5 files changed, 57 insertions, 1 deletions
diff --git a/src/drivers/device/device.cpp b/src/drivers/device/device.cpp
index 683455149..f1f777dce 100644
--- a/src/drivers/device/device.cpp
+++ b/src/drivers/device/device.cpp
@@ -42,6 +42,7 @@
 #include <nuttx/arch.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <drivers/drv_device.h>
 
 namespace device
 {
@@ -93,6 +94,13 @@ Device::Device(const char *name,
 	_irq_attached(false)
 {
 	sem_init(&_lock, 0, 1);
+        
+	/* setup a default device ID. When bus_type is UNKNOWN the
+	   other fields are invalid */
+	_device_id.devid_s.bus_type = DeviceBusType_UNKNOWN;
+	_device_id.devid_s.bus = 0;
+	_device_id.devid_s.address = 0;
+	_device_id.devid_s.devtype = 0;
 }
 
 Device::~Device()
@@ -238,6 +246,10 @@ Device::write(unsigned offset, void *data, unsigned count)
 int
 Device::ioctl(unsigned operation, unsigned &arg)
 {
+	switch (operation) {
+	case DEVIOCGDEVICEID:
+		return (int)_device_id.devid;
+	}
 	return -ENODEV;
 }
 
diff --git a/src/drivers/device/device.h b/src/drivers/device/device.h
index d99f22922..c98386eb0 100644
--- a/src/drivers/device/device.h
+++ b/src/drivers/device/device.h
@@ -124,9 +124,34 @@ public:
 	 */
 	virtual int	ioctl(unsigned operation, unsigned &arg);
 
+	/*
+	  device bus types for DEVID
+	 */
+	enum DeviceBusType {
+		DeviceBusType_UNKNOWN = 0,
+		DeviceBusType_I2C     = 1,
+		DeviceBusType_SPI     = 2
+	};
+
+	/*
+	  broken out 
+	 */
+	struct DeviceStructure {
+		enum DeviceBusType bus_type;
+		uint8_t bus;       // which instance of the bus type
+		uint8_t address;   // address on the bus (eg. I2C address)
+		uint8_t devtype;   // device class specific device type
+	};
+
+	union DeviceId {
+		struct DeviceStructure devid_s;
+		uint32_t devid;
+	};
+
 protected:
 	const char	*_name;			/**< driver name */
 	bool		_debug_enabled;		/**< if true, debug messages are printed */
+	union DeviceId	_device_id;             /**< device identifier information */
 
 	/**
 	 * Constructor
diff --git a/src/drivers/device/i2c.cpp b/src/drivers/device/i2c.cpp
index a416801eb..286778c01 100644
--- a/src/drivers/device/i2c.cpp
+++ b/src/drivers/device/i2c.cpp
@@ -62,6 +62,12 @@ I2C::I2C(const char *name,
 	_frequency(frequency),
 	_dev(nullptr)
 {
+	// fill in _device_id fields for a I2C device
+	_device_id.devid_s.bus_type = DeviceBusType_I2C;
+	_device_id.devid_s.bus = bus;
+	_device_id.devid_s.address = address;
+	// devtype needs to be filled in by the driver
+	_device_id.devid_s.devtype = 0;     
 }
 
 I2C::~I2C()
@@ -201,4 +207,4 @@ I2C::transfer(i2c_msg_s *msgv, unsigned msgs)
 	return ret;
 }
 
-} // namespace device
-\ No newline at end of file
+} // namespace device
diff --git a/src/drivers/device/spi.cpp b/src/drivers/device/spi.cpp
index 1ab1dc699..200acac05 100644
--- a/src/drivers/device/spi.cpp
+++ b/src/drivers/device/spi.cpp
@@ -75,6 +75,12 @@ SPI::SPI(const char *name,
 	_dev(nullptr),
 	_bus(bus)
 {
+	// fill in _device_id fields for a SPI device
+	_device_id.devid_s.bus_type = DeviceBusType_SPI;
+	_device_id.devid_s.bus = bus;
+	_device_id.devid_s.address = (uint8_t)device;
+	// devtype needs to be filled in by the driver
+	_device_id.devid_s.devtype = 0; 
 }
 
 SPI::~SPI()
diff --git a/src/drivers/drv_device.h b/src/drivers/drv_device.h
index b310beb74..19d55cef3 100644
--- a/src/drivers/drv_device.h
+++ b/src/drivers/drv_device.h
@@ -59,4 +59,11 @@
 /** check publication block status */
 #define DEVIOCGPUBBLOCK	_DEVICEIOC(1)
 
+/**
+ * Return device ID, to enable matching of configuration parameters
+ * (such as compass offsets) to specific sensors
+ */
+#define DEVIOCGDEVICEID	_DEVICEIOC(2)
+
+
 #endif /* _DRV_DEVICE_H */