xref: /kernel/linux/linux-6.6/Documentation/devicetree/bindings/i3c/i3c.yaml (revision 62306a36)

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/i3c/i3c.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: I3C bus

maintainers:
  - Alexandre Belloni <alexandre.belloni@bootlin.com>
  - Miquel Raynal <miquel.raynal@bootlin.com>

description: |
  I3C busses can be described with a node for the primary I3C controller device
  and a set of child nodes for each I2C or I3C slave on the bus. Each of them
  may, during the life of the bus, request mastership.

properties:
  $nodename:
    pattern: "^i3c-master@[0-9a-f]+$"

  "#address-cells":
    const: 3
    description: |
      Each I2C device connected to the bus should be described in a subnode.

      All I3C devices are supposed to support DAA (Dynamic Address Assignment),
      and are thus discoverable. So, by default, I3C devices do not have to be
      described in the device tree. This being said, one might want to attach
      extra resources to these devices, and those resources may have to be
      described in the device tree, which in turn means we have to describe
      I3C devices.

      Another use case for describing an I3C device in the device tree is when
      this I3C device has a static I2C address and we want to assign it a
      specific I3C dynamic address before the DAA takes place (so that other
      devices on the bus can't take this dynamic address).

  "#size-cells":
    const: 0

  i3c-scl-hz:
    description: |
      Frequency of the SCL signal used for I3C transfers. When undefined, the
      default value should be 12.5MHz.

      May not be supported by all controllers.

  i2c-scl-hz:
    description: |
      Frequency of the SCL signal used for I2C transfers. When undefined, the
      default should be to look at LVR (Legacy Virtual Register) values of
      I2C devices described in the device tree to determine the maximum I2C
      frequency.

      May not be supported by all controllers.

required:
  - "#address-cells"
  - "#size-cells"

patternProperties:
  "@[0-9a-f]+$":
    type: object
    description: |
      I2C child, should be named: <device-type>@<i2c-address>

      All properties described in Documentation/devicetree/bindings/i2c/i2c.txt
      are valid here, except the reg property whose content is changed.

    properties:
      compatible:
        description:
          Compatible of the I2C device.

      reg:
        items:
          - items:
              - description: |
                  I2C address. 10 bit addressing is not supported. Devices with
                  10-bit address can't be properly passed through DEFSLVS
                  command.
                minimum: 0
                maximum: 0x7f
              - const: 0
              - description: |
                  Shall encode the I3C LVR (Legacy Virtual Register):
                    bit[31:8]: unused/ignored
                    bit[7:5]: I2C device index. Possible values:
                      * 0: I2C device has a 50 ns spike filter
                      * 1: I2C device does not have a 50 ns spike filter but
                           supports high frequency on SCL
                      * 2: I2C device does not have a 50 ns spike filter and is
                           not tolerant to high frequencies
                      * 3-7: reserved
                    bit[4]: tell whether the device operates in FM (Fast Mode)
                            or FM+ mode:
                      * 0: FM+ mode
                      * 1: FM mode
                    bit[3:0]: device type
                      * 0-15: reserved

    required:
      - compatible
      - reg

  "@[0-9a-f]+,[0-9a-f]+$":
    type: object
    description: |
      I3C child, should be named: <device-type>@<static-i2c-address>,<i3c-pid>

    properties:
      reg:
        items:
          - items:
              - description: |
                  Encodes the static I2C address. Should be 0 if the device does
                  not have one (0 is not a valid I2C address).
                minimum: 0
                maximum: 0x7f
              - description: |
                  First half of the Provisional ID (following the PID
                  definition provided by the I3C specification).

                  Contains the manufacturer ID left-shifted by 1.
              - description: |
                  Second half of the Provisional ID (following the PID
                  definition provided by the I3C specification).

                  Contains the ORing of the part ID left-shifted by 16,
                  the instance ID left-shifted by 12 and extra information.

      assigned-address:
        $ref: /schemas/types.yaml#/definitions/uint32
        minimum: 0x1
        maximum: 0xff
        description: |
          Dynamic address to be assigned to this device. In case static address is
          present (first cell of the reg property != 0), this address is assigned
          through SETDASA. If static address is not present, this address is assigned
          through SETNEWDA after assigning a temporary address via ENTDAA.

    required:
      - reg

additionalProperties: true

examples:
  - |
    i3c-master@d040000 {
        compatible = "cdns,i3c-master";
        clocks = <&coreclock>, <&i3csysclock>;
        clock-names = "pclk", "sysclk";
        interrupts = <3 0>;
        reg = <0x0d040000 0x1000>;
        #address-cells = <3>;
        #size-cells = <0>;
        i2c-scl-hz = <100000>;

        /* I2C device. */
        eeprom@57 {
            compatible = "atmel,24c01";
            reg = <0x57 0x0 0x10>;
            pagesize = <0x8>;
        };

        /* I3C device with a static I2C address and assigned address. */
        thermal_sensor: sensor@68,39200144004 {
            reg = <0x68 0x392 0x144004>;
            assigned-address = <0xa>;
        };

        /* I3C device with only assigned address. */
        pressure_sensor: sensor@0,39200124004 {
            reg = <0x0 0x392 0x124000>;
            assigned-address = <0xc>;
        };

        /*
         * I3C device without a static I2C address but requiring
         * resources described in the DT.
         */
        sensor@0,39200154004 {
            reg = <0x0 0x392 0x154004>;
            clocks = <&clock_provider 0>;
        };
    };