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 frequnecy
65 given at the initialization.
67 comment "DEVFREQ Drivers"
69 config 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
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.
81 config ARM_EXYNOS5_BUS_DEVFREQ
82 tristate "ARM Exynos5250 Bus DEVFREQ Driver"
83 depends on SOC_EXYNOS5250
84 select DEVFREQ_GOV_SIMPLE_ONDEMAND
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.
91 config ARM_TEGRA_DEVFREQ
92 tristate "Tegra DEVFREQ Driver"
93 depends on ARCH_TEGRA_124_SOC
94 select DEVFREQ_GOV_SIMPLE_ONDEMAND
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.
101 source "drivers/devfreq/event/Kconfig"