[libcamera-devel] [PATCH] libcamera: camera_sensor: Cache pixel rate

[Andrei Konovalov]

Hi Paul,

It doesn't look like it will always work, as there is at least one sensor/driver
for which the pixel rate depends on the mode:

https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L46

https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L692
https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L715
https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L738
https://github.com/raspberrypi/linux/blob/rpi-6.1.y/drivers/media/i2c/imx708.c#L738


Thanks,
Andrei

On 19.01.2024 14:07, Paul Elder via libcamera-devel wrote:
> Cache the pixel rate at initialization time instead of fetching it from
> the v4l2 subdev every time it's needed.
> 
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> ---
>   include/libcamera/internal/camera_sensor.h | 2 ++
>   src/libcamera/camera_sensor.cpp            | 5 ++++-
>   2 files changed, 6 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..33fdb4c8e 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>();
> +
>   	return 0;
>   }
>   
> @@ -1080,7 +1083,7 @@ 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>();