Using SPI on F39 with Raspberry Pi

Ask Fedora
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1

Problem

When enabling SPI using /boot/efi/config.txt the /dev/spidev0.* doesn’t get automatically created

Cause

Spi isn’t binding to that device
https://www.kernel.org/doc/html/latest/spi/spidev.html

Related Issues

Haven’t found any

Workarounds

echo spidev > /sys/bus/spi/devices/spiB.C/driver_override
echo spiB.C > /sys/bus/spi/drivers/spidev/bind

where B is the bus and C is the Chip select

My hacky solution to have this on boot is to create a systemd service that runs this as a script

2

I’m not familiar with Raspberry Pi and SPI. Do you think this problem affects a large portion of Raspberry Pi users?

Also, does this affect all RPi devices? Or which models? Is the workaround specific to just your device, or universal? Is this a new problem in Fedora 39 (i.e. did it work automatically in Fedora 38)?

A bug needs to exist, if this is to be documented as a Common Issue. And we need more detailed description.

Thanks.

3

No idea, someone who wants to use spi on a raspberry pi running Fedora.

I can only test it on a Raspberry Pi 3b, but I think that it affects all models. It appears after a fresh installation and enabling spi by putting “dtparam=spi=on” in /boot/efi/config.txt and rebooting
On a raspbian install, it automatically creates /dev/spidev0.* but not on fedora

This is a universal workaround because I bind it using the API of sysfs.

I don’t know only tested on Fedora 39. I use this Pi for active development, so I can’t just reinstall my OS multiple times.

How to reproduce:
put “dtparam=spi=on” in /boot/efi/config.txt and reboot

/sys/bus/spi/devices will show a folder spi0.* but there is no device file created (/dev/spidev0.*)

4

Ok, if this works on Raspbian and not on Fedora, please file a bug to RH bugzilla (probably against kernel?) and also email the arm mailing list and ask about it (attach a link to that bug). Let’s see if we can get some developer feedback. Thanks.

Also ping @coremodule @lbrabec - what are your thoughts on this?

5

This doesn’t seem to be moving forward, so I’ll move this to Ask Fedora instead. People can still find it there.

6

From Proposed Common Issues to Ask Fedora