Documentation/devicetree/bindings/bus/simple-pm-bus.txt

   1 Simple Power-Managed Bus
   2 ========================
   3
   4 A Simple Power-Managed Bus is a transparent bus that doesn't need a real
   5 driver, as it's typically initialized by the boot loader.
   6
   7 However, its bus controller is part of a PM domain, or under the control of a
   8 functional clock.  Hence, the bus controller's PM domain and/or clock must be
   9 enabled for child devices connected to the bus (either on-SoC or externally)
  10 to function.
  11
  12 While "simple-pm-bus" follows the "simple-bus" set of properties, as specified
  13 in ePAPR, it is not an extension of "simple-bus".
  14
  15
  16 Required properties:
  17   - compatible: Must contain at least "simple-pm-bus".
  18                 Must not contain "simple-bus".
  19                 It's recommended to let this be preceded by one or more
  20                 vendor-specific compatible values.
  21   - #address-cells, #size-cells, ranges: Must describe the mapping between
  22                 parent address and child address spaces.
  23
  24 Optional platform-specific properties for clock or PM domain control (at least
  25 one of them is required):
  26   - clocks: Must contain a reference to the functional clock(s),
  27   - power-domains: Must contain a reference to the PM domain.
  28 Please refer to the binding documentation for the clock and/or PM domain
  29 providers for more details.
  30
  31
  32 Example:
  33
  34         bsc: bus@fec10000 {
  35                 compatible = "renesas,bsc-sh73a0", "renesas,bsc",
  36                              "simple-pm-bus";
  37                 #address-cells = <1>;
  38                 #size-cells = <1>;
  39                 ranges = <0 0 0x20000000>;
  40                 reg = <0xfec10000 0x400>;
  41                 interrupts = <0 39 IRQ_TYPE_LEVEL_HIGH>;
  42                 clocks = <&zb_clk>;
  43                 power-domains = <&pd_a4s>;
  44         };