Documentation/devicetree/bindings/opp/opp-v2-base.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/opp/opp-v2-base.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Generic OPP (Operating Performance Points) Common Properties

maintainers:
  - Viresh Kumar <viresh.kumar@linaro.org>

description: |
  Devices work at voltage-current-frequency combinations and some implementations
  have the liberty of choosing these. These combinations are called Operating
  Performance Points aka OPPs. This document defines bindings for these OPPs
  applicable across wide range of devices. For illustration purpose, this document
  uses CPU as a device.

  This describes the OPPs belonging to a device.

select: false

properties:
  $nodename:
    pattern: '^opp-table(-[a-z0-9]+)?$'

  opp-shared:
    description:
      Indicates that device nodes using this OPP Table Node's phandle switch
      their DVFS state together, i.e. they share clock/voltage/current lines.
      Missing property means devices have independent clock/voltage/current
      lines, but they share OPP tables.
    type: boolean

patternProperties:
  '^opp(-?[0-9]+)*$':
    type: object
    description:
      One or more OPP nodes describing voltage-current-frequency combinations.
      Their name isn't significant but their phandle can be used to reference an
      OPP. These are mandatory except for the case where the OPP table is
      present only to indicate dependency between devices using the opp-shared
      property.

    properties:
      opp-hz:
        description:
          Frequency in Hz, expressed as a 64-bit big-endian integer. This is a
          required property for all device nodes, unless another "required"
          property to uniquely identify the OPP nodes exists. Devices like power
          domains must have another (implementation dependent) property.

          Entries for multiple clocks shall be provided in the same field, as
          array of frequencies.  The OPP binding doesn't provide any provisions
          to relate the values to their clocks or the order in which the clocks
          need to be configured and that is left for the implementation
          specific binding.
        minItems: 1
        maxItems: 16
        items:
          maxItems: 1

      opp-microvolt:
        description: |
          Voltage for the OPP

          A single regulator's voltage is specified with an array of size one or three.
          Single entry is for target voltage and three entries are for <target min max>
          voltages.

          Entries for multiple regulators shall be provided in the same field separated
          by angular brackets <>. The OPP binding doesn't provide any provisions to
          relate the values to their power supplies or the order in which the supplies
          need to be configured and that is left for the implementation specific
          binding.

          Entries for all regulators shall be of the same size, i.e. either all use a
          single value or triplets.
        minItems: 1
        maxItems: 8   # Should be enough regulators
        items:
          minItems: 1
          maxItems: 3

      opp-microamp:
        description: |
          The maximum current drawn by the device in microamperes considering
          system specific parameters (such as transients, process, aging,
          maximum operating temperature range etc.) as necessary. This may be
          used to set the most efficient regulator operating mode.

          Should only be set if opp-microvolt or opp-microvolt-<name> is set for
          the OPP.

          Entries for multiple regulators shall be provided in the same field
          separated by angular brackets <>. If current values aren't required
          for a regulator, then it shall be filled with 0. If current values
          aren't required for any of the regulators, then this field is not
          required. The OPP binding doesn't provide any provisions to relate the
          values to their power supplies or the order in which the supplies need
          to be configured and that is left for the implementation specific
          binding.
        minItems: 1
        maxItems: 8   # Should be enough regulators

      opp-microwatt:
        description: |
          The power for the OPP in micro-Watts.

          Entries for multiple regulators shall be provided in the same field
          separated by angular brackets <>. If power values aren't required
          for a regulator, then it shall be filled with 0. If power values
          aren't required for any of the regulators, then this field is not
          required. The OPP binding doesn't provide any provisions to relate the
          values to their power supplies or the order in which the supplies need
          to be configured and that is left for the implementation specific
          binding.
        minItems: 1
        maxItems: 8   # Should be enough regulators

      opp-level:
        description:
          A value representing the performance level of the device.
        $ref: /schemas/types.yaml#/definitions/uint32

      opp-peak-kBps:
        description:
          Peak bandwidth in kilobytes per second, expressed as an array of
          32-bit big-endian integers. Each element of the array represents the
          peak bandwidth value of each interconnect path. The number of elements
          should match the number of interconnect paths.
        minItems: 1
        maxItems: 32  # Should be enough

      opp-avg-kBps:
        description:
          Average bandwidth in kilobytes per second, expressed as an array
          of 32-bit big-endian integers. Each element of the array represents the
          average bandwidth value of each interconnect path. The number of elements
          should match the number of interconnect paths. This property is only
          meaningful in OPP tables where opp-peak-kBps is present.
        minItems: 1
        maxItems: 32  # Should be enough

      clock-latency-ns:
        description:
          Specifies the maximum possible transition latency (in nanoseconds) for
          switching to this OPP from any other OPP.

      turbo-mode:
        description:
          Marks the OPP to be used only for turbo modes. Turbo mode is available
          on some platforms, where the device can run over its operating
          frequency for a short duration of time limited by the device's power,
          current and thermal limits.
        type: boolean

      opp-suspend:
        description:
          Marks the OPP to be used during device suspend. If multiple OPPs in
          the table have this, the OPP with highest opp-hz will be used.
        type: boolean

      opp-supported-hw:
        description: |
          This property allows a platform to enable only a subset of the OPPs
          from the larger set present in the OPP table, based on the current
          version of the hardware (already known to the operating system).

          Each block present in the array of blocks in this property, represents
          a sub-group of hardware versions supported by the OPP. i.e. <sub-group
          A>, <sub-group B>, etc. The OPP will be enabled if _any_ of these
          sub-groups match the hardware's version.

          Each sub-group is a platform defined array representing the hierarchy
          of hardware versions supported by the platform. For a platform with
          three hierarchical levels of version (X.Y.Z), this field shall look
          like

          opp-supported-hw = <X1 Y1 Z1>, <X2 Y2 Z2>, <X3 Y3 Z3>.

          Each level (eg. X1) in version hierarchy is represented by a 32 bit
          value, one bit per version and so there can be maximum 32 versions per
          level. Logical AND (&) operation is performed for each level with the
          hardware's level version and a non-zero output for _all_ the levels in
          a sub-group means the OPP is supported by hardware. A value of
          0xFFFFFFFF for each level in the sub-group will enable the OPP for all
          versions for the hardware.
        $ref: /schemas/types.yaml#/definitions/uint32-matrix
        maxItems: 32
        items:
          minItems: 1
          maxItems: 4

      required-opps:
        description:
          This contains phandle to an OPP node in another device's OPP table. It
          may contain an array of phandles, where each phandle points to an OPP
          of a different device. It should not contain multiple phandles to the
          OPP nodes in the same OPP table. This specifies the minimum required
          OPP of the device(s), whose OPP's phandle is present in this property,
          for the functioning of the current device at the current OPP (where
          this property is present).
        $ref: /schemas/types.yaml#/definitions/phandle-array
        items:
          maxItems: 1

    patternProperties:
      '^opp-microvolt-':
        description:
          Named opp-microvolt property. This is exactly similar to the above
          opp-microvolt property, but allows multiple voltage ranges to be
          provided for the same OPP. At runtime, the platform can pick a <name>
          and matching opp-microvolt-<name> property will be enabled for all
          OPPs. If the platform doesn't pick a specific <name> or the <name>
          doesn't match with any opp-microvolt-<name> properties, then
          opp-microvolt property shall be used, if present.
        $ref: /schemas/types.yaml#/definitions/uint32-matrix
        minItems: 1
        maxItems: 8   # Should be enough regulators
        items:
          minItems: 1
          maxItems: 3

      '^opp-microamp-':
        description:
          Named opp-microamp property. Similar to opp-microvolt-<name> property,
          but for microamp instead.
        $ref: /schemas/types.yaml#/definitions/uint32-array
        minItems: 1
        maxItems: 8   # Should be enough regulators

      '^opp-microwatt-':
        description:
          Named opp-microwatt property. Similar to opp-microamp-<name> property,
          but for microwatt instead.
        $ref: /schemas/types.yaml#/definitions/uint32-array
        minItems: 1
        maxItems: 8   # Should be enough regulators

    dependencies:
      opp-avg-kBps: [ opp-peak-kBps ]

required:
  - compatible

additionalProperties: true

...