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1 | * Generic PM domains | ||
2 | |||
3 | System on chip designs are often divided into multiple PM domains that can be | ||
4 | used for power gating of selected IP blocks for power saving by reduced leakage | ||
5 | current. | ||
6 | |||
7 | This device tree binding can be used to bind PM domain consumer devices with | ||
8 | their PM domains provided by PM domain providers. A PM domain provider can be | ||
9 | represented by any node in the device tree and can provide one or more PM | ||
10 | domains. A consumer node can refer to the provider by a phandle and a set of | ||
11 | phandle arguments (so called PM domain specifiers) of length specified by the | ||
12 | #power-domain-cells property in the PM domain provider node. | ||
13 | |||
14 | ==PM domain providers== | ||
15 | |||
16 | Required properties: | ||
17 | - #power-domain-cells : Number of cells in a PM domain specifier; | ||
18 | Typically 0 for nodes representing a single PM domain and 1 for nodes | ||
19 | providing multiple PM domains (e.g. power controllers), but can be any value | ||
20 | as specified by device tree binding documentation of particular provider. | ||
21 | |||
22 | Example: | ||
23 | |||
24 | power: power-controller@12340000 { | ||
25 | compatible = "foo,power-controller"; | ||
26 | reg = <0x12340000 0x1000>; | ||
27 | #power-domain-cells = <1>; | ||
28 | }; | ||
29 | |||
30 | The node above defines a power controller that is a PM domain provider and | ||
31 | expects one cell as its phandle argument. | ||
32 | |||
33 | ==PM domain consumers== | ||
34 | |||
35 | Required properties: | ||
36 | - power-domains : A phandle and PM domain specifier as defined by bindings of | ||
37 | the power controller specified by phandle. | ||
38 | |||
39 | Example: | ||
40 | |||
41 | leaky-device@12350000 { | ||
42 | compatible = "foo,i-leak-current"; | ||
43 | reg = <0x12350000 0x1000>; | ||
44 | power-domains = <&power 0>; | ||
45 | }; | ||
46 | |||
47 | The node above defines a typical PM domain consumer device, which is located | ||
48 | inside a PM domain with index 0 of a power controller represented by a node | ||
49 | with the label "power". | ||