fix(uart): terminates uart driver whenever rx and tx are detached

Author: SuGlider

cores/esp32/HardwareSerial.cpp

@@ -483,9 +483,6 @@ void HardwareSerial::end() {
   // including any tasks or debug message channel (log_x()) - but not for IDF log messages!
   _onReceiveCB = NULL;
   _onReceiveErrorCB = NULL;
-  if (uartGetDebug() == _uart_nr) {
-    uartSetDebug(0);
-  }
   _rxFIFOFull = 0;
   uartEnd(_uart_nr);    // fully detach all pins and delete the UART driver
   _destroyEventTask();  // when IDF uart driver is deleted, _eventTask must finish too

cores/esp32/esp32-hal-uart.c

@@ -284,13 +284,21 @@ static bool _uartDetachBus_RX(void *busptr) {
   // sanity check - it should never happen
   assert(busptr && "_uartDetachBus_RX bus NULL pointer.");
   uart_t *bus = (uart_t *)busptr;
+  if (bus->_txPin < 0) { // both rx and tx pins are detached, terminate the uart driver
+    uartEnd(bus->num);
+    return true;  
+  }
   return _uartDetachPins(bus->num, bus->_rxPin, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
 }
 
 static bool _uartDetachBus_TX(void *busptr) {
   // sanity check - it should never happen
   assert(busptr && "_uartDetachBus_TX bus NULL pointer.");
   uart_t *bus = (uart_t *)busptr;
+  if (bus->_rxPin < 0) { // both rx and tx pins are detached, terminate the uart driver
+    uartEnd(bus->num);
+    return true;  
+  }
   return _uartDetachPins(bus->num, UART_PIN_NO_CHANGE, bus->_txPin, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
 }
 
@@ -986,6 +994,9 @@ void uartEnd(uint8_t uart_num) {
   if (uart_is_driver_installed(uart_num)) {
     uart_driver_delete(uart_num);
   }
+  if (uartGetDebug() == uart_num) {
+    uartSetDebug(0);
+  }
   UART_MUTEX_UNLOCK();
 }