[libcamera-devel] [RFC 3/7] libcamera: camera_sensor: Factorize out properties

[Jacopo Mondi]

Factorize CameraSensor properties initialization to a dedicated virtual
function that dervied classes could subclass to register sensor-specific
properties.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/camera_sensor.cpp       | 94 ++++++++++++++++-----------
 src/libcamera/include/camera_sensor.h |  5 +-
 2 files changed, 60 insertions(+), 39 deletions(-)

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index d1c9c9bcd58f..9692895d9b7b 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -77,7 +77,7 @@ CameraSensor *CameraSensorFactory::create(const MediaEntity *entity)
  * Once constructed the instance must be initialized with init().
  */
 CameraSensor::CameraSensor(const MediaEntity *entity)
-	: entity_(entity), properties_(properties::properties)
+	: properties_(properties::properties), entity_(entity)
 {
 	subdev_ = new V4L2Subdevice(entity);
 }
@@ -119,42 +119,6 @@ int CameraSensor::init()
 	if (ret < 0)
 		return ret;
 
-	/* Retrieve and store the camera sensor properties. */
-	const ControlInfoMap &controls = subdev_->controls();
-	int32_t propertyValue;
-
-	/* Camera Location: default is front location. */
-	const auto &locationControl = controls.find(V4L2_CID_CAMERA_SENSOR_LOCATION);
-	if (locationControl != controls.end()) {
-		int32_t v4l2Location =
-			locationControl->second.def().get<int32_t>();
-		switch (v4l2Location) {
-		case V4L2_LOCATION_EXTERNAL:
-			propertyValue = properties::CameraLocationExternal;
-			break;
-		case V4L2_LOCATION_FRONT:
-			propertyValue = properties::CameraLocationFront;
-			break;
-		case V4L2_LOCATION_BACK:
-			propertyValue = properties::CameraLocationBack;
-			break;
-		default:
-			LOG(CameraSensor, Error)
-				<< "Unsupported camera location: " << v4l2Location;
-			return -EINVAL;
-		}
-	} else {
-		propertyValue = properties::CameraLocationFront;
-	}
-	properties_.set(properties::Location, propertyValue);
-
-	/* Camera Rotation: default is 0 degrees. */
-	propertyValue = 0;
-	const auto &rotationControl = controls.find(V4L2_CID_CAMERA_SENSOR_ROTATION);
-	if (rotationControl != controls.end())
-		propertyValue = rotationControl->second.def().get<int32_t>();
-	properties_.set(properties::Rotation, propertyValue);
-
 	/* Enumerate and cache media bus codes and sizes. */
 	const ImageFormats formats = subdev_->formats(0);
 	if (formats.isEmpty()) {
@@ -185,6 +149,62 @@ int CameraSensor::init()
 	std::sort(mbusCodes_.begin(), mbusCodes_.end());
 	std::sort(sizes_.begin(), sizes_.end());
 
+	return initProperties(subdev_->controls());
+}
+
+/**
+ * \brief Initialize the camera sensor properties
+ * \param[in] controlMap The map of control information provided by the sensor
+ *
+ * This method initializes the camera sensor properties, by inspecting the
+ * control information reported by the sensor media entity in \a controlMap.
+ * For each supported standard V4L2 control reported by the sensor, a libcamera
+ * property is created and registered in the list of properties supported by the
+ * sensor.
+ *
+ * Derived classes are free to override this method to register sensor specific
+ * properties as they like, by inspecting custom controls or by adding
+ * properties with pre-defined values, and eventually call this base class
+ * implementation to register standard ones.
+ *
+ * \return 0 on success, a negative error code otherwise
+ */
+int CameraSensor::initProperties(const ControlInfoMap &controlMap)
+{
+	int32_t propertyValue;
+
+	/* Camera Location: default is front location. */
+	const auto &locationControl = controlMap.find(V4L2_CID_CAMERA_SENSOR_LOCATION);
+	if (locationControl != controlMap.end()) {
+		int32_t v4l2Location =
+			locationControl->second.def().get<int32_t>();
+		switch (v4l2Location) {
+		case V4L2_LOCATION_EXTERNAL:
+			propertyValue = properties::CameraLocationExternal;
+			break;
+		case V4L2_LOCATION_FRONT:
+			propertyValue = properties::CameraLocationFront;
+			break;
+		case V4L2_LOCATION_BACK:
+			propertyValue = properties::CameraLocationBack;
+			break;
+		default:
+			LOG(CameraSensor, Error)
+				<< "Unsupported camera location: " << v4l2Location;
+			return -EINVAL;
+		}
+	} else {
+		propertyValue = properties::CameraLocationFront;
+	}
+	properties_.set(properties::Location, propertyValue);
+
+	/* Camera Rotation: default is 0 degrees. */
+	propertyValue = 0;
+	const auto &rotationControl = controlMap.find(V4L2_CID_CAMERA_SENSOR_ROTATION);
+	if (rotationControl != controlMap.end())
+		propertyValue = rotationControl->second.def().get<int32_t>();
+	properties_.set(properties::Rotation, propertyValue);
+
 	return 0;
 }
 
diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
index 2c09b1bdb61b..43748a6c8535 100644
--- a/src/libcamera/include/camera_sensor.h
+++ b/src/libcamera/include/camera_sensor.h
@@ -38,6 +38,7 @@ public:
 	CameraSensor &operator=(const CameraSensor &) = delete;
 
 	int init();
+	virtual int initProperties(const ControlInfoMap &controlMap);
 
 	const MediaEntity *entity() const { return entity_; }
 	const std::vector<unsigned int> &mbusCodes() const { return mbusCodes_; }
@@ -55,6 +56,8 @@ public:
 	const ControlList &properties() const { return properties_; }
 
 protected:
+	ControlList properties_;
+
 	friend class CameraSensorFactory;
 	explicit CameraSensor(const MediaEntity *entity);
 	std::string logPrefix() const;
@@ -65,8 +68,6 @@ private:
 
 	std::vector<unsigned int> mbusCodes_;
 	std::vector<Size> sizes_;
-
-	ControlList properties_;
 };
 
 } /* namespace libcamera */
-- 
2.24.0