[libcamera-devel,v3,05/14] libcamera: camera: Provide a list of ControlInfo
diff mbox series

Message ID 20190630233817.10130-6-laurent.pinchart@ideasonboard.com
State Superseded
Headers show
Series
  • libcamera Controls
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Commit Message

Laurent Pinchart June 30, 2019, 11:38 p.m. UTC 
From: Kieran Bingham <kieran.bingham@ideasonboard.com>

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>
---
 include/libcamera/camera.h               |  3 +++
 include/libcamera/controls.h             |  2 ++
 src/libcamera/camera.cpp                 | 12 ++++++++++++
 src/libcamera/controls.cpp               |  5 +++++
 src/libcamera/include/pipeline_handler.h |  4 ++++
 src/libcamera/pipeline_handler.cpp       | 19 +++++++++++++++++++
 6 files changed, 45 insertions(+)

Comments

Kieran Bingham July 1, 2019, 9:20 a.m. UTC | #1 
Hi Laurent,

On 01/07/2019 00:38, Laurent Pinchart wrote:
> From: Kieran Bingham <kieran.bingham@ideasonboard.com>
> 
> 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>

Extending the std::hash does make the declaration of ControlInfoMap here
nicer.

Thanks for your updates.

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>



> ---
>  include/libcamera/camera.h               |  3 +++
>  include/libcamera/controls.h             |  2 ++
>  src/libcamera/camera.cpp                 | 12 ++++++++++++
>  src/libcamera/controls.cpp               |  5 +++++
>  src/libcamera/include/pipeline_handler.h |  4 ++++
>  src/libcamera/pipeline_handler.cpp       | 19 +++++++++++++++++++
>  6 files changed, 45 insertions(+)
> 
> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> index fb2f7ba3423c..6d693d9a6c7a 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 ad2d49d522c5..9b37dfb16b89 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 617ea99cdf71..592dfd39eacc 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -548,6 +548,18 @@ int Camera::release()
>  	return 0;
>  }
>  
> +/**
> + * \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
>   *
> diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> index 22db2b93eff2..e4c41b97a354 100644
> --- a/src/libcamera/controls.cpp
> +++ b/src/libcamera/controls.cpp
> @@ -315,6 +315,11 @@ bool operator==(const ControlInfo &lhs, const ControlId &rhs)
>  	return lhs.id() == rhs;
>  }
>  
> +/**
> + * \typedef ControlInfoMap
> + * \brief A map of ControlId to ControlInfo
> + */
> +
>  /**
>   * \class ControlList
>   * \brief Associates a list of ControlIds with their values for a Camera.
> diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
> index a4cbc593a179..f836d5d1a600 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 c91ef2f7d336..0283e4e5ad51 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -88,6 +88,14 @@ LOG_DEFINE_CATEGORY(Pipeline)
>   * PipelineHandler::completeRequest()
>   */
>  
> +/**
> + * \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
> @@ -217,6 +225,17 @@ void PipelineHandler::unlock()
>  		media->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
>
Jacopo Mondi July 1, 2019, 4:48 p.m. UTC | #2 
HI Laurent,

On Mon, Jul 01, 2019 at 02:38:08AM +0300, Laurent Pinchart wrote:
> From: Kieran Bingham <kieran.bingham@ideasonboard.com>
>
> 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>
> ---
>  include/libcamera/camera.h               |  3 +++
>  include/libcamera/controls.h             |  2 ++
>  src/libcamera/camera.cpp                 | 12 ++++++++++++
>  src/libcamera/controls.cpp               |  5 +++++
>  src/libcamera/include/pipeline_handler.h |  4 ++++
>  src/libcamera/pipeline_handler.cpp       | 19 +++++++++++++++++++
>  6 files changed, 45 insertions(+)
>
> diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> index fb2f7ba3423c..6d693d9a6c7a 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();

can't this be called on const instances?
Or there is no such a thing as a const Camera instances? Same question
for the pipeline handler operation, but in that case I doubt we'll
have any const pipeline handler.

This apart
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

> +
>  	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 ad2d49d522c5..9b37dfb16b89 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 617ea99cdf71..592dfd39eacc 100644
> --- a/src/libcamera/camera.cpp
> +++ b/src/libcamera/camera.cpp
> @@ -548,6 +548,18 @@ int Camera::release()
>  	return 0;
>  }
>
> +/**
> + * \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
>   *
> diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> index 22db2b93eff2..e4c41b97a354 100644
> --- a/src/libcamera/controls.cpp
> +++ b/src/libcamera/controls.cpp
> @@ -315,6 +315,11 @@ bool operator==(const ControlInfo &lhs, const ControlId &rhs)
>  	return lhs.id() == rhs;
>  }
>
> +/**
> + * \typedef ControlInfoMap
> + * \brief A map of ControlId to ControlInfo
> + */
> +
>  /**
>   * \class ControlList
>   * \brief Associates a list of ControlIds with their values for a Camera.
> diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
> index a4cbc593a179..f836d5d1a600 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 c91ef2f7d336..0283e4e5ad51 100644
> --- a/src/libcamera/pipeline_handler.cpp
> +++ b/src/libcamera/pipeline_handler.cpp
> @@ -88,6 +88,14 @@ LOG_DEFINE_CATEGORY(Pipeline)
>   * PipelineHandler::completeRequest()
>   */
>
> +/**
> + * \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
> @@ -217,6 +225,17 @@ void PipelineHandler::unlock()
>  		media->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
> --
> Regards,
>
> Laurent Pinchart
>
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel@lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel
Laurent Pinchart July 1, 2019, 5:11 p.m. UTC | #3 
Hi Jacopo,

On Mon, Jul 01, 2019 at 06:48:14PM +0200, Jacopo Mondi wrote:
> On Mon, Jul 01, 2019 at 02:38:08AM +0300, Laurent Pinchart wrote:
> > From: Kieran Bingham <kieran.bingham@ideasonboard.com>
> >
> > 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>
> > ---
> >  include/libcamera/camera.h               |  3 +++
> >  include/libcamera/controls.h             |  2 ++
> >  src/libcamera/camera.cpp                 | 12 ++++++++++++
> >  src/libcamera/controls.cpp               |  5 +++++
> >  src/libcamera/include/pipeline_handler.h |  4 ++++
> >  src/libcamera/pipeline_handler.cpp       | 19 +++++++++++++++++++
> >  6 files changed, 45 insertions(+)
> >
> > diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
> > index fb2f7ba3423c..6d693d9a6c7a 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();
> 
> can't this be called on const instances?
> Or there is no such a thing as a const Camera instances? Same question
> for the pipeline handler operation, but in that case I doubt we'll
> have any const pipeline handler.

If we want to call this on const Camera instance we need const
PipelineHandler instances, and it trickles down to more classes, until
it creates compilation errors that were hard to fix last time I tried.
As we have no const Camera instance, I don't think it's an issue.

> This apart
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
> 
> > +
> >  	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 ad2d49d522c5..9b37dfb16b89 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 617ea99cdf71..592dfd39eacc 100644
> > --- a/src/libcamera/camera.cpp
> > +++ b/src/libcamera/camera.cpp
> > @@ -548,6 +548,18 @@ int Camera::release()
> >  	return 0;
> >  }
> >
> > +/**
> > + * \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
> >   *
> > diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> > index 22db2b93eff2..e4c41b97a354 100644
> > --- a/src/libcamera/controls.cpp
> > +++ b/src/libcamera/controls.cpp
> > @@ -315,6 +315,11 @@ bool operator==(const ControlInfo &lhs, const ControlId &rhs)
> >  	return lhs.id() == rhs;
> >  }
> >
> > +/**
> > + * \typedef ControlInfoMap
> > + * \brief A map of ControlId to ControlInfo
> > + */
> > +
> >  /**
> >   * \class ControlList
> >   * \brief Associates a list of ControlIds with their values for a Camera.
> > diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
> > index a4cbc593a179..f836d5d1a600 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 c91ef2f7d336..0283e4e5ad51 100644
> > --- a/src/libcamera/pipeline_handler.cpp
> > +++ b/src/libcamera/pipeline_handler.cpp
> > @@ -88,6 +88,14 @@ LOG_DEFINE_CATEGORY(Pipeline)
> >   * PipelineHandler::completeRequest()
> >   */
> >
> > +/**
> > + * \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
> > @@ -217,6 +225,17 @@ void PipelineHandler::unlock()
> >  		media->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

Patch
diff mbox series 

diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index fb2f7ba3423c..6d693d9a6c7a 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 ad2d49d522c5..9b37dfb16b89 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 617ea99cdf71..592dfd39eacc 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -548,6 +548,18 @@  int Camera::release()
 	return 0;
 }
 
+/**
+ * \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
  *
diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
index 22db2b93eff2..e4c41b97a354 100644
--- a/src/libcamera/controls.cpp
+++ b/src/libcamera/controls.cpp
@@ -315,6 +315,11 @@  bool operator==(const ControlInfo &lhs, const ControlId &rhs)
 	return lhs.id() == rhs;
 }
 
+/**
+ * \typedef ControlInfoMap
+ * \brief A map of ControlId to ControlInfo
+ */
+
 /**
  * \class ControlList
  * \brief Associates a list of ControlIds with their values for a Camera.
diff --git a/src/libcamera/include/pipeline_handler.h b/src/libcamera/include/pipeline_handler.h
index a4cbc593a179..f836d5d1a600 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 c91ef2f7d336..0283e4e5ad51 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -88,6 +88,14 @@  LOG_DEFINE_CATEGORY(Pipeline)
  * PipelineHandler::completeRequest()
  */
 
+/**
+ * \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
@@ -217,6 +225,17 @@  void PipelineHandler::unlock()
 		media->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