Documentation/devicetree/bindings/power/power_domain.txt

   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".