From 00349bc2db2e8b09d1fec528ddd8946f7de842cb Mon Sep 17 00:00:00 2001 From: MyungJoo Ham Date: Mon, 14 Nov 2011 23:31:35 +0100 Subject: [PATCH] --- yaml --- r: 275624 b: refs/heads/master c: 6c81f90588972b8631bda4d538ffd0199a3e1b41 h: refs/heads/master v: v3 --- [refs] | 2 +- trunk/drivers/devfreq/Kconfig | 41 +++++++++++++++-------------------- 2 files changed, 18 insertions(+), 25 deletions(-) diff --git a/[refs] b/[refs] index 124c52b17bc9..72d59e6fb349 100644 --- a/[refs] +++ b/[refs] @@ -1,2 +1,2 @@ --- -refs/heads/master: 9f3bdd4f937a75c4589a867dc1f8fefe09c1a618 +refs/heads/master: 6c81f90588972b8631bda4d538ffd0199a3e1b41 diff --git a/trunk/drivers/devfreq/Kconfig b/trunk/drivers/devfreq/Kconfig index 643b055ed3cd..8f0491037080 100644 --- a/trunk/drivers/devfreq/Kconfig +++ b/trunk/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