From a83bea7c1170ad8c68d65ed2fff6a533e68f67a4 Mon Sep 17 00:00:00 2001 From: Doug Anderson <dianders@chromium.org> Date: Tue, 29 Apr 2014 10:30:51 -0700 Subject: [PATCH] i2c: mux: Add more warnings to i2c-arb-gpio-challenge docs This adds some more warnings to the i2c-arb-gpio-challenge docs to help encourage people not to use it in their designs unless they have no choice. Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> --- .../devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt index 1ac8ea8ade1dc4..bfeabb843941e0 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt @@ -8,6 +8,12 @@ the standard I2C multi-master rules. Using GPIOs is generally useful in the case where there is a device on the bus that has errata and/or bugs that makes standard multimaster mode not feasible. +Note that this scheme works well enough but has some downsides: +* It is nonstandard (not using standard I2C multimaster) +* Having two masters on a bus in general makes it relatively hard to debug + problems (hard to tell if i2c issues were caused by one master, another, or + some device on the bus). + Algorithm: -- GitLab