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Diffstat (limited to 'kernel/Documentation/devicetree/bindings/power/power_domain.txt')
-rw-r--r-- | kernel/Documentation/devicetree/bindings/power/power_domain.txt | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/kernel/Documentation/devicetree/bindings/power/power_domain.txt b/kernel/Documentation/devicetree/bindings/power/power_domain.txt new file mode 100644 index 000000000..0f8ed3710 --- /dev/null +++ b/kernel/Documentation/devicetree/bindings/power/power_domain.txt @@ -0,0 +1,78 @@ +* Generic PM domains + +System on chip designs are often divided into multiple PM domains that can be +used for power gating of selected IP blocks for power saving by reduced leakage +current. + +This device tree binding can be used to bind PM domain consumer devices with +their PM domains provided by PM domain providers. A PM domain provider can be +represented by any node in the device tree and can provide one or more PM +domains. A consumer node can refer to the provider by a phandle and a set of +phandle arguments (so called PM domain specifiers) of length specified by the +#power-domain-cells property in the PM domain provider node. + +==PM domain providers== + +Required properties: + - #power-domain-cells : Number of cells in a PM domain specifier; + Typically 0 for nodes representing a single PM domain and 1 for nodes + providing multiple PM domains (e.g. power controllers), but can be any value + as specified by device tree binding documentation of particular provider. + +Optional properties: + - power-domains : A phandle and PM domain specifier as defined by bindings of + the power controller specified by phandle. + Some power domains might be powered from another power domain (or have + other hardware specific dependencies). For representing such dependency + a standard PM domain consumer binding is used. When provided, all domains + created by the given provider should be subdomains of the domain + specified by this binding. More details about power domain specifier are + available in the next section. + +Example: + + power: power-controller@12340000 { + compatible = "foo,power-controller"; + reg = <0x12340000 0x1000>; + #power-domain-cells = <1>; + }; + +The node above defines a power controller that is a PM domain provider and +expects one cell as its phandle argument. + +Example 2: + + parent: power-controller@12340000 { + compatible = "foo,power-controller"; + reg = <0x12340000 0x1000>; + #power-domain-cells = <1>; + }; + + child: power-controller@12340000 { + compatible = "foo,power-controller"; + reg = <0x12341000 0x1000>; + power-domains = <&parent 0>; + #power-domain-cells = <1>; + }; + +The nodes above define two power controllers: 'parent' and 'child'. +Domains created by the 'child' power controller are subdomains of '0' power +domain provided by the 'parent' power controller. + +==PM domain consumers== + +Required properties: + - power-domains : A phandle and PM domain specifier as defined by bindings of + the power controller specified by phandle. + +Example: + + leaky-device@12350000 { + compatible = "foo,i-leak-current"; + reg = <0x12350000 0x1000>; + power-domains = <&power 0>; + }; + +The node above defines a typical PM domain consumer device, which is located +inside a PM domain with index 0 of a power controller represented by a node +with the label "power". |