[PATCH v4 1/5] libcamera: converter: Add interface for feature flags

[Umang Jain]

This patch intends to extend the converter interface to have feature
flags, which enables each converter to expose the set of features
it supports.

Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
---
 include/libcamera/internal/converter.h        | 13 ++++++++++-
 .../internal/converter/converter_v4l2_m2m.h   |  2 +-
 src/libcamera/converter.cpp                   | 22 ++++++++++++++++++-
 .../converter/converter_v4l2_m2m.cpp          |  5 +++--
 4 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/include/libcamera/internal/converter.h b/include/libcamera/internal/converter.h
index b51563d7..15bc7dca 100644
--- a/include/libcamera/internal/converter.h
+++ b/include/libcamera/internal/converter.h
@@ -17,6 +17,7 @@
 #include <vector>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/flags.h>
 #include <libcamera/base/signal.h>
 
 #include <libcamera/geometry.h>
@@ -32,7 +33,13 @@ struct StreamConfiguration;
 class Converter
 {
 public:
-	Converter(MediaDevice *media);
+	enum class Feature {
+		None = (1 << 0),
+	};
+
+	using Features = Flags<Feature>;
+
+	Converter(MediaDevice *media, Features features = Feature::None);
 	virtual ~Converter();
 
 	virtual int loadConfiguration(const std::string &filename) = 0;
@@ -61,8 +68,12 @@ public:
 
 	const std::string &deviceNode() const { return deviceNode_; }
 
+	Features getFeatures() const { return features_; }
+
 private:
 	std::string deviceNode_;
+
+	Features features_;
 };
 
 class ConverterFactoryBase
diff --git a/include/libcamera/internal/converter/converter_v4l2_m2m.h b/include/libcamera/internal/converter/converter_v4l2_m2m.h
index b9e59899..91701dbe 100644
--- a/include/libcamera/internal/converter/converter_v4l2_m2m.h
+++ b/include/libcamera/internal/converter/converter_v4l2_m2m.h
@@ -35,7 +35,7 @@ class V4L2M2MDevice;
 class V4L2M2MConverter : public Converter
 {
 public:
-	V4L2M2MConverter(MediaDevice *media);
+	V4L2M2MConverter(MediaDevice *media, Features features = Feature::None);
 
 	int loadConfiguration([[maybe_unused]] const std::string &filename) { return 0; }
 	bool isValid() const { return m2m_ != nullptr; }
diff --git a/src/libcamera/converter.cpp b/src/libcamera/converter.cpp
index c5e38937..2dc7d984 100644
--- a/src/libcamera/converter.cpp
+++ b/src/libcamera/converter.cpp
@@ -34,14 +34,27 @@ LOG_DEFINE_CATEGORY(Converter)
  * parameters from the same input stream.
  */
 
+/**
+ * \enum Converter::Feature
+ * \brief Specify the features supported by the converter
+ * \var Converter::Feature::None
+ * \brief No extra features supported by the converter
+ */
+
+/**
+ * \typedef Converter::Features
+ * \brief A bitwise combination of features supported by the converter
+ */
+
 /**
  * \brief Construct a Converter instance
  * \param[in] media The media device implementing the converter
+ * \param[in] features Features flags representing supported features
  *
  * This searches for the entity implementing the data streaming function in the
  * media graph entities and use its device node as the converter device node.
  */
-Converter::Converter(MediaDevice *media)
+Converter::Converter(MediaDevice *media, Features features)
 {
 	const std::vector<MediaEntity *> &entities = media->entities();
 	auto it = std::find_if(entities.begin(), entities.end(),
@@ -56,6 +69,7 @@ Converter::Converter(MediaDevice *media)
 	}
 
 	deviceNode_ = (*it)->deviceNode();
+	features_ = features;
 }
 
 Converter::~Converter()
@@ -163,6 +177,12 @@ Converter::~Converter()
  * \return The converter device node string
  */
 
+/**
+ * \fn Converter::getFeatures()
+ * \brief Gets the supported features by the converter
+ * \return The converter Features flag
+ */
+
 /**
  * \class ConverterFactoryBase
  * \brief Base class for converter factories
diff --git a/src/libcamera/converter/converter_v4l2_m2m.cpp b/src/libcamera/converter/converter_v4l2_m2m.cpp
index 2e77872e..4aeb7dd9 100644
--- a/src/libcamera/converter/converter_v4l2_m2m.cpp
+++ b/src/libcamera/converter/converter_v4l2_m2m.cpp
@@ -191,10 +191,11 @@ void V4L2M2MConverter::V4L2M2MStream::captureBufferReady(FrameBuffer *buffer)
  * \fn V4L2M2MConverter::V4L2M2MConverter
  * \brief Construct a V4L2M2MConverter instance
  * \param[in] media The media device implementing the converter
+ * \param[in] features Features flags representing supported features
  */
 
-V4L2M2MConverter::V4L2M2MConverter(MediaDevice *media)
-	: Converter(media)
+V4L2M2MConverter::V4L2M2MConverter(MediaDevice *media, Features features)
+	: Converter(media, features)
 {
 	if (deviceNode().empty())
 		return;
-- 
2.44.0