Simple GPIO library for Raspberry Pi in Go

This module implements a Go module to manipulate the GPIO pins. It has been created as a first try to understand the Raspberry Pi programming and GPIO. If you look for a decent implementation that will work in furture linux versions have a look at gpiod.

Features

• only uses the sysfs mappings
• with a proper setup it can be used without being root
• tested on Raspberry Pi 3 / Raspberry Pi 4
• tested with Ubuntu Server 20.10 (Groovy Gorilla)

GPIO

This module uses the pins to identify the GPIO ports.

This image from https://pinout.xyz proved helpful to find the right associations.

Setup

I started with a fresh operating system image. To enable user access to the gpio via sysfs one has to add these configurations.

add group to allow gpio access

Add a group to be used as owner of the gpio sys file entries

~ addgroup gpio
~ adduser ubuntu gpio

add configuration to udev rules

Add a file ´´/etc/udev/rules.d/99-gpio.rules´´ with the following content, reboot your pi

~ sudo su -
~ cat /etc/udev/rules.d/99-gpio.rules
#
# gpio access for group gpio
#
SUBSYSTEM=="gpio", GROUP="gpio", MODE="0660"
SUBSYSTEM=="gpio*", PROGRAM="/bin/sh -c '\
chown -R root:gpio /sys/class/gpio && chmod -R 770 /sys/class/gpio;\
chown -R root:gpio /sys/devices/virtual/gpio && chmod -R 770 /sys/devices/virtual/gpio;\
chown -R root:gpio /sys$devpath && chmod -R 770 /sys$devpath\
'"
~ reboot now