1.\" $NetBSD: gpioow.4,v 1.5 2014/03/18 18:20:39 riastradh Exp $ 2.\" $OpenBSD: gpioow.4,v 1.3 2006/03/06 10:24:46 grange Exp $ 3.\" 4.\" Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org> 5.\" 6.\" Permission to use, copy, modify, and distribute this software for any 7.\" purpose with or without fee is hereby granted, provided that the above 8.\" copyright notice and this permission notice appear in all copies. 9.\" 10.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17.\" 18.Dd July 19, 2009 19.Dt GPIOOW 4 20.Os 21.Sh NAME 22.Nm gpioow 23.Nd 1-Wire bus bit-banging through GPIO pin 24.Sh SYNOPSIS 25.Cd "gpioow* at gpio? offset 0 mask 0x1" 26.Cd "gpioow* at gpio?" 27.Cd "onewire* at gpioow?" 28.Sh DESCRIPTION 29The 30.Nm 31driver allows bit-banging a 1-Wire bus as a master using one GPIO pin. 32The pin is used as a data signal. 33The GPIO pin must be able to drive an output and read an input. 34.Pp 35The pin number is specified in the kernel configuration with the 36.Ar offset 37locator. 38The 39.Ar mask 40locator should always be 0x1. 41The 42.Ar offset 43and 44.Ar mask 45can also be specified when 46.Nm 47is attached at runtime using the 48.Dv GPIOATTACH 49.Xr ioctl 2 50on the 51.Xr gpio 4 52device. 53.Sh SEE ALSO 54.Xr gpio 4 , 55.Xr intro 4 , 56.Xr onewire 4 57.Sh HISTORY 58The 59.Nm 60driver first appeared in 61.Ox 4.0 62and 63.Nx 4.0 . 64.Sh AUTHORS 65.An -nosplit 66The 67.Nm 68driver was written by 69.An Alexander Yurchenko Aq Mt grange@openbsd.org 70and was ported to 71.Nx 72by 73.An Jeff Rizzo Aq Mt riz@NetBSD.org . 74