[libcamera-devel] [PATCH v2] libcamera: ipu3: Add rotation to ipu3 pipeline

[Jacopo Mondi]

Hi Fabian,

On Sat, Jan 16, 2021 at 04:02:58PM +0100, Fabian Wüthrich wrote:
> Use the same transformation logic as in the raspberry pipeline to
> implement rotations in the ipu3 pipeline.
>
> Tested on a Surface Book 2 with an experimental driver for OV5693.
>
> Signed-off-by: Fabian Wüthrich <me at fabwu.ch>
> ---
> Changes in v2:
>  - Cache rotationTransform in CameraData
>  - Use separate controls for sensor
>
>  src/libcamera/pipeline/ipu3/ipu3.cpp | 81 +++++++++++++++++++++++++++-
>  1 file changed, 79 insertions(+), 2 deletions(-)
>
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index 73304ea7..8db5f2f1 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -14,6 +14,7 @@
>  #include <libcamera/camera.h>
>  #include <libcamera/control_ids.h>
>  #include <libcamera/formats.h>
> +#include <libcamera/property_ids.h>
>  #include <libcamera/request.h>
>  #include <libcamera/stream.h>
>
> @@ -62,6 +63,15 @@ public:
>  	Stream outStream_;
>  	Stream vfStream_;
>  	Stream rawStream_;
> +
> +	/* Save transformation given by the sensor rotation */
> +	Transform rotationTransform_;
> +
> +	/*
> +	 * Manage horizontal and vertical flips supported (or not) by the
> +	 * sensor.
> +	 */
> +	bool supportsFlips_;
>  };
>
>  class IPU3CameraConfiguration : public CameraConfiguration
> @@ -74,6 +84,9 @@ public:
>  	const StreamConfiguration &cio2Format() const { return cio2Configuration_; }
>  	const ImgUDevice::PipeConfig imguConfig() const { return pipeConfig_; }
>
> +	/* Cache the combinedTransform_ that will be applied to the sensor */
> +	Transform combinedTransform_;
> +
>  private:
>  	/*
>  	 * The IPU3CameraData instance is guaranteed to be valid as long as the
> @@ -143,11 +156,49 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
>  	if (config_.empty())
>  		return Invalid;
>
> -	if (transform != Transform::Identity) {
> -		transform = Transform::Identity;
> +	Transform combined = transform * data_->rotationTransform_;
> +
> +	/*
> +	 * We combine the platform and user transform, but must "adjust away"
> +	 * any combined result that includes a transposition, as we can't do those.
> +	 * In this case, flipping only the transpose bit is helpful to
> +	 * applications - they either get the transform they requested, or have
> +	 * to do a simple transpose themselves (they don't have to worry about
> +	 * the other possible cases).
> +	 */
> +	if (!!(combined & Transform::Transpose)) {
> +		/*
> +		 * Flipping the transpose bit in "transform" flips it in the
> +		 * combined result too (as it's the last thing that happens),
> +		 * which is of course clearing it.
> +		 */
> +		transform ^= Transform::Transpose;
> +		combined &= ~Transform::Transpose;
>  		status = Adjusted;
>  	}
>
> +	/*
> +	 * We also check if the sensor doesn't do h/vflips at all, in which
> +	 * case we clear them, and the application will have to do everything.
> +	 */
> +	if (!data_->supportsFlips_ && !!combined) {
> +		/*
> +		 * If the sensor can do no transforms, then combined must be
> +		 * changed to the identity. The only user transform that gives
> +		 * rise to this is the inverse of the rotation. (Recall that
> +		 * combined = transform * rotationTransform.)
> +		 */
> +		transform = -data_->rotationTransform_;
> +		combined = Transform::Identity;
> +		status = Adjusted;
> +	}
> +
> +	/*
> +	 * Store the final combined transform that configure() will need to
> +	 * apply to the sensor to save us working it out again.
> +	 */
> +	combinedTransform_ = combined;
> +
>  	/* Cap the number of entries to the available streams. */
>  	if (config_.size() > IPU3_MAX_STREAMS) {
>  		config_.resize(IPU3_MAX_STREAMS);
> @@ -540,6 +591,19 @@ int PipelineHandlerIPU3::configure(Camera *camera, CameraConfiguration *c)
>  		return ret;
>  	}
>
> +	/*
> +	 * Configure the H/V flip controls based on the combination of
> +	 * the sensor and user transform.
> +	 */
> +	if (data->supportsFlips_) {
> +		ControlList sensor_ctrls(cio2->sensor()->controls());
> +		sensor_ctrls.set(V4L2_CID_HFLIP,
> +				 static_cast<int32_t>(!!(config->combinedTransform_ & Transform::HFlip)));
> +		sensor_ctrls.set(V4L2_CID_VFLIP,
> +				 static_cast<int32_t>(!!(config->combinedTransform_ & Transform::VFlip)));
> +		cio2->sensor()->setControls(&sensor_ctrls);
> +	}
> +
>  	return 0;
>  }
>
> @@ -775,9 +839,22 @@ int PipelineHandlerIPU3::registerCameras()
>  		/* Initialize the camera properties. */
>  		data->properties_ = cio2->sensor()->properties();
>
> +		/* Convert the sensor rotation to a transformation */
> +		int32_t rotation = data->properties_.get(properties::Rotation);

There's no guarantee the CameraSensor class register the Rotation
property. It was defaulted to 0 if the information was not available
from the firmware interface.

It is now not anymore (a very recent change, sorry)
https://git.libcamera.org/libcamera/libcamera.git/commit/?id=c35123e6f91b6269cf6f5ae9216aeccebc545c75

Not sure what would be best, default to 0 in each pipeline handler
that need that information ?

> +		bool success;
> +		data->rotationTransform_ = transformFromRotation(rotation, &success);
> +		if (!success)
> +			LOG(IPU3, Warning) << "Invalid rotation of " << rotation << " degrees - ignoring";
> +
>  		/* Initialze the camera controls. */
>  		data->controlInfo_ = IPU3Controls;
>
> +		ControlList ctrls = cio2->sensor()->getControls({ V4L2_CID_HFLIP });
> +		if (!ctrls.empty()) {
> +			/* We assume it will support vflips too... */
> +			data->supportsFlips_ = true;
> +		}
> +
>  		/**
>  		 * \todo Dynamically assign ImgU and output devices to each
>  		 * stream and camera; as of now, limit support to two cameras
> --
> 2.30.0
>