[PATCH v2] libcamera: camera_sensor: Cache pixel rate

[Umang Jain]

Hi Paul

On 1/22/24 5:43 PM, Paul Elder wrote:
> Cache the pixel rate at set format time instead of fetching it from the
> v4l2 subdev every time it's needed.
>
> It needs to be cached at set format time as opposed to initialization
> time as some sensor drives (eg. imx708) change the pixel rate depending
> on the mode.
>
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
>
> ---
> Changes in v2:
> - Cache the pixel rate at set format time instead of at initialization
>    time
> ---
>   include/libcamera/internal/camera_sensor.h | 2 ++
>   src/libcamera/camera_sensor.cpp            | 8 +++++++-
>   2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
> index 60a8b106d..da3bf12b3 100644
> --- a/include/libcamera/internal/camera_sensor.h
> +++ b/include/libcamera/internal/camera_sensor.h
> @@ -105,6 +105,8 @@ private:
>   	std::string model_;
>   	std::string id_;
>   
> +	uint64_t pixelRate_;
> +
>   	V4L2Subdevice::Formats formats_;
>   	std::vector<unsigned int> mbusCodes_;
>   	std::vector<Size> sizes_;
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index 0ef78d9c8..127610321 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -515,6 +515,9 @@ int CameraSensor::initProperties()
>   		properties_.set(properties::draft::ColorFilterArrangement, cfa);
>   	}
>   
> +	ControlList ctrls = subdev_->getControls({ V4L2_CID_PIXEL_RATE });
> +	pixelRate_ = ctrls.get(V4L2_CID_PIXEL_RATE).get<int64_t>();
> +

Do we have to cache it at two places? One initProperties() and other in 
setFormat() ?

In the change log, you have used ' instead of '  so I am a bit confused..
>   	return 0;
>   }
>   
> @@ -814,6 +817,9 @@ int CameraSensor::setFormat(V4L2SubdeviceFormat *format, Transform transform)
>   	if (ret)
>   		return ret;
>   
> +	ControlList ctrls = subdev_->getControls({ V4L2_CID_PIXEL_RATE });
> +	pixelRate_ = ctrls.get(V4L2_CID_PIXEL_RATE).get<int64_t>();
> +
>   	updateControlInfo();
>   	return 0;
>   }
> @@ -1080,7 +1086,7 @@ int CameraSensor::sensorInfo(IPACameraSensorInfo *info) const
>   		return -EINVAL;
>   	}
>   
> -	info->pixelRate = ctrls.get(V4L2_CID_PIXEL_RATE).get<int64_t>();
> +	info->pixelRate = pixelRate_;
>   
>   	const ControlInfo hblank = ctrls.infoMap()->at(V4L2_CID_HBLANK);
>   	info->minLineLength = info->outputSize.width + hblank.min().get<int32_t>();