[libcamera-devel] [PATCH v2 2/4] ipa: rpi: Provide a Camera Helper for the OV64A40

[Jacopo Mondi]

Hi Dave,

On Mon, Dec 04, 2023 at 03:44:21PM +0000, Dave Stevenson via libcamera-devel wrote:
> Hi Jacopo
>
> On Mon, 4 Dec 2023 at 09:11, Jacopo Mondi via libcamera-devel
> <libcamera-devel at lists.libcamera.org> wrote:
> >
> > Support the OV64A40 sensor with a camera helper to manage the gain
> > model, light sensitivity, and control delays.
> >
> > Signed-off-by: Lee Jackson <lee.jackson at arducam.com>
> > Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
> > Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
> > ---
> >  src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp | 73 +++++++++++++++++++
> >  src/ipa/rpi/cam_helper/meson.build            |  1 +
> >  2 files changed, 74 insertions(+)
> >  create mode 100644 src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp
> >
> > diff --git a/src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp b/src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp
> > new file mode 100644
> > index 000000000000..041c32dd9222
> > --- /dev/null
> > +++ b/src/ipa/rpi/cam_helper/cam_helper_ov64a40.cpp
> > @@ -0,0 +1,73 @@
> > +/* SPDX-License-Identifier: BSD-2-Clause */
> > +/*
> > + * Copyright (C) 2021, Raspberry Pi Ltd
> > + *
> > + * cam_helper_ov64a40.cpp - camera information for ov64a40 sensor
> > + */
> > +
> > +#include <assert.h>
> > +
> > +#include "cam_helper.h"
> > +
> > +using namespace RPiController;
> > +
> > +class CamHelperOv64a40 : public CamHelper
> > +{
> > +public:
> > +       CamHelperOv64a40();
> > +       uint32_t gainCode(double gain) const override;
> > +       double gain(uint32_t gainCode) const override;
> > +       void getDelays(int &exposureDelay, int &gainDelay,
> > +                      int &vblankDelay, int &hblankDelay) const override;
> > +       double getModeSensitivity(const CameraMode &mode) const override;
> > +
> > +private:
> > +       /*
> > +        * Smallest difference between the frame length and integration time,
> > +        * in units of lines.
> > +        */
> > +       static constexpr int frameIntegrationDiff = 4;
>
> Just noticing this in passing. Your driver PR has
> #define OV64A40_EXPOSURE_MARGIN 32
> yet this defines the difference to be 4. AIUI they are the same
> parameter, so presumably one of them is wrong.

You're right! thanks for spotting. The correct value to use is 32,
I'll update this one!

>
>   Dave
>
> > +};
> > +
> > +CamHelperOv64a40::CamHelperOv64a40()
> > +       : CamHelper({}, frameIntegrationDiff)
> > +{
> > +}
> > +
> > +uint32_t CamHelperOv64a40::gainCode(double gain) const
> > +{
> > +       return static_cast<uint32_t>(gain * 128.0);
> > +}
> > +
> > +double CamHelperOv64a40::gain(uint32_t gainCode) const
> > +{
> > +       return static_cast<double>(gainCode) / 128.0;
> > +}
> > +
> > +void CamHelperOv64a40::getDelays(int &exposureDelay, int &gainDelay,
> > +                                int &vblankDelay, int &hblankDelay) const
> > +{
> > +       /* The driver appears to behave as follows: */
> > +       exposureDelay = 2;
> > +       gainDelay = 2;
> > +       vblankDelay = 2;
> > +       hblankDelay = 2;
> > +}
> > +
> > +double CamHelperOv64a40::getModeSensitivity(const CameraMode &mode) const
> > +{
> > +       if (mode.binX >= 2 && mode.scaleX >= 4) {
> > +               return 4.0;
> > +       } else if (mode.binX >= 2 && mode.scaleX >= 2) {
> > +               return 2.0;
> > +       } else {
> > +               return 1.0;
> > +       }
> > +}
> > +
> > +static CamHelper *create()
> > +{
> > +       return new CamHelperOv64a40();
> > +}
> > +
> > +static RegisterCamHelper reg("ov64a40", &create);
> > diff --git a/src/ipa/rpi/cam_helper/meson.build b/src/ipa/rpi/cam_helper/meson.build
> > index bdf2db8eb742..7262505742f3 100644
> > --- a/src/ipa/rpi/cam_helper/meson.build
> > +++ b/src/ipa/rpi/cam_helper/meson.build
> > @@ -9,6 +9,7 @@ rpi_ipa_cam_helper_sources = files([
> >      'cam_helper_imx477.cpp',
> >      'cam_helper_imx519.cpp',
> >      'cam_helper_imx708.cpp',
> > +    'cam_helper_ov64a40.cpp',
> >      'cam_helper_ov9281.cpp',
> >      'md_parser_smia.cpp',
> >  ])
> > --
> > 2.41.0
> >