Documentation/devicetree/bindings/i2c/i2c-mux.txt

   1 Common i2c bus multiplexer/switch properties.
   2
   3 An i2c bus multiplexer/switch will have several child busses that are
   4 numbered uniquely in a device dependent manner.  The nodes for an i2c bus
   5 multiplexer/switch will have one child node for each child
   6 bus.
   7
   8 Required properties:
   9 - #address-cells = <1>;
  10 - #size-cells = <0>;
  11
  12 Required properties for child nodes:
  13 - #address-cells = <1>;
  14 - #size-cells = <0>;
  15 - reg : The sub-bus number.
  16
  17 Optional properties for child nodes:
  18 - Other properties specific to the multiplexer/switch hardware.
  19 - Child nodes conforming to i2c bus binding
  20
  21
  22 Example :
  23
  24         /*
  25            An NXP pca9548 8 channel I2C multiplexer at address 0x70
  26            with two NXP pca8574 GPIO expanders attached, one each to
  27            ports 3 and 4.
  28          */
  29
  30         mux@70 {
  31                 compatible = "nxp,pca9548";
  32                 reg = <0x70>;
  33                 #address-cells = <1>;
  34                 #size-cells = <0>;
  35
  36                 i2c@3 {
  37                         #address-cells = <1>;
  38                         #size-cells = <0>;
  39                         reg = <3>;
  40
  41                         gpio1: gpio@38 {
  42                                 compatible = "nxp,pca8574";
  43                                 reg = <0x38>;
  44                                 #gpio-cells = <2>;
  45                                 gpio-controller;
  46                         };
  47                 };
  48                 i2c@4 {
  49                         #address-cells = <1>;
  50                         #size-cells = <0>;
  51                         reg = <4>;
  52
  53                         gpio2: gpio@38 {
  54                                 compatible = "nxp,pca8574";
  55                                 reg = <0x38>;
  56                                 #gpio-cells = <2>;
  57                                 gpio-controller;
  58                         };
  59                 };
  60         };