power_supply: Add power_supply_get_by_phandle

Add method to get power supply by device tree phandle.

Signed-off-by: Sebastian Reichel <sre@debian.org>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 3e28fe1..c9dc4e0 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -244,6 +244,14 @@
 extern int power_supply_reg_notifier(struct notifier_block *nb);
 extern void power_supply_unreg_notifier(struct notifier_block *nb);
 extern struct power_supply *power_supply_get_by_name(const char *name);
+#ifdef CONFIG_OF
+extern struct power_supply *power_supply_get_by_phandle(struct device_node *np,
+							const char *property);
+#else /* !CONFIG_OF */
+static inline struct power_supply *
+power_supply_get_by_phandle(struct device_node *np, const char *property)
+{ return NULL; }
+#endif /* CONFIG_OF */
 extern void power_supply_changed(struct power_supply *psy);
 extern int power_supply_am_i_supplied(struct power_supply *psy);
 extern int power_supply_set_battery_charged(struct power_supply *psy);