correct assoc_itf_count for bth driver

src/device/usbd.c

@@ -921,6 +921,17 @@ static bool process_set_config(uint8_t rhport, uint8_t cfg_num)
     }
 #endif
 
+#if CFG_TUD_BTH && CFG_TUD_BTH_ISO_ALT_COUNT
+    // BTH implementation currently does not use IAD. TODO should also use IAD for composite device
+    if (1                                  == assoc_itf_count              &&
+        TUD_BT_APP_CLASS                   == desc_itf->bInterfaceClass    &&
+        TUD_BT_APP_SUBCLASS                == desc_itf->bInterfaceSubClass &&
+        TUD_BT_PROTOCOL_PRIMARY_CONTROLLER == desc_itf->bInterfaceProtocol)
+    {
+      assoc_itf_count = 2;
+    }
+#endif
+
     uint16_t const drv_len = tu_desc_get_interface_total_len(desc_itf, assoc_itf_count, desc_end-p_desc);
     TU_ASSERT(drv_len >= sizeof(tusb_desc_interface_t));
 

src/device/usbd.h

@@ -777,6 +777,7 @@ TU_ATTR_WEAK bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage, tusb
 
 // BT Primary controller descriptor
 // Interface number, string index, attributes, event endpoint, event endpoint size, interval, data in, data out, data endpoint size, iso endpoint sizes
+// TODO BTH should also use IAD like CDC for composite device
 #define TUD_BTH_DESCRIPTOR(_itfnum, _stridx, _ep_evt, _ep_evt_size, _ep_evt_interval, _ep_in, _ep_out, _ep_size,...) \
   TUD_BTH_PRI_ITF(_itfnum, _stridx, _ep_evt, _ep_evt_size, _ep_evt_interval, _ep_in, _ep_out, _ep_size) \
   TUD_BTH_ISO_ITFS(_itfnum + 1, _ep_in + 1, _ep_out + 1, __VA_ARGS__)