libcamera: pipeline: uvcvideo: Add controls support

Implement control support in the UVC pipeline handler by dynamically
querying the V4L2 device for the supported V4L2 controls and populating
the list of camera controls accordingly.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 113 insertions, 9 deletions

diff --git a/src/libcamera/pipeline/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo.cpp
index 2e22523d..72313cfd 100644
--- a/src/libcamera/pipeline/uvcvideo.cpp
+++ b/src/libcamera/pipeline/uvcvideo.cpp
@@ -6,8 +6,11 @@
  */
 
 #include <algorithm>
+#include <iomanip>
+#include <tuple>
 
 #include <libcamera/camera.h>
+#include <libcamera/controls.h>
 #include <libcamera/request.h>
 #include <libcamera/stream.h>
 
@@ -16,6 +19,7 @@
 #include "media_device.h"
 #include "pipeline_handler.h"
 #include "utils.h"
+#include "v4l2_controls.h"
 #include "v4l2_videodevice.h"
 
 namespace libcamera {
@@ -35,6 +39,7 @@ public:
 		delete video_;
 	}
 
+	int init(MediaEntity *entity);
 	void bufferReady(Buffer *buffer);
 
 	V4L2VideoDevice *video_;
@@ -71,6 +76,8 @@ public:
 	bool match(DeviceEnumerator *enumerator) override;
 
 private:
+	int processControls(UVCCameraData *data, Request *request);
+
 	UVCCameraData *cameraData(const Camera *camera)
 	{
 		return static_cast<UVCCameraData *>(
@@ -216,6 +223,56 @@ void PipelineHandlerUVC::stop(Camera *camera)
 	PipelineHandler::stop(camera);
 }
 
+int PipelineHandlerUVC::processControls(UVCCameraData *data, Request *request)
+{
+	V4L2ControlList controls;
+
+	for (auto it : request->controls()) {
+		const ControlInfo *ci = it.first;
+		ControlValue &value = it.second;
+
+		switch (ci->id()) {
+		case Brightness:
+			controls.add(V4L2_CID_BRIGHTNESS, value.getInt());
+			break;
+
+		case Contrast:
+			controls.add(V4L2_CID_CONTRAST, value.getInt());
+			break;
+
+		case Saturation:
+			controls.add(V4L2_CID_SATURATION, value.getInt());
+			break;
+
+		case ManualExposure:
+			controls.add(V4L2_CID_EXPOSURE_AUTO, 1);
+			controls.add(V4L2_CID_EXPOSURE_ABSOLUTE, value.getInt());
+			break;
+
+		case ManualGain:
+			controls.add(V4L2_CID_GAIN, value.getInt());
+			break;
+
+		default:
+			break;
+		}
+	}
+
+	for (const V4L2Control &ctrl : controls)
+		LOG(UVC, Debug)
+			<< "Setting control 0x"
+			<< std::hex << std::setw(8) << ctrl.id() << std::dec
+			<< " to " << ctrl.value();
+
+	int ret = data->video_->setControls(&controls);
+	if (ret) {
+		LOG(UVC, Error) << "Failed to set controls: " << ret;
+		return ret < 0 ? ret : -EINVAL;
+	}
+
+	return ret;
+}
+
 int PipelineHandlerUVC::queueRequest(Camera *camera, Request *request)
 {
 	UVCCameraData *data = cameraData(camera);
@@ -227,7 +284,11 @@ int PipelineHandlerUVC::queueRequest(Camera *camera, Request *request)
 		return -ENOENT;
 	}
 
-	int ret = data->video_->queueBuffer(buffer);
+	int ret = processControls(data, request);
+	if (ret < 0)
+		return ret;
+
+	ret = data->video_->queueBuffer(buffer);
 	if (ret < 0)
 		return ret;
 
@@ -247,24 +308,20 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 
 	std::unique_ptr<UVCCameraData> data = utils::make_unique<UVCCameraData>(this);
 
-	/* Locate and open the default video node. */
+	/* Locate and initialise the camera data with the default video node. */
 	for (MediaEntity *entity : media->entities()) {
 		if (entity->flags() & MEDIA_ENT_FL_DEFAULT) {
-			data->video_ = new V4L2VideoDevice(entity);
+			if (data->init(entity))
+				return false;
 			break;
 		}
 	}
 
-	if (!data->video_) {
+	if (!data) {
 		LOG(UVC, Error) << "Could not find a default video device";
 		return false;
 	}
 
-	if (data->video_->open())
-		return false;
-
-	data->video_->bufferReady.connect(data.get(), &UVCCameraData::bufferReady);
-
 	/* Create and register the camera. */
 	std::set<Stream *> streams{ &data->stream_ };
 	std::shared_ptr<Camera> camera = Camera::create(this, media->model(), streams);
@@ -276,6 +333,53 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator)
 	return true;
 }
 
+int UVCCameraData::init(MediaEntity *entity)
+{
+	int ret;
+
+	/* Create and open the video device. */
+	video_ = new V4L2VideoDevice(entity);
+	ret = video_->open();
+	if (ret)
+		return ret;
+
+	video_->bufferReady.connect(this, &UVCCameraData::bufferReady);
+
+	/* Initialise the supported controls. */
+	const V4L2ControlInfoMap &controls = video_->controls();
+	for (const auto &ctrl : controls) {
+		unsigned int v4l2Id = ctrl.first;
+		const V4L2ControlInfo &info = ctrl.second;
+		ControlId id;
+
+		switch (v4l2Id) {
+		case V4L2_CID_BRIGHTNESS:
+			id = Brightness;
+			break;
+		case V4L2_CID_CONTRAST:
+			id = Contrast;
+			break;
+		case V4L2_CID_SATURATION:
+			id = Saturation;
+			break;
+		case V4L2_CID_EXPOSURE_ABSOLUTE:
+			id = ManualExposure;
+			break;
+		case V4L2_CID_GAIN:
+			id = ManualGain;
+			break;
+		default:
+			continue;
+		}
+
+		controlInfo_.emplace(std::piecewise_construct,
+				     std::forward_as_tuple(id),
+				     std::forward_as_tuple(id, info.min(), info.max()));
+	}
+
+	return 0;
+}
+
 void UVCCameraData::bufferReady(Buffer *buffer)
 {
 	Request *request = queuedRequests_.front();