[RFC,0/4] Sub-device configuration models

Message

Sakari Ailus Oct. 11, 2024, 7:55 a.m. UTC

Hello everyone,

I've been recently working (with others) on sub-device streams support as
well as on internal pads. The two can be used to make sub-device
configuration more versatile.

At the same time, the added interfaces are much more useful if we require
specific semantics of those interfaces, so that the user space knows
exactly what e.g. a given selection target signifies. However, as the same
selection rectangle could be used for a different purpose on a non-raw
sensor device, we need a way to tell how should the user space determine
how to use a given interface.

I'm proposing to solve this problem by introducing sub-device
configuration models, and by the common raw sensor model, also present in
this patchset, in particular.

This has been (and will, for some time, continue to be) the reason why I
have reviewed few sensor driver related patches lately. As we're
introducing a new interface, it's beneficial to be able to use that
interface right from the start, rather than trying to later on offer
compatibility support, which is almost always a fair amount of work with
less than desirable results in the driver.

With this solved, I believe we can enable the use of the streams UAPI.

Comments are welcome.

The compiled documentation can be found in
<URL:https://www.retiisi.eu/~sailus/v4l2/tmp/meta-format/output/userspace-api/media/v4l/dev-subdev.html#sub-device-configuration-models>
and the patches here
<URL:https://git.linuxtv.org/sailus/media_tree.git/log/?h=metadata>, i.e.
they're on top of the metadata set.

Sakari Ailus (4):
  media: Documentation: Rework embedded data documentation
  media: Documentation: Reword split of sensor driver to two classes
  media: Documentation: Add subdev configuration models, raw sensor
    model
  media: v4l: ctrl: Add V4L2_CID_CONFIG_MODEL control

 .../media/drivers/camera-sensor.rst           |  28 +-
 .../media/v4l/common-raw-sensor.dia           | 441 ++++++++++++++++++
 .../media/v4l/common-raw-sensor.svg           | 134 ++++++
 .../userspace-api/media/v4l/dev-subdev.rst    |   2 +
 .../media/v4l/ext-ctrls-image-process.rst     |   4 +
 .../media/v4l/subdev-config-model.rst         | 182 ++++++++
 drivers/media/v4l2-core/v4l2-ctrls-defs.c     |   5 +
 include/uapi/linux/v4l2-controls.h            |   3 +
 8 files changed, 788 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/userspace-api/media/v4l/common-raw-sensor.dia
 create mode 100644 Documentation/userspace-api/media/v4l/common-raw-sensor.svg
 create mode 100644 Documentation/userspace-api/media/v4l/subdev-config-model.rst


base-commit: 8e1285c798e1c1838a1ba68497849b2f57969fbc