GPIO(3lua)

NAME
gpio - access gpio(4) pins from Lua

SYNOPSIS
local gpio = require 'gpio'

gpiodev = gpio.open(path)
pins = gpio.info(gpiodev)
gpio.close(gpiodev)
gpio.set(gpiodev, pin, flags)
gpio.unset(gpiodev, pin)
state = gpio.read(gpiodev, pin)
oldstate = gpio.write(gpiodev, pin, state)
gpio.toggle(gpiodev, pin)
gpio.attach(gpiodev, driver, offset, mask [, flags])

DESCRIPTION
The gpio Lua binding provides access to a gpio(4) device using the ioctl(2) interface.

gpiodev = gpio.open(path)
    Open the gpio device and return an object to access its pins.

pins = gpio.info(gpiodev)
    Returns the number of pins. As with all remaining functions, this can also be called using the : notation, i.e. as gpiodev:info().

gpio.close(gpiodev)
    Close the gpio device.

gpio.set(gpiodev, pin, flags)
    Set gpio pin flags. Note that the pin number in this and all remaining functions is zero based and not one based, this to avoid confusion with tools like gpioctl(8) which also number pins starting at zero. The following flags are defined:

    gpio.PIN_INPUT
        Pin is an input.

    gpio.PIN_OUTPUT
        Pin is an output.

    gpio.PIN_INOUT
        Pin is birectional.

    gpio.PIN_OPENDRAIN
        Pin is an open-drain output.

    gpio.PIN_PUSHPULL
        Pin is a push-pull output.

    gpio.PIN_TRISTATE
        Pin is tri-state (output disabled).

    gpio.PIN_PULLUP
        Pin has an internal pull-up enabled.

    gpio.PIN_PULLDOWN
        Pin has an internal pull-down enabled.

    gpio.PIN_INVIN
        Invert input.

    gpio.PIN_INVOUT
        Invert output.

    gpio.PIN_USER
        Pin accessible by users.

    gpio.PIN_PULSATE
        Pulsate pin at a hardware set frequency.

    gpio.PIN_SET
        Pin is set.

gpio.unset(gpiodev, pin)
    Unset gpio pin.

stat = gpio.read(gpiodev, pin)
    Read the current pin state.

oldstate = gpio.write(gpiodev, pin, state)
    Write the pin state returning the old state. The following states are defined:

    gpio.PIN_LOW
        Pin is in the low state.

    gpio.PIN_HIGH
        Pin is in the high state.

gpio.toggle(gpiodev, pin)
    Toggle pin state.

gpio.attach(gpiodev, driver, offset, mask [, flags])
    Attach a device driver with offset, mask, and optional flags at a pin.

EXAMPLES
The following example code opens /dev/gpio0 and prints all pin values:

    local gpio = require 'gpio'
    gpiodev = gpio.open('/dev/gpio0')
    local npins = gpiodev:info()
    for n = 1, npins do
    	print('pin ' .. n .. ': ' .. gpiodev:read(n - 1))
    end

SEE ALSO
lua(1), luac(1), intro(3lua), gpio(4)

HISTORY
A gpio manual appeared in NetBSD 7.0.

AUTHORS
-nosplit The gpio Lua binding was written by Marc Balmer <mbalmer@NetBSD.org>.