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40 lines
1.5 KiB
Plaintext
40 lines
1.5 KiB
Plaintext
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config ARCH_HAS_DEVFREQ
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bool
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depends on ARCH_HAS_OPP
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help
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Denotes that the architecture supports DEVFREQ. If the architecture
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supports multiple OPP entries per device and the frequency of the
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devices with OPPs may be altered dynamically, the architecture
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supports DEVFREQ.
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menuconfig PM_DEVFREQ
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bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
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depends on PM_OPP && ARCH_HAS_DEVFREQ
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help
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With OPP support, a device may have a list of frequencies and
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voltages available. DEVFREQ, a generic DVFS framework can be
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registered for a device with OPP support in order to let the
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governor provided to DEVFREQ choose an operating frequency
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based on the OPP's list and the policy given with DEVFREQ.
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Each device may have its own governor and policy. DEVFREQ can
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reevaluate the device state periodically and/or based on the
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OPP list changes (each frequency/voltage pair in OPP may be
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disabled or enabled).
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Like some CPUs with CPUFREQ, a device may have multiple clocks.
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However, because the clock frequencies of a single device are
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determined by the single device's state, an instance of DEVFREQ
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is attached to a single device and returns a "representative"
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clock frequency from the OPP of the device, which is also attached
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to a device by 1-to-1. The device registering DEVFREQ takes the
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responsiblity to "interpret" the frequency listed in OPP and
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to set its every clock accordingly with the "target" callback
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given to DEVFREQ.
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if PM_DEVFREQ
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comment "DEVFREQ Drivers"
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endif # PM_DEVFREQ
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