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

[Jacopo Mondi]

Hi Paul,

On Mon, Dec 28, 2020 at 05:26:57PM +0900, paul.elder at ideasonboard.com wrote:
> 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?

Do you mean 'validateSensorDriver()' returns -EINVAL ? In that case
CameraSensor::init() bails out before calling this method. Or have I
mis-understood your question ?

One thing I would add: reading a control might fail for other reason
than not being implemented in the driver. I should probably check for
        if (ctrl.empty())
nonetheless

>
> > +	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.
>

We don't get here if validation fails if that's what you mean.

And in case reading the control fails for unrelated reasons, I would
fail instead of zeroing...

> > +	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/ ?

Good catch!

Thanks
  j

>
>
> 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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> > libcamera-devel at lists.libcamera.org
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