From de9c739435b47e7d39e448b2cc4c8154cabc9e5a Mon Sep 17 00:00:00 2001 From: MyungJoo Ham Date: Tue, 5 Feb 2013 18:40:17 +0900 Subject: PM / devfreq: add comments and Documentation - Added missing ABI documents - Added comments to clarify the objectives of functions Signed-off-by: MyungJoo Ham Acked-by: Nishanth Menon Acked-by: Rajagopal Venkat --- Documentation/ABI/testing/sysfs-class-devfreq | 20 ++++++++++++++++++++ drivers/devfreq/devfreq.c | 10 ++++++++++ include/linux/devfreq.h | 2 ++ 3 files changed, 32 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq index 0ba6ea2f89d9..ee39acacf6f8 100644 --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -78,3 +78,23 @@ Contact: Nishanth Menon Description: The /sys/class/devfreq/.../available_governors shows currently available governors in the system. + +What: /sys/class/devfreq/.../min_freq +Date: January 2013 +Contact: MyungJoo Ham +Description: + The /sys/class/devfreq/.../min_freq shows and stores + the minimum frequency requested by users. It is 0 if + the user does not care. min_freq overrides the + frequency requested by governors. + +What: /sys/class/devfreq/.../max_freq +Date: January 2013 +Contact: MyungJoo Ham +Description: + The /sys/class/devfreq/.../max_freq shows and stores + the maximum frequency requested by users. It is 0 if + the user does not care. max_freq overrides the + frequency requested by governors and min_freq. + The max_freq overrides min_freq because max_freq may be + used to throttle devices to avoid overheating. diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index abfa14dd8b4c..44c407986f64 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -527,6 +527,8 @@ EXPORT_SYMBOL(devfreq_add_device); /** * devfreq_remove_device() - Remove devfreq feature from a device. * @devfreq: the devfreq instance to be removed + * + * The opposite of devfreq_add_device(). */ int devfreq_remove_device(struct devfreq *devfreq) { @@ -542,6 +544,10 @@ EXPORT_SYMBOL(devfreq_remove_device); /** * devfreq_suspend_device() - Suspend devfreq of a device. * @devfreq: the devfreq instance to be suspended + * + * This function is intended to be called by the pm callbacks + * (e.g., runtime_suspend, suspend) of the device driver that + * holds the devfreq. */ int devfreq_suspend_device(struct devfreq *devfreq) { @@ -559,6 +565,10 @@ EXPORT_SYMBOL(devfreq_suspend_device); /** * devfreq_resume_device() - Resume devfreq of a device. * @devfreq: the devfreq instance to be resumed + * + * This function is intended to be called by the pm callbacks + * (e.g., runtime_resume, resume) of the device driver that + * holds the devfreq. */ int devfreq_resume_device(struct devfreq *devfreq) { diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index fe8c4476f7e4..5f1ab92107e6 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -181,6 +181,8 @@ extern struct devfreq *devfreq_add_device(struct device *dev, const char *governor_name, void *data); extern int devfreq_remove_device(struct devfreq *devfreq); + +/* Supposed to be called by PM_SLEEP/PM_RUNTIME callbacks */ extern int devfreq_suspend_device(struct devfreq *devfreq); extern int devfreq_resume_device(struct devfreq *devfreq); -- cgit v1.2.2