Documentation/devicetree/bindings/power/power-domain.yaml

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

title: Generic PM domains

maintainers:
  - Rafael J. Wysocki <rjw@rjwysocki.net>
  - Kevin Hilman <khilman@kernel.org>
  - Ulf Hansson <ulf.hansson@linaro.org>

description: |+
  System on chip designs are often divided into multiple PM domains that can be
  used for power gating of selected IP blocks for power saving by reduced
  leakage current. Moreover, in some cases the similar PM domains may also be
  capable of scaling performance for a group of IP blocks.

  This device tree binding can be used to bind PM domain consumer devices with
  their PM domains provided by PM domain providers. A PM domain provider can be
  represented by any node in the device tree and can provide one or more PM
  domains. A consumer node can refer to the provider by a phandle and a set of
  phandle arguments (so called PM domain specifiers) of length specified by the
  \#power-domain-cells property in the PM domain provider node.

properties:
  $nodename:
    pattern: "^(power-controller|power-domain|performance-domain)([@-].*)?$"

  domain-idle-states:
    $ref: /schemas/types.yaml#/definitions/phandle-array
    items:
      maxItems: 1
    description: |
      Phandles of idle states that defines the available states for the
      power-domain provider. The idle state definitions are compatible with the
      domain-idle-state bindings, specified in ./domain-idle-state.yaml.

      Note that, the domain-idle-state property reflects the idle states of this
      PM domain and not the idle states of the devices or sub-domains in the PM
      domain. Devices and sub-domains have their own idle states independent of
      the parent domain's idle states. In the absence of this property, the
      domain would be considered as capable of being powered-on or powered-off.

  operating-points-v2:
    description:
      Phandles to the OPP tables of power domains that are capable of scaling
      performance, provided by a power domain provider. If the provider provides
      a single power domain only or all the power domains provided by the
      provider have identical OPP tables, then this shall contain a single
      phandle. Refer to ../opp/opp-v2-base.yaml for more information.

  "#power-domain-cells":
    description:
      Number of cells in a PM domain specifier. Typically 0 for nodes
      representing a single PM domain and 1 for nodes providing multiple PM
      domains (e.g. power controllers), but can be any value as specified
      by device tree binding documentation of particular provider.

  power-domains:
    description:
      A phandle and PM domain specifier as defined by bindings of the power
      controller specified by phandle. Some power domains might be powered
      from another power domain (or have other hardware specific
      dependencies). For representing such dependency a standard PM domain
      consumer binding is used. When provided, all domains created
      by the given provider should be subdomains of the domain specified
      by this binding.

required:
  - "#power-domain-cells"

additionalProperties: true

examples:
  - |
    power: power-controller@12340000 {
        compatible = "foo,power-controller";
        reg = <0x12340000 0x1000>;
        #power-domain-cells = <1>;
    };

    // The node above defines a power controller that is a PM domain provider and
    // expects one cell as its phandle argument.

  - |
    parent2: power-controller@12340000 {
        compatible = "foo,power-controller";
        reg = <0x12340000 0x1000>;
        #power-domain-cells = <1>;
    };

    child2: power-controller@12341000 {
        compatible = "foo,power-controller";
        reg = <0x12341000 0x1000>;
        power-domains = <&parent2 0>;
        #power-domain-cells = <1>;
    };

    // The nodes above define two power controllers: 'parent' and 'child'.
    // Domains created by the 'child' power controller are subdomains of '0' power
    // domain provided by the 'parent' power controller.

  - |
    parent3: power-controller@12340000 {
        compatible = "foo,power-controller";
        reg = <0x12340000 0x1000>;
        #power-domain-cells = <0>;
        domain-idle-states = <&DOMAIN_RET>, <&DOMAIN_PWR_DN>;
    };

    child3: power-controller@12341000 {
        compatible = "foo,power-controller";
        reg = <0x12341000 0x1000>;
        power-domains = <&parent3>;
        #power-domain-cells = <0>;
        domain-idle-states = <&DOMAIN_PWR_DN>;
    };

    domain-idle-states {
        DOMAIN_RET: domain-retention {
            compatible = "domain-idle-state";
            entry-latency-us = <1000>;
            exit-latency-us = <2000>;
            min-residency-us = <10000>;
        };

        DOMAIN_PWR_DN: domain-pwr-dn {
            compatible = "domain-idle-state";
            entry-latency-us = <5000>;
            exit-latency-us = <8000>;
            min-residency-us = <7000>;
        };
    };