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.

Debian                                            June 26, 2019                                           OWC(4)