Raspberry Pi running Archlinux

While doing some spring cleaning I discovered I had a Raspberry Pi 3 that was purchased at retail price years ago. This was the perfect candidate for a sprinkler controller I’ve been thinking of building for some now so I figured I’d poke around with a bit.

In the past I’ve found that Raspbian/Ubuntu tends to get into some odd defunct state where updates just stop working and I’m forced to reinstall the latest version and start over. This time I’m hoping to run Arch Linux instead as I tend to find that distro much easier to manage. The Pi of course has an ARM chip so Arch Linux ARM to the rescue.

The instructions here are pretty straightforward and I followed them without issue but I found I had to make some adjusted. Here’s a list of commands I ran and perhaps even a small note about what it does.

sudo groupadd gpio

cat << EOF > gpio.rules
SUBSYSTEM=="gpio", KERNEL=="gpiochip[0-4]", GROUP="gpio", MODE="0660"

SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio", MODE="0660"
EOF

sudo chown root:root gpio.rules
sudo mv gpio.rules /etc/udev/rules.d/

sudo usermod -a -G gpio alarm

In short, I created a group gpio and made sure that /dev/gpiochip* where in the group so that the gpio pins can be used by non-root user. Reboot or retrigger udev rules and verify permission.

Notes: Review this page and possibly adjust config: https://www.udoo.org/forum/threads/gpio-permissions-for-libgpiod-sudo-or-not.32453/