PM / devfreq: add devfreq_suspend/resume() functions

This patch adds implementation for global suspend/resume for
devfreq framework. System suspend will next use these functions.

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>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 46517b61b3a2..0ae3de76833b 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -935,6 +935,50 @@ 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_err(&devfreq->dev,
+                                "failed to suspend devfreq device\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,
+                                 "failed to resume devfreq device\n");
+        }
+        mutex_unlock(&devfreq_list_lock);
+}
+
+/**
  * devfreq_add_governor() - Add devfreq governor
  * @governor:   the devfreq governor to be added
  */