libcamera: camera: Add Camera properties

Add a method to the Camera class to retrieve the Camera properties
registered by the pipeline handler.

While at it, reword the Camera::controls() operation documentation to
specify that the camera control information are constant during the
camera lifetime not their value, while the camera properties value are
the actually static information.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

include/libcamera/camera.h

@@ -86,6 +86,7 @@ public:
 	int release();
 
 	const ControlInfoMap &controls();
+	const ControlList &properties();
 
 	const std::set<Stream *> &streams() const;
 	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles);

src/libcamera/camera.cpp

@@ -652,7 +652,8 @@ int Camera::release()
 /**
  * \brief Retrieve the list of controls supported by the camera
  *
- * Camera controls remain constant through the lifetime of the camera.
+ * The list of controls supported by the camera and their associated
+ * constraints remain constant through the lifetime of the Camera object.
  *
  * \context This function is \threadsafe.
  *
@@ -663,6 +664,19 @@ const ControlInfoMap &Camera::controls()
 	return p_->pipe_->controls(this);
 }
 
+/**
+ * \brief Retrieve the list of properties of the camera
+ *
+ * Camera properties are static information that describe the capabilities of
+ * the camera. They remain constant through the lifetime of the Camera object.
+ *
+ * \return A ControlList of properties supported by the camera
+ */
+const ControlList &Camera::properties()
+{
+	return p_->pipe_->properties(this);
+}
+
 /**
  * \brief Retrieve all the camera's stream information
  *