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linux-next/Documentation/devicetree/bindings/bus/simple-pm-bus.txt
Frank Rowand 076fb0c4b6 of: update ePAPR references to point to Devicetree Specification
The Devicetree Specification has superseded the ePAPR as the
base specification for bindings.  Update files in Documentation
to reference the new document.

First reference to ePAPR in Documentation/devicetree/bindings/arm/cci.txt
is generic, remove it.

Some files are not updated because there is no hypervisor chapter
in the Devicetree Specification:
   Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt
   Documenation/virtual/kvm/api.txt
   Documenation/virtual/kvm/ppc-pv.txt

Signed-off-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2017-06-22 11:22:06 -05:00

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Simple Power-Managed Bus
========================
A Simple Power-Managed Bus is a transparent bus that doesn't need a real
driver, as it's typically initialized by the boot loader.
However, its bus controller is part of a PM domain, or under the control of a
functional clock. Hence, the bus controller's PM domain and/or clock must be
enabled for child devices connected to the bus (either on-SoC or externally)
to function.
While "simple-pm-bus" follows the "simple-bus" set of properties, as specified
in the Devicetree Specification, it is not an extension of "simple-bus".
Required properties:
- compatible: Must contain at least "simple-pm-bus".
Must not contain "simple-bus".
It's recommended to let this be preceded by one or more
vendor-specific compatible values.
- #address-cells, #size-cells, ranges: Must describe the mapping between
parent address and child address spaces.
Optional platform-specific properties for clock or PM domain control (at least
one of them is required):
- clocks: Must contain a reference to the functional clock(s),
- power-domains: Must contain a reference to the PM domain.
Please refer to the binding documentation for the clock and/or PM domain
providers for more details.
Example:
bsc: bus@fec10000 {
compatible = "renesas,bsc-sh73a0", "renesas,bsc",
"simple-pm-bus";
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0 0x20000000>;
reg = <0xfec10000 0x400>;
interrupts = <0 39 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&zb_clk>;
power-domains = <&pd_a4s>;
};