diff --git a/src/drivers/device/device.cpp b/src/drivers/device/device.cpp
index 04a5222c36..c3ee77b1ca 100644
--- a/src/drivers/device/device.cpp
+++ b/src/drivers/device/device.cpp
@@ -223,5 +223,22 @@ interrupt(int irq, void *context)
 	return OK;
 }
 
+int
+Device::read(unsigned offset, void *data, unsigned count)
+{
+	return -ENODEV;
+}
 
-} // namespace device
\ No newline at end of file
+int
+Device::write(unsigned offset, void *data, unsigned count)
+{
+	return -ENODEV;
+}
+
+int
+Device::ioctl(unsigned operation, unsigned &arg)
+{
+	return -ENODEV;
+}
+
+} // namespace device
diff --git a/src/drivers/device/device.h b/src/drivers/device/device.h
index 7d375aab91..a9ed5d77c2 100644
--- a/src/drivers/device/device.h
+++ b/src/drivers/device/device.h
@@ -68,11 +68,62 @@ namespace device __EXPORT
 class __EXPORT Device
 {
 public:
+	/**
+	 * Destructor.
+	 *
+	 * Public so that anonymous devices can be destroyed.
+	 */
+	virtual ~Device();
+
 	/**
 	 * Interrupt handler.
 	 */
 	virtual void	interrupt(void *ctx);	/**< interrupt handler */
 
+	/*
+	 * Direct access methods.
+	 */
+
+	/**
+	 * Initialise the driver and make it ready for use.
+	 *
+	 * @return	OK if the driver initialized OK, negative errno otherwise;
+	 */
+	virtual int	init();
+
+	/**
+	 * Read directly from the device.
+	 *
+	 * The actual size of each unit quantity is device-specific.
+	 *
+	 * @param offset	The device address at which to start reading
+	 * @param data		The buffer into which the read values should be placed.
+	 * @param count		The number of items to read.
+	 * @return		The number of items read on success, negative errno otherwise.
+	 */
+	virtual int	read(unsigned address, void *data, unsigned count);
+
+	/**
+	 * Write directly to the device.
+	 *
+	 * The actual size of each unit quantity is device-specific.
+	 *
+	 * @param address	The device address at which to start writing.
+	 * @param data		The buffer from which values should be read.
+	 * @param count		The number of items to write.
+	 * @return		The number of items written on success, negative errno otherwise.
+	 */	 
+	virtual int	write(unsigned address, void *data, unsigned count);
+
+	/**
+	 * Perform a device-specific operation.
+	 *
+	 * @param operation	The operation to perform.
+	 * @param arg		An argument to the operation.
+	 * @return		Negative errno on error, OK or positive value on success.
+	 */
+	virtual int	ioctl(unsigned operation, unsigned &arg);
+
 protected:
 	const char	*_name;			/**< driver name */
 	bool		_debug_enabled;		/**< if true, debug messages are printed */
@@ -85,14 +136,6 @@ protected:
 	 */
 	Device(const char *name,
 	       int irq = 0);
-	~Device();
-
-	/**
-	 * Initialise the driver and make it ready for use.
-	 *
-	 * @return	OK if the driver initialised OK.
-	 */
-	virtual int	init();
 
 	/**
 	 * Enable the device interrupt
@@ -189,7 +232,7 @@ public:
 	/**
 	 * Destructor
 	 */
-	~CDev();
+	virtual ~CDev();
 
 	virtual int	init();
 
@@ -282,6 +325,7 @@ public:
 	 * Test whether the device is currently open.
 	 *
 	 * This can be used to avoid tearing down a device that is still active.
+	 * Note - not virtual, cannot be overridden by a subclass.
 	 *
 	 * @return              True if the device is currently open.
 	 */
@@ -396,9 +440,9 @@ public:
 	    const char *devname,
 	    uint32_t base,
 	    int irq = 0);
-	~PIO();
+	virtual ~PIO();
 
-	int		init();
+	virtual int	init();
 
 protected:
 
@@ -407,7 +451,7 @@ protected:
 	 *
 	 * @param offset	Register offset in bytes from the base address.
 	 */
-	uint32_t reg(uint32_t offset) {
+	uint32_t	reg(uint32_t offset) {
 		return *(volatile uint32_t *)(_base + offset);
 	}
 
@@ -444,4 +488,4 @@ private:
 
 } // namespace device
 
-#endif /* _DEVICE_DEVICE_H */
\ No newline at end of file
+#endif /* _DEVICE_DEVICE_H */
diff --git a/src/drivers/device/i2c.h b/src/drivers/device/i2c.h
index b4a9cdd536..5498793523 100644
--- a/src/drivers/device/i2c.h
+++ b/src/drivers/device/i2c.h
@@ -55,13 +55,11 @@ class __EXPORT I2C : public CDev
 
 public:
 
-    /**
-     * Get the address
-     */
-    uint16_t get_address() {
-      return _address;
-    }
-
+	/**
+	 * Get the address
+	 */
+	int16_t		get_address() { return _address; }
+	
 protected:
 	/**
 	 * The number of times a read or write operation will be retried on
@@ -90,7 +88,7 @@ protected:
 	    uint16_t address,
 	    uint32_t frequency,
 	    int irq = 0);
-	~I2C();
+	virtual ~I2C();
 
 	virtual int	init();
 
diff --git a/src/drivers/device/spi.h b/src/drivers/device/spi.h
index d2d01efb35..e0122372a0 100644
--- a/src/drivers/device/spi.h
+++ b/src/drivers/device/spi.h
@@ -71,7 +71,7 @@ protected:
 	    enum spi_mode_e mode,
 	    uint32_t frequency,
 	    int irq = 0);
-	~SPI();
+	virtual ~SPI();
 
 	virtual int	init();