[libcamera-devel] [PATCH 2/5] libcamera: camera_sensor: Initialize controls

[paul.elder at ideasonboard.com]

Hi Jacopo,

On Wed, Dec 23, 2020 at 07:45:13PM +0100, Jacopo Mondi wrote:
> Initialize the ControlInfoMap of sensor available controls by
> reporting the sensor exposure time range.
> 
> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> ---
>  include/libcamera/internal/camera_sensor.h |  2 ++
>  src/libcamera/camera_sensor.cpp            | 42 +++++++++++++++++++++-
>  2 files changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
> index aee10aa6e3c7..0357b2a630f7 100644
> --- a/include/libcamera/internal/camera_sensor.h
> +++ b/include/libcamera/internal/camera_sensor.h
> @@ -71,6 +71,7 @@ private:
>  	int generateId();
>  	int validateSensorDriver();
>  	int initProperties();
> +	int initControls();
>  
>  	const MediaEntity *entity_;
>  	std::unique_ptr<V4L2Subdevice> subdev_;
> @@ -85,6 +86,7 @@ private:
>  	std::vector<Size> sizes_;
>  
>  	ControlList properties_;
> +	ControlInfoMap controls_;
>  };
>  
>  } /* namespace libcamera */
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index 3a65ac3de5bc..609f948c56a6 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -15,6 +15,7 @@
>  #include <regex>
>  #include <string.h>
>  
> +#include <libcamera/control_ids.h>
>  #include <libcamera/property_ids.h>
>  
>  #include "libcamera/internal/bayer_format.h"
> @@ -215,7 +216,7 @@ int CameraSensor::init()
>  	if (ret)
>  		return ret;
>  
> -	return 0;
> +	return initControls();
>  }
>  
>  int CameraSensor::validateSensorDriver()
> @@ -229,6 +230,7 @@ int CameraSensor::validateSensorDriver()
>  	const std::vector<uint32_t> mandatoryControls{
>  		V4L2_CID_PIXEL_RATE,
>  		V4L2_CID_HBLANK,
> +		V4L2_CID_EXPOSURE,
>  	};
>  
>  	ControlList ctrls = subdev_->getControls(mandatoryControls);
> @@ -430,6 +432,44 @@ int CameraSensor::initProperties()
>  	return 0;
>  }
>  
> +int CameraSensor::initControls()
> +{
> +	const ControlInfoMap &v4l2Controls = subdev_->controls();
> +
> +	/* Exposure time limits expressed in micro-seconds. */
> +
> +	/* Calculate the line length in pixels. */
> +	ControlList ctrls = subdev_->getControls({ V4L2_CID_HBLANK });

I see that the presence of this control is declared as mandatory in
validateSensorDriver() in 1/5, but it just returns -EINVAL and
continues; would that cause a problem here?

> +	int32_t hblank = ctrls.get(V4L2_CID_HBLANK).get<int32_t>();

Would it just make this zero and continue? And the user has been warned
of unexpected behavior in the validation step already.

> +	V4L2SubdeviceFormat format{};
> +	int ret = subdev_->getFormat(pad_, &format);
> +	if (ret)
> +		return ret;
> +	int32_t ppl = format.size.width + hblank;
> +
> +	const ControlInfo &v4l2ExposureInfo = v4l2Controls.find(V4L2_CID_EXPOSURE)->second;
> +	int32_t minExposurePixels = v4l2ExposureInfo.min().get<int32_t>() * ppl;
> +	int32_t maxExposurePixels = v4l2ExposureInfo.max().get<int32_t>() * ppl;
> +	int32_t defExposurePixels = v4l2ExposureInfo.max().get<int32_t>() * ppl;

s/max/def/ ?


Paul

> +
> +	/* Get the pixel rate (in useconds) and calculate the exposure timings. */
> +	const ControlInfo &pixelRateInfo = v4l2Controls.find(V4L2_CID_PIXEL_RATE)->second;
> +	float minPixelRate = pixelRateInfo.min().get<int64_t>() / 1e6f;
> +	float maxPixelRate = pixelRateInfo.max().get<int64_t>() / 1e6f;
> +	float defPixelRate = pixelRateInfo.def().get<int64_t>() / 1e6f;
> +
> +	int32_t minExposure = static_cast<int32_t>(minExposurePixels / maxPixelRate);
> +	int32_t maxExposure = static_cast<int32_t>(maxExposurePixels / minPixelRate);
> +	int32_t defExposure = static_cast<int32_t>(defExposurePixels / defPixelRate);
> +
> +	ControlInfoMap::Map map;
> +	map[&controls::ExposureTime] = ControlInfo(minExposure, maxExposure,
> +						   defExposure);
> +	controls_ = std::move(map);
> +
> +	return 0;
> +}
> +
>  /**
>   * \fn CameraSensor::model()
>   * \brief Retrieve the sensor model name
> -- 
> 2.29.2
> 
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