linux.git/include/media/v4l2-subdev.h, branch v6.13

media: Documentation: Improve v4l2_subdev_{en,dis}able_streams documentation

2024-10-16T07:32:41+00:00

Document that callers of v4l2_subdev_{en,dis}able_streams() need to set
the mask to BIT_ULL(0).

Signed-off-by: Sakari Ailus 
Reviewed-by: Tomi Valkeinen 
Reviewed-by: Laurent Pinchart 
Signed-off-by: Mauro Carvalho Chehab

media: Documentation: Update {enable,disable}_streams documentation

2024-10-16T07:32:40+00:00

Document the expected {enable,disable}_streams callback behaviour for
drivers that are stream-unaware i.e. don't specify the
V4L2_SUBDEV_CAP_STREAMS sub-device capability flag. In this specific case,
the mask argument can be ignored.

Signed-off-by: Sakari Ailus 
Reviewed-by: Tomi Valkeinen 
Reviewed-by: Laurent Pinchart 
Signed-off-by: Mauro Carvalho Chehab

media: Documentation: Deprecate s_stream video op, update docs

2024-10-16T07:32:40+00:00

The scope of the s_stream video operation is now fully supported by
{enable,disable}_streams. Explicitly document the s_stream() op as
deprecated and update the related documentation.

Signed-off-by: Sakari Ailus 
Reviewed-by: Laurent Pinchart 
Reviewed-by: Tomi Valkeinen 
Signed-off-by: Mauro Carvalho Chehab

media: v4l2-subdev: Support hybrid links in v4l2_subdev_link_validate()

2024-08-26T13:36:14+00:00

The v4l2_subdev_link_validate() helper function is meant to be used as a
drop-in implementation of a V4L2 subdev entity .link_validate() handler.
It supports subdev-to-subdev links only, and complains if one end of the
link is not a subdev. This forces drivers that have video output devices
connected to subdevs to implement a custom .link_validate() handler,
calling v4l2_subdev_link_validate() for the subdev-to-subdev links, and
performing manual link validation for the video-to-subdev links.

Video devices embed a media entity, and therefore also have a
.link_validate() operation. For video capture devices, the operation
should be manually implemented by drivers for validate the
subdev-to-video links. For video output devices, on the other hand, that
operation is never called, as link validation is performed in the
context of the sink entity.

As a result, we end up forcing drivers to implement a custom
.link_validate() handler for subdevs connected to video output devices,
when the video devices provide an operation that could be used for that
purpose.

To improve that situation, make v4l2_subdev_link_validate() delegate
link validation to the source's .link_validate() operation when the link
source is a video device and the link sink is a subdev. This allows
broader usage of v4l2_subdev_link_validate(), and simplifies drivers by
making video device link validation easy to implement in the video
device .link_validate(), regardless of whether the video device is an
output device or a capture device.

Signed-off-by: Laurent Pinchart 
Reviewed-by: Tomi Valkeinen 
Acked-by: Sakari Ailus

media: v4l: subdev: Fix typo in documentation

2024-06-26T06:14:03+00:00

Replace the incorrect reference to the v4l2_subdev_enable_stream()
function with the correct v4l2_subdev_enable_streams() spelling.

Fixes: d0749adb3070 ("media: v4l2-subdev: Add subdev .(enable|disable)_streams() operations")
Reviewed-by: Tomi Valkeinen 
Link: https://lore.kernel.org/r/20240619225343.15873-1-laurent.pinchart@ideasonboard.com
Signed-off-by: Laurent Pinchart

media: v4l2-subdev: Provide const-aware subdev state accessors

2024-06-04T06:31:25+00:00

It would be useful to mark instances of v4l2_subdev_state structures as
const when code needs to access them read-only. This isn't currently
possible, as the v4l2_subdev_state_get_*() accessor functions take a
non-const pointer to the state.

Use _Generic() to provide two different versions of the accessors, for
const and non-const states respectively. The former returns a const
pointer to the requested format, rectangle or interval, implementing
const-correctness. The latter returns a non-const pointer, preserving
the current behaviour for drivers.

Signed-off-by: Laurent Pinchart 
Reviewed-by: Sakari Ailus 
Reviewed-by: Tomi Valkeinen 
[Sakari Ailus: Drop the word "below" from the text.]
Signed-off-by: Sakari Ailus 
Signed-off-by: Hans Verkuil

media: v4l2-subdev: Fix v4l2_subdev_state_get_format() documentation

2024-06-04T06:31:25+00:00

The documentation of the v4l2_subdev_state_get_format() macro
incorrectly references __v4l2_subdev_state_get_format() instead of
__v4l2_subdev_state_gen_call(). Fix it, and also update the list of
similar macros to add the missing v4l2_subdev_state_get_interval().

Suggested-by: Sakari Ailus 
Signed-off-by: Laurent Pinchart 
Reviewed-by: Sakari Ailus 
Signed-off-by: Sakari Ailus 
Signed-off-by: Hans Verkuil

media: subdev: Improve s_stream documentation

2024-06-04T06:31:25+00:00

Now that enable/disable_streams operations are available for
single-stream subdevices too, there's no reason to use the old s_stream
operation on new drivers. Extend the documentation reflecting this.

Signed-off-by: Tomi Valkeinen 
Reviewed-by: Umang Jain
Reviewed-by: Laurent Pinchart 
Signed-off-by: Sakari Ailus 
Signed-off-by: Hans Verkuil

media: subdev: Add v4l2_subdev_is_streaming()

2024-06-04T06:31:24+00:00

Add a helper function which returns whether the subdevice is streaming,
i.e. if .s_stream or .enable_streams has been called successfully.

Reviewed-by: Umang Jain 
Reviewed-by: Laurent Pinchart 
Tested-by: Umang Jain 
Signed-off-by: Tomi Valkeinen 
Signed-off-by: Sakari Ailus 
Signed-off-by: Hans Verkuil

media: subdev: Improve v4l2_subdev_enable/disable_streams_fallback

2024-06-04T06:31:24+00:00

v4l2_subdev_enable/disable_streams_fallback() supports falling back to
.s_stream() for subdevs with a single source pad. It also tracks the
enabled streams for that one pad in the sd->enabled_streams field.

Tracking the enabled streams with sd->enabled_streams does not make
sense, as with .s_stream() there can only be a single stream per pad.
Thus, as the v4l2_subdev_enable/disable_streams_fallback() only supports
a single source pad, all we really need is a boolean which tells whether
streaming has been enabled on this pad or not.

However, as we only need a true/false state for a pad (instead of
tracking which streams have been enabled for a pad), we can easily
extend the fallback mechanism to support multiple source pads as we only
need to keep track of which pads have been enabled.

Change the sd->enabled_streams field to sd->enabled_pads, which is a
64-bit bitmask tracking the enabled source pads. With this change we can
remove the restriction that
v4l2_subdev_enable/disable_streams_fallback() only supports a single
source pad.

Reviewed-by: Laurent Pinchart 
Tested-by: Umang Jain 
Signed-off-by: Tomi Valkeinen 
Signed-off-by: Sakari Ailus 
Signed-off-by: Hans Verkuil