[PATCH v6 08/13] usb: roles: Introduce stubs for the exiting functions in role.h.

[Yu Chen <chenyu56@huawei.com>]

This patch adds stubs for the exiting functions while
CONFIG_USB_ROLE_SWITCH does not enabled.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Yu Chen <chenyu56@huawei.com>
---
 include/linux/usb/role.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
index c05ffa6abda9..da2b9641b877 100644
--- a/include/linux/usb/role.h
+++ b/include/linux/usb/role.h
@@ -42,6 +42,8 @@ struct usb_role_switch_desc {
 	bool allow_userspace_control;
 };
 
+
+#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
 int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role);
 enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw);
 struct usb_role_switch *usb_role_switch_get(struct device *dev);
@@ -51,5 +53,33 @@ struct usb_role_switch *
 usb_role_switch_register(struct device *parent,
 			 const struct usb_role_switch_desc *desc);
 void usb_role_switch_unregister(struct usb_role_switch *sw);
+#else
+static inline int usb_role_switch_set_role(struct usb_role_switch *sw,
+		enum usb_role role)
+{
+	return 0;
+}
+
+static inline enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
+{
+	return USB_ROLE_NONE;
+}
+
+static inline struct usb_role_switch *usb_role_switch_get(struct device *dev)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void usb_role_switch_put(struct usb_role_switch *sw) { }
+
+static inline struct usb_role_switch *
+usb_role_switch_register(struct device *parent,
+			 const struct usb_role_switch_desc *desc)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void usb_role_switch_unregister(struct usb_role_switch *sw) { }
+#endif
 
 #endif /* __LINUX_USB_ROLE_H */
-- 
2.15.0-rc2