PM / devfreq: Add devfreq_get_devfreq_by_node function

Split off part of devfreq_get_devfreq_by_phandle into a separate
function. This allows callers to fetch devfreq instances by enumerating
devicetree instead of explicit phandles.
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
[cw00.choi: Export devfreq_get_devfreq_by_node function and
 add function to devfreq.h when CONFIG_PM_DEVFREQ is enabled.]
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/devfreq/devfreq.c

@@ -983,6 +983,32 @@ struct devfreq *devm_devfreq_add_device(struct device *dev,
 EXPORT_SYMBOL(devm_devfreq_add_device);
 
 #ifdef CONFIG_OF
+/*
+ * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
+ * @node - pointer to device_node
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+	struct devfreq *devfreq;
+
+	if (!node)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&devfreq_list_lock);
+	list_for_each_entry(devfreq, &devfreq_list, node) {
+		if (devfreq->dev.parent
+			&& devfreq->dev.parent->of_node == node) {
+			mutex_unlock(&devfreq_list_lock);
+			return devfreq;
+		}
+	}
+	mutex_unlock(&devfreq_list_lock);
+
+	return ERR_PTR(-ENODEV);
+}
+
 /*
  * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
  * @dev - instance to the given device
@@ -1005,26 +1031,24 @@ struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 	if (!node)
 		return ERR_PTR(-ENODEV);
 
-	mutex_lock(&devfreq_list_lock);
-	list_for_each_entry(devfreq, &devfreq_list, node) {
-		if (devfreq->dev.parent
-			&& devfreq->dev.parent->of_node == node) {
-			mutex_unlock(&devfreq_list_lock);
-			of_node_put(node);
-			return devfreq;
-		}
-	}
-	mutex_unlock(&devfreq_list_lock);
+	devfreq = devfreq_get_devfreq_by_node(node);
 	of_node_put(node);
 
-	return ERR_PTR(-EPROBE_DEFER);
+	return devfreq;
 }
+
 #else
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
 {
 	return ERR_PTR(-ENODEV);
 }
 #endif /* CONFIG_OF */
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
 EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
 
 /**

include/linux/devfreq.h

@@ -261,6 +261,7 @@ void devm_devfreq_unregister_notifier(struct device *dev,
 				struct devfreq *devfreq,
 				struct notifier_block *nb,
 				unsigned int list);
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
 struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index);
 
 #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
@@ -414,6 +415,11 @@ static inline void devm_devfreq_unregister_notifier(struct device *dev,
 {
 }
 
+static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
 					int index)
 {