Module Name: src
Committed By: thorpej
Date: Thu Jun 7 13:30:49 UTC 2018
Modified Files:
src/sys/dev/i2c: i2c.c i2cvar.h
Log Message:
Changes / enhancements to i2c indirect device auto-configuration:
— iic_search() chooses a “probe strategy” based on the
"i2c-indirect-probe-strategy” property on the “iic” instance.
Valid values are "smbus-quick-write”, "smbus-receive-byte”, and
“none”. If no value is specified, the default is "smbus-quick-write”.
— If the "i2c-indirect-device-whitelist” exists on the “iic” instance,
iic_search() will first check the driver name in the cfdata_t against
this list, and only allow the match/probe to move forward if the
cfdata_t driver name is in the list. This is primarily to accommodate
the Intel integrated memory controller neutered-i2c-thing.
— If the cfdata_t specifies a wildcard address, each address of the i2c
bus will be consulted. If the cfdata_t contains a nailed-down address,
then we limit the bus scan to that specific address.
— We explicitly skip reserved / special i2c addresses, such as the
General-Call address, etc.
— We introduce the notion of a “match quality” for i2c drivers. From
lowest-quality to highest-quality: matched by plausible address only,
matched by plausible address and poking at the bus to see if the
device looks reasonable, matched by direct-config “compatible” string,
matched by direct-config “driver name” string.
— If the “match quality” is merely “plausible address only”, then
iic_search() will use the probe strategy selected above to see if
a device responds to that address.
To generate a diff of this commit:
cvs rdiff -u -r1.60 -r1.61 src/sys/dev/i2c/i2c.c
cvs rdiff -u -r1.12 -r1.13 src/sys/dev/i2c/i2cvar.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
