[PATCH v3 4/5] PM / devfreq: Cache OPP table reference in devfreq

[Saravana Kannan]

The OPP table can be used often in devfreq. Trying to get it each time can
be expensive, so cache it in the devfreq struct.

Signed-off-by: Saravana Kannan <saravanak@xxxxxxxxxx>
Reviewed-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Acked-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
---
 drivers/devfreq/devfreq.c | 6 ++++++
 include/linux/devfreq.h   | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 784c08e4f931..7984b01d585d 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -594,6 +594,8 @@ static void devfreq_dev_release(struct device *dev)
 	if (devfreq->profile->exit)
 		devfreq->profile->exit(devfreq->dev.parent);
 
+	if (devfreq->opp_table)
+		dev_pm_opp_put_opp_table(devfreq->opp_table);
 	mutex_destroy(&devfreq->lock);
 	kfree(devfreq);
 }
@@ -674,6 +676,10 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->max_freq = devfreq->scaling_max_freq;
 
 	devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
+	devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
+	if (IS_ERR(devfreq->opp_table))
+		devfreq->opp_table = NULL;
+
 	atomic_set(&devfreq->suspend_count, 0);
 
 	dev_set_name(&devfreq->dev, "devfreq%d",
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 2bae9ed3c783..1c05129f76c0 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -116,6 +116,7 @@ struct devfreq_dev_profile {
  * @profile:	device-specific devfreq profile
  * @governor:	method how to choose frequency based on the usage.
  * @governor_name:	devfreq governor name for use with this devfreq
+ * @opp_table:	Reference to OPP table of dev.parent, if one exists.
  * @nb:		notifier block used to notify devfreq object that it should
  *		reevaluate operable frequencies. Devfreq users may use
  *		devfreq.nb to the corresponding register notifier call chain.
@@ -153,6 +154,7 @@ struct devfreq {
 	struct devfreq_dev_profile *profile;
 	const struct devfreq_governor *governor;
 	char governor_name[DEVFREQ_NAME_LEN];
+	struct opp_table *opp_table;
 	struct notifier_block nb;
 	struct delayed_work work;
 
-- 
2.22.0.510.g264f2c817a-goog