diff --git a/tinyusb/class/cdc.h b/tinyusb/class/cdc.h
index 5cabf1ec..2bc6448c 100644
--- a/tinyusb/class/cdc.h
+++ b/tinyusb/class/cdc.h
@@ -374,7 +374,6 @@ typedef struct ATTR_PACKED
   } bmCapabilities;
 }cdc_desc_func_telephone_call_state_reporting_capabilities_t;
 
-static inline uint8_t cdc_functional_desc_typeof(uint8_t const * p_desc) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline uint8_t cdc_functional_desc_typeof(uint8_t const * p_desc)
 {
   return p_desc[2];
diff --git a/tinyusb/class/cdc_host.c b/tinyusb/class/cdc_host.c
index 04ca46f0..ddacdb1f 100644
--- a/tinyusb/class/cdc_host.c
+++ b/tinyusb/class/cdc_host.c
@@ -57,7 +57,6 @@
 //--------------------------------------------------------------------+
 STATIC_VAR cdch_data_t cdch_data[TUSB_CFG_HOST_DEVICE_MAX]; // TODO to be static
 
-static inline cdc_pipeid_t get_app_pipeid(pipe_handle_t pipe_hdl) ATTR_PURE  ATTR_ALWAYS_INLINE;
 static inline cdc_pipeid_t get_app_pipeid(pipe_handle_t pipe_hdl)
 {
   cdch_data_t const * p_cdc = &cdch_data[pipe_hdl.dev_addr-1];
@@ -68,8 +67,7 @@ static inline cdc_pipeid_t get_app_pipeid(pipe_handle_t pipe_hdl)
 }
 
 
-STATIC_ INLINE_ bool tusbh_cdc_is_mounted(uint8_t dev_addr) ATTR_PURE ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
-STATIC_ INLINE_ bool tusbh_cdc_is_mounted(uint8_t dev_addr)
+static inline bool tusbh_cdc_is_mounted(uint8_t dev_addr)
 {
 // FIXME cannot use mounted class flag as at the point _open_sublass is called, the flag is not set yet
 #ifdef _TEST_
diff --git a/tinyusb/class/custom_class.h b/tinyusb/class/custom_class.h
index 850f12a3..787c59ab 100644
--- a/tinyusb/class/custom_class.h
+++ b/tinyusb/class/custom_class.h
@@ -58,7 +58,7 @@ typedef struct {
 //--------------------------------------------------------------------+
 // USBH-CLASS DRIVER API
 //--------------------------------------------------------------------+
-STATIC_ INLINE_ bool tusbh_custom_is_mounted(uint8_t dev_addr, uint16_t vendor_id, uint16_t product_id)
+static inline bool tusbh_custom_is_mounted(uint8_t dev_addr, uint16_t vendor_id, uint16_t product_id)
 {
   (void) vendor_id; // TODO check this later
   (void) product_id;
diff --git a/tinyusb/class/hid_host.c b/tinyusb/class/hid_host.c
index 1263d4cf..0f39a048 100644
--- a/tinyusb/class/hid_host.c
+++ b/tinyusb/class/hid_host.c
@@ -54,7 +54,6 @@
 //--------------------------------------------------------------------+
 // HID Interface common functions
 //--------------------------------------------------------------------+
-static inline tusb_error_t hidh_interface_open(uint8_t dev_addr, uint8_t interface_number, tusb_descriptor_endpoint_t const *p_endpoint_desc, hidh_interface_info_t *p_hid) ATTR_ALWAYS_INLINE;
 static inline tusb_error_t hidh_interface_open(uint8_t dev_addr, uint8_t interface_number, tusb_descriptor_endpoint_t const *p_endpoint_desc, hidh_interface_info_t *p_hid)
 {
   p_hid->pipe_hdl         = hcd_pipe_open(dev_addr, p_endpoint_desc, TUSB_CLASS_HID);
@@ -66,7 +65,6 @@ static inline tusb_error_t hidh_interface_open(uint8_t dev_addr, uint8_t interfa
   return TUSB_ERROR_NONE;
 }
 
-static inline void hidh_interface_close(hidh_interface_info_t *p_hid) ATTR_ALWAYS_INLINE;
 static inline void hidh_interface_close(hidh_interface_info_t *p_hid)
 {
   (void) hcd_pipe_close(p_hid->pipe_hdl);
@@ -74,7 +72,6 @@ static inline void hidh_interface_close(hidh_interface_info_t *p_hid)
 }
 
 // called from public API need to validate parameters
-tusb_error_t hidh_interface_get_report(uint8_t dev_addr, void * report, hidh_interface_info_t *p_hid) ATTR_ALWAYS_INLINE;
 tusb_error_t hidh_interface_get_report(uint8_t dev_addr, void * report, hidh_interface_info_t *p_hid)
 {
   //------------- parameters validation -------------//
diff --git a/tinyusb/class/msc_host.c b/tinyusb/class/msc_host.c
index 00186ddd..cff0bf47 100644
--- a/tinyusb/class/msc_host.c
+++ b/tinyusb/class/msc_host.c
@@ -102,7 +102,6 @@ tusb_error_t tuh_msc_get_capacity(uint8_t dev_addr, uint32_t* p_last_lba, uint32
 //--------------------------------------------------------------------+
 // PUBLIC API: SCSI COMMAND
 //--------------------------------------------------------------------+
-static inline void msc_cbw_add_signature(msc_cmd_block_wrapper_t *p_cbw, uint8_t lun) ATTR_ALWAYS_INLINE;
 static inline void msc_cbw_add_signature(msc_cmd_block_wrapper_t *p_cbw, uint8_t lun)
 {
   p_cbw->signature  = MSC_CBW_SIGNATURE;
diff --git a/tinyusb/common/common.h b/tinyusb/common/common.h
index a624b941..9a37c6c9 100644
--- a/tinyusb/common/common.h
+++ b/tinyusb/common/common.h
@@ -115,13 +115,11 @@
 
 #define arrcount(_arr)       ( sizeof(_arr) / sizeof(_arr[0]) )
 
-static inline uint8_t const * descriptor_next(uint8_t const p_desc[]) ATTR_ALWAYS_INLINE ATTR_PURE;
 static inline uint8_t const * descriptor_next(uint8_t const p_desc[])
 {
   return p_desc + p_desc[DESCRIPTOR_OFFSET_LENGTH];
 }
 
-static inline uint8_t descriptor_typeof(uint8_t const p_desc[]) ATTR_ALWAYS_INLINE ATTR_PURE;
 static inline uint8_t descriptor_typeof(uint8_t const p_desc[])
 {
   return p_desc[DESCRIPTOR_OFFSET_TYPE];
diff --git a/tinyusb/common/compiler/compiler.h b/tinyusb/common/compiler/compiler.h
index 0103bc94..bbdd6e50 100644
--- a/tinyusb/common/compiler/compiler.h
+++ b/tinyusb/common/compiler/compiler.h
@@ -53,7 +53,7 @@
 // Compile-time Assert
 //--------------------------------------------------------------------+
 #ifdef __ICCARM__
-  #define STATIC_ASSERT static_assert
+  #define STATIC_ASSERT   static_assert
 #else
   #if defined __COUNTER__ && __COUNTER__ != __COUNTER__
     #define _ASSERT_COUNTER __COUNTER__
@@ -64,32 +64,14 @@
   #define STATIC_ASSERT(const_expr, message) enum { XSTRING_CONCAT_(static_assert_, _ASSERT_COUNTER) = 1/(!!(const_expr)) }
 #endif
 
-#ifndef _TEST_
-  // TODO move some to tusb_option.h
-  #define STATIC_     static
-  #define INLINE_     inline
-  #define ATTR_TEST_WEAK
-
-  // allow debugger to watch any module-wide variables anywhere
-  #if TUSB_CFG_DEBUG
-    #define STATIC_VAR
-  #else
-    #define STATIC_VAR static
-  #endif
-
-  // function will not be inline for easy step by step debugging
-  #if TUSB_CFG_DEBUG >= 2
-    #define ATTR_ALWAYS_INLINE
-  #endif
-
-#else // TODO remove this, try to pass using compiler command option
-  #define ATTR_ALWAYS_INLINE
-  #define STATIC_
-  #define STATIC_VAR
-  #define INLINE_
-
+// allow debugger to watch any module-wide variables anywhere
+#if TUSB_CFG_DEBUG
+#define STATIC_VAR
+#else
+#define STATIC_VAR static
 #endif
 
+
 #if defined(__GNUC__)
   #include "compiler_gcc.h"
 #elif defined __ICCARM__ // IAR compiler
diff --git a/tinyusb/common/std_request.h b/tinyusb/common/std_request.h
index fc37a9c2..87d6e5d0 100644
--- a/tinyusb/common/std_request.h
+++ b/tinyusb/common/std_request.h
@@ -70,7 +70,6 @@ typedef struct ATTR_PACKED{
 STATIC_ASSERT( sizeof(tusb_control_request_t) == 8, "mostly compiler option issue");
 
 // TODO move to somewhere suitable
-static inline uint8_t bm_request_type(uint8_t direction, uint8_t type, uint8_t recipient) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t bm_request_type(uint8_t direction, uint8_t type, uint8_t recipient)
 {
   return ((uint8_t) (direction << 7)) | ((uint8_t) (type << 5)) | (recipient);
diff --git a/tinyusb/common/tusb_types.h b/tinyusb/common/tusb_types.h
index 7f774e13..d156d5e0 100644
--- a/tinyusb/common/tusb_types.h
+++ b/tinyusb/common/tusb_types.h
@@ -203,7 +203,6 @@ enum {
   INTERFACE_INVALID_NUMBER = 0xff
 };
 
-static inline uint8_t std_class_code_to_index(uint8_t std_class_code) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t std_class_code_to_index(uint8_t std_class_code)
 {
   return  (std_class_code <= TUSB_CLASS_AUDIO_VIDEO          ) ? std_class_code                    :
diff --git a/tinyusb/device/dcd_lpc43xx.c b/tinyusb/device/dcd_lpc43xx.c
index 3b69b482..f7294986 100644
--- a/tinyusb/device/dcd_lpc43xx.c
+++ b/tinyusb/device/dcd_lpc43xx.c
@@ -277,26 +277,22 @@ tusb_error_t dcd_init(void)
 // PIPE HELPER
 //--------------------------------------------------------------------+
 #if 0
-static inline uint8_t edpt_pos2phy(uint8_t pos) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t edpt_pos2phy(uint8_t pos)
 { // 0-5 --> OUT, 16-21 IN
   return (pos < DCD_QHD_MAX/2) ? (2*pos) : (2*(pos-16)+1);
 }
 #endif
 
-static inline uint8_t edpt_phy2pos(uint8_t physical_endpoint) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t edpt_phy2pos(uint8_t physical_endpoint)
 {
   return physical_endpoint/2 + ( (physical_endpoint%2) ? 16 : 0);
 }
 
-static inline uint8_t edpt_addr2phy(uint8_t endpoint_addr) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t edpt_addr2phy(uint8_t endpoint_addr)
 {
   return 2*(endpoint_addr & 0x0F) + ((endpoint_addr & TUSB_DIR_DEV_TO_HOST_MASK) ? 1 : 0);
 }
 
-static inline uint8_t edpt_phy2log(uint8_t physical_endpoint) ATTR_CONST ATTR_ALWAYS_INLINE;
 static inline uint8_t edpt_phy2log(uint8_t physical_endpoint)
 {
   return physical_endpoint/2;
@@ -323,7 +319,6 @@ static void qtd_init(dcd_qtd_t* p_qtd, void * data_ptr, uint16_t total_bytes)
 }
 
 // retval 0: invalid
-static inline uint8_t qtd_find_free(uint8_t coreid) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline uint8_t qtd_find_free(uint8_t coreid)
 {
   for(uint8_t i=2; i<DCD_QTD_MAX; i++)
@@ -383,7 +378,6 @@ tusb_error_t dcd_pipe_control_xfer(uint8_t coreid, tusb_direction_t dir, uint8_t
 //--------------------------------------------------------------------+
 // BULK/INTERRUPT/ISOCHRONOUS PIPE API
 //--------------------------------------------------------------------+
-static inline volatile uint32_t * get_reg_control_addr(uint8_t coreid, uint8_t physical_endpoint) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline volatile uint32_t * get_reg_control_addr(uint8_t coreid, uint8_t physical_endpoint)
 {
  return &(LPC_USB[coreid]->ENDPTCTRL0) + edpt_phy2log(physical_endpoint);
diff --git a/tinyusb/host/ehci/ehci.c b/tinyusb/host/ehci/ehci.c
index b3069388..167b8f2b 100644
--- a/tinyusb/host/ehci/ehci.c
+++ b/tinyusb/host/ehci/ehci.c
@@ -84,21 +84,21 @@ TUSB_CFG_ATTR_USBRAM STATIC_VAR ehci_data_t ehci_data;
 //--------------------------------------------------------------------+
 // PROTOTYPE
 //--------------------------------------------------------------------+
-STATIC_ INLINE_ ehci_registers_t*  get_operational_register(uint8_t hostid) ATTR_PURE ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
-STATIC_ INLINE_ ehci_link_t*       get_period_frame_list(uint8_t hostid) ATTR_PURE ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
-STATIC_ INLINE_ uint8_t            hostid_to_data_idx(uint8_t hostid) ATTR_ALWAYS_INLINE ATTR_CONST ATTR_WARN_UNUSED_RESULT;
+static inline ehci_registers_t*  get_operational_register(uint8_t hostid) ATTR_PURE ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
+static inline ehci_link_t*       get_period_frame_list(uint8_t hostid) ATTR_PURE ATTR_ALWAYS_INLINE ATTR_WARN_UNUSED_RESULT;
+static inline uint8_t            hostid_to_data_idx(uint8_t hostid) ATTR_ALWAYS_INLINE ATTR_CONST ATTR_WARN_UNUSED_RESULT;
 
-STATIC_ INLINE_ ehci_qhd_t*  get_async_head(uint8_t hostid) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
-STATIC_ INLINE_ ehci_link_t* get_period_head(uint8_t hostid, uint8_t interval_ms) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+static inline ehci_qhd_t*  get_async_head(uint8_t hostid) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+static inline ehci_link_t* get_period_head(uint8_t hostid, uint8_t interval_ms) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
 
-STATIC_ INLINE_ ehci_qhd_t* get_control_qhd(uint8_t dev_addr) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
-STATIC_ INLINE_ ehci_qtd_t* get_control_qtds(uint8_t dev_addr) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+static inline ehci_qhd_t* get_control_qhd(uint8_t dev_addr) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
+static inline ehci_qtd_t* get_control_qtds(uint8_t dev_addr) ATTR_ALWAYS_INLINE ATTR_PURE ATTR_WARN_UNUSED_RESULT;
 
 static inline uint8_t        qhd_get_index(ehci_qhd_t const * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
 static inline ehci_qhd_t*    qhd_next(ehci_qhd_t const * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
 static inline ehci_qhd_t*    qhd_find_free (uint8_t dev_addr) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline tusb_xfer_type_t qhd_get_xfer_type(ehci_qhd_t const * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
-STATIC_ INLINE_ ehci_qhd_t*  qhd_get_from_pipe_handle(pipe_handle_t pipe_hdl) ATTR_PURE ATTR_ALWAYS_INLINE;
+static inline ehci_qhd_t*  qhd_get_from_pipe_handle(pipe_handle_t pipe_hdl) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline pipe_handle_t  qhd_create_pipe_handle(ehci_qhd_t const * p_qhd, tusb_xfer_type_t xfer_type) ATTR_PURE ATTR_ALWAYS_INLINE;
 // determine if a queue head has bus-related error
 static inline bool qhd_has_xact_error(ehci_qhd_t * p_qhd) ATTR_ALWAYS_INLINE ATTR_PURE;
@@ -111,7 +111,7 @@ static inline bool qhd_has_xact_error(ehci_qhd_t * p_qhd)
 static void qhd_init(ehci_qhd_t *p_qhd, uint8_t dev_addr, uint16_t max_packet_size, uint8_t endpoint_addr, uint8_t xfer_type, uint8_t interval);
 
 
-STATIC_ INLINE_ ehci_qtd_t*  qtd_find_free(uint8_t dev_addr) ATTR_PURE ATTR_ALWAYS_INLINE;
+static inline ehci_qtd_t*  qtd_find_free(uint8_t dev_addr) ATTR_PURE ATTR_ALWAYS_INLINE;
 static inline ehci_qtd_t*    qtd_next(ehci_qtd_t const * p_qtd ) ATTR_PURE ATTR_ALWAYS_INLINE;
 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_remove_1st_from_qhd(ehci_qhd_t *p_qhd) ATTR_ALWAYS_INLINE;
@@ -784,13 +784,13 @@ void hcd_isr(uint8_t hostid)
 //--------------------------------------------------------------------+
 // HELPER
 //--------------------------------------------------------------------+
-STATIC_ INLINE_ ehci_registers_t* get_operational_register(uint8_t hostid)
+static inline ehci_registers_t* get_operational_register(uint8_t hostid)
 {
   return (ehci_registers_t*) (hostid ? (&LPC_USB1->USBCMD_H) : (&LPC_USB0->USBCMD_H) );
 }
 
 #if EHCI_PERIODIC_LIST // TODO refractor/group this together
-STATIC_ INLINE_ ehci_link_t* get_period_frame_list(uint8_t hostid)
+static inline ehci_link_t* get_period_frame_list(uint8_t hostid)
 {
   switch(hostid)
   {
@@ -809,7 +809,7 @@ STATIC_ INLINE_ ehci_link_t* get_period_frame_list(uint8_t hostid)
 }
 #endif
 
-STATIC_ INLINE_ uint8_t hostid_to_data_idx(uint8_t hostid)
+static inline uint8_t hostid_to_data_idx(uint8_t hostid)
 {
   #if (CONTROLLER_HOST_NUMBER == 1) && (TUSB_CFG_CONTROLLER_1_MODE & TUSB_MODE_HOST)
     (void) hostid;
@@ -820,26 +820,26 @@ STATIC_ INLINE_ uint8_t hostid_to_data_idx(uint8_t hostid)
 }
 
 //------------- queue head helper -------------//
-STATIC_ INLINE_ ehci_qhd_t* get_async_head(uint8_t hostid)
+static inline ehci_qhd_t* get_async_head(uint8_t hostid)
 {
   return &ehci_data.async_head[ hostid_to_data_idx(hostid) ];
 }
 
 #if EHCI_PERIODIC_LIST // TODO refractor/group this together
-STATIC_ INLINE_ ehci_link_t* get_period_head(uint8_t hostid, uint8_t interval_ms)
+static inline ehci_link_t* get_period_head(uint8_t hostid, uint8_t interval_ms)
 {
   return (ehci_link_t*) (&ehci_data.period_head_arr[ hostid_to_data_idx(hostid) ]
                                                     [ log2_of( min8_of(EHCI_FRAMELIST_SIZE, interval_ms) ) ] );
 }
 #endif
 
-STATIC_ INLINE_ ehci_qhd_t* get_control_qhd(uint8_t dev_addr)
+static inline ehci_qhd_t* get_control_qhd(uint8_t dev_addr)
 {
   return (dev_addr == 0) ?
       get_async_head( usbh_devices[dev_addr].core_id ) :
       &ehci_data.device[dev_addr-1].control.qhd;
 }
-STATIC_ INLINE_ ehci_qtd_t* get_control_qtds(uint8_t dev_addr)
+static inline ehci_qtd_t* get_control_qtds(uint8_t dev_addr)
 {
   return (dev_addr == 0) ?
       ehci_data.addr0_qtd :
@@ -873,7 +873,7 @@ static inline ehci_qhd_t* qhd_next(ehci_qhd_t const * p_qhd)
   return (ehci_qhd_t*) align32(p_qhd->next.address);
 }
 
-STATIC_ INLINE_ ehci_qhd_t* qhd_get_from_pipe_handle(pipe_handle_t pipe_hdl)
+static inline ehci_qhd_t* qhd_get_from_pipe_handle(pipe_handle_t pipe_hdl)
 {
   return &ehci_data.device[ pipe_hdl.dev_addr-1 ].qhd[ pipe_hdl.index ];
 }
@@ -895,7 +895,7 @@ static inline pipe_handle_t qhd_create_pipe_handle(ehci_qhd_t const * p_qhd, tus
 }
 
 //------------- TD helper -------------//
-STATIC_ INLINE_ ehci_qtd_t* qtd_find_free(uint8_t dev_addr)
+static inline ehci_qtd_t* qtd_find_free(uint8_t dev_addr)
 {
   uint8_t index=0;
   while( index<HCD_MAX_XFER && ehci_data.device[dev_addr-1].qtd[index].used )