libcamera: camera: Provide a list of ControlInfo

Extend the Camera class to expose the controls it supports. Each
pipeline should generate a list of controls supported by each camera it
creates. These are represented by a ControlInfoMap, and an associated
ControlList of default values.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

6 files changed, 45 insertions, 0 deletions

diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index fb2f7ba3..6d693d9a 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -12,6 +12,7 @@
 #include <set>
 #include <string>
 
+#include <libcamera/controls.h>
 #include <libcamera/request.h>
 #include <libcamera/signal.h>
 #include <libcamera/stream.h>
@@ -83,6 +84,8 @@ public:
 	int acquire();
 	int release();
 
+	const ControlInfoMap &controls();
+
 	const std::set<Stream *> &streams() const;
 	std::unique_ptr<CameraConfiguration> generateConfiguration(const StreamRoles &roles);
 	int configure(CameraConfiguration *config);
diff --git a/include/libcamera/controls.h b/include/libcamera/controls.h
index 22061559..18293c94 100644
--- a/include/libcamera/controls.h
+++ b/include/libcamera/controls.h
@@ -99,6 +99,8 @@ static inline bool operator!=(const ControlInfo &lhs, const ControlId &rhs)
 	return !(lhs == rhs);
 }
 
+using ControlInfoMap = std::unordered_map<ControlId, ControlInfo>;
+
 class ControlList
 {
 private:
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 617ea99c..592dfd39 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -549,6 +549,18 @@ int Camera::release()
 }
 
 /**
+ * \brief Retrieve the list of controls supported by the camera
+ *
+ * Camera controls remain constant through the lifetime of the camera.
+ *
+ * \return A ControlInfoMap listing the controls supported by the camera
+ */
+const ControlInfoMap &Camera::controls()
+{
+	return pipe_->controls(this);
+}
+
+/**
  * \brief Retrieve all the camera's stream information
  *
  * Retrieve all of the camera's static stream information. The static
diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index 7fac1169..cd2cf337 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -326,6 +326,11 @@ bool operator==(const ControlInfo &lhs, const ControlId &rhs)
 }
 
 /**
+ * \typedef ControlInfoMap
+ * \brief A map of ControlId to ControlInfo
+ */
+
+/**
  * \class ControlList
  * \brief Associate a list of ControlId with their values for a camera
  *
diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
index a4cbc593..f836d5d1 100644
--- a/src/libcamera/include/pipeline_handler.h
+++ b/src/libcamera/include/pipeline_handler.h
@@ -14,6 +14,7 @@
 #include <string>
 #include <vector>
 
+#include <libcamera/controls.h>
 #include <libcamera/stream.h>
 
 namespace libcamera {
@@ -41,6 +42,7 @@ public:
 	Camera *camera_;
 	PipelineHandler *pipe_;
 	std::list<Request *> queuedRequests_;
+	ControlInfoMap controlInfo_;
 
 private:
 	CameraData(const CameraData &) = delete;
@@ -60,6 +62,8 @@ public:
 	bool lock();
 	void unlock();
 
+	const ControlInfoMap &controls(Camera *camera);
+
 	virtual CameraConfiguration *generateConfiguration(Camera *camera,
 		const StreamRoles &roles) = 0;
 	virtual int configure(Camera *camera, CameraConfiguration *config) = 0;
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index c91ef2f7..0283e4e5 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -89,6 +89,14 @@ LOG_DEFINE_CATEGORY(Pipeline)
  */
 
 /**
+ * \var CameraData::controlInfo_
+ * \brief The set of controls supported by the camera
+ *
+ * The control information shall be initialised by the pipeline handler when
+ * creating the camera, and shall not be modified afterwards.
+ */
+
+/**
  * \class PipelineHandler
  * \brief Create and manage cameras based on a set of media devices
  *
@@ -218,6 +226,17 @@ void PipelineHandler::unlock()
 }
 
 /**
+ * \brief Retrieve the list of controls for a camera
+ * \param[in] camera The camera
+ * \return A ControlInfoMap listing the controls support by \a camera
+ */
+const ControlInfoMap &PipelineHandler::controls(Camera *camera)
+{
+	CameraData *data = cameraData(camera);
+	return data->controlInfo_;
+}
+
+/**
  * \fn PipelineHandler::generateConfiguration()
  * \brief Generate a camera configuration for a specified camera
  * \param[in] camera The camera to generate a default configuration for