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

[Daniel Scally]

Hi Laurent

On 28/11/2021 22:20, Laurent Pinchart wrote:
> Hi Daniel,
>
> Thank you for the patch.
>
> 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.

>> ---
>>
>> 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?

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