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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/dvfs/performance-domain.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Generic performance domains
maintainers:
- Sudeep Holla <sudeep.holla@arm.com>
description: |+
This binding is intended for performance management of groups of devices or
CPUs that run in the same performance domain. Performance domains must not
be confused with power domains. A performance domain is defined by a set
of devices that always have to run at the same performance level. For a given
performance domain, there is a single point of control that affects all the
devices in the domain, making it impossible to set the performance level of
an individual device in the domain independently from other devices in
that domain. For example, a set of CPUs that share a voltage domain, and
have a common frequency control, is said to be in the same performance
domain.
This device tree binding can be used to bind performance domain consumer
devices with their performance domains provided by performance domain
providers. A performance domain provider can be represented by any node in
the device tree and can provide one or more performance domains. A consumer
node can refer to the provider by a phandle and a set of phandle arguments
(so called performance domain specifiers) of length specified by the
\#performance-domain-cells property in the performance domain provider node.
select: true
properties:
"#performance-domain-cells":
description:
Number of cells in a performance domain specifier. Typically 0 for nodes
representing a single performance domain and 1 for nodes providing
multiple performance domains (e.g. performance controllers), but can be
any value as specified by device tree binding documentation of particular
provider.
enum: [ 0, 1 ]
performance-domains:
$ref: /schemas/types.yaml#/definitions/phandle-array
description:
A phandle and performance domain specifier as defined by bindings of the
performance controller/provider specified by phandle.
additionalProperties: true
examples:
- |
soc {
#address-cells = <2>;
#size-cells = <2>;
performance: performance-controller@11bc00 {
compatible = "mediatek,cpufreq-hw";
reg = <0 0x0011bc10 0 0x120>, <0 0x0011bd30 0 0x120>;
#performance-domain-cells = <1>;
};
};
// The node above defines a performance controller that is a performance
// domain provider and expects one cell as its phandle argument.
cpus {
#address-cells = <2>;
#size-cells = <0>;
cpu@0 {
device_type = "cpu";
compatible = "arm,cortex-a57";
reg = <0x0 0x0>;
performance-domains = <&performance 1>;
};
};