Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / devicetree / bindings / i2c / i2c-mux.txt

diff --git a/kernel/Documentation/devicetree/bindings/i2c/i2c-mux.txt b/kernel/Documentation/devicetree/bindings/i2c/i2c-mux.txt
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+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.
+
+Required properties:
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Required properties for child nodes:
+- #address-cells = <1>;
+- #size-cells = <0>;
+- reg : The sub-bus number.
+
+Optional properties for child nodes:
+- Other properties specific to the multiplexer/switch hardware.
+- Child nodes conforming to i2c bus binding
+
+
+Example :
+
+       /*
+          An NXP pca9548 8 channel I2C multiplexer at address 0x70
+          with two NXP pca8574 GPIO expanders attached, one each to
+          ports 3 and 4.
+        */
+
+       mux@70 {
+               compatible = "nxp,pca9548";
+               reg = <0x70>;
+               #address-cells = <1>;
+               #size-cells = <0>;
+
+               i2c@3 {
+                       #address-cells = <1>;
+                       #size-cells = <0>;
+                       reg = <3>;
+
+                       gpio1: gpio@38 {
+                               compatible = "nxp,pca8574";
+                               reg = <0x38>;
+                               #gpio-cells = <2>;
+                               gpio-controller;
+                       };
+               };
+               i2c@4 {
+                       #address-cells = <1>;
+                       #size-cells = <0>;
+                       reg = <4>;
+
+                       gpio2: gpio@38 {
+                               compatible = "nxp,pca8574";
+                               reg = <0x38>;
+                               #gpio-cells = <2>;
+                               gpio-controller;
+                       };
+               };
+       };