[libcamera-devel] [PATCH v2 00/10] Simple pipeline handler

[Laurent Pinchart]

Hello,

This patch series builds on Martijn's work to implement a pipeline
handler for simpler pipelines. Additional information about the pipeline
handler itself can be found in patch 08/10.

Compared to v1, this version has been rebased on top of the buffer
management simplification ([1]). It also includes support for simple
converters, V4L2 mem2mem device that perform format conversion, to
extend the number of supported pixel formats.

[1] https://lists.libcamera.org/pipermail/libcamera-devel/2020-March/007224.html

Patches 01/10 to 07/10 haven't been changed compare to v1. They add a
V4L2 API extension required for pipeline auto-configuration (01/10), as
well aw new utility functions and miscellaneous small extensions (02/10
to 07/10).

Patch 08/10 adds the new simple pipeline handler, patch 09/10 the
simpler converter, and patch 10/10 integrates converter support into the
simple pipeline handler. The converter API should probably be improved,
I've implemented it as a proof of concept. Other options also exist,
such as making the simple pipeline handler a base class from which more
specialized pipeline handlers could derive from, and implement support
for converters in device-specific code.

The code has been tested on an i.MX7 platform with a greyscale sensor
and the i.MX PXP as format converter to produce RGB. I've kept sun6i-csi
from Martijn's work in the list of supported drivers, but supporting
that platform will require extending the corresponding driver to support
the VIDIOC_ENUM_FMT extension. Once done, if all goes well, the platform
should work out of the box.

As before, this is meant to be compatible with the stm32 and qcom-camss
that pipeline handlers have previously been submitted for. The
respective drivers need be added to the drivers array in
SimplePipelineHandler::match(), and, as for sun6i-csi, support for the
VIDIOC_ENUM_FMT extension needs to be implemented in the drivers, which
should be fairly easy.

Laurent Pinchart (9):
  [DNI] include: linux: Extend VIDIOC_ENUM_FMT to support MC-centric
    devices
  libcamera: utils: Add string join function
  libcamera: v4l2_subdevice: Extend [gs]etFormat() to specify format
    type
  libcamera: v4l2_videodevice: Support filtering formats by media bus
    code
  libcamera: v4l2_videodevice: Expose the device capabilities
  libcamera: v4l2_videodevice: Downgrade 4CC conversion errors to
    warnings
  libcamera: v4l2_videodevice: Map V4L2_PIX_FMT_GREY to DRM FourCC
  libcamera: pipeline: simple: Add simple format converter
  libcamera: pipeline: simple: Integrate converter support

Martijn Braam (1):
  libcamera: pipeline: Add a simple pipeline handler

 include/linux/videodev2.h                   |   4 +-
 src/libcamera/include/utils.h               |  44 +
 src/libcamera/include/v4l2_subdevice.h      |  11 +-
 src/libcamera/include/v4l2_videodevice.h    |   6 +-
 src/libcamera/pipeline/meson.build          |   1 +
 src/libcamera/pipeline/simple/converter.cpp | 210 +++++
 src/libcamera/pipeline/simple/converter.h   |  60 ++
 src/libcamera/pipeline/simple/meson.build   |   4 +
 src/libcamera/pipeline/simple/simple.cpp    | 855 ++++++++++++++++++++
 src/libcamera/utils.cpp                     |  16 +
 src/libcamera/v4l2_subdevice.cpp            |  23 +-
 src/libcamera/v4l2_videodevice.cpp          |  36 +-
 test/utils.cpp                              |   7 +-
 13 files changed, 1261 insertions(+), 16 deletions(-)
 create mode 100644 src/libcamera/pipeline/simple/converter.cpp
 create mode 100644 src/libcamera/pipeline/simple/converter.h
 create mode 100644 src/libcamera/pipeline/simple/meson.build
 create mode 100644 src/libcamera/pipeline/simple/simple.cpp

-- 
Regards,

Laurent Pinchart