SPI not working on Raspberry Pi with ubuntu core

[Sebastian Weitzel]

We tried to connect an SPI sensor to a Raspberry PI that uses Ubuntu Core as an operating System but there is no device for SPI showing up. We need SPI for a CAN protocol shield for the Raspberry PI.

[Oliver Grawert (ogra)]

while it is fairly easy to enable teh spidev overlay in /boot/uboot/config.txt (and we should be easily able to set this as default in the gadget snap), there is currently no interface in snapd that allows spidev access ... adding a snapd task here ...

[Oliver Grawert (ogra)]

the option to add to /boot/uboot/config.txt is "dtparam=spi=on", you can edit this file manually for the time being and install your snapped application in --devmode until snapd and the gadget bits are fixed (to unblock development etc) as a temporary workaround.

[Sebastian Weitzel (sebastian2)]

It seems this makes it work. Thanks a lot for that!

[Oliver Grawert (ogra)]

Awesome to hear :)

If you are done with your application snap, would you mind installing it once without --devmode and capture syslog when running it ?

That way we should be able to find all required bits (via apparmor and seccomp denials that will be recorded in the log) that the spidev interface will need access to.

[Oliver Grawert (ogra)]

a fix for the pi3 gadget just landed via https://github.com/snapcore/pi3-gadget/pull/12

fixes for pi2 and cm3 (compute module) will follow shortly

the spi interface for snapd is currently in security review at https://github.com/snapcore/snapd/pull/3499

[Michael Vogt (mvo)]

AIUI the gadget snap was updated for all pi2,pi3,cm3. So this should be fixed. Please reopen if I am mistaken.

[Oliver Grawert (ogra)]

note that this is only true for the edge channel ... gadgets in stable, candidate and beta are still affected.