linux/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
Wolfram Sang 50a5ba8769 i2c: mux: demux-pinctrl: add driver
This driver allows an I2C bus to switch between multiple masters. This
is not hot-switching because connected I2C slaves will be
re-instantiated. It is meant to select the best I2C core at runtime once
the task is known. Example: Prefer i2c-gpio over another I2C core
because of HW errata affecting your use case.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2016-02-12 19:16:04 +01:00

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What: /sys/devices/platform/<i2c-demux-name>/cur_master
Date: January 2016
KernelVersion: 4.6
Contact: Wolfram Sang <wsa@the-dreams.de>
Description:
This file selects the active I2C master for a demultiplexed bus.
Write 0 there for the first master, 1 for the second etc. Reading the file will
give you a list with the active master marked. Example from a Renesas Lager
board:
root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
* 0 - /i2c@9
1 - /i2c@e6520000
2 - /i2c@e6530000
root@Lager:~# echo 2 > /sys/devices/platform/i2c@8/cur_master
root@Lager:~# cat /sys/devices/platform/i2c@8/cur_master
0 - /i2c@9
1 - /i2c@e6520000
* 2 - /i2c@e6530000