[libcamera-devel] [PATCH v3 11/13] libcamera: camera_sensor: Add method to get sensor info

[Jacopo Mondi]

Add method to retrieve the CameraSensorInfo to the CameraSensor class.

Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/camera_sensor.cpp       | 84 +++++++++++++++++++++++++++
 src/libcamera/include/camera_sensor.h |  1 +
 2 files changed, 85 insertions(+)

diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index e39f277622ae..c1ef4adb579c 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -492,6 +492,90 @@ int CameraSensor::setControls(ControlList *ctrls)
  * \return The list of camera sensor properties
  */
 
+/**
+ * \brief Assemble and return the camera sensor info
+ * \param[out] info The camera sensor info that report the sensor information
+ *
+ * The CameraSensorInfo content is assembled by inspecting the currently
+ * applied sensor configuration and the sensor static properties.
+ *
+ * \return 0 on success, a negative error code otherwise
+ */
+int CameraSensor::sensorInfo(CameraSensorInfo *info) const
+{
+	/*
+	 * Make sure the sub-device exports all the controls we need to operate.
+	 *
+	 * Currently V4L2_CID_PIXEL_RATE and V4L2_CID_HBLANK are required.
+	 *
+	 * \todo This is an hard policy that all sensors that want to export
+	 * a properly populated CameraSensorInfo have to adhere to. Consider if
+	 * it's worth relaxing it and providing default values instead.
+	 */
+	const ControlInfoMap &controlMap = subdev_->controls();
+	if (controlMap.find(V4L2_CID_PIXEL_RATE) == controlMap.end()) {
+		LOG(CameraSensor, Error) << "'Pixel rate' control not available";
+		return -EINVAL;
+	}
+
+	if (controlMap.find(V4L2_CID_HBLANK) == controlMap.end()) {
+		LOG(CameraSensor, Error) << "'HBLANK' control not available";
+		return -EINVAL;
+	}
+
+	/*
+	 * Construct the camera sensor name using the media entity name.
+	 *
+	 * \todo There is no standardized naming scheme for sensor entities
+	 * in the Linux kernel at the moment. The most common naming scheme
+	 * is the one obtained by associating the sensor name and its I2C
+	 * device and bus addresses in the form of: "devname i2c-adapt:i2c-addr"
+	 * Assume this is the standard naming scheme and parse the first part
+	 * of the entity name to obtain "devname".
+	 */
+	std::string entityName = subdev_->entity()->name();
+	info->name = *utils::split(entityName, " ").begin();
+
+	/*
+	 * Get the active area size from the ActiveAreas property.
+	 *
+	 * \todo The ActiveAreas property aims to describe multiple
+	 * active area rectangles. At the moment only a single active
+	 * area rectangle is exposed by the subdevice API. Use that single
+	 * rectangle width and height to construct the ActiveAreaSize.
+	 */
+	Span<const int> activeArea = properties_.get(properties::ActiveAreas);
+	info->activeAreaSize = { static_cast<unsigned int>(activeArea[2]),
+				 static_cast<unsigned int>(activeArea[3]) };
+
+	/* The bit-depth and image size depend on the currently applied format. */
+	V4L2SubdeviceFormat format{};
+	int ret = subdev_->getFormat(0, &format);
+	if (ret)
+		return ret;
+	info->bitsPerPixel = format.bitsPerPixel();
+	info->outputSize = format.size;
+
+	/* It's mandatory for the subdevice to report its crop rectangle. */
+	ret = subdev_->getCropRectangle(0, &info->analogCrop);
+	if (ret) {
+		LOG(CameraSensor, Error)
+			<< "Failed to construct camera sensor info: "
+			<< "the camera sensor does not report the crop rectangle";
+		return ret;
+	}
+
+	int64_t pixelRate;
+	subdev_->getControl(V4L2_CID_PIXEL_RATE, &pixelRate);
+	info->pixelClock = pixelRate;
+
+	int32_t hblank;
+	subdev_->getControl(V4L2_CID_HBLANK, &hblank);
+	info->lineLength = info->outputSize.width + hblank;
+
+	return 0;
+}
+
 std::string CameraSensor::logPrefix() const
 {
 	return "'" + subdev_->entity()->name() + "'";
diff --git a/src/libcamera/include/camera_sensor.h b/src/libcamera/include/camera_sensor.h
index e19852d4cabe..b162c3886b1d 100644
--- a/src/libcamera/include/camera_sensor.h
+++ b/src/libcamera/include/camera_sensor.h
@@ -61,6 +61,7 @@ public:
 	int setControls(ControlList *ctrls);
 
 	const ControlList &properties() const { return properties_; }
+	int sensorInfo(CameraSensorInfo *info) const;
 
 protected:
 	std::string logPrefix() const;
-- 
2.26.1