freebsd-dev/sys/dev/ow
Warner Losh ddfc9c4c59 newbus: Move from bus_child_{pnpinfo,location}_src to bus_child_{pnpinfo,location} with sbuf
Now that the upper layers all go through a layer to tie into these
information functions that translates an sbuf into char * and len. The
current interface suffers issues of what to do in cases of truncation,
etc. Instead, migrate all these functions to using struct sbuf and these
issues go away. The caller is also in charge of any memory allocation
and/or expansion that's needed during this process.

Create a bus_generic_child_{pnpinfo,location} and make it default. It
just returns success. This is for those busses that have no information
for these items. Migrate the now-empty routines to using this as
appropriate.

Document these new interfaces with man pages, and oversight from before.

Reviewed by:		jhb, bcr
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D29937
2021-06-22 20:52:06 -06:00
..
ow_temp.c
ow.c newbus: Move from bus_child_{pnpinfo,location}_src to bus_child_{pnpinfo,location} with sbuf 2021-06-22 20:52:06 -06:00
ow.h
owc_gpiobus.c Revert "Define PNP info after defining driver modules" 2021-01-23 10:59:41 -05:00
owll_if.m
owll.h
own_if.m
own.h
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).

$FreeBSD$