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.\" $OpenBSD: gpioow.4,v 1.7 2013/07/16 16:05:48 schwarze Exp $
.\"
.\" Copyright (c) 2006 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 $Mdocdate: July 16 2013 $
.Dt GPIOOW 4
.Os
.Sh NAME
.Nm gpioow
.Nd 1-Wire bus bit-banging through GPIO pin
.Sh SYNOPSIS
.Cd "gpioow* at gpio? offset 0 mask 0x1"
.Cd "gpioow* at gpio?"
.Cd "onewire* at gpioow?"
.Sh DESCRIPTION
The
.Nm
driver allows bit-banging a 1-Wire bus as a master using one GPIO pin.
The pin is used as a data signal.
The GPIO pin must be able to drive an output and read an input.
.Pp
The pin number can be specified in the kernel configuration with the
.Ar offset
locator.
The
.Ar mask
locator should always be 0x1 in this case.
The
.Ar offset
and
.Ar mask
can also be specified when
.Nm
is attached at runtime using the
.Dv GPIOATTACH
.Xr ioctl 2
on the
.Xr gpio 4
device.
.Sh SEE ALSO
.Xr gpio 4 ,
.Xr intro 4 ,
.Xr onewire 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 4.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Alexander Yurchenko Aq Mt grange@openbsd.org .
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