[libcamera-devel] [PATCH 3/5] libcamera: ipu3-cio2: Discover VCMs through ancillary links

[Laurent Pinchart]

Hi Daniel,

On Sun, Nov 28, 2021 at 11:13:26PM +0000, Daniel Scally wrote:
> On 28/11/2021 22:20, Laurent Pinchart wrote:
> > On Fri, Nov 26, 2021 at 12:31:16AM +0000, Daniel Scally wrote:
> >> Rather than attempting to discover VCMs via model name matching we
> >> should follow the ancillary links that define the relationship
> >> between the two devices to locate any entities linked to the sensor.
> >> Where we have linked entities with the function MEDIA_ENT_F_LENS we
> >> can then create an instance of CameraLens to represent it.
> >>
> >> Signed-off-by: Daniel Scally <djrscally at gmail.com>
> >
> > Given that Han-lin's patch that add model-based matching hasn't been
> > merged yet, I think this should be rebased on top of the master branch
> > directly. There's no need to merge model-based matching to replace it
> > immediately after.
> 
> Did the patch introducing the CameraLens class get merged, then? I can
> rebase onto master in that case, no problem.

Not yet. Feel free to include it in your series to develop its
integration.

> >> ---
> >>
> >> Alternatively rather than replace the matching on model names we could try
> >> the ancillary links first and then simply guard the existing model matching
> >> with an if (!lens_) ...
> >
> > I think ancillary links are good enough, there's no need for model-based
> > matching.
> 
> Righto.
> 
> >>  src/libcamera/pipeline/ipu3/cio2.cpp | 45 +++++++++++++++-------------
> >>  1 file changed, 25 insertions(+), 20 deletions(-)
> >>
> >> diff --git a/src/libcamera/pipeline/ipu3/cio2.cpp b/src/libcamera/pipeline/ipu3/cio2.cpp
> >> index 59b2f586..169e7b54 100644
> >> --- a/src/libcamera/pipeline/ipu3/cio2.cpp
> >> +++ b/src/libcamera/pipeline/ipu3/cio2.cpp
> >> @@ -161,30 +161,35 @@ int CIO2Device::init(const MediaDevice *media, unsigned int index)
> >>  	}
> >>  
> >>  	/*
> >> -	 * \todo Read the lens model from the sensor itself or from a device
> >> -	 * database. For now use default values taken from ChromeOS database.
> >> +	 * Sensors sometimes have ancillary devices such as a Lens or Flash
> >> +	 * that could be linked to the MediaEntity - search for and handle
> >> +	 * any such device (for now, we can only handle MEDIA_ENT_F_LENS)
> >> +	 *
> >> +	 * \todo Handle MEDIA_ENT_F_FLASH too.
> >>  	 */
> >> -	static std::unordered_map<std::string, std::string> sensorLens = {
> >> -		{ "ov13858", "dw9714" },
> >> -		{ "imx258", "dw9807" },
> >> -		{ "imx355", "ak7375" }
> >> -	};
> >> -
> >> -	auto it = sensorLens.find(sensor_->model());
> >> -	if (it != sensorLens.end()) {
> >> -		const std::vector<MediaEntity *> &entities = media->entities();
> >> -		for (auto ent : entities) {
> >> -			if (ent->function() == MEDIA_ENT_F_LENS) {
> >> -				lens_ = std::make_unique<CameraLens>(ent);
> >> +	const std::vector<MediaLink *> &ancillary_links = sensorEntity->ancillary_links();
> >> +	if (!ancillary_links.empty()) {
> >> +		for (auto it : ancillary_links) {
> >> +			MediaEntity *ancillaryEntity = it->ancillary();
> >> +
> >> +			switch (ancillaryEntity->function()) {
> >> +			case MEDIA_ENT_F_LENS:
> >> +				lens_ = std::make_unique<CameraLens>(ancillaryEntity);
> >>  				ret = lens_->init();
> >> -				if (!ret && lens_->model() == it->second) {
> >> -					break;
> >> +				if (ret) {
> >> +					LOG(IPU3, Error)
> >> +						<< "Error during CameraLens init";
> >> +					return ret;
> >>  				}
> >> -				lens_.reset();
> >> +				break;
> >> +			case MEDIA_ENT_F_FLASH:
> >> +				LOG(IPU3, Warning)
> >> +					<< "Flash not yet supported";
> >> +				break;
> >> +			default:
> >> +				LOG(IPU3, Warning)
> >> +					<< "Unsupported entity function";
> >>  			}
> >
> > Could we simplify the pipeline handlers a bit by moving at least the
> > lookup of the VCM entity to the CameraSensor class ?
> 
> Sure; I actually moved it to ::init() now, that sound ok?

Do you mean CameraSensor::init() ? Yes, that sounds fine (although you
may want to move it to a private function called by init(), there's lots
being done at init time already).

> >> -			if (!lens_)
> >> -				LOG(IPU3, Warning) << "Lens device "
> >> -						   << it->second << " not found";
> >>  		}
> >>  	}
> >>  

-- 
Regards,

Laurent Pinchart