From 52a15387c427e83cf6ee7973086dae47648672ee Mon Sep 17 00:00:00 2001
From: pennam <m.pennasilico@arduino.cc>
Date: Thu, 11 Mar 2021 15:22:31 +0100
Subject: [PATCH] UnbufferedSerial add is_tx_active()

---
 drivers/include/drivers/SerialBase.h       |  6 ++++++
 drivers/include/drivers/UnbufferedSerial.h |  8 ++++++++
 drivers/source/SerialBase.cpp              | 10 ++++++++++
 drivers/source/UnbufferedSerial.cpp        | 13 +++++++++++++
 4 files changed, 37 insertions(+)

diff --git a/drivers/include/drivers/SerialBase.h b/drivers/include/drivers/SerialBase.h
index 9288c271e15..33bb7a8741c 100644
--- a/drivers/include/drivers/SerialBase.h
+++ b/drivers/include/drivers/SerialBase.h
@@ -273,6 +273,12 @@ class SerialBase : private NonCopyable<SerialBase> {
      */
     int set_dma_usage_rx(DMAUsage usage);
 
+    /** Attempts to determine if the serial peripheral is already in use for TX
+     *
+     * @return Non-zero if the TX transaction is ongoing, 0 otherwise
+     */
+    int is_tx_active();
+
 #if !defined(DOXYGEN_ONLY)
 protected:
     void start_read(void *buffer, int buffer_size, char buffer_width, const event_callback_t &callback, int event, unsigned char char_match);
diff --git a/drivers/include/drivers/UnbufferedSerial.h b/drivers/include/drivers/UnbufferedSerial.h
index a330d6e92bc..dc93e764aee 100644
--- a/drivers/include/drivers/UnbufferedSerial.h
+++ b/drivers/include/drivers/UnbufferedSerial.h
@@ -211,6 +211,14 @@ class UnbufferedSerial:
      */
     void set_flow_control(Flow type, PinName flow1 = NC, PinName flow2 = NC);
 #endif // DEVICE_SERIAL_FC
+
+#if DEVICE_SERIAL_ASYNCH
+    /** Attempts to determine if the serial peripheral is already in use for TX
+    *
+    * @return Non-zero if the TX transaction is ongoing, 0 otherwise
+    */
+    int is_tx_active();
+#endif // DEVICE_SERIAL_ASYNCH
 };
 
 } // namespace mbed
diff --git a/drivers/source/SerialBase.cpp b/drivers/source/SerialBase.cpp
index 40bf7d0b618..3b56daff923 100644
--- a/drivers/source/SerialBase.cpp
+++ b/drivers/source/SerialBase.cpp
@@ -486,6 +486,16 @@ void SerialBase::interrupt_handler_asynch(void)
     }
 }
 
+int SerialBase::is_tx_active(void)
+{
+    int result = 0;
+    lock();
+    result = serial_tx_active(&_serial);
+    unlock();
+
+    return result;
+}
+
 #endif
 
 } // namespace mbed
diff --git a/drivers/source/UnbufferedSerial.cpp b/drivers/source/UnbufferedSerial.cpp
index cc86530344d..43477c06e62 100644
--- a/drivers/source/UnbufferedSerial.cpp
+++ b/drivers/source/UnbufferedSerial.cpp
@@ -122,6 +122,19 @@ void UnbufferedSerial::set_flow_control(Flow type, PinName flow1, PinName flow2)
 }
 #endif // DEVICE_SERIAL_FC
 
+#if DEVICE_SERIAL_ASYNCH
+int UnbufferedSerial::is_tx_active(void)
+{
+    int retval;
+
+    lock();
+    retval = SerialBase::is_tx_active();
+    unlock();
+
+    return retval;
+}
+#endif // DEVICE_SERIAL_ASYNCH
+
 } // namespace mbed
 
 #endif // #if DEVICE_SERIAL