SPM AVS Wrapper 2 (SAW2)
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The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the
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Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable
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power-controller that transitions a piece of hardware (like a processor or
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subsystem) into and out of low power modes via a direct connection to
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the PMIC. It can also be wired up to interact with other processors in the
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system, notifying them when a low power state is entered or exited.
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Multiple revisions of the SAW hardware are supported using these Device Nodes.
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SAW2 revisions differ in the register offset and configuration data. Also, the
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same revision of the SAW in different SoCs may have different configuration
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data due the the differences in hardware capabilities. Hence the SoC name, the
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version of the SAW hardware in that SoC and the distinction between cpu (big
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or Little) or cache, may be needed to uniquely identify the SAW register
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configuration and initialization data. The compatible string is used to
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indicate this parameter.
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PROPERTIES
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- compatible:
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Usage: required
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Value type: <string>
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Definition: Must have
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"qcom,saw2"
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A more specific value could be one of:
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"qcom,apq8064-saw2-v1.1-cpu"
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"qcom,msm8974-saw2-v2.1-cpu"
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"qcom,apq8084-saw2-v2.1-cpu"
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- reg:
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Usage: required
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Value type: <prop-encoded-array>
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Definition: the first element specifies the base address and size of
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the register region. An optional second element specifies
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the base address and size of the alias register region.
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- regulator:
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Usage: optional
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Value type: boolean
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Definition: Indicates that this SPM device acts as a regulator device
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device for the core (CPU or Cache) the SPM is attached
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to.
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Example 1:
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power-controller@2099000 {
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compatible = "qcom,saw2";
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reg = <0x02099000 0x1000>, <0x02009000 0x1000>;
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regulator;
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};
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Example 2:
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saw0: power-controller@f9089000 {
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compatible = "qcom,apq8084-saw2-v2.1-cpu", "qcom,saw2";
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reg = <0xf9089000 0x1000>, <0xf9009000 0x1000>;
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};
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