[PATCH v12 46/86] media: Documentation: ccs: Document routing

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Document which routes are available for the CCS driver (source) sub-device
and what configuration are possible.

Also update copyright.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 .../userspace-api/media/drivers/ccs.rst       | 43 ++++++++++++++++++-
 .../media/v4l/metadata-layouts.rst            |  2 +
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/Documentation/userspace-api/media/drivers/ccs.rst b/Documentation/userspace-api/media/drivers/ccs.rst
index 03015b33d5ab..67c7d2b62ed5 100644
--- a/Documentation/userspace-api/media/drivers/ccs.rst
+++ b/Documentation/userspace-api/media/drivers/ccs.rst
@@ -111,4 +111,45 @@ than in the centre.
 Shading correction needs to be enabled for luminance correction level to have an
 effect.
 
-**Copyright** |copy| 2020 Intel Corporation
+.. _media-ccs-routes:
+
+Routes
+------
+
+The CCS driver implements one or two :ref:`routes <subdev-routing>` in
+its source sub-device (scaler sub-device if it exists for the device, otherwise
+binner) depending on whether the sensor supports embedded data. (All CCS
+compliant sensors do but the CCS driver supports preceding standards that did
+not require embedded data support, too.)
+
+The first route of the CCS source sub-device is for pixel data (sink pad
+0/stream 0 -> source pad 1/stream 0) and the second one is for embedded data
+(internal sink pad 2/stream 0 -> source pad 1/stream 1).
+
+Embedded data
+~~~~~~~~~~~~~
+
+MIPI CCS supports generation of camera sensor embedded data. The metadata layout
+used for this format on the internal sink pad is :ref:`V4L2_METADATA_LAYOUT_CCS
+<media-metadata-layout-ccs>`.
+
+The bit depth of the CCS pixel data affects how the sensor will output the
+embedded data, adding padding to align with CSI-2 bus :term:`Data Unit` for that
+particular bit depth. This is indicated by the generic metadata format on the
+source pad of the sensor's source sub-device.
+
+Devices supporting embedded data for bit depths greater than or equal to 16 may
+support more dense packing or legacy single metadata byte per data unit, or both
+of these. The supported embedded data formats can be enumerated and configured
+on stream 1 of the source pad (1) of the CCS source sub-device.
+
+The use of the denser packing results in embedded data lines being longer than
+the pixel data in data units since the data units are smaller. In bytes the
+embedded data lines are still not longer than the image data lines.
+
+The embedded data format is determined by the sub-device image data format
+configured on the source sub-device. The embedded data mbus code is only changed
+when the bit depth of the image data changes in the source pad of the source
+sub-device.
+
+**Copyright** |copy| 2020, 2024--2025 Intel Corporation
diff --git a/Documentation/userspace-api/media/v4l/metadata-layouts.rst b/Documentation/userspace-api/media/v4l/metadata-layouts.rst
index cd190f453994..0f8709f2e9af 100644
--- a/Documentation/userspace-api/media/v4l/metadata-layouts.rst
+++ b/Documentation/userspace-api/media/v4l/metadata-layouts.rst
@@ -37,3 +37,5 @@ devices that fulfill all three levels above.
 This metadata layout code is only used for "2-byte simplified tagged data
 format" (code ``0xa``) but their use may be extended further in the future, to
 cover other CCS embedded data format codes.
+
+Also see :ref:`CCS driver documentation <media-ccs-routes>`.
-- 
2.47.3