1.\" 2.\" Copyright (c) 2015 M. Warner Losh 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. The name of the author may not be used to endorse or promote products 11.\" derived from this software without specific prior written permission. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd June 26, 2019 28.Dt OWC 4 29.Os 30.Sh NAME 31.Nm owc 32.Nd Dallas Semiconductor 1-Wire Controller 33.Sh SYNOPSIS 34.Cd device owc 35.Sh DESCRIPTION 36The 37.Nm 38module implements Dallas Semiconductor 1-Wire signaling. 39It attaches the 40.Xr ow 4 41driver 1-Wire bus protocol. 42The 43.Nm 44device implements the Link Layer of the 1-Wire bus protocol stack. 45.Pp 46Bit banging a pin on a 47.Xr gpiobus 4 48is the only supported controller. 49Both standard and overdrive transfer timings are implemented. 50Strong pull-up functionality needed to support parasitic mode is not 51implemented. 52.Pp 53To enable 1-Wire for FDT systems requires modifying the DTS for your 54board to add something like: 55.Bd -literal 56/ { 57 ... 58 onewire { 59 compatible = "w1-gpio"; 60 gpios = <&gpio 4 1>; 61 }; 62 ... 63}; 64.Ed 65.Pp 66The gpios property describes the GPIO pin the 1-Wire bus is connected 67to. 68For more details about the 69.Va gpios 70property, please consult 71.Pa /usr/src/sys/dts/bindings-gpio.txt . 72.Pp 73On a 74.Xr device.hints 5 75based system these values are required for the 76.Nm : 77.Bl -tag -width ".Va hint.owc.%d.atXXX" 78.It Va hint.owc.%d.at 79The 80.Nm gpiobus 81you are attaching to. 82.It Va hint.owc.%d.pins 83This is a bitmask that defines a pin on the 84.Nm gpiobus 85that is to be used for the 1-Wire bus. 86For instance, to configure pin 10, use the bitmask of 0x400. 87Please note that this mask should have only one bit set 88(any other bits - i.e., pins - will be ignored). 89.El 90.Sh SEE ALSO 91.Xr gpiobus 4 , 92.Xr ow 4 , 93.Xr ow_temp 4 , 94.Xr owll 9 , 95.Xr own 9 96.Sh LEGAL 97.Tn 1-Wire 98is a registered trademark of Maxim Integrated Products, Inc. 99.Sh HISTORY 100The 101.Nm 102driver first appeared in 103.Fx 11.0 . 104.Sh AUTHORS 105The 106.Nm 107device driver and this manual page were written by 108.An Warner Losh . 109.Sh CAVEATS 110The gpio driver implements timing by busy waiting, which can cause a 111high load on slower systems. 112.Sh BUGS 113Overdrive mode has not actually been tested. 114