xref: /linux/Documentation/devicetree/bindings/power/power-domain.yaml (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d) 
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 <rafael@kernel.org>
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
71  power-domains-child-ids:
72    $ref: /schemas/types.yaml#/definitions/uint32-array
73    description:
74      An array of child domain IDs that correspond to the power-domains
75      property. This property is only applicable to power domain providers
76      with "#power-domain-cells" > 0 (i.e., providers that supply multiple
77      power domains). It specifies which of the provider's child domains
78      should be associated with each parent domain listed in the power-domains
79      property. The number of elements in this array must match the number of
80      phandles in the power-domains property. Each element specifies the child
81      domain ID (index) that should be made a child domain of the corresponding
82      parent domain. This enables hierarchical power domain structures where
83      different child domains from the same provider can have different
84      parent domains.
85
86required:
87  - "#power-domain-cells"
88
89additionalProperties: true
90
91examples:
92  - |
93    power: power-controller@12340000 {
94        compatible = "foo,power-controller";
95        reg = <0x12340000 0x1000>;
96        #power-domain-cells = <1>;
97    };
98
99    // The node above defines a power controller that is a PM domain provider and
100    // expects one cell as its phandle argument.
101
102  - |
103    parent2: power-controller@12340000 {
104        compatible = "foo,power-controller";
105        reg = <0x12340000 0x1000>;
106        #power-domain-cells = <1>;
107    };
108
109    child2: power-controller@12341000 {
110        compatible = "foo,power-controller";
111        reg = <0x12341000 0x1000>;
112        power-domains = <&parent2 0>;
113        #power-domain-cells = <1>;
114    };
115
116    // The nodes above define two power controllers: 'parent' and 'child'.
117    // Domains created by the 'child' power controller are subdomains of '0' power
118    // domain provided by the 'parent' power controller.
119
120  - |
121    parent3: power-controller@12340000 {
122        compatible = "foo,power-controller";
123        reg = <0x12340000 0x1000>;
124        #power-domain-cells = <0>;
125        domain-idle-states = <&DOMAIN_RET>, <&DOMAIN_PWR_DN>;
126    };
127
128    child3: power-controller@12341000 {
129        compatible = "foo,power-controller";
130        reg = <0x12341000 0x1000>;
131        power-domains = <&parent3>;
132        #power-domain-cells = <0>;
133        domain-idle-states = <&DOMAIN_PWR_DN>;
134    };
135
136    domain-idle-states {
137        DOMAIN_RET: domain-retention {
138            compatible = "domain-idle-state";
139            entry-latency-us = <1000>;
140            exit-latency-us = <2000>;
141            min-residency-us = <10000>;
142        };
143
144        DOMAIN_PWR_DN: domain-pwr-dn {
145            compatible = "domain-idle-state";
146            entry-latency-us = <5000>;
147            exit-latency-us = <8000>;
148            min-residency-us = <7000>;
149        };
150    };
151
152  - |
153    // Example: SCMI domain 15 -> MAIN_PD, SCMI domain 19 -> WKUP_PD
154    MAIN_PD: power-controller-main {
155        compatible = "foo,power-controller";
156        #power-domain-cells = <0>;
157    };
158
159    WKUP_PD: power-controller-wkup {
160        compatible = "foo,power-controller";
161        #power-domain-cells = <0>;
162    };
163
164    scmi_pds: power-controller-scmi {
165        compatible = "foo,power-controller";
166        #power-domain-cells = <1>;
167        power-domains = <&MAIN_PD>, <&WKUP_PD>;
168        power-domains-child-ids = <15>, <19>;
169    };
170