179 lines
4.6 KiB
Plaintext
179 lines
4.6 KiB
Plaintext
.\" $NetBSD: gpio.3lua,v 1.5 2016/06/11 15:17:34 abhinav Exp $
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.\"
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.\" Copyright (c) 2013, 2014 Marc Balmer <mbalmer@NetBSD.org>.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\"
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.Dd January 7, 2014
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.Dt GPIO 3lua
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.Os
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.Sh NAME
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.Nm gpio
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.Nd access
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.Xr gpio 4
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pins from Lua
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.Sh SYNOPSIS
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.Cd "local gpio = require 'gpio'"
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.Pp
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.Bl -tag -width XXXX -compact
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.It Dv gpiodev = gpio.open(path)
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.It Dv pins = gpio.info(gpiodev)
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.It Dv gpio.close(gpiodev)
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.It Dv gpio.set(gpiodev, pin, flags)
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.It Dv gpio.unset(gpiodev, pin)
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.It Dv state = gpio.read(gpiodev, pin)
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.It Dv oldstate = gpio.write(gpiodev, pin, state)
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.It Dv gpio.toggle(gpiodev, pin)
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.It Dv gpio.attach(gpiodev, driver, offset, mask [, flags])
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.El
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.Sh DESCRIPTION
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The
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.Nm
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Lua binding provides access to a
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.Xr gpio 4
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device using the
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.Xr ioctl 2
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interface.
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.Pp
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.Bl -tag -width XXXX -compact
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.It Dv gpiodev = gpio.open(path)
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Open the gpio device and return an object to access its pins.
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.Pp
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.It Dv pins = gpio.info(gpiodev)
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Returns the number of pins.
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As with all remaining functions, this can also be called using the :
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notation, i.e. as
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.Em gpiodev:info() .
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.Pp
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.It Dv gpio.close(gpiodev)
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Close the gpio device.
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.Pp
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.It Dv gpio.set(gpiodev, pin, flags)
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Set gpio pin flags.
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Note that the pin number in this and all remaining functions is zero based and
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not one based, this to avoid confusion with tools like
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.Xr gpioctl 8
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which also number pins starting at zero.
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The following flags are defined:
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.Pp
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.Bl -tag -width XXXX -compact
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.It Dv gpio.PIN_INPUT
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Pin is an input.
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.Pp
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.It Dv gpio.PIN_OUTPUT
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Pin is an output.
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.Pp
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.It Dv gpio.PIN_INOUT
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Pin is birectional.
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.Pp
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.It Dv gpio.PIN_OPENDRAIN
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Pin is an open-drain output.
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.Pp
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.It Dv gpio.PIN_PUSHPULL
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Pin is a push-pull output.
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.Pp
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.It Dv gpio.PIN_TRISTATE
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Pin is tri-state (output disabled).
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.Pp
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.It Dv gpio.PIN_PULLUP
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Pin has an internal pull-up enabled.
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.Pp
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.It Dv gpio.PIN_PULLDOWN
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Pin has an internal pull-down enabled.
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.Pp
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.It Dv gpio.PIN_INVIN
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Invert input.
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.Pp
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.It Dv gpio.PIN_INVOUT
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Invert output.
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.Pp
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.It Dv gpio.PIN_USER
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Pin accessible by users.
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.Pp
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.It Dv gpio.PIN_PULSATE
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Pulsate pin at a hardware set frequency.
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.Pp
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.It Dv gpio.PIN_SET
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Pin is set.
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.El
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.Pp
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.It Dv gpio.unset(gpiodev, pin)
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Unset gpio pin.
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.Pp
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.It Dv stat = gpio.read(gpiodev, pin)
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Read the current pin state.
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.Pp
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.It Dv oldstate = gpio.write(gpiodev, pin, state)
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Write the pin state returning the old state.
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The following states are defined:
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.Pp
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.Bl -tag -width XXXX -compact
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.It Dv gpio.PIN_LOW
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Pin is in the low state.
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.Pp
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.It Dv gpio.PIN_HIGH
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Pin is in the high state.
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.El
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.Pp
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.It Dv gpio.toggle(gpiodev, pin)
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Toggle pin state.
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.Pp
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.It Dv gpio.attach(gpiodev, driver, offset, mask [, flags])
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Attach a device driver with offset, mask, and optional flags at a pin.
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.El
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.Sh EXAMPLES
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The following example code opens
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.Pa /dev/gpio0
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and prints all pin values:
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.Bd -literal
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local gpio = require 'gpio'
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gpiodev = gpio.open('/dev/gpio0')
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local npins = gpiodev:info()
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for n = 1, npins do
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print('pin ' .. n .. ': ' .. gpiodev:read(n - 1))
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end
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.Ed
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.Sh SEE ALSO
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.Xr lua 1 ,
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.Xr luac 1 ,
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.Xr intro 3lua ,
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.Xr gpio 4
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.Sh HISTORY
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A
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.Nm
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manual appeared in
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.Nx 7.0 .
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm
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Lua binding was written by
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.An Marc Balmer Aq Mt mbalmer@NetBSD.org .
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