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Developing Device Drivers for the Sensor and Location Platform

Developing Device Drivers for the Sensor and Location Platform. Frank Chen Senior Development Lead PC|3 frank.chen@microsoft.com. Sensor and Location Platform. Is a new component in Windows 7 Allows applications to query and discover sensors

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Developing Device Drivers for the Sensor and Location Platform

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  1. Developing Device Drivers for the Sensor and Location Platform • Frank Chen • Senior Development Lead • PC|3 • frank.chen@microsoft.com

  2. Sensor and Location Platform • Is a new component in Windows 7 • Allows applications to query and discover sensors • Shares sensor and location data among multiple applications • Enables scenarios • Adaptive display brightness • Automatic display orientation • Location-aware weather gadget

  3. Introduction: Sensors • Represent measurements of physical quantities or other interactions • Belong to a “sensor category” • Can be identified by “sensor type” • Have metadata and data fields • Report data and events

  4. Sensor and Location Platform Overview Location Automation API Location and Other SensorsControlPanel Location API Sensor API UMDF Sensor Device Driver Sensor Driver Class Extension

  5. Sensor and Location Platform Overview • Sensor API • Is an inproc COM DLL • Exposes interfaces • ISensorManager, ISensorManagerEvents • ISensor, ISensorEvents • Are used by client applications to discover and access sensor and sensor data • Defines • Sensor categories • Sensor types • Sensor data types • Sensor events

  6. Sensor and Location Platform Overview • Location API and Location Automation API • Are contained in an inproc COM DLL • Expose interfaces • Ilocation, ILocationEvents • ILatLongReport, IDispLatLongReport • Are used by client applications to access location data • Location and Other Sensors Control Panel • Allows users to “opt in” • Sensor Driver Class Extension • Integrates UMDF driver with Sensor Platform • Enforces the “opt in” security model

  7. Demo • Simulated GPS device driver plays back a route • Location gadget displays current location on the map • Weather gadget displays weather for current location • Users enable/disable sensors device through Location and Other Sensors Control Panel

  8. Presentation Goals • Introduce location and sensor drivers • Explain design pattern on how to use Sensor Driver Class Extension • Explain how to implement Sensor Driver Callback Class

  9. Sensor Driver Overview • Built on the user-mode driver framework (UMDF) • Requires the use of Sensor Driver Class Extension • Provides Sensor Driver Class Extension callback support ISensorClassExtension UMDF Sensor Device Driver Sensor Driver Class Extension ISensorDriver

  10. Sensor Driver Class Extension Overview • Is an inproc COM server dll • Implements ISensorClassExtension interface • Requires a callback object that supports ISensorDriver interface • Passed as a parameter in the Initialize() function • Handles Windows portable devices (WPD) control requests • De-serializes input data buffer • Serializes output data • Enforces access control for location and sensor data • Checks location and sensor data access permission • Secures event data

  11. ISensorClassExtension Methods

  12. Callback Object Overview • Implements ISensorDriver interface • The interface pointer is passed as a parameter in the ISensorClassExtension::Initialize() function • Enumerates sensor objects • Returns sensor properties and data • Changes sensor configuration • Tracks client applications and event sinks • Processes other WPD messages

  13. Introduction: Sensor Objects • A device may contain multiple sensors. • A device object is required. It is similar to WPD root object • Has the name WPD_DEVICE_OBJECT_ID • Contains device properties • Each sensor is represented by a sensor object. Sensor objects are similar to WPD functional objects • Contains sensor properties and data Device Sensor A Sensor B Sensor N …

  14. Introduction: Sensor Object Properties • Properties are identified by property keys. They are returned as property key and value pairs. • Well-known sensor property keys are listed in sensors.h • Well-known WPD property keys are listed in PortableDevice.h • Each object has a unique ID or name property in string format. It identifies the device or sensor. • Property key: WPD_OBJECT_ID • VarType: VT_LPWSTR • Each sensor has a functional category • Property key: WPD_FUNCTIONAL_OBJECT_CATEGORY • VarType: VT_CLSID

  15. Sensor Properties Example

  16. Introduction: Sensor Data • Data have associated time stamp • A latlong (latitude-longitude) location sensor must at least support following data fields • SENSOR_DATA_TYPE_TIMESTAMP • SENSOR_DATA_TYPE_LATITUDE_DEGREES • SENSOR_DATA_TYPE_LONGITUDE_DEGREES • SENSOR_DATA_TYPE_ERROR_RADIUS_METERS

  17. Sensor Data Example

  18. ISensorDriver Methods

  19. ISensorDriver Methods (Continued)

  20. Summary • A sensor device driver for Windows 7 • Must use Sensor Driver Class Extension • Calls ISensorClassExtension methods • Implements a callback object that supports ISensorDriver interface

  21. Resources • Sensor Driver Logo Kit • DDC 2008 Technical Session, Tues. 9:45-10:45 • Sensor and Location Platform: Windows Logo Program Testing for Drivers • Windows Logo Program Web sitehttp://www.microsoft.com/whdc/winlogo/default.mspx • Discussion Aliases • SensExt@Microsoft.com • LocExt@Microsoft.com

  22. Appendix

  23. ISensorClassExtension Interface • Interface definition from IDL file • interface ISensorClassExtension::IUnknown • { • HRESULT Initialize( [in] IUnknown* pWdfDeviceUnknown, • [in] IUnknown* pSensorDriverUnknown ); • HRESULT Uninitialize(); • HRESULT ProcessIoControl( [in] IWDFIoRequest* pRequest ); • HRESULT PostEvent( [in] LPWSTR pwszSensorID, • [in] IPortableDeviceValuesCollection* pEventCollection ); • HRESULT PostStateChange( [in] LPWSTR pwszSensorID, • [in] SensorState state ); • HRESULT CleanupFile( [in] IWDFFile* pWdfFile ); • };

  24. Device Driver Creates and Initializes the Class Extension Object • Sample code from Sensor Skeleton Driver sample in WDK • // IPnpCallbackHardware method • HRESULT CMyDevice::OnPrepareHardware( __in IWDFDevice* pWdfDevice ) • { • … • // Create class extension object • hr = CoCreateInstance( CLSID_SensorClassExtension, • NULL, • CLSCTX_INPROC_SERVER, • __uuidof( ISensorClassExtension ), • (void**)&m_pClassExtension ); • // Call Initialize method • hr = m_pClassExtension->Initialize( … ); • … • }

  25. Device Driver Releases the Class Extension Object Before Exiting • More sample code from WDK sample • // IPnpCallbackHardware method • HRESULT CMyDevice::OnReleaseHardware( __in IWDFDevice* pWdfDevice ) • { • … • // Release class extension • if (m_pClassExtension != NULL) • { • m_pClassExtension->Uninitialize(); • m_pClassExtension->Release(); • m_pClassExtension = NULL; • } • … • }

  26. Device Driver Must Clean Up File Handles • CleanupFile() must be called from IFileCallbackCleanup::OnCleanupFile() function • // IFileCallbackCleanup method • HRESULT CMyDevice::OnCleanupFile( __in IWDFFile* pWdfFile ) • { • if (m_pClassExtension != NULL) • { • m_pClassExtension->CleanupFile( pWdfFile ); • } • return S_OK; • }

  27. Device Driver Dispatches WPD IO Requests to Class Extension • More sample code from WDK sample • // IQueueCallbackDeviceIoControl method • Void CMyQueue::OnDeviceIoControl( __in IWDFIoQueue* FxQueue, • __in IWDFIoRequest* FxRequest, __in ULONG controlCode, • __in SIZE_T inBufSize, __in SIZE_T outBufSize ) • { • if ( IS_WPD_IOCTL( controlCode ) ) • { • CComPtr<ISensorClassExtension> p; • … • p->ProcessIoControl(FxRequest); • } • else • { // Handle other requests • … • } • }

  28. Device Driver Calls Class Extension to Post Sensor State Change Events • Calls PostStateChange to fire state change events • LPWSTR pwszSensorID; • SensorState state = SENSOR_STATE_READY; • CComPtr<ISensorClassExtension> p; • … • p->PostStateChange( pwszSensorID, state );

  29. Device Driver Calls Class Extension to Post New Data Events • Event parameters are stored in IPortableDeviceValues as property key and value pairs. • SENSOR_EVENT_PARAMETER_EVENT_ID is required. • CComPtr<IPortableDeviceValues> pEventParams; • CoCreateInstance( CLSID_PortableDeviceValues, • NULL, • CLSCTX_INPROC_SERVER, • IID_IPortableDeviceValues, • (void**)&pEventParams ); • // Set event type • pEventParams ->SetGuidValue( SENSOR_EVENT_PARAMETER_EVENT_ID, • SENSOR_EVENT_DATA_UPDATED ); • //Set other data values • …

  30. Device Driver Calls Class Extension to Post New Data Events (Continued) • IPortableDeviceValues with event parameters are added to IPortableDeviceValuesCollection • Multiple events can be bundled together • CComPtr<IPortableDeviceValuesCollection> pEventCollection; • CoCreateInstance( CLSID_PortableDeviceValuesCollection, • NULL, • CLSCTX_INPROC_SERVER, • IID_IPortableDeviceValuesCollection, • (void**)&pEventCollection ); • // Add an event • pEventCollection->Add( pEventParams ); • //Add other events • …

  31. Device Driver Calls Class Extension to Post New Data Events (Continued) • Calls PostEvent to fire new data event • LPWSTR pwszSensorID; • CComPtr<ISensorClassExtension> p; • … • p->PostEvent( pwszSensorID, pEventCollection );

  32. Device Driver Provides Sensor Properties and Data through Callback Interface: ISensorDriver • Interface definition from IDL file • interface ISensorDriver::IUnknown • { • HRESULT OnGetSupportedSensorObjects( • [out] IPortableDeviceValuesCollection** ppSensorObjectCollection ); • HRESULT OnGetSupportedProperties( • [in] LPWSTR pwszSensorID, • [out] IPortableDeviceKeyCollection** ppSupportedProperties ); • HRESULT OnGetSupportedDataFields( • [in] LPWSTR pwszSensorID, • [out] IPortableDeviceKeyCollection** ppSupportedDataFields ); • HRESULT OnGetSupportedEvents( • [in] LPWSTR pwszSensorID, • [out] GUID** ppSupportedEvents, • [out] ULONG* pulEventCount );

  33. ISensorDriver Interface (Continued) HRESULT OnGetProperties( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID, [in] IPortableDeviceKeyCollection* pProperties, [out] IPortableDeviceValues** ppPropertyValues ); HRESULT OnGetDataFields( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID, [in] IPortableDeviceKeyCollection* pDataFields, [out] IPortableDeviceValues** ppDataValues ); HRESULT OnSetProperties( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID, [in] IPortableDeviceValues* pPropertiesToSet, [out] IPortableDeviceValues** ppResults ); HRESULT OnClientConnect( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID );

  34. ISensorDriver Interface (Continued) HRESULT OnClientDisconnect( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID ); HRESULT OnClientSubscribeToEvents( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID ); HRESULT OnClientUnsubscribeFromEvents( [in] IWDFFile* pClientFile, [in] LPWSTR pwszSensorID ); HRESULT OnProcessWpdMessage( [in] IUnknown* pUnkPortableDeviceValuesParams, [in] IUnknown* pUnkPortableDeviceValuesResults ); };

  35. Device Driver Returns Collection of Sensors • Each sensor is represented by its properties. • Properties of a sensor are stored in IPortableDeviceValues as property key and value pairs. • HRESULT CSensorDdi::OnGetSupportedSensorObjects( • __out IPortableDeviceValuesCollection** ppSensorObjectCollection ) • { • CComPtr<IPortableDeviceValues> pValues; • hr = CoCreateInstance( CLSID_PortableDeviceValues, • NULL, • CLSCTX_INPROC_SERVER, • IID_IPortableDeviceValues, • (VOID**) &pValues ); • pValues->SetStringValue( WPD_OBJECT_NAME, GPS_SENSOR_ID ); • pValues->SetGuidValue( WPD_FUNCTIONAL_OBJECT_CATEGORY, SENSOR_CATEGORY_LOCATION ); • pValues->SetGuidValue( SENSOR_PROPERTY_TYPE, SENSOR_TYPE_LOCATION_GPS ); • …

  36. Device Driver Returns Collection of Sensors (Continued) • IPortableDeviceValues with sensor properties are added to IPortableDeviceValuesCollection. • hr = CoCreateInstance( CLSID_PortableDeviceValuesCollection, • NULL, • CLSCTX_INPROC_SERVER, • IID_IPortableDeviceValuesCollection, • (VOID**) ppPortableDeviceValuesCollection ); • (*ppPortableDeviceValuesCollection)->Add(pValues); • … • }

  37. Device Driver Returns Collection of • Supported Data Fields for a Sensor • Property keys of data fields are stored in IPortableDeviceKeyCollection. • HRESULT CSensorDdi::OnGetSupportedDataFields( • __in LPWSTR ObjectID, • __out IPortableDeviceKeyCollection** ppKeys ) • { • hr = CoCreateInstance( CLSID_PortableDeviceKeyCollection, • NULL, • CLSCTX_INPROC_SERVER, • IID_IPortableDeviceKeyCollection, • (VOID**) ppKeys ); • *(ppKeys )->Add( SENSOR_DATA_TYPE_TIMESTAMP ); • *(ppKeys )->Add( SENSOR_DATA_TYPE_LATITUDE_DEGREES ); • *(ppKeys )->Add( SENSOR_DATA_TYPE_LONGITUDE_DEGREES ); • *(ppKeys )->Add( SENSOR_DATA_TYPE_ERROR_RADIUS_METERS ); • … • }

  38. Device Driver Processes WPD Messages • That Are Not Handled by Class Extension • Input parameters are stored in IPortableDeviceValues as property key and value pairs. • HRESULT CSensorDdi::OnProcessWpdMessage( • __in IUnknown* pUnkPortableDeviceValuesParams, • __in IUnknown* pUnkPortableDeviceValuesResults ) • { • CComPtr<IPortableDeviceValues> pParams; • PROPERTYKEY CommandKey = WPD_PROPERTY_NULL; • hr = pUnkPortableDeviceValuesParams->QueryInterface( • IID_IPortableDeviceValues, • (void**) &pParams ); • pParams->GetGuidValue( WPD_PROPERTY_COMMON_COMMAND_CATEGORY, &(CommandKey.fmtid) ); • pParams->GetUnsignedIntegerValue( WPD_PROPERTY_COMMON_COMMAND_ID, &(CommandKey.pid) ); • …

  39. Device Driver Processes WPD Messages • That Are Not Handled by Class Extension (Continued) • Object ID is stored in IPortableDeviceValues. • LPWSTR wszObjectID = NULL; • pParams-> GetStringValue( WPD_PROPERTY_OBJECT_PROPERTIES_OBJECT_ID, &wszObjectID ); • … • CoTaskMemFree( wszObjectID );

  40. Device Driver Processes WPD Messages • That Are Not Handled by Class Extension (Continued) • Results are stored in IPortableDeviceValues as property key and value pairs. • A result value is required. • CComPtr<IPortableDeviceValues> pResults; • hr = pUnkPortableDeviceValuesResults->QueryInterface( • IID_IPortableDeviceValues, • (void**) & pResults ); • … • pResults->SetErrorValue( WPD_PROPERTY_COMMON_RESULT, hr );

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