[PATCH 1/7] dt-bindings: i2c: add support for 'i2c-mux' subnode

Peter Rosin
2016-07-27T08:43:59Z

Similar to the new optional 'i2c-bus' subnode from Jon Hunter, this
adds an optional 'i2c-mux' subnode, for similar reasons. I.e. it is
bad of the i2c mux core to assume that any subnode of an i2c mux device
is a potential (when the 'reg' property matches) i2c-mux child bus,
given that i2c mux devices might do more than mux i2c traffic.

So, if an 'i2c-mux' subnode is present, dictate that all i2c-mux child
buses exist beneath that subnode.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
Documentation/devicetree/bindings/i2c/i2c-mux.txt | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux.txt b/Documentation/devicetree/bindings/i2c/i2c-mux.txt
index af84cce5cd7b..212e6779dc5c 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-mux.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux.txt
@@ -2,19 +2,32 @@ Common i2c bus multiplexer/switch properties.

An i2c bus multiplexer/switch will have several child busses that are
numbered uniquely in a device dependent manner. The nodes for an i2c bus
-multiplexer/switch will have one child node for each child
-bus.
+multiplexer/switch will have one child node for each child bus.

-Required properties:
+Optional properties:
+- #address-cells = <1>;
+ This property is required is the i2c-mux child node does not exist.
+
+- #size-cells = <0>;
+ This property is required is the i2c-mux child node does not exist.
+
+- i2c-mux
+ For i2c multiplexers/switches that have child nodes that are a mixture
+ of both i2c child busses and other child nodes, the 'i2c-mux' subnode
+ can be used for populating the i2c child busses. If an 'i2c-mux'
+ subnode is present, only subnodes of this will be considered as i2c
+ child busses.
+
+Required properties for the i2c-mux child node:
- #address-cells = <1>;
- #size-cells = <0>;

-Required properties for child nodes:
+Required properties for i2c child bus nodes:
- #address-cells = <1>;
- #size-cells = <0>;
- reg : The sub-bus number.

-Optional properties for child nodes:
+Optional properties for i2c child bus nodes:
- Other properties specific to the multiplexer/switch hardware.
- Child nodes conforming to i2c bus binding

--
2.1.4