mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-15 07:43:07 +00:00
45 lines
1.5 KiB
Text
45 lines
1.5 KiB
Text
|
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>;
|
||
|
|
};
|