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