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authorMyungJoo Ham <myungjoo.ham@samsung.com>2013-02-05 09:40:17 (GMT)
committerJonghwa Lee <jonghwa3.lee@samsung.com>2014-05-15 09:59:11 (GMT)
commite94b287efc0ef62ce72f6a83c71daaeef5fdc25d (patch)
treee98a371e3fc65bd5d0e6ab36977afefadfee346c
parent48eac23b608c6d8d65cb7a03cb64fff8c418dca1 (diff)
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PM / devfreq: add comments and Documentation
- Added missing ABI documents - Added comments to clarify the objectives of functions Change-Id: Ic2206ad6671156eedb28d450046e8e2ea876b18c Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Nishanth Menon <nm@ti.com> Acked-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
-rw-r--r--Documentation/ABI/testing/sysfs-class-devfreq20
-rw-r--r--drivers/devfreq/devfreq.c10
-rw-r--r--include/linux/devfreq.h2
3 files changed, 32 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index 0ba6ea2..ee39aca 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -78,3 +78,23 @@ Contact: Nishanth Menon <nm@ti.com>
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 <myungjoo.ham@samsung.com>
+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 <myungjoo.ham@samsung.com>
+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 abfa14d..44c4079 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 fe8c447..5f1ab92 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);