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[linux-2.6-block.git] / drivers / devfreq / Kconfig
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1menuconfig PM_DEVFREQ
2 bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
83fe27ea 3 select SRCU
a3c98b8b 4 help
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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.
a3c98b8b 9
6c81f905 10 Each device may have its own governor and policy. Devfreq can
a3c98b8b 11 reevaluate the device state periodically and/or based on the
6c81f905 12 notification to "nb", a notifier block, of devfreq.
a3c98b8b 13
6c81f905 14 Like some CPUs with CPUfreq, a device may have multiple clocks.
a3c98b8b 15 However, because the clock frequencies of a single device are
6c81f905 16 determined by the single device's state, an instance of devfreq
a3c98b8b 17 is attached to a single device and returns a "representative"
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18 clock frequency of the device, which is also attached
19 to a device by 1-to-1. The device registering devfreq takes the
6b2aac42 20 responsibility to "interpret" the representative frequency and
a3c98b8b 21 to set its every clock accordingly with the "target" callback
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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.
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28
29if PM_DEVFREQ
30
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31comment "DEVFREQ Governors"
32
33config DEVFREQ_GOV_SIMPLE_ONDEMAND
eff607fd 34 tristate "Simple Ondemand"
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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
eff607fd 43 tristate "Performance"
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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
eff607fd 51 tristate "Powersave"
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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
eff607fd 59 tristate "Userspace"
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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.
027b6934 64 Otherwise, the governor does not change the frequency
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65 given at the initialization.
66
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67comment "DEVFREQ Drivers"
68
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69config ARM_EXYNOS4_BUS_DEVFREQ
70 bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver"
ba7abeb1 71 depends on (CPU_EXYNOS4210 || SOC_EXYNOS4212 || SOC_EXYNOS4412) && !ARCH_MULTIPLATFORM
7b405038 72 select DEVFREQ_GOV_SIMPLE_ONDEMAND
b0d5068a 73 select PM_OPP
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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.
cb7063f4 79 This does not yet operate with optimal voltages.
7b405038 80
6ccce699 81config ARM_EXYNOS5_BUS_DEVFREQ
81da57e6 82 tristate "ARM Exynos5250 Bus DEVFREQ Driver"
6ccce699 83 depends on SOC_EXYNOS5250
6ccce699 84 select DEVFREQ_GOV_SIMPLE_ONDEMAND
ae29fa1d 85 select PM_OPP
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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
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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
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101source "drivers/devfreq/event/Kconfig"
102
a3c98b8b 103endif # PM_DEVFREQ