https://github.com/helins/linux.gpio.clj

Use the standard Linux GPIO API from Clojure JVM
https://github.com/helins/linux.gpio.clj

clojure gpio iot jvm linux standard

Last synced: about 10 hours ago
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Use the standard Linux GPIO API from Clojure JVM

• Host: GitHub
• URL: https://github.com/helins/linux.gpio.clj
• Owner: helins
• License: epl-1.0
• Created: 2018-05-23T15:27:01.000Z (over 6 years ago)
• Default Branch: main
• Last Pushed: 2021-03-25T07:33:29.000Z (over 3 years ago)
• Last Synced: 2024-10-14T08:13:37.842Z (about 1 month ago)
• Topics: clojure, gpio, iot, jvm, linux, standard
• Language: Clojure
• Homepage:
• Size: 42 KB
• Stars: 35
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Linux.GPIO

[![Clojars

Project](https://img.shields.io/clojars/v/io.helins/linux.gpio.svg)](https://clojars.org/io.helins/linux.gpio)

 

[![cljdoc badge](https://cljdoc.org/badge/io.helins/linux.gpio)](https://cljdoc.org/d/io.helins/linux.gpio)

Handle [GPIO](https://github.com/helins/linux-gpio.java) lines in a fast and

portable way from Clojure.

Based on [linux-gpio.java](https://github.com/helins/linux-gpio.java). Go there

for rationale and background.

In short, this API controls GPIO devices from user space by using the "new"

Linux API which is convenient, standard, and offers some advantages over

other methods (eg. automatic clean-up of resources when lines are released).

A GPIO device is a driver located in "/dev". For instance, on the Raspbian

operating system running on a Raspberry Pi, one can control all GPIO lines by using

the "/dev/gpiochip0" GPIO device.

Compatible with Linux 4.8 and higher, tested on the Raspberry Pi 3.

## Usage

This is a very brief overview.

The [full API is available on Cljdoc](https://cljdoc.org/d/io.helins/linux.gpio).

Small examples are available in the [helins.linux.gpio.example](../main/src/example/helins/linux/gpio/example.clj).

Attention, at least read permission is needed for the used GPIO devices, which

is enough even for writing to outputs.

For instance :

```clj

(require '[helins.linux.gpio :as gpio])

;; Alternating between 2 leds every time a button is released.

;;

;; After opening a GPIO device, we need a handle for driving the leds and a watcher

;; for monitoring the button. A buffer is used in conjunction with the handle in

;; order to describe the state of the leds.

(with-open [device         (gpio/device "/dev/gpiochip0")

            led-handle     (gpio/handle device

                                        {17 {:gpio/state false

                                             :gpio/tag   :led-1}

                                         18 {:gpio/state true

                                             :gpio/tag   :led-2}}

                                        {:gpio/direction :output})

            button-watcher (gpio/watcher device

                                         {22 {:gpio/direction :input}})]

  (let [buffer (gpio/buffer led-handle)]

    (loop [leds (cycle [:led-1

                        :led-2])]

      (gpio/write led-handle

                  (gpio/set-line+ buffer

                                  {(first  leds) true

                                   (second leds) false}))

      (gpio/event button-watcher)

      (recur (rest leds)))))

```

## License

Copyright © 2018 Adam Helinski

Licensed under the term of the Mozilla Public License 2.0, see LICENSE.