[PATCH v9 1/8] opp: Add dev_pm_opp_from_clk_rate()

[Dmitry Osipenko <digetx@xxxxxxxxx>]

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

Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
 drivers/opp/core.c     | 42 +++++++++++++++++++++++++++++++++++++++---
 include/linux/pm_opp.h |  6 ++++++
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 04b4691a8aac..fae5267f5218 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -939,7 +939,8 @@ 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 device *dev, struct opp_table *opp_table)
 {
 	struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
 	unsigned long freq;
@@ -961,7 +962,7 @@ static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
 		mutex_unlock(&opp_table->lock);
 	}
 
-	opp_table->current_opp = opp;
+	return opp;
 }
 
 static int _disable_opp_table(struct device *dev, struct opp_table *opp_table)
@@ -1003,7 +1004,7 @@ static int _set_opp(struct device *dev, struct opp_table *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);
+		opp_table->current_opp = _find_current_opp(dev, opp_table);
 
 	old_opp = opp_table->current_opp;
 
@@ -2931,3 +2932,38 @@ int dev_pm_opp_sync_regulators(struct device *dev)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_sync_regulators);
+
+/**
+ * dev_pm_opp_from_clk_rate() - Get OPP from current clock rate
+ * @dev:	device for which we do this operation
+ *
+ * Get OPP which corresponds to the current clock rate of a device.
+ *
+ * Return: pointer to 'struct dev_pm_opp' on success and errorno otherwise.
+ */
+struct dev_pm_opp *dev_pm_opp_from_clk_rate(struct device *dev)
+{
+	struct dev_pm_opp *opp = ERR_PTR(-ENOENT);
+	struct opp_table *opp_table;
+	unsigned long freq;
+
+	opp_table = _find_opp_table(dev);
+	if (IS_ERR(opp_table))
+		return ERR_CAST(opp_table);
+
+	if (IS_ERR(opp_table->clk)) {
+		opp = ERR_CAST(opp_table->clk);
+		goto put_table;
+	}
+
+	if (opp_table->clk) {
+		freq = clk_get_rate(opp_table->clk);
+		opp = _find_freq_ceil(opp_table, &freq);
+	}
+put_table:
+	/* Drop reference taken by _find_opp_table() */
+	dev_pm_opp_put_opp_table(opp_table);
+
+	return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_from_clk_rate);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 84150a22fd7c..57e75144dd88 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_from_clk_rate(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 struct inline dev_pm_opp *dev_pm_opp_from_clk_rate(struct device *dev)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 #endif		/* CONFIG_PM_OPP */
 
 #if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
-- 
2.32.0