Documentation/devicetree/bindings/i2c/i2c-demux-pinctrl.yaml

   1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/i2c/i2c-demux-pinctrl.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: Pinctrl-based I2C Bus Demultiplexer
   8
   9 maintainers:
  10   - Wolfram Sang <wsa+renesas@sang-engineering.com>
  11
  12 description: |
  13   This binding describes an I2C bus demultiplexer that uses pin multiplexing to
  14   route the I2C signals, and represents the pin multiplexing configuration
  15   using the pinctrl device tree bindings.  This may be used to select one I2C
  16   IP core at runtime which may have a better feature set for a given task than
  17   another I2C IP core on the SoC.  The most simple example is to fall back to
  18   GPIO bitbanging if your current runtime configuration hits an errata of the
  19   internal IP core.
  20
  21       +-------------------------------+
  22       | SoC                           |
  23       |                               |   +-----+  +-----+
  24       |   +------------+              |   | dev |  | dev |
  25       |   |I2C IP Core1|--\           |   +-----+  +-----+
  26       |   +------------+   \-------+  |      |        |
  27       |                    |Pinctrl|--|------+--------+
  28       |   +------------+   +-------+  |
  29       |   |I2C IP Core2|--/           |
  30       |   +------------+              |
  31       |                               |
  32       +-------------------------------+
  33
  34 allOf:
  35   - $ref: /schemas/i2c/i2c-controller.yaml#
  36
  37 properties:
  38   compatible:
  39     const: i2c-demux-pinctrl
  40
  41   i2c-parent:
  42     $ref: /schemas/types.yaml#/definitions/phandle-array
  43     items:
  44       maxItems: 1
  45     description:
  46       List of phandles of I2C masters available for selection.  The first one
  47       will be used as default.
  48
  49   i2c-bus-name:
  50     $ref: /schemas/types.yaml#/definitions/string
  51     description:
  52       The name of this bus.  Also needed as pinctrl-name for the I2C parents.
  53
  54 required:
  55   - compatible
  56   - i2c-parent
  57   - i2c-bus-name
  58
  59 unevaluatedProperties: false
  60
  61 examples:
  62   - |
  63     #include <dt-bindings/gpio/gpio.h>
  64     #include <dt-bindings/interrupt-controller/irq.h>
  65
  66     gpioi2c2: i2c-9 {
  67         #address-cells = <1>;
  68         #size-cells = <0>;
  69         compatible = "i2c-gpio";
  70         scl-gpios = <&gpio5 5 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
  71         sda-gpios = <&gpio5 6 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
  72         i2c-gpio,delay-us = <5>;
  73
  74         // The I2C controller must have its status "disabled".  The I2C bus
  75         // demultiplexer will enable it at runtime when needed.
  76         status = "disabled";
  77     };
  78
  79     iic2: i2c@e6520000 {
  80         reg = <0xe6520000 0x425>;
  81         pinctrl-0 = <&iic2_pins>;
  82         // The pinctrl property for the parent I2C controller needs a pinctrl
  83         // state with the same name as i2c-bus-name in the I2C bus demultiplexer
  84         // node, not "default"!
  85         pinctrl-names = "i2c-hdmi";
  86
  87         clock-frequency = <100000>;
  88
  89         // The I2C controller must have its status "disabled".  The I2C bus
  90         // demultiplexer will enable it at runtime when needed.
  91         status = "disabled";
  92     };
  93
  94     i2c2: i2c@e6530000 {
  95         reg = <0 0xe6530000 0 0x40>;
  96         pinctrl-0 = <&i2c2_pins>;
  97         // The pinctrl property for the parent I2C controller needs a pinctrl
  98         // state with the same name as i2c-bus-name in the I2C bus demultiplexer
  99         // node, not "default"!
 100         pinctrl-names = "i2c-hdmi";
 101
 102         clock-frequency = <100000>;
 103
 104         // The I2C controller must have its status "disabled".  The I2C bus
 105         // demultiplexer will enable it at runtime when needed.
 106         status = "disabled";
 107     };
 108
 109     // Example for a bus to be demuxed.  It contains various I2C clients for
 110     // HDMI, so the bus is named "i2c-hdmi":
 111     i2chdmi: i2c-mux3 {
 112         compatible = "i2c-demux-pinctrl";
 113         i2c-parent = <&iic2>, <&i2c2>, <&gpioi2c2>;
 114         i2c-bus-name = "i2c-hdmi";
 115         #address-cells = <1>;
 116         #size-cells = <0>;
 117
 118         ak4643: codec@12 {
 119             compatible = "asahi-kasei,ak4643";
 120             #sound-dai-cells = <0>;
 121             reg = <0x12>;
 122         };
 123
 124         composite-in@20 {
 125             compatible = "adi,adv7180";
 126             reg = <0x20>;
 127
 128             port {
 129                 adv7180: endpoint {
 130                     bus-width = <8>;
 131                     remote-endpoint = <&vin1ep0>;
 132                 };
 133             };
 134         };
 135
 136         hdmi@39 {
 137             compatible = "adi,adv7511w";
 138             reg = <0x39>;
 139             interrupt-parent = <&gpio1>;
 140             interrupts = <15 IRQ_TYPE_LEVEL_LOW>;
 141             clocks = <&cec_clock>;
 142             clock-names = "cec";
 143
 144             avdd-supply = <&fixedregulator1v8>;
 145             dvdd-supply = <&fixedregulator1v8>;
 146             pvdd-supply = <&fixedregulator1v8>;
 147             dvdd-3v-supply = <&fixedregulator3v3>;
 148             bgvdd-supply = <&fixedregulator1v8>;
 149
 150             adi,input-depth = <8>;
 151             adi,input-colorspace = "rgb";
 152             adi,input-clock = "1x";
 153
 154             ports {
 155                 #address-cells = <1>;
 156                 #size-cells = <0>;
 157
 158                 port@0 {
 159                     reg = <0>;
 160                     adv7511_in: endpoint {
 161                         remote-endpoint = <&lvds0_out>;
 162                     };
 163                 };
 164
 165                 port@1 {
 166                     reg = <1>;
 167                     adv7511_out: endpoint {
 168                         remote-endpoint = <&hdmi_con_out>;
 169                     };
 170                 };
 171             };
 172         };
 173     };