OWC(4)                 FreeBSD Kernel Interfaces Manual                 OWC(4)

NAME
     owc - Dallas Semiconductor 1-Wire Controller

SYNOPSIS
     device owc

DESCRIPTION
     The owc module implements Dallas Semiconductor 1-Wire signaling.  It
     attaches the ow(4) driver 1-Wire bus protocol.  The owc 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/dts/bindings-gpio.txt.

     On a device.hints(5) based system these values are required for the owc:

     hint.owc.%d.at         The gpiobus you are attaching to.

     hint.owc.%d.pins       This is a bitmask that defines a pin on the
                            gpiobus that is to be used for the 1-Wire bus.
                            For instance, to configure pin 10, use the bitmask
                            of 0x400.  Please note that this mask should have
                            only one bit set (any other bits - i.e., pins -
                            will be ignored).

SEE ALSO
     gpiobus(4), ow(4), ow_temp(4), owll(9), own(9)

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

HISTORY
     The owc driver first appeared in FreeBSD 11.0.

AUTHORS
     The owc device driver and this manual page were written by 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.

FreeBSD 13.1-RELEASE-p6          June 26, 2019         FreeBSD 13.1-RELEASE-p6