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