diff --git a/data_handler.hpp b/data_handler.hpp
index 6c660c8..1bee432 100644
--- a/data_handler.hpp
+++ b/data_handler.hpp
@@ -23,6 +23,13 @@
     virtual bool open() = 0;
 
     /**
+     * Close the data transport mechanism.
+     *
+     * @return true if successful
+     */
+    virtual bool close() = 0;
+
+    /**
      * Copy bytes from external interface (blocking call).
      *
      * @param[in] length - number of bytes to copy
diff --git a/lpc_handler.cpp b/lpc_handler.cpp
index a723461..1c441d6 100644
--- a/lpc_handler.cpp
+++ b/lpc_handler.cpp
@@ -15,6 +15,12 @@
     return true;
 }
 
+bool LpcDataHandler::close()
+{
+    /* TODO: implement ioctl call to close window. */
+    return false;
+}
+
 std::vector<std::uint8_t> LpcDataHandler::copyFrom(std::uint32_t length)
 {
     /* TODO: implement this. */
diff --git a/lpc_handler.hpp b/lpc_handler.hpp
index e74c59f..c60b782 100644
--- a/lpc_handler.hpp
+++ b/lpc_handler.hpp
@@ -27,6 +27,7 @@
     LpcDataHandler() = default;
 
     bool open() override;
+    bool close() override;
     std::vector<std::uint8_t> copyFrom(std::uint32_t length) override;
     bool write(const std::vector<std::uint8_t>& configuration) override;
     std::vector<std::uint8_t> read() override;
diff --git a/pci_handler.cpp b/pci_handler.cpp
index 3fa7ec9..dce1098 100644
--- a/pci_handler.cpp
+++ b/pci_handler.cpp
@@ -9,8 +9,15 @@
 
 bool PciDataHandler::open()
 {
-    /* For the ASPEED P2A driver, this method will enable the memory region to
-     * use.
+    /* TODO: For the ASPEED P2A driver, this method will enable the memory
+     * region to use.
+     */
+    return false;
+}
+
+bool PciDataHandler::close()
+{
+    /* TODO: Turn off the P2A bridge and region to disable host-side access.
      */
     return false;
 }
diff --git a/pci_handler.hpp b/pci_handler.hpp
index ba09d51..755ee18 100644
--- a/pci_handler.hpp
+++ b/pci_handler.hpp
@@ -23,6 +23,7 @@
     PciDataHandler() = default;
 
     bool open() override;
+    bool close() override;
     std::vector<std::uint8_t> copyFrom(std::uint32_t length) override;
     bool write(const std::vector<std::uint8_t>& configuration) override;
     std::vector<std::uint8_t> read() override;
diff --git a/test/data_mock.hpp b/test/data_mock.hpp
index 44cc376..44c3aae 100644
--- a/test/data_mock.hpp
+++ b/test/data_mock.hpp
@@ -13,6 +13,7 @@
     virtual ~DataHandlerMock() = default;
 
     MOCK_METHOD0(open, bool());
+    MOCK_METHOD0(close, bool());
     MOCK_METHOD1(copyFrom, std::vector<std::uint8_t>(std::uint32_t));
     MOCK_METHOD1(write, bool(const std::vector<std::uint8_t>&));
     MOCK_METHOD0(read, std::vector<std::uint8_t>());