OPP: Add dev_pm_opp_find_level_floor()

Add dev_pm_opp_find_level_floor(), as is done for frequency and
bandwidth.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
[ Viresh: Updated commit log and rearranged code ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: Krishna chaitanya chundru

drivers/opp/core.c

@@ -813,6 +813,31 @@ struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_ceil);
 
+/**
+ * dev_pm_opp_find_level_floor() - Search for a rounded floor level
+ * @dev:	device for which we do this operation
+ * @level:	Start level
+ *
+ * Search for the matching floor *available* OPP from a starting level
+ * for a device.
+ *
+ * Return: matching *opp and refreshes *level accordingly, else returns
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:	for bad pointer
+ * ERANGE:	no match found for search
+ * ENODEV:	if device not found in list of registered devices
+ *
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
+ */
+struct dev_pm_opp *dev_pm_opp_find_level_floor(struct device *dev,
+					       unsigned long *level)
+{
+	return _find_key_floor(dev, level, 0, true, _read_level, NULL);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_floor);
+
 /**
  * dev_pm_opp_find_bw_ceil() - Search for a rounded ceil bandwidth
  * @dev:	device for which we do this operation

include/linux/pm_opp.h

@@ -156,6 +156,9 @@ struct dev_pm_opp *dev_pm_opp_find_level_exact(struct device *dev,
 struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
 					      unsigned int *level);
 
+struct dev_pm_opp *dev_pm_opp_find_level_floor(struct device *dev,
+					       unsigned long *level);
+
 struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev,
 					   unsigned int *bw, int index);
 
@@ -320,6 +323,12 @@ static inline struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
+static inline struct dev_pm_opp *dev_pm_opp_find_level_floor(struct device *dev,
+							     unsigned long *level)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 static inline struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev,
 					unsigned int *bw, int index)
 {