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# 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 Binding
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.
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-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
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
dependencies:
opp-avg-kBps: [ opp-peak-kBps ]
required:
- compatible
additionalProperties: true
...
|
