opp: De-obscurify OPP structs and disclose find_device_opp

Move definitions of OPP structs in the header file so that its
members are public and the struct is no longer obscure.

Define interface for find_device_opp in the header file.

drivers/base/power/opp.c

@@ -59,6 +59,7 @@
  *
  * This structure stores the OPP information for a given device.
  */
+#if 0 /* Definition moved to header file */
 struct opp {
 	struct list_head node;
 
@@ -69,7 +70,7 @@ struct opp {
 	struct device_opp *dev_opp;
 	struct rcu_head head;
 };
-
+#endif
 /**
  * struct device_opp - Device opp structure
  * @node:	list node - contains the devices with OPPs that
@@ -85,14 +86,15 @@ struct opp {
  * a device. This structure is not meant to be shared to users as it is
  * meant for book keeping and private to OPP library
  */
+#if 0 /* Definition moved to header file */
 struct device_opp {
 	struct list_head node;
 
 	struct device *dev;
 	struct srcu_notifier_head head;
 	struct list_head opp_list;
 };
-
+#endif
 /*
  * The root of the list of all devices. All device_opp structures branch off
  * from here, with each device_opp containing the list of opp it supports in
@@ -116,7 +118,7 @@ static DEFINE_MUTEX(dev_opp_list_lock);
  * is a RCU protected pointer. This means that device_opp is valid as long
  * as we are under RCU lock.
  */
-static struct device_opp *find_device_opp(struct device *dev)
+struct device_opp *find_device_opp(struct device *dev)
 {
 	struct device_opp *tmp_dev_opp, *dev_opp = ERR_PTR(-ENODEV);
 

include/linux/opp.h

@@ -18,7 +18,25 @@
 #include <linux/cpufreq.h>
 #include <linux/notifier.h>
 
-struct opp;
+struct opp {
+	struct list_head node;
+
+	bool available;
+	unsigned long rate;
+	unsigned long u_volt;
+
+	struct device_opp *dev_opp;
+	struct rcu_head head;
+};
+
+struct device_opp {
+	struct list_head node;
+
+	struct device *dev;
+	struct srcu_notifier_head head;
+	struct list_head opp_list;
+};
+
 struct device;
 
 enum opp_event {
@@ -27,6 +45,8 @@ enum opp_event {
 
 #if defined(CONFIG_PM_OPP)
 
+struct device_opp *find_device_opp(struct device *dev);
+
 unsigned long opp_get_voltage(struct opp *opp);
 
 unsigned long opp_get_freq(struct opp *opp);