feat(uart): deal with esp32-p4 pin setup and detach

Author: SuGlider

cores/esp32/HardwareSerial.cpp

@@ -340,14 +340,24 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
 #if SOC_UART_HP_NUM > 2  // may save some flash bytes...
       case UART_NUM_2:
         if (rxPin < 0 && txPin < 0) {
+#ifdef RX2
           // do not change RX2/TX2 if it has already been set before
           rxPin = _rxPin < 0 ? (int8_t)RX2 : _rxPin;
+#endif
+#ifdef TX2
           txPin = _txPin < 0 ? (int8_t)TX2 : _txPin;
+#endif
         }
         break;
 #endif
     }
   }
+  // if no RX/TX pins are defined, it will not start the UART driver
+  if (rxPin < 0 && txPin < 0) {
+    log_e("No RX/TX pins defined. Please set RX/TX pins.");
+    HSERIAL_MUTEX_UNLOCK();
+    return;
+  }
 
   // IDF UART driver keeps Pin setting on restarting. Negative Pin number will keep it unmodified.
   // it will detach previous UART attached pins
@@ -425,6 +435,7 @@ void HardwareSerial::end() {
   if (uartGetDebug() == _uart_nr) {
     uartSetDebug(0);
   }
+  uart_set_loop_back(_uart_nr, false);  // disable loopback mode, if previously enabled
   _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/HardwareSerial.h

@@ -200,8 +200,6 @@ typedef enum {
 #define RX2 (gpio_num_t)4
 #elif CONFIG_IDF_TARGET_ESP32S3
 #define RX2 (gpio_num_t)19
-#elif CONFIG_IDF_TARGET_ESP32P4
-#define RX2 (gpio_num_t)15
 #endif
 #endif
 
@@ -210,8 +208,6 @@ typedef enum {
 #define TX2 (gpio_num_t)25
 #elif CONFIG_IDF_TARGET_ESP32S3
 #define TX2 (gpio_num_t)20
-#elif CONFIG_IDF_TARGET_ESP32P4
-#define TX2 (gpio_num_t)14
 #endif
 #endif
 #endif /* SOC_UART_HP_NUM > 2 */

cores/esp32/esp32-hal-uart.c

@@ -166,13 +166,15 @@ 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;
+  uart_set_loop_back(bus->num, false); // disable loopback
   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;
+  uart_set_loop_back(bus->num, false); // disable loopback
   return _uartDetachPins(bus->num, UART_PIN_NO_CHANGE, bus->_txPin, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE);
 }