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.\" $OpenBSD: gpioctl.8,v 1.1 2004/06/03 19:13:24 grange Exp $
.\"
.\" Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd May 3, 2004
.Dt GPIOCTL 8
.Os
.Sh NAME
.Nm gpioctl
.Nd control GPIO devices
.Sh SYNOPSIS
.Nm gpioctl
.Op Fl hq
.Op Fl d Ar device
.Op Ar pin
.Op Ar 0 | Ar 1 | Ar 2
.Nm gpioctl
.Op Fl hq
.Op Fl d Ar device
.Fl c
.Ar pin
.Op Ar flags
.Sh DESCRIPTION
The
.Nm
program allows to manipulate
.Tn GPIO
(General Purpose Input/Output) devices pins.
Such devices can be either part of the chipset or embedded
.Tn CPU ,
or the separate chip.
The usual way of using
.Tn GPIO
is to connect some simple devices such as leds, 1-wire termal sensors,
etc to its pins.
.Pp
Each
.Tn GPIO
device has associated device file in the
.Pa /dev
directory.
By default
.Nm
uses file
.Pa /dev/gpio0
which corresponds to the first found
.Tn GPIO
device in the system.
If more than one
.Tn GPIO
devices present alternative device file can be specified with the
.Fl d
option
in order to access particular
.Tn GPIO
device.
.Pp
When executed without any arguments
.Nm
program reads information about the
.Tn GPIO
device and displays it.
.Pp
.Tn GPIO
pins can be either ``read'' or ``written'' with the values of
logical 0 or 1.
If only
.Ar pin
number is specified in the command line pin state will be read
from the
.Tn GPIO
controller and dispalyed.
To write to a pin a value must be specified after the
.Ar pin
number.
Values can be either 0 or 1.
Value of 2 has a special meaning to ``toggle'' the pin, i.e. change its
state to the opposite.
.Pp
Each pin can be configured with the different flags with the
.Fl c
option.
The following configuration flags are supported by the
.Tn GPIO
framework:
.Pp
.Bl -tag -width XXXXX -compact
.It in
input direction
.It out
output direction
.It inout
bi-directional
.It od
open-drain output
.It pp
push-pull output
.It tri
tri-state (output disabled)
.It pu
internal pull-up enabled
.El
.Pp
Note that not all the flags can be supported by the particular
.Tn GPIO
controller.
The list of supported flags is always displayed when executing
.Nm
program with the
.Fl c
option.
If only
.Ar pin
number is specified in the command line current pin flags will be
dispalyed.
To change pin flags new flags set separated with the spaces must be
specified after the
.Ar pin
number.
.Sh FILES
.Bl -tag -width "/dev/gpiou" -compact
.It /dev/gpio Ns Ar u
GPIO device unit
.Ar u
file.
.El
.Sh EXAMPLES
.Li # gpioctl -c 20 out pp
.Pp
Configures pin 20 to have push-pull output.
.Pp
.Li # gpioctl 20 1
.Pp
Writes logical 1 to the pin 20.
.Sh SEE ALSO
.Xr gpio 4 ,
.Xr gscpcib 4 ,
.Xr nsclpcsio 4
.Sh HISTORY
The
.Nm
command first appeared in
.Ox 3.6 .
.Sh AUTHORS
The
.Nm
program was written by
.An Alexander Yurchenko Aq grange@openbsd.org .
|
