usb: Add remote wakeup support

This commit adds support for remote wakeup and extends USB api
with a wakeup request call. Remote wakeup can be dsabled in kconfig
when a specific driver does not support this feature.

Signed-off-by: Paweł Zadrożniak <pawel.zadrozniak@nordicsemi.no>

include/usb/usb_common.h

@@ -96,7 +96,10 @@
  * D5:Remote Wakeup -> 0,
  * D4...0:Reserved -> 0
  */
-#define USB_CONFIGURATION_ATTRIBUTES	0xC0
+#define USB_CONFIGURATION_ATTRIBUTES_REMOTE_WAKEUP  0x20
+#define USB_CONFIGURATION_ATTRIBUTES                0xC0       \
+	| (COND_CODE_1(CONFIG_USB_DEVICE_REMOTE_WAKEUP,        \
+	   (USB_CONFIGURATION_ATTRIBUTES_REMOTE_WAKEUP), (0)))
 
 /* Classes */
 #define COMMUNICATION_DEVICE_CLASS	0x02

include/usb/usb_device.h

@@ -418,6 +418,18 @@ int usb_transfer_sync(u8_t ep, u8_t *data, size_t dlen, unsigned int flags);
  */
 void usb_cancel_transfer(u8_t ep);
 
+/**
+ * @brief Start the USB remote wakeup procedure
+ *
+ * Function to request a remote wakeup.
+ * This feature must be enabled in configuration, otherwise
+ * it will always return -ENOTSUP error.
+ *
+ * @return 0 on success, negative errno code on fail,
+ *         i.e. when the bus is already active.
+ */
+int usb_wakeup_request(void);
+
 /**
  * @}
  */

include/usb/usbstruct.h

@@ -71,6 +71,9 @@
 #define FEA_REMOTE_WAKEUP           0x01
 #define FEA_TEST_MODE               0x02
 
+#define DEVICE_STATUS_SELF_POWERED  0x01
+#define DEVICE_STATUS_REMOTE_WAKEUP 0x02
+
 /*
  *  USB descriptors
  */