1.\" $NetBSD: gpio.3lua,v 1.1 2013/10/26 10:48:19 mbalmer Exp $ 2.\" 3.\" Copyright (c) 2013 Marc Balmer <mbalmer@NetBSD.org>. All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. Neither the name of the University nor the names of its contributors 14.\" may be used to endorse or promote products derived from this software 15.\" without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" 30.Dd October 26, 2013 31.Dt GPIO 3lua 32.Os 33.Sh NAME 34.Nm gpio 35.Nd access 36.Xr gpio 4 37pins from Lua 38.Sh SYNOPSIS 39.Cd "require 'gpio'" 40.Pp 41.Bl -tag -width XXXX -compact 42.It Dv gpiodev = gpio.open(path) 43.It Dv pins = gpio.info(gpiodev) 44.It Dv gpio.close(gpiodev) 45.It Dv gpio.set(gpiodev, pin, flags) 46.It Dv gpio.unset(gpiodev, pin) 47.It Dv state = gpio.read(gpiodev, pin) 48.It Dv oldstate = gpio.write(gpiodev, pin, state) 49.It Dv gpio.toggle(gpiodev, pin) 50.It Dv gpio.attach(gpiodev, driver, offset, mask [, flags]) 51.El 52.Sh DESCRIPTION 53The 54.Nm 55Lua provides access to a 56.Xr gpio 4 57device using the 58.Xr ioctl 2 59interface. 60.Pp 61.Bl -tag -width XXXX -compact 62.Pp 63.It Dv gpiodev = gpio.open(path) 64Open the gpio device and return an object to access its pins. 65.Pp 66.It Dv pins = gpio.info(gpiodev) 67Returns the number of pins. 68As with all remaining functions, this can also be called using the : 69notation, i.e. as 70.Em gpiodev:info() . 71.Pp 72.It Dv gpio.close(gpiodev) 73Close the gpio device. 74.Pp 75.It Dv gpio.set(gpiodev, pin, flags) 76Set gpio pin flags. 77Note that the pin number in this and all remaining functions is zero based and 78not one based, this to avoid confusion with tools like 79.Xr gpioctl 8 80which also number pins starting at zero. 81The following flags are defined: 82.Pp 83.Bl -tag -width XXXX -compact 84.It Dv gpio.PIN_INPUT 85Pin is an input. 86.Pp 87.It Dv gpio.PIN_OUTPUT 88Pin is an output. 89.Pp 90.It Dv gpio.PIN_INOUT 91Pin is birectional. 92.Pp 93.It Dv gpio.PIN_OPENDRAIN 94Pin is an open-drain output. 95.Pp 96.It Dv gpio.PIN_PUSHPULL 97Pin is a push-pull output. 98.Pp 99.It Dv gpio.PIN_TRISTATE 100Pin is tri-state (output disabled). 101.Pp 102.It Dv gpio.PIN_PULLUP 103Pin has an internal pull-up enabled. 104.Pp 105.It Dv gpio.PIN_PULLDOWN 106Pin has an internal pull-down enabled. 107.Pp 108.It Dv gpio.PIN_INVIN 109Invert input. 110.Pp 111.It Dv gpio.PIN_INVOUT 112Invert output. 113.Pp 114.It Dv gpio.PIN_USER 115Pin accessible by users. 116.Pp 117.It Dv gpio.PIN_PULSATE 118Pulsate pin at a hardware set frequency. 119.Pp 120.It Dv gpio.PIN_SET 121Pin is set. 122.El 123.Pp 124.It Dv gpio.unset(gpiodev, pin) 125Unset gpio pin. 126.Pp 127.It Dv stat = gpio.read(gpiodev, pin) 128Read the current pin state. 129.Pp 130.It Dv oldstate = gpio.write(gpiodev, pin, state) 131Write the pin state returning the old state. 132The following states are defined: 133.Pp 134.Bl -tag -width XXXX -compact 135.It Dv gpio.PIN_LOW 136Pin is in the low state. 137.Pp 138.It Dv gpio.PIN_HIGH 139Pin is in the high state. 140.El 141.Pp 142.It Dv gpio.toggle(gpiodev, pin) 143Toggle pin state. 144.Pp 145.It Dv gpio.attach(gpiodev, driver, offset, mask [, flags]) 146Attach a device driver with offset, mask, and optional flags at a pin. 147.El 148.Sh EXAMPLES 149The following example code opens 150.Pa /dev/gpio0 151and prints all pin values: 152.Bd -literal 153local gpio = require 'gpio' 154 155gpiodev = gpio.open('/dev/gpio0') 156 157local npins = gpiodev:info() 158 159for n = 1, npins do 160 print('pin ' .. n .. ': ' .. gpiodev:read(n - 1)) 161end 162.Ed 163.Sh SEE ALSO 164.Xr lua 1 , 165.Xr luac 1 , 166.Xr intro 3lua , 167.Xr gpio 4 168.Sh HISTORY 169An 170.Nm 171manual appeared in 172.Nx 7.0 . 173.Sh AUTHORS 174.An -nosplit 175The 176.Nm 177Lua binding was written by 178.An Marc Balmer Aq Mt mbalmer@NetBSD.org . 179