Re: [PATCH 0/3] Add media bdisp driver for stihxxx platforms

[Hans Verkuil <hverkuil@xs4all.nl>]

Hi Fabien,

Thank you for this driver! Good to see V4L2 support for this SoC.

I did a quick initial scan over the driver and there are a few things that
need to be addressed:

- I think bdisp as the driver name is a bit generic, perhaps something like
  stih4xx-bdisp might be more appropriate. Similar to the exynos-* drivers.

- Replace cropcap/g_crop/s_crop by the g/s_selection ioctls. The old ioctls
  are no longer supported for new drivers (the v4l2 core will automatically
  add support for those ioctls if g/s_selection is implemented in the driver).
  Read careful how crop and compose rectangles are used in a m2m device. I
  would expect that you implement cropping for the BUF_TYPE_VIDEO_OUTPUT side
  (i.e. memory to hardware) and implement composing for the BUF_TYPE_VIDEO_CAPTURE
  side (i.e. hardware to memory).

  If the hardware also support composition for output or cropping for capture,
  then let me know: in that case you will likely have to implement support for
  V4L2_SEL_TGT_NATIVE_SIZE as well.

- Several ioctl and fop helpers were added to media/v4l2-mem2mem.h (e.g.
  v4l2_m2m_ioctl_reqbufs, v4l2_m2m_fop_mmap, etc.). Use these instead of
  rolling your own.

- I would like to see the output of these v4l2-compliance commands:

	v4l2-compliance
	v4l2-compliance -s
	v4l2-compliance -f

  In all fairness: mem2mem devices are not often tested using v4l2-compliance
  and there may be problems testing this (-f will likely fail), but I still
  like to see the output so I know what works and what doesn't.

  Please use the latest v4l2-compliance code from the v4l-utils.git repository.
  I won't accept the driver unless I see the results of these compliance tests:
  running this is required for new drivers since it is a great way of verifying
  the completeness of your driver.

Regards,

	Hans

On 04/27/2015 05:56 PM, Fabien Dessenne wrote:
> This series of patches adds the support of v4l2 2D blitter driver for
> STMicroelectronics SOC.
> 
> The following features are supported and tested:
> - Color format conversion (RGB32, RGB24, RGB16, NV12, YUV420P)
> - Copy
> - Scale
> - Flip
> - Deinterlace
> - Wide (4K) picture support
> - Crop
> 
> This driver uses the v4l2 mem2mem framework and its implementation was largely
> inspired by the Exynos G-Scaler (exynos-gsc) driver.
> 
> The driver is mainly implemented across two files:
> - bdisp-v4l2.c
> - bdisp-hw.c
> bdisp-v4l2.c uses v4l2_m2m to manage the V4L2 interface with the userland. It
> calls the HW services that are implemented in bdisp-hw.c.
> 
> The additional bdisp-debug.c file manages some debugfs entries.
> 
> Fabien Dessenne (3):
>   [media] bdisp: add DT bindings documentation
>   [media] bdisp: 2D blitter driver using v4l2 mem2mem framework
>   [media] bdisp: add debug file system
> 
>  .../devicetree/bindings/media/st,stih4xx.txt       |   32 +
>  drivers/media/platform/Kconfig                     |   10 +
>  drivers/media/platform/Makefile                    |    2 +
>  drivers/media/platform/bdisp/Kconfig               |    9 +
>  drivers/media/platform/bdisp/Makefile              |    3 +
>  drivers/media/platform/bdisp/bdisp-debug.c         |  668 +++++++++
>  drivers/media/platform/bdisp/bdisp-filter.h        |  346 +++++
>  drivers/media/platform/bdisp/bdisp-hw.c            |  823 +++++++++++
>  drivers/media/platform/bdisp/bdisp-reg.h           |  235 +++
>  drivers/media/platform/bdisp/bdisp-v4l2.c          | 1492 ++++++++++++++++++++
>  drivers/media/platform/bdisp/bdisp.h               |  220 +++
>  11 files changed, 3840 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/st,stih4xx.txt
>  create mode 100644 drivers/media/platform/bdisp/Kconfig
>  create mode 100644 drivers/media/platform/bdisp/Makefile
>  create mode 100644 drivers/media/platform/bdisp/bdisp-debug.c
>  create mode 100644 drivers/media/platform/bdisp/bdisp-filter.h
>  create mode 100644 drivers/media/platform/bdisp/bdisp-hw.c
>  create mode 100644 drivers/media/platform/bdisp/bdisp-reg.h
>  create mode 100644 drivers/media/platform/bdisp/bdisp-v4l2.c
>  create mode 100644 drivers/media/platform/bdisp/bdisp.h
>