Merge tag 'media/v6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull media updates from Mauro Carvalho Chehab:

 - New V4L2 ioctl VIDIOC_REMOVE_BUFS

 - experimental support for using generic metaformats on V4L2 core

 - New drivers: Intel IPU6 controller driver, Broadcom BCM283x/BCM271x

 - More cleanups at atomisp driver

 - Usual bunch of driver cleanups, improvements and fixes

* tag 'media/v6.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (328 commits)
  media: bcm2835-unicam: Depend on COMMON_CLK
  Revert "media: v4l2-ctrls: show all owned controls in log_status"
  media: ov2740: Ensure proper reset sequence on probe()
  media: intel/ipu6: Don't print user-triggerable errors to kernel log
  media: bcm2835-unicam: Fix driver path in MAINTAINERS
  media: bcm2835-unicam: Fix a NULL vs IS_ERR() check
  media: bcm2835-unicam: Do not print error when irq not found
  media: bcm2835-unicam: Do not replace IRQ retcode during probe
  media: bcm2835-unicam: Convert to platform remove callback returning void
  media: media: intel/ipu6: Fix spelling mistake "remappinp" -> "remapping"
  media: intel/ipu6: explicitly include vmalloc.h
  media: cec.h: Fix kerneldoc
  media: uvcvideo: Refactor iterators
  media: v4l: async: refactor v4l2_async_create_ancillary_links
  media: intel/ipu6: Don't re-allocate memory for firmware
  media: dvb-frontends: tda10048: Fix integer overflow
  media: tc358746: Use the correct div_ function
  media: i2c: st-mipid02: Use the correct div function
  media: tegra-vde: Refactor timeout handling
  media: stk1160: Use min macro
  ...

1 files changed, 28 insertions, 3 deletions

diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst
index 43988516acdd..0f9eda3187f3 100644
--- a/Documentation/userspace-api/media/v4l/dev-subdev.rst
+++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst
@@ -506,6 +506,8 @@ source pads.
 
     subdev-formats
 
+.. _subdev-routing:
+
 Streams, multiplexed media pads and internal routing
 ----------------------------------------------------
 
@@ -527,9 +529,9 @@ the its sink pad and allows to route them individually to one of its source
 pads.
 
 Subdevice drivers that support multiplexed streams are compatible with
-non-multiplexed subdev drivers, but, of course, require a routing configuration
-where the link between those two types of drivers contains only a single
-stream.
+non-multiplexed subdev drivers. However, if the driver at the sink end of a link
+does not support streams, then only stream 0 of source end may be captured.
+There may be additional limitations specific to the sink device.
 
 Understanding streams
 ^^^^^^^^^^^^^^^^^^^^^
@@ -570,6 +572,29 @@ Any configurations of a stream within a pad, such as format or selections,
 are independent of similar configurations on other streams. This is
 subject to change in the future.
 
+Device types and routing setup
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Different kinds of sub-devices have differing behaviour for route activation,
+depending on the hardware. In all cases, however, only routes that have the
+``V4L2_SUBDEV_STREAM_FL_ACTIVE`` flag set are active.
+
+Devices generating the streams may allow enabling and disabling some of the
+routes or have a fixed routing configuration. If the routes can be disabled, not
+declaring the routes (or declaring them without
+``VIDIOC_SUBDEV_STREAM_FL_ACTIVE`` flag set) in ``VIDIOC_SUBDEV_S_ROUTING`` will
+disable the routes. ``VIDIOC_SUBDEV_S_ROUTING`` will still return such routes
+back to the user in the routes array, with the ``V4L2_SUBDEV_STREAM_FL_ACTIVE``
+flag unset.
+
+Devices transporting the streams almost always have more configurability with
+respect to routing. Typically any route between the sub-device's sink and source
+pads is possible, and multiple routes (usually up to certain limited number) may
+be active simultaneously. For such devices, no routes are created by the driver
+and user-created routes are fully replaced when ``VIDIOC_SUBDEV_S_ROUTING`` is
+called on the sub-device. Such newly created routes have the device's default
+configuration for format and selection rectangles.
+
 Configuring streams
 ^^^^^^^^^^^^^^^^^^^