GPIO PHP Extension

The GPIO PHP Extension provides an object-oriented wrapper to the gpio Linux Userspace ABI that gives users the ability to write code that interacts with the general-purpose input/output pins available in Linux-based Single-Board Computers such as the Raspberry Pi.

Acknowledgements

The initial version of this extension was based on libgpiod and still is heavily inspired by it.

Requirements

• PHP >= 8.0 (either NTS or ZTS version);

Note: if you are using this extension on Raspbian or Raspberry Pi OS, the user executing the script must belong to the gpio group or you may run into "Permission denied" errors.

On Raspbian or Raspberry Pi OS:

PHP 8.0:

sudo apt install php8.0-cli php8.0-dev php8.0-phpdbg

PHP 8.1:

sudo apt install php8.1-cli php8.1-dev php8.1-phpdbg

Building

phpize
./configure
make
make test

Quick start

A simple "softwire" example that reads the value from input pin #2 and writes its value to output pin #3:

$chip = new GPIO\Chip('/dev/gpiochip0');
$p2 = $chip
  ->getPin(2)
  ->asInput('softwire');
$p3 = $chip
  ->getPin(3)
  ->asOutput('softwire');

$p2->isHigh() ? $p3->setHigh() : $p3->setLow();

Stubs

After changing any of the stubs, the main stub file must be updated by running the command below.

php stubs/update-main-stup.php

Once the stub is updated, the regular build process can be executed.

Note: The main stub file (phpgpio.stub.php) is a generated file, edit the files on the stubs folder instead.

Classes

Class	Description
GPIO\Chip	Represents a GPIO chip.
GPIO\Event	Represents a GPIO event.
GPIO\Exception	GPIO base exception.
GPIO\Pin	Represents a single GPIO pin.
GPIO\Pins	Represents a collection of GPIO pins.

Tools

Name	Description
gpiodetect.php	List all GPIO chips, print their labels and number of GPIO pins.
gpioinfo.php	Print information about all pins of the specified GPIO chip(s) (or all gpiochips if none are specified).

Supported Hardware

The table below lists the supported and tested chips.

SoC	Model
BCM2835	Raspberry Pi 1 and Zero
BCM2836	Raspberry Pi 2
BCM2837	Raspberry Pi 3 (and later Raspberry Pi 2)
BCM2837B0	Raspberry Pi 3B+ and 3A+
BCM2711	Raspberry Pi 4B

Alternatives

• PiPHP/GPIO
• ronanguilloux/php-gpio
• Volantus/php-pigpio

Other Languages

• Golang: periph/conn
• Golang: warthog618/gpiod
• Java: mattjlewis/diozero
• NodeJS: sombriks/node-libgpiod

Resources

• https://elinux.org/images/9/9b/GPIO_for_Engineers_and_Makers.pdf
• https://github.com/raspberrypi/linux/blob/rpi-5.10.y/Documentation/devicetree/bindings/gpio/gpio.txt
• https://github.com/raspberrypi/linux/blob/rpi-5.10.y/include/uapi/linux/gpio.h
• https://www.kernel.org/doc/html/latest/driver-api/gpio/index.html
• https://www.raspberrypi.org/documentation/hardware/raspberrypi/gpio/README.md

License

This library is licensed under the PHP License.