From 8a5b9fc5c01aeae15db6c4c4c1ec2929481f1868 Mon Sep 17 00:00:00 2001
From: e-rk <39553874+e-rk@users.noreply.github.com>
Date: Wed, 17 Oct 2018 13:23:05 +0200
Subject: [PATCH] [nrf52840] fix NCP radio not working on USB CDC UART (#3169)

---
 examples/platforms/nrf52840/platform-nrf5.h | 6 ++++++
 examples/platforms/nrf52840/system.c        | 5 +++++
 examples/platforms/nrf52840/uart.c          | 5 +++++
 examples/platforms/nrf52840/usb-cdc-uart.c  | 7 +++++++
 4 files changed, 23 insertions(+)

diff --git a/examples/platforms/nrf52840/platform-nrf5.h b/examples/platforms/nrf52840/platform-nrf5.h
index ee9ca435a..03d24cb91 100644
--- a/examples/platforms/nrf52840/platform-nrf5.h
+++ b/examples/platforms/nrf52840/platform-nrf5.h
@@ -53,6 +53,12 @@ void nrf5UartInit(void);
  */
 void nrf5UartDeinit(void);
 
+/**
+ * Clear pending UART data.
+ *
+ */
+void nrf5UartClearPendingData(void);
+
 /**
  * This function performs UART driver processing.
  *
diff --git a/examples/platforms/nrf52840/system.c b/examples/platforms/nrf52840/system.c
index 20b21896c..9db75688a 100644
--- a/examples/platforms/nrf52840/system.c
+++ b/examples/platforms/nrf52840/system.c
@@ -81,6 +81,11 @@ void otSysInit(int argc, char *argv[])
         nrf5UartInit();
         nrf5CryptoInit();
     }
+    else
+    {
+        nrf5UartClearPendingData();
+    }
+
 #ifndef SPIS_TRANSPORT_DISABLE
     nrf5SpiSlaveInit();
 #endif
diff --git a/examples/platforms/nrf52840/uart.c b/examples/platforms/nrf52840/uart.c
index 2caf9552e..b95c47554 100644
--- a/examples/platforms/nrf52840/uart.c
+++ b/examples/platforms/nrf52840/uart.c
@@ -150,6 +150,11 @@ void nrf5UartInit(void)
     // Intentionally empty.
 }
 
+void nrf5UartClearPendingData(void)
+{
+    // Intentionally empty.
+}
+
 void nrf5UartDeinit(void)
 {
     if (sUartEnabled)
diff --git a/examples/platforms/nrf52840/usb-cdc-uart.c b/examples/platforms/nrf52840/usb-cdc-uart.c
index 9b44acd3c..6df6cd094 100644
--- a/examples/platforms/nrf52840/usb-cdc-uart.c
+++ b/examples/platforms/nrf52840/usb-cdc-uart.c
@@ -290,6 +290,13 @@ void nrf5UartDeinit(void)
     app_usbd_uninit();
 }
 
+void nrf5UartClearPendingData(void)
+{
+    sUsbState.mTransferInProgress = false;
+    sUsbState.mTxBuffer           = NULL;
+    sUsbState.mTxSize             = 0;
+}
+
 void nrf5UartProcess(void)
 {
     while (app_usbd_event_queue_process())