libcamera: media_device: Expose media device API version number

Add a MediaDevice::version() function to expose the media device API
version number. This can be useful to support driver API changes in
pipeline handlers.

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

src/libcamera/media_device.cpp

@@ -314,6 +314,15 @@ done:
  * \return The MediaDevice model name
  */
 
+/**
+ * \fn MediaDevice::version()
+ * \brief Retrieve the media device API version
+ *
+ * The version is formatted with the KERNEL_VERSION() macro.
+ *
+ * \return The MediaDevice API version
+ */
+
 /**
  * \fn MediaDevice::entities()
  * \brief Retrieve the list of entities in the media graph