freebsd-dev

History

Oleksandr Tymoshenko 108117cc22 [ofw] fix errneous checks for OF_finddevice(9) return value OF_finddevices returns ((phandle_t)-1) in case of failure. Some code in existing drivers checked return value to be equal to 0 or less/equal to 0 which is also wrong because phandle_t is unsigned type. Most of these checks were for negative cases that were never triggered so trhere was no impact on functionality. Reviewed by: nwhitehorn MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D14645		2018-03-20 00:03:49 +00:00
..
ow_temp.c
ow.c
ow.h
owc_gpiobus.c	[ofw] fix errneous checks for OF_finddevice(9) return value	2018-03-20 00:03:49 +00:00
owll_if.m
owll.h
own_if.m
own.h
README.txt

README.txt

Quick Design Document for 1-wire bus

In new bus terms, 1-wire devices are attached to 1-wire buses (ow)
which are attached to a one wire bridge (owc).

The implementation follows the terminology used in the Maxim AN927
Application note which defines the 1-wire bus as implemented for the
iButton product. This is considered to be the canonical definition of
the 1-wire bus. This means that the 1-wire bridge will implement the
owll(9) interface. ow is one wire. ll is for Link Level to mirror the ISO
stack terminology used by AN927. The 1-wire bus is implemented in the ow(4)
device, which implements the own(9) interface (n for network, the layer
described in the AN927). The presentation layer and above is the
responsibility of the client device drivers to implement.

Client drivers may only call the own(9) interface. The ow(4) driver
calls the owll(9) interface and implements the own(9).

$FreeBSD$