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Subject[PATCH v2 3/5] devfreq: add devfreq_suspend/resume() functions
Date
This patch adds implementation for global suspend/resume for
devfreq framework. System suspend will next use these functions.

The patch is based on earlier work by Tobias Jakobi.

Suggested-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Suggested-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
---
drivers/devfreq/devfreq.c | 42 ++++++++++++++++++++++++++++++++++++++++++
include/linux/devfreq.h | 6 ++++++
2 files changed, 48 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 36bed24..7d60423 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -935,6 +935,48 @@ int devfreq_resume_device(struct devfreq *devfreq)
EXPORT_SYMBOL(devfreq_resume_device);

/**
+ * devfreq_suspend() - Suspend devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycles for suspending governors
+ * and devices preserving the state for resume. On some platforms the devfreq
+ * device must have precise state (frequency) after resume in order to provide
+ * fully operating setup.
+ */
+void devfreq_suspend(void)
+{
+ struct devfreq *devfreq;
+ int ret;
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ ret = devfreq_suspend_device(devfreq);
+ if (ret)
+ dev_warn(&devfreq->dev, "device suspend failed\n");
+ }
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_resume() - Resume devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycle for resuming governors and
+ * devices that are suspended with devfreq_suspend().
+ */
+void devfreq_resume(void)
+{
+ struct devfreq *devfreq;
+ int ret;
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ ret = devfreq_resume_device(devfreq);
+ if (ret)
+ dev_warn(&devfreq->dev, "device resume failed\n");
+ }
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
* devfreq_add_governor() - Add devfreq governor
* @governor: the devfreq governor to be added
*/
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index d985199..fbffa74 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -205,6 +205,9 @@ extern void devm_devfreq_remove_device(struct device *dev,
extern int devfreq_suspend_device(struct devfreq *devfreq);
extern int devfreq_resume_device(struct devfreq *devfreq);

+extern void devfreq_suspend(void);
+extern void devfreq_resume(void);
+
/**
* update_devfreq() - Reevaluate the device and configure frequency
* @devfreq: the devfreq device
@@ -331,6 +334,9 @@ static inline int devfreq_resume_device(struct devfreq *devfreq)
return 0;
}

+static inline void devfreq_suspend(void) {}
+static inline void devfreq_resume(void) {}
+
static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
unsigned long *freq, u32 flags)
{
--
2.7.4
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