I have an RPi4 running Fedora 35. It hadn't been updated in a while, so
I applied updates today. When I boot to the kernel 5.16.11-200, I lose
the PPS device from my GPS hat. Boot back to 5.14.16-301.fc35 and it
works.
I'm booting with EFI firmware, and with a device tree config.txt that
has "dtoverlay=pps-gpio,gpiopin=4" in it. I removed the /boot/dtb
symlink and set /etc/u-boot.conf to not re-add it.
When I boot 5.16, I see /proc/device-tree, and it has
/proc/device-tree/pps@4 in it (and the contents look correct), but
loading the pps-gpio kernel module just gives:
pps-gpio: probe of pps@4 failed with error -22
--
Chris Adams <linux(a)cmadams.net>