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
7 title: Generic PM domains
8
9 maintainers:
10 - Rafael J. Wysocki <rjw@rjwysocki.net>
11 - Kevin Hilman <khilman@kernel.org>
12 - Ulf Hansson <ulf.hansson@linaro.org>
13
14 description: |+
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
27 properties:
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 required:
72 - "#power-domain-cells"
73
74 additionalProperties: true
75
76 examples:
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 };
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