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 67comment "DEVFREQ Drivers" 68 69config ARM_EXYNOS4_BUS_DEVFREQ 70 bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver" 71 depends on (CPU_EXYNOS4210 || SOC_EXYNOS4212 || SOC_EXYNOS4412) && !ARCH_MULTIPLATFORM 72 select DEVFREQ_GOV_SIMPLE_ONDEMAND 73 select PM_OPP 74 help 75 This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int) 76 and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int). 77 It reads PPMU counters of memory controllers and adjusts 78 the operating frequencies and voltages with OPP support. 79 This does not yet operate with optimal voltages. 80 81config ARM_EXYNOS5_BUS_DEVFREQ 82 tristate "ARM Exynos5250 Bus DEVFREQ Driver" 83 depends on SOC_EXYNOS5250 84 select DEVFREQ_GOV_SIMPLE_ONDEMAND 85 select PM_OPP 86 help 87 This adds the DEVFREQ driver for Exynos5250 bus interface (vdd_int). 88 It reads PPMU counters of memory controllers and adjusts the 89 operating frequencies and voltages with OPP support. 90 91config ARM_TEGRA_DEVFREQ 92 tristate "Tegra DEVFREQ Driver" 93 depends on ARCH_TEGRA_124_SOC 94 select DEVFREQ_GOV_SIMPLE_ONDEMAND 95 select PM_OPP 96 help 97 This adds the DEVFREQ driver for the Tegra family of SoCs. 98 It reads ACTMON counters of memory controllers and adjusts the 99 operating frequencies and voltages with OPP support. 100 101source "drivers/devfreq/event/Kconfig" 102 103endif # PM_DEVFREQ 104