2 bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
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.
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.
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
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.
31 comment "DEVFREQ Governors"
33 config DEVFREQ_GOV_SIMPLE_ONDEMAND
34 tristate "Simple Ondemand"
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().
42 config DEVFREQ_GOV_PERFORMANCE
43 tristate "Performance"
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
50 config DEVFREQ_GOV_POWERSAVE
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
58 config DEVFREQ_GOV_USERSPACE
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.
67 config DEVFREQ_GOV_PASSIVE
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.
75 comment "DEVFREQ Drivers"
77 config ARM_EXYNOS_BUS_DEVFREQ
78 tristate "ARM EXYNOS Generic Memory Bus DEVFREQ Driver"
79 depends on ARCH_EXYNOS || COMPILE_TEST
80 select DEVFREQ_GOV_SIMPLE_ONDEMAND
81 select DEVFREQ_GOV_PASSIVE
82 select DEVFREQ_EVENT_EXYNOS_PPMU
83 select PM_DEVFREQ_EVENT
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.
93 config ARM_TEGRA_DEVFREQ
94 tristate "Tegra DEVFREQ Driver"
95 depends on ARCH_TEGRA_124_SOC
96 select DEVFREQ_GOV_SIMPLE_ONDEMAND
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.
103 config ARM_RK3399_DMC_DEVFREQ
104 tristate "ARM RK3399 DMC DEVFREQ Driver"
105 depends on ARCH_ROCKCHIP
106 select DEVFREQ_EVENT_ROCKCHIP_DFI
107 select DEVFREQ_GOV_SIMPLE_ONDEMAND
108 select PM_DEVFREQ_EVENT
111 This adds the DEVFREQ driver for the RK3399 DMC(Dynamic Memory Controller).
112 It sets the frequency for the memory controller and reads the usage counts
115 source "drivers/devfreq/event/Kconfig"