libcamera: camera_sensor: Provide fall-back for sensor properties

Support for the V4L2 selection API is currently optional in the
CameraSensor class. Properties registered by using values read through
that API are defaulted in several different places (the Android camera
HAL or the CameraSensor class).

In the future support for the selection API will be made mandatory, but to
give time to sensor drivers in all test platforms to be updated, use
sensor resolution as fallback values for sensor pixel array properties
and cache them as class member variables.

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

2 files changed, 24 insertions, 36 deletions

diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
index aee10aa6..86902b85 100644
--- a/include/libcamera/internal/camera_sensor.h
+++ b/include/libcamera/internal/camera_sensor.h
@@ -84,6 +84,9 @@ private:
 	std::vector<unsigned int> mbusCodes_;
 	std::vector<Size> sizes_;
 
+	Size pixelArraySize_;
+	Rectangle activeArea_;
+
 	ControlList properties_;
 };
 
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 048fcd6a..0c9bd4f5 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -269,15 +269,21 @@ int CameraSensor::validateSensorDriver()
 	Rectangle rect;
 	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_BOUNDS, &rect);
 	if (ret) {
+		rect = Rectangle(resolution());
 		LOG(CameraSensor, Warning)
-			<< "Failed to retrieve the readable pixel array size";
+			<< "The PixelArraySize property has been defaulted to "
+			<< rect.toString();
 		err = -EINVAL;
 	}
+	pixelArraySize_.width = rect.width;
+	pixelArraySize_.height = rect.height;
 
-	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &rect);
+	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &activeArea_);
 	if (ret) {
+		activeArea_ = Rectangle(pixelArraySize_);
 		LOG(CameraSensor, Warning)
-			<< "Failed to retrieve the active pixel array size";
+			<< "The PixelArrayActiveAreas property has been defaulted to "
+			<< activeArea_.toString();
 		err = -EINVAL;
 	}
 
@@ -373,24 +379,8 @@ int CameraSensor::initProperties()
 		propertyValue = 0;
 	properties_.set(properties::Rotation, propertyValue);
 
-	Rectangle bounds;
-	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_BOUNDS, &bounds);
-	if (!ret)
-		properties_.set(properties::PixelArraySize, bounds.size());
-
-	Rectangle crop;
-	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &crop);
-	if (!ret) {
-		/*
-		 * V4L2_SEL_TGT_CROP_DEFAULT and V4L2_SEL_TGT_CROP_BOUNDS are
-		 * defined relatively to the sensor full pixel array size,
-		 * while properties::PixelArrayActiveAreas is defined relatively
-		 * to properties::PixelArraySize. Adjust it.
-		 */
-		crop.x -= bounds.x;
-		crop.y -= bounds.y;
-		properties_.set(properties::PixelArrayActiveAreas, { crop });
-	}
+	properties_.set(properties::PixelArraySize, pixelArraySize_);
+	properties_.set(properties::PixelArrayActiveAreas, { activeArea_ });
 
 	/* Color filter array pattern, register only for RAW sensors. */
 	for (const auto &format : formats_) {
@@ -646,20 +636,15 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 {
 	info->model = model();
 
-	/* Get the active area size. */
-	Rectangle rect;
-	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP_DEFAULT, &rect);
-	if (ret) {
-		LOG(CameraSensor, Error)
-			<< "Failed to construct camera sensor info: "
-			<< "the camera sensor does not report the active area";
-
-		return ret;
-	}
-	info->activeAreaSize = { rect.width, rect.height };
+	/*
+	 * The active area size is a static property, while the crop
+	 * rectangle needs to be re-read as it depends on the sensor
+	 * configuration.
+	 */
+	info->activeAreaSize = { activeArea_.width, activeArea_.height };
 
 	/* It's mandatory for the subdevice to report its crop rectangle. */
-	ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &info->analogCrop);
+	int ret = subdev_->getSelection(pad_, V4L2_SEL_TGT_CROP, &info->analogCrop);
 	if (ret) {
 		LOG(CameraSensor, Error)
 			<< "Failed to construct camera sensor info: "
@@ -672,10 +657,10 @@ int CameraSensor::sensorInfo(CameraSensorInfo *info) const
 	 * are defined relatively to the active pixel area, while V4L2's
 	 * TGT_CROP target is defined in respect to the full pixel array.
 	 *
-	 * Compensate it by subtracting the active areas offset.
+	 * Compensate it by subtracting the active area offset.
 	 */
-	info->analogCrop.x -= rect.x;
-	info->analogCrop.y -= rect.y;
+	info->analogCrop.x -= activeArea_.x;
+	info->analogCrop.y -= activeArea_.y;
 
 	/* The bit depth and image size depend on the currently applied format. */
 	V4L2SubdeviceFormat format{};