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

[paul.elder at ideasonboard.com]

Hi Jacopo,

On Mon, Dec 28, 2020 at 10:39:25AM +0100, Jacopo Mondi wrote:
> 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

Ah yeah, I mean in the case that the mandatory control is not present,
so validateSensorDriver() returns -EINVAL.

> CameraSensor::init() bails out before calling this method. Or have I

Wouldn't that mean that this method won't be called either if the
optional controls aren't present in the driver?

> 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.

I see.


Paul

> 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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