extcon: Add an API to get extcon device from dt node

Added an API of_extcon_get_extcon_dev() to be used by drivers to get
extcon device in the case of dt boot (this can be used instead of
extcon_get_extcon_dev()).

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

include/linux/extcon/of_extcon.h

@@ -0,0 +1,31 @@
+/*
+ * OF helpers for External connector (extcon) framework
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ * Kishon Vijay Abraham I <kishon@ti.com>
+ *
+ * Copyright (C) 2013 Samsung Electronics
+ * Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __LINUX_OF_EXTCON_H
+#define __LINUX_OF_EXTCON_H
+
+#include <linux/err.h>
+
+#if IS_ENABLED(CONFIG_OF_EXTCON)
+extern struct extcon_dev
+	*of_extcon_get_extcon_dev(struct device *dev, int index);
+#else
+static inline struct extcon_dev
+	*of_extcon_get_extcon_dev(struct device *dev, int index)
+{
+	return ERR_PTR(-ENOSYS);
+}
+#endif /* CONFIG_OF_EXTCON */
+#endif /* __LINUX_OF_EXTCON_H */