cdc: add uart status notification support.

src/class/cdc/cdc.h

@@ -412,6 +412,35 @@ typedef struct TU_ATTR_PACKED
 
 TU_VERIFY_STATIC(sizeof(cdc_line_control_state_t) == 2, "size is not correct");
 
+//--------------------------------------------------------------------+
+// Notifications
+//--------------------------------------------------------------------+
+typedef struct TU_ATTR_PACKED
+{
+  uint16_t bRxCarrier  : 1;
+  uint16_t bTxCarrier  : 1;
+  uint16_t bBreak      : 1;
+  uint16_t bRingSignal : 1;
+  uint16_t bFraming    : 1;
+  uint16_t bParity     : 1;
+  uint16_t bOverRun    : 1;
+  uint16_t             : 9;
+} cdc_uart_state_t;
+
+typedef struct TU_ATTR_PACKED
+{
+  uint8_t  bmRequestType;
+  uint8_t  bNotification;
+  uint16_t wValue;
+  uint16_t wIndex;
+  uint16_t wLength;
+  cdc_uart_state_t bmUartState;
+} cdc_notif_serial_state_t;
+
+TU_VERIFY_STATIC(sizeof(cdc_notif_serial_state_t) == 10, "size is not correct");
+
+#define CDC_REQ_TYPE_NOTIF 0xA1 ///< Direction IN; Type Class; Recipient Interface
+
 TU_ATTR_PACKED_END  // End of all packed definitions
 TU_ATTR_BIT_FIELD_ORDER_END
 

src/class/cdc/cdc_device.c

@@ -71,6 +71,7 @@ typedef struct
   OSAL_MUTEX_DEF(tx_ff_mutex);
 
   // Endpoint Transfer buffer
+  CFG_TUSB_MEM_ALIGN cdc_notif_serial_state_t serial_state_buf;
   CFG_TUSB_MEM_ALIGN uint8_t epout_buf[CFG_TUD_CDC_EP_BUFSIZE];
   CFG_TUSB_MEM_ALIGN uint8_t epin_buf[CFG_TUD_CDC_EP_BUFSIZE];
 
@@ -130,6 +131,27 @@ void tud_cdc_n_get_line_coding (uint8_t itf, cdc_line_coding_t* coding)
   (*coding) = _cdcd_itf[itf].line_coding;
 }
 
+bool tud_cdc_n_send_uart_state (uint8_t itf, cdc_uart_state_t state)
+{
+  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
+
+  // Skip if usb is not ready yet
+  TU_VERIFY( tud_ready(), 0 );
+
+  // claim endpoint
+  TU_VERIFY(usbd_edpt_claim(p_cdc->rhport, p_cdc->ep_notif));
+
+  p_cdc->serial_state_buf.bmRequestType = CDC_REQ_TYPE_NOTIF;
+  p_cdc->serial_state_buf.bNotification = CDC_NOTIF_SERIAL_STATE;
+  p_cdc->serial_state_buf.wValue = 0;
+  p_cdc->serial_state_buf.wIndex = p_cdc->itf_num;
+  p_cdc->serial_state_buf.wLength = 2;
+  p_cdc->serial_state_buf.bmUartState = state;
+
+  // transfer
+  return usbd_edpt_xfer(p_cdc->rhport, p_cdc->ep_notif, (uint8_t *)&p_cdc->serial_state_buf, sizeof(p_cdc->serial_state_buf));
+}
+
 void tud_cdc_n_set_wanted_char (uint8_t itf, char wanted)
 {
   _cdcd_itf[itf].wanted_char = wanted;
@@ -457,7 +479,7 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
   for (itf = 0; itf < CFG_TUD_CDC; itf++)
   {
     p_cdc = &_cdcd_itf[itf];
-    if ( ( ep_addr == p_cdc->ep_out ) || ( ep_addr == p_cdc->ep_in ) ) break;
+    if ( ( ep_addr == p_cdc->ep_out ) || ( ep_addr == p_cdc->ep_in ) || ( ep_addr == p_cdc->ep_notif )) break;
   }
   TU_ASSERT(itf < CFG_TUD_CDC);
 

src/class/cdc/cdc_device.h

@@ -64,6 +64,9 @@ uint8_t  tud_cdc_n_get_line_state  (uint8_t itf);
 // Get current line encoding: bit rate, stop bits parity etc ..
 void     tud_cdc_n_get_line_coding (uint8_t itf, cdc_line_coding_t* coding);
 
+// Send UART status notification: DCD, DSR etc ..
+bool     tud_cdc_n_send_uart_state (uint8_t itf, cdc_uart_state_t state);
+
 // Set special character that will trigger tud_cdc_rx_wanted_cb() callback on receiving
 void     tud_cdc_n_set_wanted_char (uint8_t itf, char wanted);
 
@@ -109,6 +112,7 @@ bool tud_cdc_n_write_clear (uint8_t itf);
 static inline bool     tud_cdc_connected       (void);
 static inline uint8_t  tud_cdc_get_line_state  (void);
 static inline void     tud_cdc_get_line_coding (cdc_line_coding_t* coding);
+static inline bool     tud_cdc_send_uart_state (cdc_uart_state_t state);
 static inline void     tud_cdc_set_wanted_char (char wanted);
 
 static inline uint32_t tud_cdc_available       (void);
@@ -180,6 +184,11 @@ static inline void tud_cdc_get_line_coding (cdc_line_coding_t* coding)
   tud_cdc_n_get_line_coding(0, coding);
 }
 
+static inline bool tud_cdc_send_uart_state (cdc_uart_state_t state)
+{
+  return tud_cdc_n_send_uart_state(0, state);
+}
+
 static inline void tud_cdc_set_wanted_char (char wanted)
 {
   tud_cdc_n_set_wanted_char(0, wanted);