media: Documentation: Update link frequency driver documentation

Add the get_mbus_config() as the means for conveying the link frequency
towards the receiver drivers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/Documentation/driver-api/media/tx-rx.rst b/Documentation/driver-api/media/tx-rx.rst
index c71003f74b1c3ee70a3ec71efc260efc405f191f..6f9eba189a9f4241f8899a4a79f32f3c16bc68c9 100644 (file)
--- a/Documentation/driver-api/media/tx-rx.rst
+++ b/Documentation/driver-api/media/tx-rx.rst
@@ -49,6 +49,10 @@ Link frequency
 The :ref:`V4L2_CID_LINK_FREQ <v4l2-cid-link-freq>` control is used to tell the
 receiver the frequency of the bus (i.e. it is not the same as the symbol rate).
 
+Drivers that do not have user-configurable link frequency should report it
+through the ``.get_mbus_config()`` subdev pad operation, in the ``link_freq``
+field of struct v4l2_mbus_config, instead of through controls.
+
 ``.enable_streams()`` and ``.disable_streams()`` callbacks
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^