owc (4)

Leading comments

Copyright (c) 2015 M. Warner Losh
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PRO...

(The comments found at the beginning of the groff file "man4/owc.4freebsd".)

NAME

owc - Dallas Semiconductor 1-Wire Controller

SYNOPSIS

device owc

DESCRIPTION

The module implements Dallas Semiconductor 1-Wire signaling. It attaches the ow(4) driver 1-Wire bus protocol. The device implements the Link Layer of the 1-Wire bus protocol stack.

Bit banging a pin on a gpiobus(4) is the only supported controller. Both standard and overdrive transfer timings are implemented. Strong pull-up functionality needed to support parasitic mode is not implemented.

To enable 1-Wire for FDT systems requires modifying the DTS for your board to add something like:

/ {
        ...
        onewire {
                compatible = "w1-gpio";
                gpios = <&gpio 4 1>;
        };
        ...
};

The gpios property describes the GPIO pin the 1-Wire bus is connected to. For more details about the gpios property, please consult /usr/src/sys/boot/fdt/dts/bindings-gpio.txt

SEE ALSO

gpiobus(4), ow(4), ow_temp4, owll(9), own(9)

LEGAL

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

HISTORY

The driver first appeared in Fx 11.0 .

AUTHORS

The device driver and this manual page were written by An Warner Losh .

CAVEATS

The gpio driver implements timing by busy waiting, which can cause a high load on slower systems.

BUGS

Overdrive mode has not actually been tested.