Fixes UART detach. Fixes espressif#3878 (espressif#3894)

* Fixes UART detach.  Fixes espressif#3878

* 0 is not a good holder value for pins!

* 0 is not a good holder value for pins!

Author: lbernstone

cores/esp32/HardwareSerial.cpp

@@ -53,6 +53,8 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
     }
 
     _uart = uartBegin(_uart_nr, baud ? baud : 9600, config, rxPin, txPin, 256, invert);
+    _tx_pin = txPin;
+    _rx_pin = rxPin;
 
     if(!baud) {
         uartStartDetectBaudrate(_uart);
@@ -70,6 +72,8 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
         } else {
             log_e("Could not detect baudrate. Serial data at the port must be present within the timeout for detection to be possible");
             _uart = NULL;
+            _tx_pin = 255;
+            _rx_pin = 255;
         }
     }
 }
@@ -84,7 +88,8 @@ void HardwareSerial::end()
     if(uartGetDebug() == _uart_nr) {
         uartSetDebug(0);
     }
-    uartEnd(_uart);
+    log_v("pins %d %d",_tx_pin, _rx_pin);
+    uartEnd(_uart, _tx_pin, _rx_pin);
     _uart = 0;
 }
 

cores/esp32/HardwareSerial.h

@@ -104,6 +104,8 @@ class HardwareSerial: public Stream
 protected:
     int _uart_nr;
     uart_t* _uart;
+    uint8_t _tx_pin;
+    uint8_t _rx_pin;
 };
 
 extern void serialEventRun(void) __attribute__((weak));

cores/esp32/esp32-hal-uart.c

@@ -124,21 +124,21 @@ void uartDisableInterrupt(uart_t* uart)
     UART_MUTEX_UNLOCK();
 }
 
-void uartDetachRx(uart_t* uart)
+void uartDetachRx(uart_t* uart, uint8_t rxPin)
 {
     if(uart == NULL) {
         return;
     }
-    pinMatrixInDetach(UART_RXD_IDX(uart->num), false, false);
+    pinMatrixInDetach(rxPin, false, false);
     uartDisableInterrupt(uart);
 }
 
-void uartDetachTx(uart_t* uart)
+void uartDetachTx(uart_t* uart, uint8_t txPin)
 {
     if(uart == NULL) {
         return;
     }
-    pinMatrixOutDetach(UART_TXD_IDX(uart->num), false, false);
+    pinMatrixOutDetach(txPin, false, false);
 }
 
 void uartAttachRx(uart_t* uart, uint8_t rxPin, bool inverted)
@@ -226,7 +226,7 @@ uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rx
     return uart;
 }
 
-void uartEnd(uart_t* uart)
+void uartEnd(uart_t* uart, uint8_t txPin, uint8_t rxPin)
 {
     if(uart == NULL) {
         return;
@@ -243,8 +243,8 @@ void uartEnd(uart_t* uart)
 
     UART_MUTEX_UNLOCK();
 
-    uartDetachRx(uart);
-    uartDetachTx(uart);
+    uartDetachRx(uart, rxPin);
+    uartDetachTx(uart, txPin);
 }
 
 size_t uartResizeRxBuffer(uart_t * uart, size_t new_size) {

cores/esp32/esp32-hal-uart.h

@@ -52,7 +52,7 @@ struct uart_struct_t;
 typedef struct uart_struct_t uart_t;
 
 uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rxPin, int8_t txPin, uint16_t queueLen, bool inverted);
-void uartEnd(uart_t* uart);
+void uartEnd(uart_t* uart, uint8_t rxPin, uint8_t txPin);
 
 uint32_t uartAvailable(uart_t* uart);
 uint32_t uartAvailableForWrite(uart_t* uart);