[PATCH v8 03/20] PM / devfreq: Add devfreq_get_devfreq_by_phandle()

Chanwoo Choi
2016-04-08T04:24:52Z

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").

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>
---
drivers/devfreq/devfreq.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/devfreq.h | 9 +++++++++
2 files changed, 53 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 984c5e9e7bdd..20a9422c2552 100644
--- 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;
@@ -639,6 +640,49 @@ 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 6fa02a20eb63..aa0b8424ebc3 100644
--- 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;
--
1.9.1