ae1f3df434
only gpiobus configured via FDT is supported. Bus enumeration is supported. Devices are created for each device found. 1-Wire temperature controllers are supported, but other drivers could be written. Temperatures are polled and reported via a sysctl. Errors are reported via sysctl counters. Mis-wired bus detection is included for more trouble shooting. See ow(4), owc(4) and ow_temp(4) for details of what's supported and known issues. This has been tested on Raspberry Pi-B, Pi2 and Beagle Bone Black with up to 7 devices. Differential Revision: https://reviews.freebsd.org/D2956 Relnotes: yes MFC after: 2 weeks Reviewed by: loos@ (with many insightful comments) |
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ow_temp.c | ||
ow.c | ||
ow.h | ||
owc_gpiobus.c | ||
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). $FreeBSD$