PM / devfreq: correct Kconfig dependency
Devfreq does not depend on OPP. The dependency is removed.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 643b055..8f04910 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -1,36 +1,29 @@
-config ARCH_HAS_DEVFREQ
- bool
- depends on ARCH_HAS_OPP
- help
- Denotes that the architecture supports DEVFREQ. If the architecture
- supports multiple OPP entries per device and the frequency of the
- devices with OPPs may be altered dynamically, the architecture
- supports DEVFREQ.
-
menuconfig PM_DEVFREQ
bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support"
- depends on PM_OPP && ARCH_HAS_DEVFREQ
help
- With OPP support, a device may have a list of frequencies and
- voltages available. DEVFREQ, a generic DVFS framework can be
- registered for a device with OPP support in order to let the
- governor provided to DEVFREQ choose an operating frequency
- based on the OPP's list and the policy given with DEVFREQ.
+ 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
+ Each device may have its own governor and policy. Devfreq can
reevaluate the device state periodically and/or based on the
- OPP list changes (each frequency/voltage pair in OPP may be
- disabled or enabled).
+ notification to "nb", a notifier block, of devfreq.
- Like some CPUs with CPUFREQ, a device may have multiple clocks.
+ 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
+ determined by the single device's state, an instance of devfreq
is attached to a single device and returns a "representative"
- clock frequency from the OPP of the device, which is also attached
- to a device by 1-to-1. The device registering DEVFREQ takes the
- responsiblity to "interpret" the frequency listed in OPP and
+ clock frequency of the device, which is also attached
+ to a device by 1-to-1. The device registering devfreq takes the
+ responsiblity to "interpret" the representative frequency and
to set its every clock accordingly with the "target" callback
- given to DEVFREQ.
+ 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