53 lines
1.8 KiB
Plaintext
53 lines
1.8 KiB
Plaintext
* Actions Semi Owl Clock Management Unit (CMU)
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The Actions Semi Owl Clock Management Unit generates and supplies clock
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to various controllers within the SoC. The clock binding described here is
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applicable to S900, S700 and S500 SoC's.
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Required Properties:
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- compatible: should be one of the following,
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"actions,s900-cmu"
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"actions,s700-cmu"
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"actions,s500-cmu"
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- reg: physical base address of the controller and length of memory mapped
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region.
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- clocks: Reference to the parent clocks ("hosc", "losc")
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- #clock-cells: should be 1.
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- #reset-cells: should be 1.
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Each clock is assigned an identifier, and client nodes can use this identifier
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to specify the clock which they consume.
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All available clocks are defined as preprocessor macros in corresponding
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dt-bindings/clock/actions,s900-cmu.h or actions,s700-cmu.h or
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actions,s500-cmu.h header and can be used in device tree sources.
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External clocks:
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The hosc clock used as input for the plls is generated outside the SoC. It is
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expected that it is defined using standard clock bindings as "hosc".
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Actions Semi S900 CMU also requires one more clock:
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- "losc" - internal low frequency oscillator
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Example: Clock Management Unit node:
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cmu: clock-controller@e0160000 {
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compatible = "actions,s900-cmu";
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reg = <0x0 0xe0160000 0x0 0x1000>;
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clocks = <&hosc>, <&losc>;
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#clock-cells = <1>;
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#reset-cells = <1>;
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};
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Example: UART controller node that consumes clock generated by the clock
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management unit:
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uart: serial@e012a000 {
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compatible = "actions,s900-uart", "actions,owl-uart";
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reg = <0x0 0xe012a000 0x0 0x2000>;
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interrupts = <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
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clocks = <&cmu CLK_UART5>;
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};
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