[libcamera-devel] [PATCH v7 4/9] libcamera: camera_sensor: Generate a sensor ID

[Niklas Söderlund]

The ID is generated from information in the firmware description of the
sensor if available or from module and model information if the sensor
is virtual (for example VIMC).

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
* Changes sinve v6
- Do not allow for subclassing
- Add support for virtual sensors
- Use new sysfs:: helper.

* Changes since v5
- Use new utils:: helper.
- Allow for subclassing

* Changes since v4
- Fix spelling.

* Changes since v3
- Update commit message.
- Add description of how ID are generated to comment.
---
 include/libcamera/internal/camera_sensor.h |  3 ++
 src/libcamera/camera_sensor.cpp            | 38 ++++++++++++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/include/libcamera/internal/camera_sensor.h b/include/libcamera/internal/camera_sensor.h
index 06c8292ca30129de..0f65fca46877e89a 100644
--- a/include/libcamera/internal/camera_sensor.h
+++ b/include/libcamera/internal/camera_sensor.h
@@ -67,11 +67,14 @@ protected:
 	std::string logPrefix() const override;
 
 private:
+	int generateId();
+
 	const MediaEntity *entity_;
 	std::unique_ptr<V4L2Subdevice> subdev_;
 	unsigned int pad_;
 
 	std::string model_;
+	std::string id_;
 
 	V4L2Subdevice::Formats formats_;
 	Size resolution_;
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 350f49accad99c7b..3952d16b053ae20e 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -9,6 +9,7 @@
 
 #include <algorithm>
 #include <float.h>
+#include <fstream>
 #include <iomanip>
 #include <limits.h>
 #include <math.h>
@@ -16,7 +17,9 @@
 
 #include <libcamera/property_ids.h>
 
+#include "libcamera/internal/file.h"
 #include "libcamera/internal/formats.h"
+#include "libcamera/internal/sysfs.h"
 #include "libcamera/internal/utils.h"
 
 /**
@@ -204,6 +207,11 @@ int CameraSensor::init()
 	if (ret < 0)
 		return ret;
 
+	/* Generate a unique ID for the sensor. */
+	ret = generateId();
+	if (ret)
+		return ret;
+
 	/* Retrieve and store the camera sensor properties. */
 	const ControlInfoMap &controls = subdev_->controls();
 	int32_t propertyValue;
@@ -541,4 +549,34 @@ std::string CameraSensor::logPrefix() const
 	return "'" + entity_->name() + "'";
 }
 
+int CameraSensor::generateId()
+{
+	const std::string devPath = subdev_->devicePath();
+
+	/* Try to get ID from firmware description. */
+	if (!sysfs::firmwareId(devPath, &id_))
+		return 0;
+
+	/* Virtual sensors not described in firmware, use modalias and model. */
+	std::string path = devPath + "/modalias";
+	if (File::exists(path)) {
+		std::ifstream file(path.c_str());
+
+		if (!file.is_open()) {
+			LOG(CameraSensor, Error) << "Failed to read modalias";
+			return -EINVAL;
+		}
+
+		std::string modalias;
+		std::getline(file, modalias);
+		file.close();
+
+		id_ = modalias + " " + model();
+		return 0;
+	}
+
+	LOG(CameraSensor, Error) << "Can't generate sensor ID";
+	return -EINVAL;
+}
+
 } /* namespace libcamera */
-- 
2.28.0