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

[Dave Stevenson]

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.

  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
>