Odyssey X86J4125 enabling spidev on arch linux

Products & Technology ODYSSEY Serials
#1

I am using Arch linux on the Odyssey X86J4125 and would like to use the python-spidev library, but the seeed wiki only shows how to enable userspace SPI for ubuntu and debian.

I have installed the iasl tool and was able to generate spidev1.*.aml files using the command:
$: iasl spidev1.0.asl
$: cp spidev.1.0.asl /usr/lib/firmware/acpi-upgrades/

Then I need to use the mckinitcpio command instead of update-initramfs to update the initram, so I tried this:
$: sudo mkinitcpio -p linux513

It succesfully generates the new image but after rebooting and running the command:
$: ls /dev/spidev*

I don’t see anything, and spidev.1.0 and spidev.1.1 are not available.

I think maybe when I run the mkinitcpio command it isn’t finding the .aml files in /lib/firmware/acpi-upgrades

Has anyone setup SPI on arch linux and know how to enable userspace SPI for arch linux?

#2

Hi，
Actually, you need to put the aml file in the initramfs directory kernel/firmware/acpi. Our guide was written based on using update-initramfs, which places /lib/firmware/acpi into the directory mentioned in the procedure. So if you are not using this tool, then it does not work. You can refer to the following link that.
linux/initrd_table_override.rst at master · torvalds/linux (github.com)

#3

Ok thanks @lht856 the link was really helpful, it is working now!

Here are the steps for Manjaro or Arch linux users:

Download the spi-enable.zip from the seeed wiki

Install iasl and cpio:
pacman -Syu iasl cpio

Unzip spi-enable.zip and generate .aml files using iasl:

$: cd ~/Downloads
$: unzip spi-enable.zip
$: cd spi-enable
$: iasl spidev1.0.asl
$: iasl spidev1.1.asl

Change to root user and change to /tmp directory to work in:

$: su -
$: cd /tmp

Make a directory to patch the acpi tables:
$: mkdir -p kernel/firmware/acpi

Move the generated .aml files into the directory (replace USER with your username):
$: mv /home/USER/Downloads/spi-enable/*.aml /tmp/kernel/firmware/acpi/

Now create a new cpio image with the directory and .aml files:
$: find kernel | cpio -H newc --create > /boot/initramfs-custom.img

Append your current initramfs image to the end of the custom image:
note: your initramfs image might have a different name depending on the kernel, so do ls /boot and replace the .img name in the following commands with one that matches your kernel.

$: cat /boot/initramfs-5.13-x86_64.img >> /boot/initramfs-custom.img

Backup your current initramfs image:
$: cp /boot/initramfs-5.13-x86_64.img /boot/initramfs-5.13-x86_64.img.backup

Now replace your original initramfs image with the custom image:
$: mv /boot/initramfs-custom.img /boot/initramfs-5.13-x86_64.img

Verify that the .aml files have been added:
$: lsinitcpio /boot/initramfs-5.13-x86_64.img | head

The output should be:

kernel
kernel/firmware
kernel/firmware/acpi
kernel/firmware/acpi/spidev1.1.aml
kernel/firmware/acpi/spidev1.0.aml

now reboot and do ls /dev/spi* you should see the ports now!

I don’t know how to automate this on Arch linux so it will be written over the next time a kernel updates.

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