xref: /kernel/linux/linux-6.6/Documentation/devicetree/bindings/i2c/i2c-mux.yaml

# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/i2c/i2c-mux.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Common i2c bus multiplexer/switch properties.

maintainers:
  - Peter Rosin <peda@axentia.se>

description: |+
  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.

  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.

properties:
  $nodename:
    pattern: '^(i2c-?)?mux'

  '#address-cells':
    const: 1

  '#size-cells':
    const: 0

patternProperties:
  '^i2c@[0-9a-f]+$':
    $ref: /schemas/i2c/i2c-controller.yaml
    unevaluatedProperties: false

    properties:
      reg:
        description: The mux selector sub-bus number for the child I2C bus.
        maxItems: 1

additionalProperties: true

examples:
  - |
    /*
     * An NXP pca9548 8 channel I2C multiplexer at address 0x70
     * with two NXP pca8574 GPIO expanders attached, one each to
     * ports 3 and 4.
     */
    i2c {
        #address-cells = <1>;
        #size-cells = <0>;

        i2c-mux@70 {
            compatible = "nxp,pca9548";
            reg = <0x70>;
            #address-cells = <1>;
            #size-cells = <0>;

            i2c@3 {
                #address-cells = <1>;
                #size-cells = <0>;
                reg = <3>;

                gpio@20 {
                    compatible = "nxp,pca9555";
                    gpio-controller;
                    #gpio-cells = <2>;
                    reg = <0x20>;
                };
            };
            i2c@4 {
                #address-cells = <1>;
                #size-cells = <0>;
                reg = <4>;

                gpio@20 {
                    compatible = "nxp,pca9555";
                    gpio-controller;
                    #gpio-cells = <2>;
                    reg = <0x20>;
                };
            };
        };
    };
...