media: v4l: fwnode: Add convenience function for parsing common external refs

Add v4l2_fwnode_parse_reference_sensor_common for parsing common
sensor properties that refer to adjacent devices such as flash or lens
driver chips.

As this is an association only, there's little a regular driver needs to
know about these devices as such.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

include/media/v4l2-fwnode.h

@@ -319,4 +319,25 @@ int v4l2_async_notifier_parse_fwnode_endpoints_by_port(
 			      struct v4l2_fwnode_endpoint *vep,
 			      struct v4l2_async_subdev *asd));
 
+/**
+ * v4l2_fwnode_reference_parse_sensor_common - parse common references on
+ *					       sensors for async sub-devices
+ * @dev: the device node the properties of which are parsed for references
+ * @notifier: the async notifier where the async subdevs will be added
+ *
+ * Parse common sensor properties for remote devices related to the
+ * sensor and set up async sub-devices for them.
+ *
+ * Any notifier populated using this function must be released with a call to
+ * v4l2_async_notifier_release() after it has been unregistered and the async
+ * sub-devices are no longer in use, even in the case the function returned an
+ * error.
+ *
+ * Return: 0 on success
+ *	   -ENOMEM if memory allocation failed
+ *	   -EINVAL if property parsing failed
+ */
+int v4l2_async_notifier_parse_fwnode_sensor_common(
+	struct device *dev, struct v4l2_async_notifier *notifier);
+
 #endif /* _V4L2_FWNODE_H */