[PATCH v10 1/8] opp: Add dev_pm_opp_get_current()

[Dmitry Osipenko <digetx@gmail.com>]

Add dev_pm_opp_get_current() helper that returns OPP corresponding
to the current clock rate of a device.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/opp/core.c     | 43 +++++++++++++++++++++++++++++++++++++++---
 include/linux/pm_opp.h |  6 ++++++
 2 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 04b4691a8aac..dde8a5cc948c 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -939,7 +939,7 @@ static int _set_required_opps(struct device *dev,
 	return ret;
 }
 
-static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
+static struct dev_pm_opp *_find_current_opp(struct opp_table *opp_table)
 {
 	struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
 	unsigned long freq;
@@ -949,6 +949,18 @@ static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
 		opp = _find_freq_ceil(opp_table, &freq);
 	}
 
+	return opp;
+}
+
+static void _find_and_set_current_opp(struct opp_table *opp_table)
+{
+	struct dev_pm_opp *opp;
+
+	if (opp_table->current_opp)
+		return;
+
+	opp = _find_current_opp(opp_table);
+
 	/*
 	 * Unable to find the current OPP ? Pick the first from the list since
 	 * it is in ascending order, otherwise rest of the code will need to
@@ -1002,8 +1014,7 @@ static int _set_opp(struct device *dev, struct opp_table *opp_table,
 		return _disable_opp_table(dev, opp_table);
 
 	/* Find the currently set OPP if we don't know already */
-	if (unlikely(!opp_table->current_opp))
-		_find_current_opp(dev, opp_table);
+	_find_and_set_current_opp(opp_table);
 
 	old_opp = opp_table->current_opp;
 
@@ -2931,3 +2942,29 @@ int dev_pm_opp_sync_regulators(struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_sync_regulators);
+
+/**
+ * dev_pm_opp_get_current() - Get current OPP
+ * @dev:	device for which we do this operation
+ *
+ * Get current OPP of a device based on current clock rate or by other means.
+ *
+ * Return: pointer to 'struct dev_pm_opp' on success and errorno otherwise.
+ */
+struct dev_pm_opp *dev_pm_opp_get_current(struct device *dev)
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *opp;
+
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return ERR_CAST(opp_table);
+
+	opp = _find_current_opp(opp_table);
+
+	/* Drop reference taken by _find_opp_table() */
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_current);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 84150a22fd7c..c8091977efb8 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -168,6 +168,7 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 void dev_pm_opp_remove_table(struct device *dev);
 void dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask);
 int dev_pm_opp_sync_regulators(struct device *dev);
+struct dev_pm_opp *dev_pm_opp_get_current(struct device *dev);
 #else
 static inline struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
 {
@@ -434,6 +435,11 @@ static inline int dev_pm_opp_sync_regulators(struct device *dev)
 	return -EOPNOTSUPP;
 }
 
+static inline struct dev_pm_opp *dev_pm_opp_get_current(struct device *dev)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 #endif		/* CONFIG_PM_OPP */
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
-- 
2.32.0