linux/drivers/devfreq/Kconfig
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   1menuconfig PM_DEVFREQ
   2        bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
   3        help
   4          A device may have a list of frequencies and voltages available.
   5          devfreq, a generic DVFS framework can be registered for a device
   6          in order to let the governor provided to devfreq choose an
   7          operating frequency based on the device driver's policy.
   8
   9          Each device may have its own governor and policy. Devfreq can
  10          reevaluate the device state periodically and/or based on the
  11          notification to "nb", a notifier block, of devfreq.
  12
  13          Like some CPUs with CPUfreq, a device may have multiple clocks.
  14          However, because the clock frequencies of a single device are
  15          determined by the single device's state, an instance of devfreq
  16          is attached to a single device and returns a "representative"
  17          clock frequency of the device, which is also attached
  18          to a device by 1-to-1. The device registering devfreq takes the
  19          responsibility to "interpret" the representative frequency and
  20          to set its every clock accordingly with the "target" callback
  21          given to devfreq.
  22
  23          When OPP is used with the devfreq device, it is recommended to
  24          register devfreq's nb to the OPP's notifier head.  If OPP is
  25          used with the devfreq device, you may use OPP helper
  26          functions defined in devfreq.h.
  27
  28if PM_DEVFREQ
  29
  30comment "DEVFREQ Governors"
  31
  32config DEVFREQ_GOV_SIMPLE_ONDEMAND
  33        tristate "Simple Ondemand"
  34        help
  35          Chooses frequency based on the recent load on the device. Works
  36          similar as ONDEMAND governor of CPUFREQ does. A device with
  37          Simple-Ondemand should be able to provide busy/total counter
  38          values that imply the usage rate. A device may provide tuned
  39          values to the governor with data field at devfreq_add_device().
  40
  41config DEVFREQ_GOV_PERFORMANCE
  42        tristate "Performance"
  43        help
  44          Sets the frequency at the maximum available frequency.
  45          This governor always returns UINT_MAX as frequency so that
  46          the DEVFREQ framework returns the highest frequency available
  47          at any time.
  48
  49config DEVFREQ_GOV_POWERSAVE
  50        tristate "Powersave"
  51        help
  52          Sets the frequency at the minimum available frequency.
  53          This governor always returns 0 as frequency so that
  54          the DEVFREQ framework returns the lowest frequency available
  55          at any time.
  56
  57config DEVFREQ_GOV_USERSPACE
  58        tristate "Userspace"
  59        help
  60          Sets the frequency at the user specified one.
  61          This governor returns the user configured frequency if there
  62          has been an input to /sys/devices/.../power/devfreq_set_freq.
  63          Otherwise, the governor does not change the frequnecy
  64          given at the initialization.
  65
  66comment "DEVFREQ Drivers"
  67
  68config ARM_EXYNOS4_BUS_DEVFREQ
  69        bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver"
  70        depends on CPU_EXYNOS4210 || CPU_EXYNOS4212 || CPU_EXYNOS4412
  71        select ARCH_HAS_OPP
  72        select DEVFREQ_GOV_SIMPLE_ONDEMAND
  73        help
  74          This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int)
  75          and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int).
  76          It reads PPMU counters of memory controllers and adjusts
  77          the operating frequencies and voltages with OPP support.
  78          To operate with optimal voltages, ASV support is required
  79          (CONFIG_EXYNOS_ASV).
  80
  81endif # PM_DEVFREQ
  82
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