1menuconfig PM_DEVFREQ 2 bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support" 3 select SRCU 4 help 5 A device may have a list of frequencies and voltages available. 6 devfreq, a generic DVFS framework can be registered for a device 7 in order to let the governor provided to devfreq choose an 8 operating frequency based on the device driver's policy. 9 10 Each device may have its own governor and policy. Devfreq can 11 reevaluate the device state periodically and/or based on the 12 notification to "nb", a notifier block, of devfreq. 13 14 Like some CPUs with CPUfreq, a device may have multiple clocks. 15 However, because the clock frequencies of a single device are 16 determined by the single device's state, an instance of devfreq 17 is attached to a single device and returns a "representative" 18 clock frequency of the device, which is also attached 19 to a device by 1-to-1. The device registering devfreq takes the 20 responsibility to "interpret" the representative frequency and 21 to set its every clock accordingly with the "target" callback 22 given to devfreq. 23 24 When OPP is used with the devfreq device, it is recommended to 25 register devfreq's nb to the OPP's notifier head. If OPP is 26 used with the devfreq device, you may use OPP helper 27 functions defined in devfreq.h. 28 29if PM_DEVFREQ 30 31comment "DEVFREQ Governors" 32 33config DEVFREQ_GOV_SIMPLE_ONDEMAND 34 tristate "Simple Ondemand" 35 help 36 Chooses frequency based on the recent load on the device. Works 37 similar as ONDEMAND governor of CPUFREQ does. A device with 38 Simple-Ondemand should be able to provide busy/total counter 39 values that imply the usage rate. A device may provide tuned 40 values to the governor with data field at devfreq_add_device(). 41 42config DEVFREQ_GOV_PERFORMANCE 43 tristate "Performance" 44 help 45 Sets the frequency at the maximum available frequency. 46 This governor always returns UINT_MAX as frequency so that 47 the DEVFREQ framework returns the highest frequency available 48 at any time. 49 50config DEVFREQ_GOV_POWERSAVE 51 tristate "Powersave" 52 help 53 Sets the frequency at the minimum available frequency. 54 This governor always returns 0 as frequency so that 55 the DEVFREQ framework returns the lowest frequency available 56 at any time. 57 58config DEVFREQ_GOV_USERSPACE 59 tristate "Userspace" 60 help 61 Sets the frequency at the user specified one. 62 This governor returns the user configured frequency if there 63 has been an input to /sys/devices/.../power/devfreq_set_freq. 64 Otherwise, the governor does not change the frequency 65 given at the initialization. 66 67config DEVFREQ_GOV_PASSIVE 68 tristate "Passive" 69 help 70 Sets the frequency based on the frequency of its parent devfreq 71 device. This governor does not change the frequency by itself 72 through sysfs entries. The passive governor recommends that 73 devfreq device uses the OPP table to get the frequency/voltage. 74 75comment "DEVFREQ Drivers" 76 77config ARM_EXYNOS_BUS_DEVFREQ 78 bool "ARM EXYNOS Generic Memory Bus DEVFREQ Driver" 79 depends on ARCH_EXYNOS 80 select DEVFREQ_GOV_SIMPLE_ONDEMAND 81 select DEVFREQ_GOV_PASSIVE 82 select DEVFREQ_EVENT_EXYNOS_PPMU 83 select PM_DEVFREQ_EVENT 84 select PM_OPP 85 help 86 This adds the common DEVFREQ driver for Exynos Memory bus. Exynos 87 Memory bus has one more group of memory bus (e.g, MIF and INT block). 88 Each memory bus group could contain many memoby bus block. It reads 89 PPMU counters of memory controllers by using DEVFREQ-event device 90 and adjusts the operating frequencies and voltages with OPP support. 91 This does not yet operate with optimal voltages. 92 93config ARM_TEGRA_DEVFREQ 94 tristate "Tegra DEVFREQ Driver" 95 depends on ARCH_TEGRA_124_SOC 96 select DEVFREQ_GOV_SIMPLE_ONDEMAND 97 select PM_OPP 98 help 99 This adds the DEVFREQ driver for the Tegra family of SoCs. 100 It reads ACTMON counters of memory controllers and adjusts the 101 operating frequencies and voltages with OPP support. 102 103source "drivers/devfreq/event/Kconfig" 104 105endif # PM_DEVFREQ 106