xref: /linux/Documentation/devicetree/bindings/power/power-domain.yaml (revision a23e1966932464e1c5226cb9ac4ce1d5fc10ba22) 
1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/power/power-domain.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Generic PM domains
8
9maintainers:
10  - Rafael J. Wysocki <rjw@rjwysocki.net>
11  - Kevin Hilman <khilman@kernel.org>
12  - Ulf Hansson <ulf.hansson@linaro.org>
13
14description: |+
15  System on chip designs are often divided into multiple PM domains that can be
16  used for power gating of selected IP blocks for power saving by reduced
17  leakage current. Moreover, in some cases the similar PM domains may also be
18  capable of scaling performance for a group of IP blocks.
19
20  This device tree binding can be used to bind PM domain consumer devices with
21  their PM domains provided by PM domain providers. A PM domain provider can be
22  represented by any node in the device tree and can provide one or more PM
23  domains. A consumer node can refer to the provider by a phandle and a set of
24  phandle arguments (so called PM domain specifiers) of length specified by the
25  \#power-domain-cells property in the PM domain provider node.
26
27properties:
28  $nodename:
29    pattern: "^(power-controller|power-domain|performance-domain)([@-].*)?$"
30
31  domain-idle-states:
32    $ref: /schemas/types.yaml#/definitions/phandle-array
33    items:
34      maxItems: 1
35    description: |
36      Phandles of idle states that defines the available states for the
37      power-domain provider. The idle state definitions are compatible with the
38      domain-idle-state bindings, specified in ./domain-idle-state.yaml.
39
40      Note that, the domain-idle-state property reflects the idle states of this
41      PM domain and not the idle states of the devices or sub-domains in the PM
42      domain. Devices and sub-domains have their own idle states independent of
43      the parent domain's idle states. In the absence of this property, the
44      domain would be considered as capable of being powered-on or powered-off.
45
46  operating-points-v2:
47    description:
48      Phandles to the OPP tables of power domains that are capable of scaling
49      performance, provided by a power domain provider. If the provider provides
50      a single power domain only or all the power domains provided by the
51      provider have identical OPP tables, then this shall contain a single
52      phandle. Refer to ../opp/opp-v2-base.yaml for more information.
53
54  "#power-domain-cells":
55    description:
56      Number of cells in a PM domain specifier. Typically 0 for nodes
57      representing a single PM domain and 1 for nodes providing multiple PM
58      domains (e.g. power controllers), but can be any value as specified
59      by device tree binding documentation of particular provider.
60
61  power-domains:
62    description:
63      A phandle and PM domain specifier as defined by bindings of the power
64      controller specified by phandle. Some power domains might be powered
65      from another power domain (or have other hardware specific
66      dependencies). For representing such dependency a standard PM domain
67      consumer binding is used. When provided, all domains created
68      by the given provider should be subdomains of the domain specified
69      by this binding.
70
71required:
72  - "#power-domain-cells"
73
74additionalProperties: true
75
76examples:
77  - |
78    power: power-controller@12340000 {
79        compatible = "foo,power-controller";
80        reg = <0x12340000 0x1000>;
81        #power-domain-cells = <1>;
82    };
83
84    // The node above defines a power controller that is a PM domain provider and
85    // expects one cell as its phandle argument.
86
87  - |
88    parent2: power-controller@12340000 {
89        compatible = "foo,power-controller";
90        reg = <0x12340000 0x1000>;
91        #power-domain-cells = <1>;
92    };
93
94    child2: power-controller@12341000 {
95        compatible = "foo,power-controller";
96        reg = <0x12341000 0x1000>;
97        power-domains = <&parent2 0>;
98        #power-domain-cells = <1>;
99    };
100
101    // The nodes above define two power controllers: 'parent' and 'child'.
102    // Domains created by the 'child' power controller are subdomains of '0' power
103    // domain provided by the 'parent' power controller.
104
105  - |
106    parent3: power-controller@12340000 {
107        compatible = "foo,power-controller";
108        reg = <0x12340000 0x1000>;
109        #power-domain-cells = <0>;
110        domain-idle-states = <&DOMAIN_RET>, <&DOMAIN_PWR_DN>;
111    };
112
113    child3: power-controller@12341000 {
114        compatible = "foo,power-controller";
115        reg = <0x12341000 0x1000>;
116        power-domains = <&parent3>;
117        #power-domain-cells = <0>;
118        domain-idle-states = <&DOMAIN_PWR_DN>;
119    };
120
121    domain-idle-states {
122        DOMAIN_RET: domain-retention {
123            compatible = "domain-idle-state";
124            entry-latency-us = <1000>;
125            exit-latency-us = <2000>;
126            min-residency-us = <10000>;
127        };
128
129        DOMAIN_PWR_DN: domain-pwr-dn {
130            compatible = "domain-idle-state";
131            entry-latency-us = <5000>;
132            exit-latency-us = <8000>;
133            min-residency-us = <7000>;
134        };
135    };
136