Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

Hi Balamanikandan,

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:

Hi,

This patch series has a set of enhancements to the Microchip Image Sensor
Controller driver. The objective is to expand its image processing
capabilities and to improve the colors.

This series also introduces a new stats driver that exposes the histogram
data to userspace via v4l2 controls. This allows applications such as
libcamera to access real time image statistics for advanced image
processing like automatic exposure, white balance adjustments etc.

Most of this series is fine, but the histogram part needs more work.

I would recommend splitting up this series in two parts: one for the
various fixes and improvements, and one for the histogram feature.

The first series with the fixes I can take easily. In fact, if you
post that this week (no later than Thursday), then I can pick it
up in time for v6.19.

As mentioned the histogram part needs more work. Mostly small stuff,
but the documentation is the major missing part.

I also want to see the output of 'v4l2-compliance -m0 -s' (i.e.
with streaming) in the cover letter of the histogram series to be
certain nothing was forgotten.

Make sure you compile v4l2-compliance straight from the git repo,
don't use a distro version since that's usually out of date.

Regards,

	Hans

Balakrishnan Sambath (11):
  media: microchip-isc: Enable GDC and CBC module flags for RGB formats
  media: microchip-isc: Improve histogram calculation with outlier
    rejection
  media: microchip-isc: Use channel averages for Grey World AWB
  media: microchip-isc: Add range based black level correction
  media: platform: microchip: Extend gamma table and control range
  media: platform: microchip: Add new histogram submodule
  media: microchip-isc: Register and unregister statistics device
  media: microchip-isc: Always enable histogram for all RAW formats
  media: microchip-isc: fix histogram state initialization order
  media: microchip-isc: decouple histogram cycling from AWB mode
  media: microchip-isc: enable userspace histogram statistics export

Balamanikandan Gunasundar (7):
  media: platform: microchip: set maximum resolution for sam9x7
  media: platform: microchip: Include DPC modules flags in pipeline
  media: microchip-isc: expose hue and saturation as v4l2 controls
  media: microchip-isc: Rename CBC to CBHS
  media: microchip-isc: Store histogram data of all channels
  media: videodev2.h, v4l2-ioctl: Add microchip statistics format
  media: microchip-isc: expose color correction registers as v4l2
    controls

 drivers/media/platform/microchip/Kconfig      |   2 +
 drivers/media/platform/microchip/Makefile     |   2 +-
 .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
 .../platform/microchip/microchip-isc-regs.h   |   3 +
 .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
 .../media/platform/microchip/microchip-isc.h  |  44 +-
 .../microchip/microchip-sama5d2-isc.c         |   2 +-
 .../microchip/microchip-sama7g5-isc.c         |  73 ++-
 drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
 include/linux/atmel-isc-media.h               |  13 +
 include/uapi/linux/videodev2.h                |   3 +
 11 files changed, 1001 insertions(+), 64 deletions(-)
 create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c