[PATCH v6 00/11] media: subdev: Improve stream enable/disable machinery

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

This series works on the .s_stream, .enable_streams, .disable_streams
related code. The main feature introduced here, in the last two patchs,
is adding support for .enable/disable_streams() for subdevs that do not
implement full streams support.

Additionally we add support for the privacy led when
v4l2_subdev_enable/disable_streams() is used.

I have tested this on RPi5.

 Tomi

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
Changes in v6:
- v4l2_subdev_enable_streams() and v4l2_subdev_disable_streams()
  accidentally returned -EINVAL when a stream was already
  enabled/disabled. Change it back to -EALREADY.
- Add TODO note about privacy leds to "media: subdev: Support
  single-stream case in v4l2_subdev_enable/disable_streams()"
- New commit "media: subdev: Improve s_stream documentation"
- Link to v5: https://lore.kernel.org/r/20240416-enable-streams-impro-v5-0-bd5fcea49388@ideasonboard.com

Changes in v5:
- Fix issues with non-routing case:
  - Always set 'found_streams' variable instead of leaving it
    uninitialized in "Support single-stream case in
    v4l2_subdev_enable/disable_streams()"
  - Fix the "implicit" stream from bit 1 to bit 0 in "Support
    non-routing subdevs in v4l2_subdev_s_stream_helper()"
- Link to v4: https://lore.kernel.org/r/20240416-enable-streams-impro-v4-0-1d370c9c2b6d@ideasonboard.com

Changes in v4:
- Added Rb tags
- Rename 'streaming_enabled' to 's_stream_enabled'
- Cosmetic changes (comments / patch descs)
- Added new patch "media: subdev: Support non-routing subdevs in  v4l2_subdev_s_stream_helper()".
- Link to v3: https://lore.kernel.org/r/20240410-enable-streams-impro-v3-0-e5e7a5da7420@ideasonboard.com

Changes in v3:
- Rebased on top of "[PATCH v2 1/1] media: v4l: Don't turn on privacy LED if streamon fails"
- Drop extra "!!" in "media: subdev: Fix use of sd->enabled_streams in  call_s_stream()"
- Enable privacy LED after a succesfull stream enable in  "media: subdev: Support privacy led in v4l2_subdev_enable/disable_streams()"
- Init 'cfg' variable when declaring in "media: subdev: Refactor v4l2_subdev_enable/disable_streams()"
- Link to v2: https://lore.kernel.org/r/20240405-enable-streams-impro-v2-0-22bca967665d@ideasonboard.com

Changes in v2:
- New patches for privacy led
- Use v4l2_subdev_has_op()
- Use BITS_PER_BYTE instead of 8
- Fix 80+ line issues
- Fix typos
- Check for pad < 64 also in the non-routing .enable/disable_streams code path
- Dropped "media: subdev: Support enable/disable_streams for non-streams
  subdevs", which is implemented in a different way in new patches in this series
- Link to v1: https://lore.kernel.org/r/20240404-enable-streams-impro-v1-0-1017a35bbe07@ideasonboard.com

---
Tomi Valkeinen (11):
      media: subdev: Add privacy led helpers
      media: subdev: Use v4l2_subdev_has_op() in v4l2_subdev_enable/disable_streams()
      media: subdev: Add checks for subdev features
      media: subdev: Fix use of sd->enabled_streams in call_s_stream()
      media: subdev: Improve v4l2_subdev_enable/disable_streams_fallback
      media: subdev: Add v4l2_subdev_is_streaming()
      media: subdev: Support privacy led in v4l2_subdev_enable/disable_streams()
      media: subdev: Refactor v4l2_subdev_enable/disable_streams()
      media: subdev: Support single-stream case in v4l2_subdev_enable/disable_streams()
      media: subdev: Support non-routing subdevs in v4l2_subdev_s_stream_helper()
      media: subdev: Improve s_stream documentation

 drivers/media/v4l2-core/v4l2-subdev.c | 385 ++++++++++++++++++++--------------
 include/media/v4l2-subdev.h           |  34 ++-
 2 files changed, 261 insertions(+), 158 deletions(-)
---
base-commit: e42a204f0519a2540f1507ac2798be2aeaa76bee
change-id: 20240404-enable-streams-impro-db8bcd898471

Best regards,
-- 
Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>