libcamera: properties: Add model property

The model name must to the extent possible describe the sensor. For most
devices this is the model name of the sensor. While for some devices the
sensor model is unavailable as the sensor or the entire camera is part
of a larger unit and exposed as a black-box to the system. In such cases
the model name of the smallest component closest to the sensor must be
used.

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

src/libcamera/property_ids.yaml

@@ -387,6 +387,29 @@ controls:
                               |                    |
                               +--------------------+
 
+  - Model:
+      type: string
+      description: |
+        The model name shall to the extent possible describe the sensor. For
+        most devices this is the model name of the sensor. While for some
+        devices the sensor model is unavailable as the sensor or the entire
+        camera is part of a larger unit and exposed as a black-box to the
+        system. In such cases the model name of the smallest device that
+        contains the camera sensor shall be used.
+
+        The model name is not meant to be a camera name displayed to the
+        end-user, but may be combined with other camera information to create a
+        camera name.
+
+        The model name is not guaranteed to be unique in the system nor is
+        it guaranteed to be stable or have any other properties required to make
+        it a good candidate to be used as a permanent identifier of a camera.
+
+        The model name shall describe the camera in a human readable format and
+        shall be encoded in ASCII.
+
+        Example model names are 'ov5670', 'imx219' or 'Logitech Webcam C930e'.
+
   - UnitCellSize:
       type: Size
       description: |