[libcamera-devel] [PATCH v5 2/4] libcamera: add model() for retriving model name in V4L2Subdevice

[Han-Lin Chen]

CameraSensor retrives model name from media entity. Move the heuristics
method into V4L2Subdevice, so CameraLens can reuse the function.

Signed-off-by: Han-Lin Chen <hanlinchen at chromium.org>
---
 include/libcamera/internal/v4l2_subdevice.h |  5 +++
 src/libcamera/camera_sensor.cpp             | 13 ++-----
 src/libcamera/v4l2_subdevice.cpp            | 40 +++++++++++++++++++++
 3 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
index 97b89fb9..794c80c6 100644
--- a/include/libcamera/internal/v4l2_subdevice.h
+++ b/include/libcamera/internal/v4l2_subdevice.h
@@ -61,6 +61,8 @@ public:
 	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 		      Whence whence = ActiveFormat);
 
+	std::string model() { return model_; }
+
 	static std::unique_ptr<V4L2Subdevice>
 	fromEntityName(const MediaDevice *media, const std::string &entity);
 
@@ -73,8 +75,11 @@ private:
 	std::vector<unsigned int> enumPadCodes(unsigned int pad);
 	std::vector<SizeRange> enumPadSizes(unsigned int pad,
 					    unsigned int code);
+	void generateModel();
 
 	const MediaEntity *entity_;
+
+	std::string model_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
index 9fdb8c09..3659ff2d 100644
--- a/src/libcamera/camera_sensor.cpp
+++ b/src/libcamera/camera_sensor.cpp
@@ -13,7 +13,6 @@
 #include <iomanip>
 #include <limits.h>
 #include <math.h>
-#include <regex>
 #include <string.h>
 
 #include <libcamera/property_ids.h>
@@ -366,15 +365,7 @@ int CameraSensor::initProperties()
 	 * part of the entity name before the first space if the name contains
 	 * an I2C address, and use the full entity name otherwise.
 	 */
-	std::string entityName = entity_->name();
-	std::regex i2cRegex{ " [0-9]+-[0-9a-f]{4}" };
-	std::smatch match;
-
-	if (std::regex_search(entityName, match, i2cRegex))
-		model_ = entityName.substr(0, entityName.find(' '));
-	else
-		model_ = entityName;
-
+	model_ = subdev_->model();
 	properties_.set(properties::Model, utils::toAscii(model_));
 
 	/* Generate a unique ID for the sensor. */
@@ -832,7 +823,7 @@ int CameraSensor::generateId()
 	/*
 	 * Virtual sensors not described in firmware
 	 *
-	 * Verify it's a platform device and construct ID from the deive path
+	 * Verify it's a platform device and construct ID from the device path
 	 * and model of sensor.
 	 */
 	if (devPath.find("/sys/devices/platform/", 0) == 0) {
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 023e2328..0e194081 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -9,6 +9,7 @@
 
 #include <fcntl.h>
 #include <iomanip>
+#include <regex>
 #include <sstream>
 #include <string.h>
 #include <sys/ioctl.h>
@@ -239,6 +240,7 @@ uint8_t V4L2SubdeviceFormat::bitsPerPixel() const
 V4L2Subdevice::V4L2Subdevice(const MediaEntity *entity)
 	: V4L2Device(entity->deviceNode()), entity_(entity)
 {
+	generateModel();
 }
 
 V4L2Subdevice::~V4L2Subdevice()
@@ -442,6 +444,12 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
 	return 0;
 }
 
+/**
+ * \fn V4L2Subdevice::model()
+ * \brief Retrieve the model name
+ * \return The model name of the device
+ */
+
 /**
  * \brief Create a new video subdevice instance from \a entity in media device
  * \a media
@@ -525,4 +533,36 @@ std::vector<SizeRange> V4L2Subdevice::enumPadSizes(unsigned int pad,
 	return sizes;
 }
 
+void V4L2Subdevice::generateModel()
+{
+	/*
+	 * Extract model name from the media entity name.
+	 *
+	 * There is no standardized naming scheme for sensor entities in the
+	 * Linux kernel at the moment.
+	 *
+	 * - The most common rule, used by I2C sensors, associates the model
+	 *   name with the I2C bus number and address (e.g. 'imx219 0-0010').
+	 *
+	 * - When the sensor exposes multiple subdevs, the model name is
+	 *   usually followed by a function name, as in the smiapp driver (e.g.
+	 *   'jt8ew9 pixel_array 0-0010').
+	 *
+	 * - The vimc driver names its sensors 'Sensor A' and 'Sensor B'.
+	 *
+	 * Other schemes probably exist. As a best effort heuristic, use the
+	 * part of the entity name before the first space if the name contains
+	 * an I2C address, and use the full entity name otherwise.
+	 */
+	std::string entityName = entity_->name();
+	std::regex i2cRegex{ " [0-9]+-[0-9a-f]{4}" };
+	std::smatch match;
+
+	std::string model;
+	if (std::regex_search(entityName, match, i2cRegex))
+		model_ = entityName.substr(0, entityName.find(' '));
+	else
+		model_ = entityName;
+}
+
 } /* namespace libcamera */
-- 
2.34.0.rc2.393.gf8c9666880-goog