[libcamera-devel] [PATCH] 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>
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 76 +++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 2 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index f1151733..76d75a74 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 +63,12 @@ public:
 	Stream outStream_;
 	Stream vfStream_;
 	Stream rawStream_;
+
+	/*
+	 * Manage horizontal and vertical flips supported (or not) by the
+	 * sensor.
+	 */
+	bool supportsFlips_;
 };
 
 class IPU3CameraConfiguration : public CameraConfiguration
@@ -74,6 +81,9 @@ 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 +153,54 @@ CameraConfiguration::Status IPU3CameraConfiguration::validate()
 	if (config_.empty())
 		return Invalid;
 
-	if (transform != Transform::Identity) {
-		transform = Transform::Identity;
+	int32_t rotation = data_->cio2_.sensor()->properties().get(properties::Rotation);
+	bool success;
+	Transform rotationTransform = transformFromRotation(rotation, &success);
+	if (!success)
+		LOG(IPU3, Warning) << "Invalid rotation of " << rotation << " degrees - ignoring";
+	Transform combined = transform * rotationTransform;
+
+	/*
+	 * We combine the platform and user transform, but must "adjust away"
+	 * any combined result that includes a transform, 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, ad 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 the inverse of the rotation. (Recall that
+		 * combined = transform * rotationTransform.)
+		 */
+		transform = -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 +593,19 @@ 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_) {
+		ctrls = cio2->sensor()->controls();
+		ctrls.set(V4L2_CID_HFLIP,
+			  static_cast<int32_t>(!!(config->combinedTransform_ & Transform::HFlip)));
+		ctrls.set(V4L2_CID_VFLIP,
+			  static_cast<int32_t>(!!(config->combinedTransform_ & Transform::VFlip)));
+		cio2->sensor()->setControls(&ctrls);
+	}
+
 	return 0;
 }
 
@@ -779,6 +845,12 @@ int PipelineHandlerIPU3::registerCameras()
 		/* 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