[libcamera-devel] [PATCH 4/5] ipa: rpi: agc: Add AgcChannelConstraint class

[Naushir Patuck]

Hi David,

Thank you for your work.

On Mon, 31 Jul 2023 at 10:46, David Plowman via libcamera-devel
<libcamera-devel at lists.libcamera.org> wrote:
>
> A channel constraint is somewhat similar to the upper/lower bound
> constraints that we use elsewhere, but these constraints apply between
> multiple AGC channels. For example, it lets you say things like "don't
> let the channel 1 total exposure be more than 8x that of channel 0",
> and so on. By using both an upper and lower bound constraint, you
> could fix one AGC channel always to be a fixed ratio of another.
>
> Also read a vector of them (if present) when loading the tuning file.
>
> Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> ---
>  src/ipa/rpi/controller/rpi/agc_channel.cpp | 42 ++++++++++++++++++++++
>  src/ipa/rpi/controller/rpi/agc_channel.h   | 10 ++++++
>  2 files changed, 52 insertions(+)
>
> diff --git a/src/ipa/rpi/controller/rpi/agc_channel.cpp b/src/ipa/rpi/controller/rpi/agc_channel.cpp
> index ddec611f..ed8a3b30 100644
> --- a/src/ipa/rpi/controller/rpi/agc_channel.cpp
> +++ b/src/ipa/rpi/controller/rpi/agc_channel.cpp
> @@ -173,6 +173,42 @@ readConstraintModes(std::map<std::string, AgcConstraintMode> &constraintModes,
>         return { 0, first };
>  }
>
> +int AgcChannelConstraint::read(const libcamera::YamlObject &params)
> +{
> +       std::string boundString = params["bound"].get<std::string>("");
> +       transform(boundString.begin(), boundString.end(),
> +                 boundString.begin(), ::toupper);
> +       if (boundString != "UPPER" && boundString != "LOWER") {
> +               LOG(RPiAgc, Error) << "AGC channelconstraint type should be UPPER or LOWER";
> +               return -EINVAL;
> +       }
> +       bound = boundString == "UPPER" ? Bound::UPPER : Bound::LOWER;
> +
> +       auto value = params["factor"].get<double>();
> +       if (!value)
> +               return -EINVAL;
> +       factor = *value;
> +
> +       return 0;
> +}
> +
> +int readChannelConstraints(std::vector<AgcChannelConstraint> channelConstraints,
> +                          const libcamera::YamlObject &params)

Make this function static?


> +{
> +       int ret = 0;
> +
> +       for (const auto &p : params.asList()) {
> +               AgcChannelConstraint constraint;
> +               ret = constraint.read(p);
> +               if (ret)
> +                       return ret;
> +
> +               channelConstraints.push_back(std::move(constraint));

Do we need to move here?  Probably no practical difference though.

Reviewed-by: Naushir Patuck <naush at raspberrypi.com>

> +       }
> +
> +       return ret;
> +}
> +
>  int AgcConfig::read(const libcamera::YamlObject &params)
>  {
>         LOG(RPiAgc, Debug) << "AgcConfig";
> @@ -191,6 +227,12 @@ int AgcConfig::read(const libcamera::YamlObject &params)
>         if (ret)
>                 return ret;
>
> +       if (params.contains("channel_constraints")) {
> +               ret = readChannelConstraints(channelConstraints, params["channel_constraints"]);
> +               if (ret)
> +                       return ret;
> +       }
> +
>         ret = yTarget.read(params["y_target"]);
>         if (ret)
>                 return ret;
> diff --git a/src/ipa/rpi/controller/rpi/agc_channel.h b/src/ipa/rpi/controller/rpi/agc_channel.h
> index 0e3d44b0..446125ef 100644
> --- a/src/ipa/rpi/controller/rpi/agc_channel.h
> +++ b/src/ipa/rpi/controller/rpi/agc_channel.h
> @@ -42,11 +42,21 @@ struct AgcConstraint {
>
>  typedef std::vector<AgcConstraint> AgcConstraintMode;
>
> +struct AgcChannelConstraint {
> +       enum class Bound { LOWER = 0,
> +                          UPPER = 1 };
> +       Bound bound;
> +       unsigned int channel;
> +       double factor;
> +       int read(const libcamera::YamlObject &params);
> +};
> +
>  struct AgcConfig {
>         int read(const libcamera::YamlObject &params);
>         std::map<std::string, AgcMeteringMode> meteringModes;
>         std::map<std::string, AgcExposureMode> exposureModes;
>         std::map<std::string, AgcConstraintMode> constraintModes;
> +       std::vector<AgcChannelConstraint> channelConstraints;
>         Pwl yTarget;
>         double speed;
>         uint16_t startupFrames;
> --
> 2.30.2
>