From 7ce0c2d6631265afd6ecabcb659ab852ed2f0de7 Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Wed, 6 Sep 2023 19:42:34 +0200
Subject: [PATCH 1/7] Add support for register_hotplug_callback() for H7 boards

---
 src/Arduino_POSIXStorage.cpp | 37 +++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/src/Arduino_POSIXStorage.cpp b/src/Arduino_POSIXStorage.cpp
index 4c0d451..b092390 100644
--- a/src/Arduino_POSIXStorage.cpp
+++ b/src/Arduino_POSIXStorage.cpp
@@ -480,7 +480,8 @@ int mountOrFormat(const enum StorageDevices deviceName,
                   const enum FileSystems fileSystem,
                   const enum ActionTypes mountOrFormat)
 {
-  // Determine if we're running on Machine Control or not on the first call to mount() or mkfs() -->
+  // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(), or
+  // register_hotplug_callback()  -->
   if (false == hasMountedBefore)
   {
     hasMountedBefore = true;
@@ -599,6 +600,24 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
     case DEV_USB:
       { // Curly braces necessary to keep new variables inside the case statement
 
+      // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(), or
+      // register_hotplug_callback()  -->
+      if (false == hasMountedBefore)
+      {
+        hasMountedBefore = true;
+        if (BOARD_MACHINE_CONTROL == detectBoardType())
+        {
+          runningOnMachineControl = true;
+        }
+      }
+      // <--
+#if defined(ARDUINO_PORTENTA_H7_M7)
+      if (true == runningOnMachineControl)
+      {
+        // We need to apply power manually to the female USB A connector on the Machine Control
+        mbed::DigitalOut enablePower(PB_14, 0);
+      }
+#endif
       // A USB mass storage device is already mounted at that mount point, or
       // registered for the hotplug event
       if (nullptr != usb.device)
@@ -606,11 +625,6 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
         errno = EBUSY;
         return -1;
       }
-#if defined(ARDUINO_PORTENTA_H7_M7) || defined(ARDUINO_OPTA)
-      // There is no support for callbacks in the USBHostMSD class on this platform
-      errno = ENOTSUP;
-      return -1;
-#else      
       // We must create a USBHostMSD object to attach the callback to, but we
       // don't create a file system object because we don't fully mount() anything
       USBHostMSD *usbHostDevice = nullptr;
@@ -620,10 +634,15 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
         errno = ENOTBLK;
         return -1;
       }
+#if ((defined(ARDUINO_PORTENTA_H7_M7) || defined(ARDUINO_OPTA)))
+      // The Arduino_USBHostMbed5 library doesn't initialize the USB stack until
+      // the first connect() call because of an older bugfix (commit 72d0aa6), so
+      // we perform one connect() here to initialize the stack
+      usbHostDevice->connect();
+#endif
       if (false == (usbHostDevice->attach_detected_callback(callbackFunction)))
       {
-        delete usbHostDevice;   // Ok to delete, because this isn't on the H7
-        usbHostDevice = nullptr;
+        deleteDevice(DEV_USB, &usb);
         errno = EINVAL;
         return -1;
       }
@@ -632,7 +651,7 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
       // Prevent multiple registrations
       hotplugCallbackAlreadyRegistered = true;
       return 0;
-#endif
+
       } // Curly braces necessary to keep new variables inside the case statement
     default:
       errno = ENOTBLK;

From ba43834113dfea921c8f1f8dc0b0f7ec70324eab Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Wed, 20 Sep 2023 18:00:00 +0200
Subject: [PATCH 2/7] Add function to register a disconnect callback and adapt
 tests

Adds a function to register a disconnect callback for USB thumb drives. Also adapts the tests to
this new functionality, as well as the previous addition of callback support for the H7 boards.
---
 .../Arduino_POSIXStorage_Test.ino             | 115 ++++++---
 src/Arduino_POSIXStorage.cpp                  | 235 +++++++++++-------
 src/Arduino_POSIXStorage.h                    |  17 +-
 3 files changed, 234 insertions(+), 133 deletions(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index 4f5aee4..1b3e461 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -24,7 +24,7 @@ enum TestTypes : uint8_t
 
 // !!! TEST CONFIGURATION !!! -->
 
-constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
+constexpr enum TestTypes selectedTest = TEST_PORTENTA_H7_USB;
 
 // Notice that formtting tests can take a while to complete
 
@@ -35,12 +35,18 @@ constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
 // <-- !!! TEST CONFIGURATION !!!
 
 volatile bool usbAttached = false;
+volatile bool usbDetached = false;
 
 void usbCallback()
 {
   usbAttached = true;
 }
 
+void usbCallback2()
+{
+  usbDetached = true;
+}
+
 void setup() {
   bool allTestsOk = true;
   enum StorageDevices deviceName;
@@ -104,60 +110,55 @@ void setup() {
   }
   // <-- Register hotplug callback for SD Card test
 
-  if (TEST_PORTENTA_C33_USB == selectedTest)
+  // Register unplug callback for SD Card test -->
+  if (DEV_SDCARD == deviceName)
   {
-    // Register nullptr callback test -->
-    retVal = register_hotplug_callback(DEV_USB, nullptr);
-    if ((-1 != retVal) || (EFAULT != errno))
+    // Using usbCallback2() is fine because it doesn't get registered anyway
+    retVal = register_unplug_callback(DEV_SDCARD, usbCallback2);
+    if ((-1 != retVal) || (ENOTSUP != errno))
     {
       allTestsOk = false;
-      Serial.print("[FAIL] Register nullptr callback test failed");
+      Serial.print("[FAIL] Register unplug callback for SD Card test failed");
       Serial.println();
     }
-    // <-- Register nullptr callback test
   }
+  // <-- Register unplug callback for SD Card test
 
-  if ((TEST_PORTENTA_H7_USB == selectedTest) || (TEST_PORTENTA_MACHINE_CONTROL_USB == selectedTest) || (TEST_OPTA_USB == selectedTest))
+  if (DEV_USB == deviceName)
   {
-    // Register unsupported callback test -->
-    retVal = register_hotplug_callback(DEV_USB, usbCallback);
-    if ((-1 != retVal) || (ENOTSUP != errno))
+    // Register nullptr callback test (hotplug) -->
+    retVal = register_hotplug_callback(DEV_USB, nullptr);
+    if ((-1 != retVal) || (EFAULT != errno))
     {
       allTestsOk = false;
-      Serial.println("[FAIL] Register unsupported callback test");
+      Serial.print("[FAIL] Register nullptr callback test failed (hotplug)");
       Serial.println();
     }
-    // <-- Register unsupported callback test
+    // <-- Register nullptr callback test (hotplug)
+
+    // Register nullptr callback test (unplug) -->
+    retVal = register_unplug_callback(DEV_USB, nullptr);
+    if ((-1 != retVal) || (EFAULT != errno))
+    {
+      allTestsOk = false;
+      Serial.print("[FAIL] Register nullptr callback test failed (unplug)");
+      Serial.println();
+    }
+    // <-- Register nullptr callback test (unplug)
   }
 
-  // This isn't a test, just wait for a USB thumb drive -->
+  // Wait for a USB thumb drive -->
   if (DEV_USB == deviceName)
   {
     Serial.println("Please insert a thumb drive");
-    if (TEST_PORTENTA_C33_USB == selectedTest)
-    {
-      // This board supports hotplug callbacks
-      (void) register_hotplug_callback(DEV_USB, usbCallback);
-      while (false == usbAttached) {
-        delay(500);
-      }
-    }
-    else if ((TEST_PORTENTA_H7_USB == selectedTest) || (TEST_PORTENTA_MACHINE_CONTROL_USB == selectedTest) || (TEST_OPTA_USB == selectedTest))
-    {
-      // These boards don't support hotplug callbacks, so loop on mount() tries
-      while (0 != mount(DEV_USB, FS_FAT, MNT_DEFAULT)) {
-        delay(500);
-      }
-      (void) umount(DEV_USB);
-    }
-    else
-    {
-      for ( ; ;) ;  // Shouldn't get here unless there's a bug in the test code
+    (void) register_hotplug_callback(DEV_USB, usbCallback);
+    while (false == usbAttached) {
+      delay(500);
     }
     Serial.println("Thank you!");
     Serial.println();
   }
-  // <-- This isn't a test, just wait for a USB thumb drive
+  // <-- Wait for a USB thumb drive
   
 #if defined(PERFORM_FORMATTING_TESTS)
   Serial.println("The formatting tests you selected can take a while to complete");
@@ -335,26 +336,35 @@ void setup() {
   (void) umount(deviceName);
   // <-- mount() when already mounted test
 
-  if (TEST_PORTENTA_C33_USB == selectedTest)
+  if (DEV_USB == deviceName)
   {
-    // Register multiple callbacks test -->
+    // Register multiple callbacks test (hotplug) -->
     retVal = register_hotplug_callback(DEV_USB, usbCallback);
     if ((-1 != retVal) || (EBUSY != errno))
     {
       allTestsOk = false;
-      Serial.println("[FAIL] Register multiple callbacks test failed");
+      Serial.println("[FAIL] Register multiple callbacks test failed (hotplug)");
     }
-    // <-- Register multiple callbacks test
+    // <-- Register multiple callbacks test (hotplug)
   }
 
-  // Deregister callback not supported test -->
+  // Deregister callback not supported test (hotplug) -->
   retVal = deregister_hotplug_callback(DEV_USB);
   if ((-1 != retVal) || (ENOSYS != errno))
   {
     allTestsOk = false;
     Serial.println("[FAIL] Deregister callback not supported test failed");
   }
-  // <-- Deregister callback not supported test
+  // <-- Deregister callback not supported test (hotplug)
+
+  // Deregister callback not supported test (unplug) -->
+  retVal = deregister_unplug_callback(DEV_USB);
+  if ((-1 != retVal) || (ENOSYS != errno))
+  {
+    allTestsOk = false;
+    Serial.println("[FAIL] Deregister callback not supported test failed");
+  }
+  // <-- Deregister callback not supported test (unplug)
 
   // Remove before persistent storage test -->
   (void) mount(deviceName, FS_FAT, MNT_DEFAULT);
@@ -451,6 +461,31 @@ void setup() {
   (void) umount(deviceName);
   // <-- Persistent storage test
 
+  // Wait for USB thumb drive removal -->
+  if (DEV_USB == deviceName)
+  {
+    Serial.println();
+    Serial.println("Please remove the thumb drive");
+    (void) register_unplug_callback(DEV_USB, usbCallback2);
+    while (false == usbDetached) {
+      delay(500);
+    }
+    Serial.println("Thank you!");
+  }
+  // <-- Wait for USB thumb drive removal
+
+  if (DEV_USB == deviceName)
+  {
+    // Register multiple callbacks test (unplug) -->
+    retVal = register_unplug_callback(DEV_USB, usbCallback);
+    if ((-1 != retVal) || (EBUSY != errno))
+    {
+      allTestsOk = false;
+      Serial.println("[FAIL] Register multiple callbacks test failed (unplug)");
+    }
+    // <-- Register multiple callbacks test (unplug)
+  }
+
   // Final report -->
   Serial.println();
   Serial.println("Testing complete.");
diff --git a/src/Arduino_POSIXStorage.cpp b/src/Arduino_POSIXStorage.cpp
index b092390..5b5c6e0 100644
--- a/src/Arduino_POSIXStorage.cpp
+++ b/src/Arduino_POSIXStorage.cpp
@@ -72,8 +72,6 @@
   #error "The POSIXStorage library does not support this board"
 #endif
 
-
-
 /*
 *********************************************************************************************************
 *                                  Library-internal using declarations
@@ -116,6 +114,12 @@ enum BoardTypes : uint8_t
   BOARD_PORTENTA_C33
 };
 
+enum CallbackTypes : uint8_t
+{
+  CALLBACK_HOTPLUG,
+  CALLBACK_UNPLUG
+};
+
 /*
 *********************************************************************************************************
 *                       Unnamed namespace for library-internal global variables
@@ -130,6 +134,7 @@ struct DeviceFileSystemCombination usb    = {nullptr, nullptr};
 // <--
 
 bool hotplugCallbackAlreadyRegistered = false;
+bool unplugCallbackAlreadyRegistered = false;
 
 // Used to handle special case (powering USB A female socket separately) for Machine Control -->
 bool hasMountedBefore = false;
@@ -235,6 +240,28 @@ enum BoardTypes detectBoardType()
 #endif
 }   // End of detectBoardType()
 
+void portentaMachineControlPowerHandling()
+{
+  // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(),
+  // register_hotplug_callback(), or register_unplug_callback()  -->
+  if (false == hasMountedBefore)
+  {
+    hasMountedBefore = true;
+    if (BOARD_MACHINE_CONTROL == detectBoardType())
+    {
+      runningOnMachineControl = true;
+    }
+  }
+  // <--
+#if defined(ARDUINO_PORTENTA_H7_M7)
+  if (true == runningOnMachineControl)
+  {
+    // We need to apply power manually to the female USB A connector on the Machine Control
+    mbed::DigitalOut enablePower(PB_14, 0);
+  }
+#endif
+} // End of portentaMachineControl()
+
 void deleteDevice(const enum StorageDevices deviceName, struct DeviceFileSystemCombination * const deviceFileSystemCombination)
 {
   // The USBHostMSD class for the H7 doesn't correctly support object destruction, so we only delete
@@ -411,14 +438,6 @@ int mountOrFormatSDCard(const enum FileSystems fileSystem,
 int mountOrFormatUSBDevice(const enum FileSystems fileSystem,
                            const enum ActionTypes mountOrFormat)
 {
-#if defined(ARDUINO_PORTENTA_H7_M7) 
-  if (true == runningOnMachineControl)
-  {
-    // We need to apply power manually to the female USB A connector on the Machine Control
-    mbed::DigitalOut enablePower(PB_14, 0);
-  }
-#endif
-
   // We'll need a USBHostMSD pointer because connect() and connected() we'll use later aren't member
   // functions of the base class BlockDevice
   USBHostMSD *usbHostDevice = nullptr;
@@ -480,17 +499,7 @@ int mountOrFormat(const enum StorageDevices deviceName,
                   const enum FileSystems fileSystem,
                   const enum ActionTypes mountOrFormat)
 {
-  // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(), or
-  // register_hotplug_callback()  -->
-  if (false == hasMountedBefore)
-  {
-    hasMountedBefore = true;
-    if (BOARD_MACHINE_CONTROL == detectBoardType())
-    {
-      runningOnMachineControl = true;
-    }
-  }
-  // <--
+  portentaMachineControlPowerHandling();
   switch (deviceName)
   {
     case DEV_SDCARD:
@@ -502,6 +511,91 @@ int mountOrFormat(const enum StorageDevices deviceName,
   }
 }   // End of mountOrFormat()
 
+// WARNING: Don't set errno and return -1 in this function - just return 0 for success or the errno code!
+int register_callback(const enum StorageDevices deviceName, void (* const callbackFunction)(), enum CallbackTypes callbackType)
+{
+  if (((CALLBACK_HOTPLUG == callbackType) && (true == hotplugCallbackAlreadyRegistered)) ||
+     ((CALLBACK_UNPLUG == callbackType) && (true == unplugCallbackAlreadyRegistered)))
+  {
+    return EBUSY;
+  }
+  if (nullptr == callbackFunction)
+  {
+    return EFAULT;
+  }
+  switch (deviceName)
+  {
+    case DEV_SDCARD:    // There is no support for callbacks in the any of the SD Card block device classes
+      return ENOTSUP;
+    case DEV_USB:
+      { // Curly braces necessary to keep new variables inside the case statement
+
+      portentaMachineControlPowerHandling();
+      USBHostMSD *usbHostDevice = nullptr;
+      if (nullptr == usb.device)
+      {
+        // We must create a USBHostMSD object to attach the callback to, but we
+        // don't create a file system object because we don't fully mount() anything
+        usbHostDevice = new(std::nothrow) USBHostMSD;
+        if (nullptr == usbHostDevice)
+        {
+          return ENOTBLK;
+        }
+#if ((defined(ARDUINO_PORTENTA_H7_M7) || defined(ARDUINO_OPTA)))
+        // The Arduino_USBHostMbed5 library doesn't initialize the USB stack until
+        // the first connect() call because of an older bugfix (commit 72d0aa6), so
+        // we perform one connect() here to initialize the stack
+        usbHostDevice->connect();
+#endif
+        // This is necessary for future calls to mount(), umount(), and mkfs()
+        usb.device = usbHostDevice;
+      }
+      else
+      {
+        // Ok to downcast with static_cast because we know for sure that usb.device isn't pointing to a
+        // base-class object, and dynamic_cast wouldn't work anyway because compilation is done with -fno-rtti
+        usbHostDevice = static_cast<USBHostMSD*>(usb.device);
+      }
+      bool attachCallbackReturn = false;
+      if (CALLBACK_HOTPLUG == callbackType)
+      {
+        attachCallbackReturn = usbHostDevice->attach_detected_callback(callbackFunction);
+      }
+      else if (CALLBACK_UNPLUG == callbackType)
+      {
+        attachCallbackReturn = usbHostDevice->attach_removed_callback(callbackFunction);
+      }
+      else
+      {
+        // This should only happen if there's a bug in the code
+        attachCallbackReturn = false;
+      }
+      if (false == attachCallbackReturn)
+      {
+        deleteDevice(DEV_USB, &usb);
+        return EINVAL;
+      }
+      // Prevent multiple registrations
+      if (CALLBACK_HOTPLUG == callbackType)
+      {
+        hotplugCallbackAlreadyRegistered = true;
+      }
+      else if (CALLBACK_UNPLUG == callbackType)
+      {
+        unplugCallbackAlreadyRegistered = true;
+      }
+      else
+      {
+        // This should only happen if there's a bug in the code
+      }
+      return 0;
+
+      } // Curly braces necessary to keep new variables inside the case statement
+    default:
+      return ENOTBLK;
+  }
+}   // End of register_unplug_callback()
+
 }   // End of unnamed namespace
 
 /*
@@ -582,90 +676,47 @@ int umount(const enum StorageDevices deviceName)
 
 int register_hotplug_callback(const enum StorageDevices deviceName, void (* const callbackFunction)())
 {
-  if (true == hotplugCallbackAlreadyRegistered)
+  const int callbackReturn = register_callback(deviceName, callbackFunction, CALLBACK_HOTPLUG);
+  if (0 != callbackReturn)
   {
-    errno = EBUSY;
+    errno = callbackReturn;
     return -1;
   }
-  if (nullptr == callbackFunction)
+  else
   {
-    errno = EFAULT;
-    return -1;
+    return 0;
   }
-  switch (deviceName)
-  {
-    case DEV_SDCARD:    // There is no support for callbacks in the any of the SD Card block device classes
-      errno = ENOTSUP;
-      return -1;
-    case DEV_USB:
-      { // Curly braces necessary to keep new variables inside the case statement
+}   // End of register_hotplug_callback()
 
-      // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(), or
-      // register_hotplug_callback()  -->
-      if (false == hasMountedBefore)
-      {
-        hasMountedBefore = true;
-        if (BOARD_MACHINE_CONTROL == detectBoardType())
-        {
-          runningOnMachineControl = true;
-        }
-      }
-      // <--
-#if defined(ARDUINO_PORTENTA_H7_M7)
-      if (true == runningOnMachineControl)
-      {
-        // We need to apply power manually to the female USB A connector on the Machine Control
-        mbed::DigitalOut enablePower(PB_14, 0);
-      }
-#endif
-      // A USB mass storage device is already mounted at that mount point, or
-      // registered for the hotplug event
-      if (nullptr != usb.device)
-      {
-        errno = EBUSY;
-        return -1;
-      }
-      // We must create a USBHostMSD object to attach the callback to, but we
-      // don't create a file system object because we don't fully mount() anything
-      USBHostMSD *usbHostDevice = nullptr;
-      usbHostDevice = new(std::nothrow) USBHostMSD;
-      if (nullptr == usbHostDevice)
-      {
-        errno = ENOTBLK;
-        return -1;
-      }
-#if ((defined(ARDUINO_PORTENTA_H7_M7) || defined(ARDUINO_OPTA)))
-      // The Arduino_USBHostMbed5 library doesn't initialize the USB stack until
-      // the first connect() call because of an older bugfix (commit 72d0aa6), so
-      // we perform one connect() here to initialize the stack
-      usbHostDevice->connect();
-#endif
-      if (false == (usbHostDevice->attach_detected_callback(callbackFunction)))
-      {
-        deleteDevice(DEV_USB, &usb);
-        errno = EINVAL;
-        return -1;
-      }
-      // This is necessary for future calls to mount(), umount(), and mkfs()
-      usb.device = usbHostDevice;
-      // Prevent multiple registrations
-      hotplugCallbackAlreadyRegistered = true;
-      return 0;
+// Not supported by the layer below on these platforms, but might be on other platforms
+int deregister_hotplug_callback(const enum StorageDevices deviceName)
+{
+  (void) deviceName;    // Remove when implemented, only here to silence -Wunused-parameter
+  errno = ENOSYS;
+  return -1;
+}   // End of deregister_hotplug_callback()
 
-      } // Curly braces necessary to keep new variables inside the case statement
-    default:
-      errno = ENOTBLK;
-      return -1;
-  }        
-}   // End of hotplug_register_callback()
+int register_unplug_callback(const enum StorageDevices deviceName, void (* const callbackFunction)())
+{
+  const int callbackReturn = register_callback(deviceName, callbackFunction, CALLBACK_UNPLUG);
+  if (0 != callbackReturn)
+  {
+    errno = callbackReturn;
+    return -1;
+  }
+  else
+  {
+    return 0;
+  }
+}   // End of register__unplug_callback()
 
 // Not supported by the layer below on these platforms, but might be on other platforms
-int deregister_hotplug_callback(const enum StorageDevices deviceName)
+int deregister_unplug_callback(const enum StorageDevices deviceName)
 {
   (void) deviceName;    // Remove when implemented, only here to silence -Wunused-parameter
   errno = ENOSYS;
   return -1;
-}   // End of hotplug_deregister_callback()
+}   // End of deregister_unplug_callback()
 
 /*
 *********************************************************************************************************
diff --git a/src/Arduino_POSIXStorage.h b/src/Arduino_POSIXStorage.h
index d38bdbd..dec1730 100644
--- a/src/Arduino_POSIXStorage.h
+++ b/src/Arduino_POSIXStorage.h
@@ -135,7 +135,7 @@ int mount(const enum StorageDevices deviceName,
 int umount(const enum StorageDevices deviceName);
 
 /**
-* @brief Register a hotplug callback function. Currently only supported for DEV_USB on Portenta C33.
+* @brief Register a hotplug callback function.
 * @param deviceName The device to register for: DEV_SDCARD or DEV_USB.
 * @param callbackFunction A function pointer to the callback.
 * @return On success: 0. On failure: -1 with an error code in the errno variable.
@@ -149,6 +149,21 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
 */
 int deregister_hotplug_callback(const enum StorageDevices deviceName);
 
+/**
+* @brief Register an unplug callback function.
+* @param deviceName The device to register for: DEV_SDCARD or DEV_USB.
+* @param callbackFunction A function pointer to the callback.
+* @return On success: 0. On failure: -1 with an error code in the errno variable.
+*/
+int register_unplug_callback(const enum StorageDevices deviceName, void (* const callbackFunction)());
+
+/**
+* @brief Deregister a previously registered unplug callback function. Not currently supported on any platform.
+* @param deviceName The device to deregister for: DEV_SDCARD or DEV_USB.
+* @return On success: 0. On failure: -1 with an error code in the errno variable.
+*/
+int deregister_unplug_callback(const enum StorageDevices deviceName);
+
 /**
 * @brief Format a device (make file system).
 * @param deviceName The device to format: DEV_SDCARD or DEV_USB.

From a74c369502661ce809bfd676664b9ca34986a229 Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Thu, 21 Sep 2023 17:32:36 +0200
Subject: [PATCH 3/7] Make minor improvements to the code

Some minor imporovements after reviewing the code before the final tests.
---
 .../Arduino_POSIXStorage_Test.ino             |  4 +-
 src/Arduino_POSIXStorage.cpp                  | 37 ++++++++-----------
 2 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index 1b3e461..48aeee9 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -24,7 +24,7 @@ enum TestTypes : uint8_t
 
 // !!! TEST CONFIGURATION !!! -->
 
-constexpr enum TestTypes selectedTest = TEST_PORTENTA_H7_USB;
+constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
 
 // Notice that formtting tests can take a while to complete
 
@@ -477,7 +477,7 @@ void setup() {
   if (DEV_USB == deviceName)
   {
     // Register multiple callbacks test (unplug) -->
-    retVal = register_unplug_callback(DEV_USB, usbCallback);
+    retVal = register_unplug_callback(DEV_USB, usbCallback2);
     if ((-1 != retVal) || (EBUSY != errno))
     {
       allTestsOk = false;
diff --git a/src/Arduino_POSIXStorage.cpp b/src/Arduino_POSIXStorage.cpp
index 5b5c6e0..7333db1 100644
--- a/src/Arduino_POSIXStorage.cpp
+++ b/src/Arduino_POSIXStorage.cpp
@@ -243,7 +243,7 @@ enum BoardTypes detectBoardType()
 void portentaMachineControlPowerHandling()
 {
   // Determine if we're running on Machine Control or not on the first call to mount(), mkfs(),
-  // register_hotplug_callback(), or register_unplug_callback()  -->
+  // register_hotplug_callback(), or register_unplug_callback()
   if (false == hasMountedBefore)
   {
     hasMountedBefore = true;
@@ -251,16 +251,15 @@ void portentaMachineControlPowerHandling()
     {
       runningOnMachineControl = true;
     }
-  }
-  // <--
 #if defined(ARDUINO_PORTENTA_H7_M7)
-  if (true == runningOnMachineControl)
-  {
-    // We need to apply power manually to the female USB A connector on the Machine Control
-    mbed::DigitalOut enablePower(PB_14, 0);
-  }
+    if (true == runningOnMachineControl)
+    {
+      // We need to apply power manually to the female USB A connector on the Machine Control
+      mbed::DigitalOut enablePower(PB_14, 0);
+    }
 #endif
-} // End of portentaMachineControl()
+  }
+} // End of portentaMachineControlPowerHandling()
 
 void deleteDevice(const enum StorageDevices deviceName, struct DeviceFileSystemCombination * const deviceFileSystemCombination)
 {
@@ -556,7 +555,7 @@ int register_callback(const enum StorageDevices deviceName, void (* const callba
         // base-class object, and dynamic_cast wouldn't work anyway because compilation is done with -fno-rtti
         usbHostDevice = static_cast<USBHostMSD*>(usb.device);
       }
-      bool attachCallbackReturn = false;
+      bool attachCallbackReturn;
       if (CALLBACK_HOTPLUG == callbackType)
       {
         attachCallbackReturn = usbHostDevice->attach_detected_callback(callbackFunction);
@@ -657,7 +656,7 @@ int umount(const enum StorageDevices deviceName)
     return -1;
   }
   // See note (1) at the bottom of the file
-  int unmountRet = deviceFileSystemCombination->fileSystem->unmount();
+  const int unmountRet = deviceFileSystemCombination->fileSystem->unmount();
   if (0 == unmountRet)
   {
     // Ok to delete with base class pointer because the destructor of the base class is virtual
@@ -682,13 +681,10 @@ int register_hotplug_callback(const enum StorageDevices deviceName, void (* cons
     errno = callbackReturn;
     return -1;
   }
-  else
-  {
-    return 0;
-  }
+  return 0;
 }   // End of register_hotplug_callback()
 
-// Not supported by the layer below on these platforms, but might be on other platforms
+// Currently not supported on any platform, but might be in the future
 int deregister_hotplug_callback(const enum StorageDevices deviceName)
 {
   (void) deviceName;    // Remove when implemented, only here to silence -Wunused-parameter
@@ -704,13 +700,10 @@ int register_unplug_callback(const enum StorageDevices deviceName, void (* const
     errno = callbackReturn;
     return -1;
   }
-  else
-  {
-    return 0;
-  }
-}   // End of register__unplug_callback()
+  return 0;
+}   // End of register_unplug_callback()
 
-// Not supported by the layer below on these platforms, but might be on other platforms
+// Currently not supported on any platform, but might be in the future
 int deregister_unplug_callback(const enum StorageDevices deviceName)
 {
   (void) deviceName;    // Remove when implemented, only here to silence -Wunused-parameter

From 9a53b8fb5387db7720aedef50816d054469bc8ef Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Thu, 21 Sep 2023 17:42:35 +0200
Subject: [PATCH 4/7] Add minor improvements in the test sketch

---
 .../Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index 48aeee9..8c950b2 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -353,7 +353,7 @@ void setup() {
   if ((-1 != retVal) || (ENOSYS != errno))
   {
     allTestsOk = false;
-    Serial.println("[FAIL] Deregister callback not supported test failed");
+    Serial.println("[FAIL] Deregister callback not supported test failed (hotplug)");
   }
   // <-- Deregister callback not supported test (hotplug)
 
@@ -362,7 +362,7 @@ void setup() {
   if ((-1 != retVal) || (ENOSYS != errno))
   {
     allTestsOk = false;
-    Serial.println("[FAIL] Deregister callback not supported test failed");
+    Serial.println("[FAIL] Deregister callback not supported test failed (unplug)");
   }
   // <-- Deregister callback not supported test (unplug)
 

From 8a75ab20a25e1ce164f10f35ccc049606c5fe38c Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Thu, 21 Sep 2023 17:51:09 +0200
Subject: [PATCH 5/7] Add check for Opta before disconnect tests

We can't perform the disconnect tests because we log to USB on the Opta.
---
 .../Arduino_POSIXStorage_Test.ino             | 44 ++++++++++---------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index 8c950b2..ab93599 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -24,13 +24,13 @@ enum TestTypes : uint8_t
 
 // !!! TEST CONFIGURATION !!! -->
 
-constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
+constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_USB;
 
 // Notice that formtting tests can take a while to complete
 
 // Uncomment the line below to include testing of LITTLEFS and FAT formatting with mkfs():
 
-//#define PERFORM_FORMATTING_TESTS
+#define PERFORM_FORMATTING_TESTS
 
 // <-- !!! TEST CONFIGURATION !!!
 
@@ -461,29 +461,33 @@ void setup() {
   (void) umount(deviceName);
   // <-- Persistent storage test
 
-  // Wait for USB thumb drive removal -->
-  if (DEV_USB == deviceName)
+  // These tests can't be performed on the Opta because we log to USB
+  if (TEST_OPTA_USB != selectedTest)
   {
-    Serial.println();
-    Serial.println("Please remove the thumb drive");
-    (void) register_unplug_callback(DEV_USB, usbCallback2);
-    while (false == usbDetached) {
-      delay(500);
+    // Wait for USB thumb drive removal -->
+    if (DEV_USB == deviceName)
+    {
+      Serial.println();
+      Serial.println("Please remove the thumb drive");
+      (void) register_unplug_callback(DEV_USB, usbCallback2);
+      while (false == usbDetached) {
+        delay(500);
+      }
+      Serial.println("Thank you!");
     }
-    Serial.println("Thank you!");
-  }
-  // <-- Wait for USB thumb drive removal
+    // <-- Wait for USB thumb drive removal
 
-  if (DEV_USB == deviceName)
-  {
-    // Register multiple callbacks test (unplug) -->
-    retVal = register_unplug_callback(DEV_USB, usbCallback2);
-    if ((-1 != retVal) || (EBUSY != errno))
+    if (DEV_USB == deviceName)
     {
-      allTestsOk = false;
-      Serial.println("[FAIL] Register multiple callbacks test failed (unplug)");
+      // Register multiple callbacks test (unplug) -->
+      retVal = register_unplug_callback(DEV_USB, usbCallback2);
+      if ((-1 != retVal) || (EBUSY != errno))
+      {
+        allTestsOk = false;
+        Serial.println("[FAIL] Register multiple callbacks test failed (unplug)");
+      }
+      // <-- Register multiple callbacks test (unplug)
     }
-    // <-- Register multiple callbacks test (unplug)
   }
 
   // Final report -->

From 783a3fc21f8ac5b95702282a8a5fb52e9b799466 Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Thu, 21 Sep 2023 20:33:36 +0200
Subject: [PATCH 6/7] Minor changes to Opta tests

---
 .../Arduino_POSIXStorage_Test.ino             | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index ab93599..6a12c32 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -18,13 +18,13 @@ enum TestTypes : uint8_t
   TEST_PORTENTA_H7_USB,
   TEST_PORTENTA_MACHINE_CONTROL_SDCARD,
   TEST_PORTENTA_MACHINE_CONTROL_USB,
-  TEST_OPTA_SDCARD,
-  TEST_OPTA_USB
+  TEST_OPTA_SDCARD,   // Not currently implemented
+  TEST_OPTA_USB       // Logging to thumb drive
 };
 
 // !!! TEST CONFIGURATION !!! -->
 
-constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_USB;
+constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
 
 // Notice that formtting tests can take a while to complete
 
@@ -77,13 +77,15 @@ void setup() {
   Serial.println("Testing started, please wait...");
   Serial.println();
 
-  if ((TEST_PORTENTA_MACHINE_CONTROL_SDCARD == selectedTest) || (TEST_OPTA_SDCARD == selectedTest))
+  if (TEST_PORTENTA_MACHINE_CONTROL_SDCARD == selectedTest)
   {
-    // Machine Control and Opta no SD Card supported test -->
+    // Machine Control no SD Card supported test -->
     retVal = mount(DEV_SDCARD, FS_FAT, MNT_DEFAULT);
     if ((-1 != retVal) || (ENOTBLK != errno))
     {
-      Serial.println("[FAIL] Machine Control and Opta no SD Card supported test failed");
+      Serial.println("[FAIL] Machine Control no SD Card supported test failed");
+      Serial.println();
+      Serial.println("FAILURE: Finished with errors (see list above for details)");
     }
     else
     {
@@ -91,8 +93,8 @@ void setup() {
       Serial.println();
       Serial.println("SUCCESS: Finished without errors");
       (void) umount(DEV_SDCARD);
-      for ( ; ; ) ;   // Stop testing here
     }
+    for ( ; ; ) ;   // Stop testing here
     // <-- Machine Control and Opta no SD Card supported test
   }
 
@@ -507,7 +509,7 @@ void setup() {
   // Opta final report -->
   if (TEST_OPTA_USB == selectedTest)
   {
-    (void) mount(deviceName, FS_FAT, MNT_DEFAULT);
+    (void) mount(DEV_USB, FS_FAT, MNT_DEFAULT);
     FILE *logFile = fopen("/usb/testlog.txt", "w");
     if (true == allTestsOk)
     {
@@ -519,7 +521,7 @@ void setup() {
       fprintf(logFile, "FAILURE: Finished with errors");
       fclose(logFile);      
     }
-    (void) umount(deviceName);
+    (void) umount(DEV_USB);
   }
   // <--
 }

From d565fff05020dacd026893d44f9f89491fa65a9f Mon Sep 17 00:00:00 2001
From: Alrik Vidstrom <a.vidstrom@arduino.cc>
Date: Thu, 21 Sep 2023 20:49:21 +0200
Subject: [PATCH 7/7] Turn off formatting tests by default

---
 .../Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino     | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
index 6a12c32..0cf71ff 100644
--- a/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
+++ b/extras/tests/Arduino_POSIXStorage_Test/Arduino_POSIXStorage_Test.ino
@@ -30,7 +30,7 @@ constexpr enum TestTypes selectedTest = TEST_PORTENTA_C33_SDCARD;
 
 // Uncomment the line below to include testing of LITTLEFS and FAT formatting with mkfs():
 
-#define PERFORM_FORMATTING_TESTS
+//#define PERFORM_FORMATTING_TESTS
 
 // <-- !!! TEST CONFIGURATION !!!