| menuconfig PM_DEVFREQ | |
| bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support" | |
| help | |
| A device may have a list of frequencies and voltages available. | |
| devfreq, a generic DVFS framework can be registered for a device | |
| in order to let the governor provided to devfreq choose an | |
| operating frequency based on the device driver's policy. | |
| Each device may have its own governor and policy. Devfreq can | |
| reevaluate the device state periodically and/or based on the | |
| notification to "nb", a notifier block, of devfreq. | |
| Like some CPUs with CPUfreq, a device may have multiple clocks. | |
| However, because the clock frequencies of a single device are | |
| determined by the single device's state, an instance of devfreq | |
| is attached to a single device and returns a "representative" | |
| clock frequency of the device, which is also attached | |
| to a device by 1-to-1. The device registering devfreq takes the | |
| responsibility to "interpret" the representative frequency and | |
| to set its every clock accordingly with the "target" callback | |
| given to devfreq. | |
| When OPP is used with the devfreq device, it is recommended to | |
| register devfreq's nb to the OPP's notifier head. If OPP is | |
| used with the devfreq device, you may use OPP helper | |
| functions defined in devfreq.h. | |
| if PM_DEVFREQ | |
| comment "DEVFREQ Governors" | |
| config DEVFREQ_GOV_SIMPLE_ONDEMAND | |
| bool "Simple Ondemand" | |
| help | |
| Chooses frequency based on the recent load on the device. Works | |
| similar as ONDEMAND governor of CPUFREQ does. A device with | |
| Simple-Ondemand should be able to provide busy/total counter | |
| values that imply the usage rate. A device may provide tuned | |
| values to the governor with data field at devfreq_add_device(). | |
| config DEVFREQ_GOV_PERFORMANCE | |
| bool "Performance" | |
| help | |
| Sets the frequency at the maximum available frequency. | |
| This governor always returns UINT_MAX as frequency so that | |
| the DEVFREQ framework returns the highest frequency available | |
| at any time. | |
| config DEVFREQ_GOV_POWERSAVE | |
| bool "Powersave" | |
| help | |
| Sets the frequency at the minimum available frequency. | |
| This governor always returns 0 as frequency so that | |
| the DEVFREQ framework returns the lowest frequency available | |
| at any time. | |
| config DEVFREQ_GOV_USERSPACE | |
| bool "Userspace" | |
| help | |
| Sets the frequency at the user specified one. | |
| This governor returns the user configured frequency if there | |
| has been an input to /sys/devices/.../power/devfreq_set_freq. | |
| Otherwise, the governor does not change the frequnecy | |
| given at the initialization. | |
| comment "DEVFREQ Drivers" | |
| config ARM_EXYNOS4_BUS_DEVFREQ | |
| bool "ARM Exynos4210/4212/4412 Memory Bus DEVFREQ Driver" | |
| depends on CPU_EXYNOS4210 || CPU_EXYNOS4212 || CPU_EXYNOS4412 | |
| select ARCH_HAS_OPP | |
| select DEVFREQ_GOV_SIMPLE_ONDEMAND | |
| help | |
| This adds the DEVFREQ driver for Exynos4210 memory bus (vdd_int) | |
| and Exynos4212/4412 memory interface and bus (vdd_mif + vdd_int). | |
| It reads PPMU counters of memory controllers and adjusts | |
| the operating frequencies and voltages with OPP support. | |
| To operate with optimal voltages, ASV support is required | |
| (CONFIG_EXYNOS_ASV). | |
| endif # PM_DEVFREQ |