add thin wrapper for tud api

Author: hathach

cores/nRF5/usb/Adafruit_TinyUSB_core/Adafruit_USBD_Device.cpp

@@ -53,7 +53,6 @@ uint16_t const * const string_desc_arr [] =
 };
 
 // tud_desc_set is required by tinyusb stack
-// since CFG_TUD_DESC_AUTO is enabled, we only need to set string_arr
 tud_desc_set_t tud_desc_set =
 {
   .device       = NULL, // update later
@@ -134,10 +133,11 @@ Adafruit_USBD_Device::Adafruit_USBD_Device(void)
 bool Adafruit_USBD_Device::addInterface(Adafruit_USBD_Interface& itf)
 {
   uint8_t* desc = _desc_cfg+_desc_cfglen;
-  uint16_t len = itf.getDescriptor(desc, sizeof(_desc_cfg)-_desc_cfglen);
-
+  uint16_t const len = itf.getDescriptor(desc, sizeof(_desc_cfg)-_desc_cfglen);
   uint8_t* desc_end = desc+len;
 
+  if ( !len ) return false;
+
   // Handle IAD
   if ( desc[1] == TUSB_DESC_INTERFACE_ASSOCIATION )
   {

cores/nRF5/usb/Adafruit_TinyUSB_core/Adafruit_USBD_Device.h

@@ -52,6 +52,11 @@ class Adafruit_USBD_Device
     bool addInterface(Adafruit_USBD_Interface& itf);
 
     bool begin(uint16_t vid, uint16_t pid);
+
+    bool mounted(void) { return tud_mounted(); }
+    bool suspended(void) { return tud_suspended(); }
+    bool ready(void) { return tud_ready(); }
+    bool remoteWakeup(void) { return tud_remote_wakeup(); }
 };
 
 extern Adafruit_USBD_Device USBDevice;