[libcamera-devel] [PATCH v1 0/5] Vendor controls and properties

[Laurent Pinchart]

Hi Kieran,

On Mon, Nov 20, 2023 at 06:34:44AM +0000, Kieran Bingham wrote:
> Quoting Laurent Pinchart via libcamera-devel (2023-11-20 02:32:35)
> > On Fri, Nov 10, 2023 at 10:59:57AM +0000, Naushir Patuck via libcamera-devel wrote:
> > > Hi,
> > > 
> > > This change introduces a first attempt at implementing vendor specific controls
> > > and properties in libcamera.  Vendor controls and properties live in their own
> > > namespace, and each vendor must now reserve a numeric control id range to avoid
> > > any id value clashes.  Vendor controls may either live in the libcamera
> > > control_ids.yaml/property_ids.yaml files or preferably separate vendor specific
> > > files.
> > > 
> > > To designate a vendor control, the YAML control description must contain a
> > > "vendor: <vendor_string>" tag.  For example,
> > > 
> > > - RaspberryPiExampleControl:
> > >     type: string
> > >     vendor: rpi
> > >     description: |
> > >       Example vendor control with the "rpi" vendor tag.
> > 
> > I'm concerned that having to tag each control with the vendor, coupled
> > with the ability to declare vendor controls in the main control_ids.yaml
> > file, will make it a bit messy and difficult to maintain. I would prefer
> > enforcing separation of vendor controls in per-vendor files right away.
> > You can then add the vendor property at the top level in the YAML file,
> > instead of specifying it per-control.
> > 
> > I'm also thinking that we should probably move the control and property
> > YAML files to a subdirectory, but that's something I can do on top.
> 
> I would also likely prefer a per-vendor file.
> 
> > > will create a control in the libcamera::controls::rpi namespace, with the
> > > numeric id value taken from the "rpi" reservation.  Additionally, a #define
> > > LIBCAMERA_RPI_VENDOR_CONTROL will be available for applications to selectively
> > > compile in vendor control support.  Similar applies to the property generation.
> > > 
> > > The current mechanism for draft controls and propertiers have been deprecated,
> > > and now these are designated with the "draft" vendor tag.  Note that this causes
> > > an API breaking change since the numeric control id values for draft control
> > > have their own designated range and namespace.  So, for example, the use of
> > > controls::NOISE_REDUCTION_MODE will need to be replaced with
> > > controls::draft::NOISE_REDUCTION_MODE.
> > 
> > I like that, thanks.
> 
> Yes, moving draft controls to become 'a vendor' set is a good
> demonstration and abstraction here I think.
> 
> 
> Interestingly, or rather ... annoyingly - that wasn't identified by the
> abi-compatibility checker ...
> 
> (
> ```
> sudo apt install abi-compliance-checker 
> ./utils/abi-compat.sh origin/master HEAD
> ```
> )

As the tool has been unmaintained for 2 years, trying it libabigail may
be a good idea when time permits. When :-)

> > > Naushir Patuck (5):
> > >   controls: Add vendor control/property support to generation scripts
> > >   controls: build: Allow separate vendor control YAML files
> > >   libcamera: control: Add vendor control id range reservation
> > >   libcamera: controls: Use vendor tags for draft controls and properties
> > >   documentation: Document vendor specific control and properties
> > >     handling
> > > 
> > >  Documentation/guides/pipeline-handler.rst     |  53 ++++++
> > >  include/libcamera/control_ids.h.in            |   6 +-
> > >  include/libcamera/meson.build                 |  58 +++++-
> > >  include/libcamera/property_ids.h.in           |   8 +-
> > >  meson.build                                   |   2 +
> > >  src/ipa/rpi/common/ipa_base.cpp               |   2 +-
> > >  src/ipa/rpi/vc4/vc4.cpp                       |   2 +-
> > >  src/libcamera/control_ids.cpp.in              |  16 +-
> > >  src/libcamera/control_ids.yaml                |  20 +--
> > >  src/libcamera/control_ids_rpi.yaml            |  17 ++
> > >  src/libcamera/control_ranges.yaml             |  17 ++
> > >  src/libcamera/meson.build                     |  20 ++-
> > >  src/libcamera/property_ids.cpp.in             |  16 +-
> > >  src/libcamera/property_ids.yaml               |   2 +-
> > >  src/py/libcamera/gen-py-controls.py           |  31 +++-
> > >  src/py/libcamera/meson.build                  |  26 +--
> > >  src/py/libcamera/py_controls_generated.cpp.in |   6 +-
> > >  .../libcamera/py_properties_generated.cpp.in  |   4 +-
> > >  utils/gen-controls.py                         | 169 +++++++++++++-----
> > >  19 files changed, 348 insertions(+), 127 deletions(-)
> > >  create mode 100644 src/libcamera/control_ids_rpi.yaml
> > >  create mode 100644 src/libcamera/control_ranges.yaml

-- 
Regards,

Laurent Pinchart