[libcamera-devel] [RFC PATCH 8/8] libcamera: camera_sensor: Parse configuration properties

[Kieran Bingham]

Search for a camera_sensor.json configuration file specific to libcamera
and parse it to see if any properties specific to this CameraSensor are
applicable.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 include/libcamera/internal/camera_sensor.h |  1 +
 src/libcamera/camera_sensor.cpp            | 50 ++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
index b9eba89f00fb..646f24a966bd 100644
--- a/include/libcamera/internal/camera_sensor.h
+++ b/include/libcamera/internal/camera_sensor.h
@@ -69,6 +69,7 @@ protected:
 
 private:
 	int generateId();
+	int parseConfigurationFile();
 
 	const MediaEntity *entity_;
 	std::unique_ptr<V4L2Subdevice> subdev_;
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 935de528c496..5a1bda483b9d 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -17,6 +17,7 @@
 
 #include <libcamera/property_ids.h>
 
+#include "libcamera/internal/configuration.h"
 #include "libcamera/internal/formats.h"
 #include "libcamera/internal/sysfs.h"
 #include "libcamera/internal/utils.h"
@@ -251,6 +252,12 @@ int CameraSensor::init()
 		propertyValue = 0;
 	properties_.set(properties::Rotation, propertyValue);
 
+	/*
+	 * Properties are pulled from a configuration file on a best effort.
+	 * If the file doesn't exist, or has no properties there is no failure.
+	 */
+	parseConfigurationFile();
+
 	/* Enumerate, sort and cache media bus codes and sizes. */
 	formats_ = subdev_->formats(pad_);
 	if (formats_.empty()) {
@@ -584,4 +591,47 @@ int CameraSensor::generateId()
 	return -EINVAL;
 }
 
+int CameraSensor::parseConfigurationFile()
+{
+	Configuration c;
+
+	int ret = c.open("camera_sensor.json");
+	if (ret) {
+		LOG(CameraSensor, Debug) << "No configuration file available";
+		return -ENODATA;
+	}
+
+	/* Find properties based on the Camera model_ */
+	/* Todo: Spilt parsing out for multiple paths. */
+
+	/* Find properties based around the Camera Sensor ID */
+	json::iterator it = c.data().find(id_);
+	if (it == c.data().end())
+		return -ENOENT;
+
+	json j = *it;
+	it = j.find("properties");
+	if (it == j.end())
+		return -ENOENT;
+
+	json deviceProperties = *it;
+
+	for (auto &[key, value] : deviceProperties.items()) {
+		LOG(CameraSensor, Debug) << "Key: " << key << " Value: " << value;
+
+		if (!value.is_number()) {
+			LOG(CameraSensor, Debug) << "Not a number: " << value;
+			continue;
+		}
+
+		if (key == "Rotation")
+			properties_.set(properties::Rotation, value);
+
+		if (key == "Location")
+			properties_.set(properties::Location, value);
+	}
+
+	return 0;
+}
+
 } /* namespace libcamera */
-- 
2.25.1