[libcamera-devel,v2,1/2] ipa: Create a camera sensor helper class

12552 diff mbox series

diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp
new file mode 100644
index 00000000..c2bb055a
--- /dev/null
+++ b/src/ipa/libipa/camera_sensor_helper.cpp
@@ -0,0 +1,322 @@ 
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2021, Google Inc.
+ *
+ * camera_sensor_helper.cpp - helper class providing camera information
+ */
+#include "camera_sensor_helper.h"
+
+#include <map>
+
+#include "libcamera/internal/log.h"
+
+/**
+ * \file camera_sensor_helper.h
+ * \brief Create helper class for each sensor
+ *
+ * Each camera sensor supported by libcamera may need specific informations to
+ * be sent (analogue gain is sensor dependant for instance).
+ *
+ * Every subclass of CameraSensorHelper shall be registered with libipa using
+ * the REGISTER_CAMERA_SENSOR_HELPER() macro.
+ */
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(CameraSensorHelper)
+
+namespace ipa {
+
+/**
+ * \class CameraSensorHelper
+ * \brief Create and give helpers for each camera sensor in the pipeline
+ *
+ * CameraSensorHelper instances are unique and sensor dependant.
+ */
+
+/**
+ * \brief Construct a CameraSensorHelper instance
+ * \param[in] name The sensor model name
+ *
+ * The CameraSensorHelper instances shall never be constructed manually, but always
+ * through the CameraSensorHelperFactory::create() method.
+ */
+
+CameraSensorHelper::CameraSensorHelper()
+{
+}
+
+CameraSensorHelper::~CameraSensorHelper()
+{
+}
+
+/**
+ * \fn CameraSensorHelper::GainCode(double gain)
+ * \brief Get the analogue gain code to pass to V4L2 subdev control
+ * \param[in] gain The real gain to pass
+ * \return the gain code to pass to V4l2
+ *
+ * This function aims to abstract the calculation of the gain letting the IPA
+ * use the real gain for its estimations.
+ *
+ * The parameters come from the MIPI Alliance Camera Specification for
+ * Camera Command Set (CCS).
+ */
+uint32_t CameraSensorHelper::GainCode(double gain) const
+{
+	ASSERT((analogueGainConstants_.m0 == 0) || (analogueGainConstants_.m1 == 0));
+	ASSERT(analogueGainConstants_.type == AnalogueGainLinear);
+	
+	return (analogueGainConstants_.c0 - analogueGainConstants_.c1 * gain) /
+	       (analogueGainConstants_.m1 * gain - analogueGainConstants_.m0);
+}
+
+/**
+ * \fn CameraSensorHelper::Gain
+ * \brief Get the real gain from the V4l2 subdev control gain
+ * \param[in] gainCode The V4l2 subdev control gain
+ * \return The real gain
+ *
+ * This function aims to abstract the calculation of the gain letting the IPA
+ * use the real gain for its estimations. It is the counterpart of the function
+ * CameraSensorHelper::getGainCode.
+ *
+ * The parameters come from the MIPI Alliance Camera Specification for
+ * Camera Command Set (CCS).
+ */
+double CameraSensorHelper::Gain(uint32_t gainCode) const
+{
+	ASSERT((analogueGainConstants_.m0 == 0) || (analogueGainConstants_.m1 == 0));
+	ASSERT(analogueGainConstants_.type == AnalogueGainLinear);
+
+	return (analogueGainConstants_.m0 * gainCode + analogueGainConstants_.c0) /
+	       (analogueGainConstants_.m1 * gainCode + analogueGainConstants_.c1);
+}
+
+/**
+ * \enum CameraSensorHelper::AnalogueGainType
+ * \brief Specify the Gain mode supported by the sensor
+ *
+ * Describes the image sensor analog Gain capabilities.
+ * Two modes are possible, depending on the sensor: Global and Alternate.
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainLinear
+ * \brief Sensor supports linear gain
+ *
+ * The relationship between the integer Gain parameter and the resulting Gain
+ * multiplier is given by the following equation:
+ *
+ * \f$gain=\frac{m0x+c0}{m1x+c1}\f$
+ *
+ * Where 'x' is the gain control parameter, and m0, m1, c0 and c1 are
+ * image-sensor-specific constants exposed by the sensor.
+ * These constants are static parameters, and for any given image sensor either
+ * m0 or m1 shall be zero.
+ *
+ * The full Gain equation therefore reduces to either:
+ *
+ * \f$gain=\frac{c0}{m1x+c1}\f$ or \f$\frac{m0x+c0}{c1}\f$
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainExponential
+ * \brief Sensor supports exponential gain (introduced in CCS v1.1)
+ *
+ * Starting with CCS v1.1, Alternate Global Analog Gain is also available.
+ * If the image sensor supports it, then the global analog Gain can be controlled
+ * by linear and exponential gain formula:
+ *
+ * \f$gain = analogLinearGainGlobal * 2^{analogExponentialGainGlobal}\f$
+ * \todo not implemented in libipa
+ */
+
+/**
+ * \struct CameraSensorHelper::AnalogueGainConstants
+ * \brief Analogue gain constants used for gain calculation
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainConstants::type
+ * \brief Analogue gain coding type
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainConstants::m0
+ * \brief Constant used in the analog Gain control coding/decoding
+ *
+ * Note: either m0 or m1 shall be zero.
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainConstants::c0
+ * \brief Constant used in the analog Gain control coding/decoding
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainConstants::m1
+ * \brief Constant used in the analog Gain control coding/decoding
+ *
+ * Note: either m0 or m1 shall be zero.
+ */
+
+/**
+ * \var CameraSensorHelper::AnalogueGainConstants::c1
+ * \brief Constant used in the analog Gain control coding/decoding
+ */
+
+/**
+ * \var CameraSensorHelper::analogueGainConstants_
+ * \brief The analogue gain parameters used for calculation
+ *
+ * The analogue gain is calculated through a formula, and its parameters are
+ * sensor specific. Use this variable to store the values at init time.
+ *
+ */
+
+/**
+ * \class CameraSensorHelperFactory
+ * \brief Registration of CameraSensorHelperFactory classes and creation of instances
+ *
+ * To facilitate discovery and instantiation of CameraSensorHelper classes, the
+ * CameraSensorHelperFactory class maintains a registry of camera sensor helper
+ * classes. Each CameraSensorHelper subclass shall register itself using the
+ * REGISTER_CAMERA_SENSOR_HELPER() macro, which will create a corresponding
+ * instance of a CameraSensorHelperFactory subclass and register it with the
+ * static list of factories.
+ */
+
+/**
+ * \brief Construct a camera sensor helper factory
+ * \param[in] name Name of the camera sensor helper class
+ *
+ * Creating an instance of the factory registers it with the global list of
+ * factories, accessible through the factories() function.
+ *
+ * The factory \a name is used for debug purpose and shall be unique.
+ */
+
+CameraSensorHelperFactory::CameraSensorHelperFactory(const std::string name)
+	: name_(name)
+{
+	registerType(this);
+}
+
+/**
+ * \brief Create an instance of the CameraSensorHelper corresponding to the factory
+ *
+ * \return A unique pointer to a new instance of the CameraSensorHelper subclass
+ * corresponding to the factory
+ */
+std::unique_ptr<CameraSensorHelper> CameraSensorHelperFactory::create(const std::string &name)
+{
+	std::vector<CameraSensorHelperFactory *> &factories =
+		CameraSensorHelperFactory::factories();
+
+	for (CameraSensorHelperFactory *factory : factories) {
+		if (name != factory->name_)
+			continue;
+
+		CameraSensorHelper *helper = factory->createInstance();
+		return std::unique_ptr<CameraSensorHelper>(helper);
+	}
+	return nullptr;
+}
+
+/**
+ * \brief Add a camera sensor helper class to the registry
+ * \param[in] factory Factory to use to construct the camera sensor helper
+ *
+ * The caller is responsible to guarantee the uniqueness of the camera sensor helper
+ * name.
+ */
+void CameraSensorHelperFactory::registerType(CameraSensorHelperFactory *factory)
+{
+	std::vector<CameraSensorHelperFactory *> &factories = CameraSensorHelperFactory::factories();
+
+	factories.push_back(factory);
+}
+
+/**
+ * \brief Retrieve the list of all camera sensor helper factories
+ *
+ * The static factories map is defined inside the function to ensures it gets
+ * initialized on first use, without any dependency on link order.
+ *
+ * \return The list of camera sensor helper factories
+ */
+std::vector<CameraSensorHelperFactory *> &CameraSensorHelperFactory::factories()
+{
+	static std::vector<CameraSensorHelperFactory *> factories;
+	return factories;
+}
+
+/**
+ * \fn CameraSensorHelperFactory::createInstance()
+ * \brief Create an instance of the CameraSensorHelper corresponding to the factory
+ *
+ * This virtual function is implemented by the REGISTER_CAMERA_SENSOR_HELPER()
+ * macro. It creates a camera sensor helper instance associated with the camera
+ * sensor model.
+ *
+ * \return A pointer to a newly constructed instance of the CameraSensorHelper
+ * subclass corresponding to the factory
+ */
+
+/**
+ * \def REGISTER_CAMERA_SENSOR_HELPER
+ * \brief Register a camera sensor helper with the camera sensor helper factory
+ * \param[in] name Sensor model name used to register the class
+ * \param[in] helper Class name of CameraSensorHelper derived class to register
+ *
+ * Register a CameraSensorHelper subclass with the factory and make it available to
+ * try and match devices.
+ */
+
+/**
+ * \class CameraSensorHelperImx219
+ * \brief Create and give helpers for the imx219 sensor
+ */
+class CameraSensorHelperImx219 : public CameraSensorHelper
+{
+public:
+	CameraSensorHelperImx219()
+	{
+		analogueGainConstants_ = { AnalogueGainLinear, 0, -1, 256, 256 };
+	}
+};
+REGISTER_CAMERA_SENSOR_HELPER("imx219", CameraSensorHelperImx219)
+
+/**
+ * \class CameraSensorHelperOv5670
+ * \brief Create and give helpers for the ov5670 sensor
+ */
+class CameraSensorHelperOv5670 : public CameraSensorHelper
+{
+public:
+	CameraSensorHelperOv5670()
+	{
+		analogueGainConstants_ = { AnalogueGainLinear, 1, 0, 0, 256 };
+	}
+};
+REGISTER_CAMERA_SENSOR_HELPER("ov5670", CameraSensorHelperOv5670)
+
+/**
+ * \class CameraSensorHelperOv5693
+ * \brief Create and give helpers for the ov5693 sensor
+ */
+class CameraSensorHelperOv5693 : public CameraSensorHelper
+{
+public:
+	CameraSensorHelperOv5693()
+	{
+		analogueGainConstants_ = { AnalogueGainLinear, 1, 0, 0, 16 };
+	}
+};
+REGISTER_CAMERA_SENSOR_HELPER("ov5693", CameraSensorHelperOv5693)
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
+
diff --git a/src/ipa/libipa/camera_sensor_helper.h b/src/ipa/libipa/camera_sensor_helper.h
new file mode 100644
index 00000000..976f8d33
--- /dev/null
+++ b/src/ipa/libipa/camera_sensor_helper.h
@@ -0,0 +1,89 @@ 
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2021, Google Inc.
+ *
+ * camera_sensor_helper.h - helper class providing camera information
+ */
+#ifndef __LIBCAMERA_IPA_LIBIPA_CAMERA_SENSOR_HELPER_H__
+#define __LIBCAMERA_IPA_LIBIPA_CAMERA_SENSOR_HELPER_H__
+
+#include <stdint.h>
+
+#include <string>
+
+#include <libcamera/class.h>
+#include <libcamera/object.h>
+
+namespace libcamera {
+
+namespace ipa {
+
+class CameraSensorHelper;
+
+class CameraSensorHelper
+{
+public:
+	CameraSensorHelper();
+	virtual ~CameraSensorHelper();
+
+	uint32_t GainCode(double gain) const;
+	double Gain(uint32_t gainCode) const;
+
+protected:
+	enum AnalogueGainType {
+		AnalogueGainLinear = 0,
+		AnalogueGainExponential = 2,
+	};
+
+	struct AnalogueGainConstants {
+		uint16_t type;
+		int16_t m0;
+		int16_t c0;
+		int16_t m1;
+		int16_t c1;
+	};
+
+	AnalogueGainConstants analogueGainConstants_;
+
+private:
+	LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelper)
+};
+
+class CameraSensorHelperFactory
+{
+public:
+	CameraSensorHelperFactory(const std::string name);
+	virtual ~CameraSensorHelperFactory() = default;
+
+	static std::unique_ptr<CameraSensorHelper> create(const std::string &name);
+
+	static void registerType(CameraSensorHelperFactory *factory);
+	static std::vector<CameraSensorHelperFactory *> &factories();
+
+private:
+	LIBCAMERA_DISABLE_COPY_AND_MOVE(CameraSensorHelperFactory)
+	virtual CameraSensorHelper *createInstance() = 0;
+
+	std::string name_;
+};
+
+#define REGISTER_CAMERA_SENSOR_HELPER(name, helper)               \
+class helper##Factory final : public CameraSensorHelperFactory    \
+{                                                                 \
+public:                                                           \
+	helper##Factory() : CameraSensorHelperFactory(name) {} \
+								  \
+private:                                                          \
+	CameraSensorHelper *createInstance()                      \
+	{                                                         \
+		return new helper();                          \
+	}                                                         \
+};                                                                \
+static helper##Factory global_##helper##Factory;
+
+} /* namespace ipa */
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_IPA_LIBIPA_CAMERA_SENSOR_HELPER_H__ */
+
diff --git a/src/ipa/libipa/meson.build b/src/ipa/libipa/meson.build
index 038fc490..dc90542c 100644
--- a/src/ipa/libipa/meson.build
+++ b/src/ipa/libipa/meson.build
@@ -2,11 +2,13 @@ 
 
 libipa_headers = files([
     'algorithm.h',
+    'camera_sensor_helper.h',
     'histogram.h'
 ])
 
 libipa_sources = files([
     'algorithm.cpp',
+    'camera_sensor_helper.cpp',
     'histogram.cpp'
 ])