[libcamera-devel] [PATCH v4] libcamera: ipu3: Add rotation to ipu3 pipeline

[Fabian Wüthrich]

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

Changes in v3:
 - Default rotation to 0 if sensor doesn't expose it

Changes in v4:
 - Init rotation to 0
 - Drop unnecessary braces

 src/libcamera/pipeline/ipu3/ipu3.cpp | 80 +++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 2 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index 61f7bf43..550984d1 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -15,6 +15,7 @@
 #include <libcamera/control_ids.h>
 #include <libcamera/formats.h>
 #include <libcamera/ipa/ipu3.h>
+#include <libcamera/property_ids.h>
 #include <libcamera/request.h>
 #include <libcamera/stream.h>
 
@@ -74,6 +75,9 @@ public:
 
 	uint32_t exposureTime_;
 	Rectangle cropRegion_;
+	bool supportsFlips_;
+	Transform rotationTransform_;
+
 	std::unique_ptr<DelayedControls> delayedCtrls_;
 	IPU3Frames frameInfos_;
 
@@ -91,6 +95,9 @@ 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
@@ -163,11 +170,49 @@ 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);
@@ -560,6 +605,19 @@ 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;
 }
 
@@ -999,6 +1057,24 @@ int PipelineHandlerIPU3::registerCameras()
 		data->cio2_.frameStart().connect(data->delayedCtrls_.get(),
 						 &DelayedControls::applyControls);
 
+		/* Convert the sensor rotation to a transformation */
+		int32_t rotation = 0;
+		if (data->properties_.contains(properties::Rotation))
+			rotation = data->properties_.get(properties::Rotation);
+		else
+			LOG(IPU3, Warning) << "Rotation control not exposed by " << cio2->sensor()->id()
+					   << ". Assume rotation 0.";
+
+		bool success;
+		data->rotationTransform_ = transformFromRotation(rotation, &success);
+		if (!success)
+			LOG(IPU3, Warning) << "Invalid rotation of " << rotation << " degrees - ignoring";
+
+		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
-- 
2.30.1