1.\" $OpenBSD: gpioow.4,v 1.7 2013/07/16 16:05:48 schwarze Exp $ 2.\" 3.\" Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org> 4.\" 5.\" Permission to use, copy, modify, and distribute this software for any 6.\" purpose with or without fee is hereby granted, provided that the above 7.\" copyright notice and this permission notice appear in all copies. 8.\" 9.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16.\" 17.Dd $Mdocdate: July 16 2013 $ 18.Dt GPIOOW 4 19.Os 20.Sh NAME 21.Nm gpioow 22.Nd 1-Wire bus bit-banging through GPIO pin 23.Sh SYNOPSIS 24.Cd "gpioow* at gpio? offset 0 mask 0x1" 25.Cd "gpioow* at gpio?" 26.Cd "onewire* at gpioow?" 27.Sh DESCRIPTION 28The 29.Nm 30driver allows bit-banging a 1-Wire bus as a master using one GPIO pin. 31The pin is used as a data signal. 32The GPIO pin must be able to drive an output and read an input. 33.Pp 34The pin number can be specified in the kernel configuration with the 35.Ar offset 36locator. 37The 38.Ar mask 39locator should always be 0x1 in this case. 40The 41.Ar offset 42and 43.Ar mask 44can also be specified when 45.Nm 46is attached at runtime using the 47.Dv GPIOATTACH 48.Xr ioctl 2 49on the 50.Xr gpio 4 51device. 52.Sh SEE ALSO 53.Xr gpio 4 , 54.Xr intro 4 , 55.Xr onewire 4 56.Sh HISTORY 57The 58.Nm 59driver first appeared in 60.Ox 4.0 . 61.Sh AUTHORS 62.An -nosplit 63The 64.Nm 65driver was written by 66.An Alexander Yurchenko Aq Mt grange@openbsd.org . 67