i2c: add binding to mark a bus as SMBus

SMBus is largely compatible with I2C but there are some specifics. In
case we need them on a bus, we can now use this new binding.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index a21c359b9f0266f808972dc68680beb229b9353b..df41f72afc8785802a99ed63994524f34d676d23 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt
@@ -87,6 +87,11 @@ wants to support one of the below features, it should adapt these bindings.
        this information to detect a stalled bus more reliably, for example.
        Can not be combined with 'multi-master'.
 
+- smbus
+       states that additional SMBus restrictions and features apply to this bus.
+       Examples of features are SMBusHostNotify and SMBusAlert. Examples of
+       restrictions are more reserved addresses and timeout definitions.
+
 Required properties (per child device)
 --------------------------------------