diff --git a/tinyusb/host/ehci/ehci.c b/tinyusb/host/ehci/ehci.c
index 989d9dea2..4131d3592 100644
--- a/tinyusb/host/ehci/ehci.c
+++ b/tinyusb/host/ehci/ehci.c
@@ -57,6 +57,7 @@
 // INTERNAL OBJECT & FUNCTION DECLARATION
 //--------------------------------------------------------------------+
 STATIC_ ehci_data_t ehci_data TUSB_CFG_ATTR_USBRAM;
+//TODO removed if not use period list
 STATIC_ ehci_link_t period_frame_list0[EHCI_FRAMELIST_SIZE] ATTR_ALIGNED(4096) TUSB_CFG_ATTR_USBRAM;
 #if CONTROLLER_HOST_NUMBER > 1
 STATIC_ ehci_link_t period_frame_list1[EHCI_FRAMELIST_SIZE] ATTR_ALIGNED(4096) TUSB_CFG_ATTR_USBRAM;
@@ -111,8 +112,8 @@ STATIC_ INLINE_ ehci_qhd_t* get_period_head(uint8_t hostid)
   return &ehci_data.period_head[ hostid_to_data_idx(hostid) ];
 }
 
-static inline uint8_t get_qhd_index(ehci_qhd_t * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
-static inline uint8_t get_qhd_index(ehci_qhd_t * p_qhd)
+static inline uint8_t qhd_get_index(ehci_qhd_t * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
+static inline uint8_t qhd_get_index(ehci_qhd_t * p_qhd)
 {
   return p_qhd - ehci_data.device[p_qhd->device_address-1].qhd;
 }
@@ -129,8 +130,8 @@ static inline void qtd_remove_1st_from_qhd(ehci_qhd_t *p_qhd)
   }
 }
 
-static inline void insert_qtd_to_qhd(ehci_qhd_t *p_qhd, ehci_qtd_t *p_qtd_new) ATTR_ALWAYS_INLINE;
-static inline void insert_qtd_to_qhd(ehci_qhd_t *p_qhd, ehci_qtd_t *p_qtd_new)
+static inline void qtd_insert_to_qhd(ehci_qhd_t *p_qhd, ehci_qtd_t *p_qtd_new) ATTR_ALWAYS_INLINE;
+static inline void qtd_insert_to_qhd(ehci_qhd_t *p_qhd, ehci_qtd_t *p_qtd_new)
 {
   if (p_qhd->p_qtd_list_head == NULL) // empty list
   {
@@ -230,8 +231,8 @@ void async_advance_isr(ehci_qhd_t * const async_head)
           qtd_remove_1st_from_qhd(p_qhd);
         }
       }
-    }
-  }
+    }// end qhd list loop
+  } // end for device[] loop
 }
 
 void port_connect_status_change_isr(uint8_t hostid)
@@ -267,7 +268,7 @@ void async_list_process_isr(ehci_qhd_t * const async_head, ehci_registers_t * co
           if (p_qhd->endpoint_number) // if not Control, can only be Bulk
           {
             pipe_hdl.xfer_type = TUSB_XFER_BULK;
-            pipe_hdl.index = get_qhd_index(p_qhd);
+            pipe_hdl.index = qhd_get_index(p_qhd);
           }
           usbh_isr( pipe_hdl, p_qhd->class_code); // call USBH call back
         }
@@ -611,7 +612,7 @@ pipe_handle_t hcd_pipe_open(uint8_t dev_addr, tusb_descriptor_endpoint_t const *
   list_insert( (ehci_link_t*) list_head,
                (ehci_link_t*) p_qhd, EHCI_QUEUE_ELEMENT_QHD);
 
-  return (pipe_handle_t) { .dev_addr = dev_addr, .xfer_type = p_endpoint_desc->bmAttributes.xfer, .index = get_qhd_index(p_qhd) };
+  return (pipe_handle_t) { .dev_addr = dev_addr, .xfer_type = p_endpoint_desc->bmAttributes.xfer, .index = qhd_get_index(p_qhd) };
 }
 
 STATIC_ INLINE_ ehci_qhd_t* get_qhd_from_pipe_handle(pipe_handle_t pipe_hdl) ATTR_PURE ATTR_ALWAYS_INLINE;
@@ -652,7 +653,7 @@ tusb_error_t  hcd_pipe_xfer(pipe_handle_t pipe_hdl, uint8_t buffer[], uint16_t t
   }
 
   //------------- insert TD to TD list -------------//
-  insert_qtd_to_qhd(p_qhd, p_qtd);
+  qtd_insert_to_qhd(p_qhd, p_qtd);
 
   return TUSB_ERROR_NONE;
 }
diff --git a/tinyusb/host/usbh.h b/tinyusb/host/usbh.h
index 8d632f139..e0a1bc0e7 100644
--- a/tinyusb/host/usbh.h
+++ b/tinyusb/host/usbh.h
@@ -93,41 +93,6 @@
 //  TUSB_CLASS_APPLICATION_SPECIFIC = 0xEF ,
 //  TUSB_CLASS_VENDOR_SPECIFIC      = 0xFF
 
-enum {
-  TUSB_FLAGS_CLASS_UNSPECIFIED          = BIT_(0)    , ///< 0
-  TUSB_FLAGS_CLASS_AUDIO                = BIT_(1)    , ///< 1
-  TUSB_FLAGS_CLASS_CDC                  = BIT_(2)    , ///< 2
-  TUSB_FLAGS_CLASS_HID_GENERIC          = BIT_(3)    , ///< 3
-  TUSB_FLAGS_CLASS_RESERVED_4           = BIT_(4)    , ///< 4
-  TUSB_FLAGS_CLASS_PHYSICAL             = BIT_(5)    , ///< 5
-  TUSB_FLAGS_CLASS_IMAGE                = BIT_(6)    , ///< 6
-  TUSB_FLAGS_CLASS_PRINTER              = BIT_(7)    ,  ///< 7
-  TUSB_FLAGS_CLASS_MSC                  = BIT_(8)    ,  ///< 8
-  TUSB_FLAGS_CLASS_HUB                  = BIT_(9)    ,  ///< 9
-  TUSB_FLAGS_CLASS_CDC_DATA             = BIT_(10)   ,  ///< 10
-  TUSB_FLAGS_CLASS_SMART_CARD           = BIT_(11)   ,  ///< 11
-  TUSB_FLAGS_CLASS_RESERVED_12          = BIT_(12)   , ///< 12
-  TUSB_FLAGS_CLASS_CONTENT_SECURITY     = BIT_(13)   ,  ///< 13
-  TUSB_FLAGS_CLASS_VIDEO                = BIT_(14)   ,  ///< 14
-  TUSB_FLAGS_CLASS_PERSONAL_HEALTHCARE  = BIT_(15)   ,  ///< 15
-  TUSB_FLAGS_CLASS_AUDIO_VIDEO          = BIT_(16)   ,  ///< 16
-  // reserved from 17 to 20
-  TUSB_FLAGS_CLASS_RESERVED_20          = BIT_(20)    , ///< 3
-
-  TUSB_FLAGS_CLASS_HID_KEYBOARD         = BIT_(21)    , ///< 3
-  TUSB_FLAGS_CLASS_HID_MOUSE            = BIT_(22)    , ///< 3
-
-  // reserved from 25 to 26
-  TUSB_FLAGS_CLASS_RESERVED_25          = BIT_(25)    , ///< 3
-  TUSB_FLAGS_CLASS_RESERVED_26          = BIT_(26)    , ///< 3
-
-  TUSB_FLAGS_CLASS_DIAGNOSTIC           = BIT_(27),
-  TUSB_FLAGS_CLASS_WIRELESS_CONTROLLER  = BIT_(28),
-  TUSB_FLAGS_CLASS_MISC                 = BIT_(29),
-  TUSB_FLAGS_CLASS_APPLICATION_SPECIFIC = BIT_(30),
-  TUSB_FLAGS_CLASS_VENDOR_SPECIFIC      = BIT_(31) // TODO out of range for int type
-};
-
 /// Device Status
 enum tusbh_device_status_{
   TUSB_DEVICE_STATUS_UNPLUG      = 0,