board, on the same pins.

I have spent countless hours trying to understand how to activate SPI, with no luck.

I am using the rock-3c_debian_bullseye_cli_b33 image from https://github.com/radxa-build/rock-3c/releases

I have read instructions telling to configure with /boot/uEnv.txt, which is marked obsolote.
I can find overlays in /boot/dtbo and also in /usr/lib/linux-image-4.19.193-4-rk356x (which is the path specified in /boot/extlinux/extlinux.conf).

My software is expecting to find /dev/spidev0.0. I tried to load several (spidev) overlays and never got the expected device.

Any help appreciated!

#2

The signal output to ‘Pins 19, 21, 23, 24’ is the signal from ‘SPI3’.
The ‘SPI0 (/dev/spidev0.0)’ you want is in use for other purposes and cannot be assigned to other purposes by the user.
So you need to substitute with ‘SPI3’.

—
root@rock-3c:~# uname -a
Linux rock-3c 4.19.193-4-rk356x #24c58c676 SMP Mon Apr 24 03:29:51 UTC 2023 aarch64 GNU/Linux

root@rock-3c:~# ls -la /dev/spi*
crw------- 1 root root 153, 0 May 19 00:12 /dev/spidev3.0

#3

t4_4t’s reply was a first hint: I have to activate SPI3, not SPI1.
Finding the right overlay was the next one.

Here is how I finally managed to have a usable /dev/spidev3.0

root@rock-3c:~# mv /boot/dtbo/rk3568-spi3-m1-cs0-spidev.dtbo.disabled /boot/dtbo/rk3568-spi3-m1-cs0-spidev.dtbo
root@rock-3c:~# u-boot-update
root@rock-3c:~# reboot
root@rock-3c:~# ls -l /dev/spi*
crw------- 1 root root 153, 0 May 19 16:50 /dev/spidev3.0