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authorDoug Anderson <dianders@chromium.org>2014-04-29 17:30:51 (GMT)
committerWolfram Sang <wsa@the-dreams.de>2014-05-22 08:09:22 (GMT)
commita83bea7c1170ad8c68d65ed2fff6a533e68f67a4 (patch)
tree0bf15296942f62d84c0e67be5622b316eaa5e388
parent482116badacba9308abd6c5cae2f5f19e2f81449 (diff)
downloadlinux-a83bea7c1170ad8c68d65ed2fff6a533e68f67a4.tar.xz
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>
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt
index 1ac8ea8..bfeabb8 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: