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From:   Lukasz Luba <l.luba@partner.samsung.com>
To:     linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, devicetree@vger.kernel.org
Cc:     tjakobi@math.uni-bielefeld.de, myungjoo.ham@samsung.com,
        kyungmin.park@samsung.com, cw00.choi@samsung.com,
        rjw@rjwysocki.net, len.brown@intel.com, pavel@ucw.cz,
        gregkh@linuxfoundation.org, keescook@chromium.org,
        anton@enomsg.org, ccross@android.com, tony.luck@intel.com,
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        krzk@kernel.org, m.szyprowski@samsung.com,
        b.zolnierkie@samsung.com, Lukasz Luba <l.luba@partner.samsung.com>
Subject: [PATCH v2 3/5] devfreq: add devfreq_suspend/resume() functions
Date:   Mon,  3 Dec 2018 15:31:13 +0100
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        <CGME20181203143132eucas1p128c029a7c7461e1127924a08e4a71811@eucas1p1.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
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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