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authorWolfram Sang <wsa+renesas@sang-engineering.com>2016-01-13 17:29:27 +0300
committerWolfram Sang <wsa@the-dreams.de>2016-02-12 21:16:04 +0300
commit50a5ba876908147b36441c754e835588143c6b54 (patch)
treec280d50a5f6d1a4fde1537a13e87cd423cb775bd /Documentation/ABI
parent388f7b1d6e8ca06762e2454d28d6c3c55ad0fe95 (diff)
downloadlinux-50a5ba876908147b36441c754e835588143c6b54.tar.xz
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>
Diffstat (limited to 'Documentation/ABI')
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diff --git a/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl b/Documentation/ABI/testing/sysfs-platform-i2c-demux-pinctrl
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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