UPSTREAM: PM / devfreq: Add devfreq_get_devfreq_by_phandle()

This patch adds the new devfreq_get_devfreq_by_phandle() OF helper function
which can find the instance of devfreq device by using phandle ("devfreq").

Change-Id: I0d0ed78930811e896215c2b7a9125cad69310407
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
[m.reichl and linux.amoon: Tested it on exynos4412-odroidu3 board]
Tested-by: Markus Reichl <m.reichl@fivetechno.de>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
(cherry picked from commit 8f510aeb223b26c4ffbece9fa92e4befea470f57)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index ca848cc6a8fd1313bc56e5b93674b3d795814779..f1df56200b0e6993bc32cd979db3552a56c5ecc1 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -25,6 +25,7 @@
 #include <linux/list.h>
 #include <linux/printk.h>
 #include <linux/hrtimer.h>
+#include <linux/of.h>
 #include "governor.h"
 
 static struct class *devfreq_class;
@@ -593,6 +594,49 @@ struct devfreq *devm_devfreq_add_device(struct device *dev,
 }
 EXPORT_SYMBOL(devm_devfreq_add_device);
 
+#ifdef CONFIG_OF
+/*
+ * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
+ * @dev - instance to the given device
+ * @index - index into list of devfreq
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
+{
+       struct device_node *node;
+       struct devfreq *devfreq;
+
+       if (!dev)
+               return ERR_PTR(-EINVAL);
+
+       if (!dev->of_node)
+               return ERR_PTR(-EINVAL);
+
+       node = of_parse_phandle(dev->of_node, "devfreq", 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);
+                       return devfreq;
+               }
+       }
+       mutex_unlock(&devfreq_list_lock);
+
+       return ERR_PTR(-EPROBE_DEFER);
+}
+#else
+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_phandle);
+
 /**
  * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
  * @dev:       the device to add devfreq feature.

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 68030e22af3527958ac39006031dd62388228091..2f856650a74a00e7a91b96d870bdc76abd448570 100644 (file)
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -208,6 +208,9 @@ extern int devm_devfreq_register_opp_notifier(struct device *dev,
 extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
                                                struct devfreq *devfreq);
 
+extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+                                               int index);
+
 /**
  * devfreq_update_stats() - update the last_status pointer in struct devfreq
  * @df:                the devfreq instance whose status needs updating
@@ -307,6 +310,12 @@ static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
 {
 }
 
+static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+                                                       int index)
+{
+       return ERR_PTR(-ENODEV);
+}
+
 static inline int devfreq_update_stats(struct devfreq *df)
 {
        return -EINVAL;