[v8,14/55,media] media: add functions to allow creating interfaces

Commit Message

Mauro Carvalho Chehab Aug. 30, 2015, 3:06 a.m. UTC

Interfaces are different than entities: they represent a
Kernel<->userspace interaction, while entities represent a
piece of hardware/firmware/software that executes a function.

Let's distinguish them by creating a separate structure to
store the interfaces.

Latter patches should change the existing drivers and logic
to split the current interface embedded inside the entity
structure (device nodes) into a separate object of the graph.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

Comments

Hans Verkuil Aug. 31, 2015, 10:20 a.m. UTC | #1

On 08/30/2015 05:06 AM, Mauro Carvalho Chehab wrote:
> Interfaces are different than entities: they represent a
> Kernel<->userspace interaction, while entities represent a
> piece of hardware/firmware/software that executes a function.
> 
> Let's distinguish them by creating a separate structure to
> store the interfaces.
> 
> Latter patches should change the existing drivers and logic

s/Latter/Later/

FYI: you almost never use 'latter' in English texts. The only common use
of 'latter' is in the phrase "the latter of two options" where 'latter' means
'second'.

> to split the current interface embedded inside the entity
> structure (device nodes) into a separate object of the graph.
> 
> Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
> 
> diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> index a23c93369a04..583666e2cc25 100644
> --- a/drivers/media/media-entity.c
> +++ b/drivers/media/media-entity.c
> @@ -44,11 +44,41 @@ static inline const char *gobj_type(enum media_gobj_type type)
>  		return "pad";
>  	case MEDIA_GRAPH_LINK:
>  		return "link";
> +	case MEDIA_GRAPH_INTF_DEVNODE:
> +		return "intf_devnode";

You use '-' below for 'v4l-subdev' and 'unknown-intf', so I think this too should
use '-'. My opinion though.

It's a nitpick, so I give my Ack anyway:

Acked-by: Hans Verkuil <[e-mail]>

Regards,

	Hans

>  	default:
>  		return "unknown";
>  	}
>  }
>  
> +static inline const char *intf_type(struct media_interface *intf)
> +{
> +	switch (intf->type) {
> +	case MEDIA_INTF_T_DVB_FE:
> +		return "frontend";
> +	case MEDIA_INTF_T_DVB_DEMUX:
> +		return "demux";
> +	case MEDIA_INTF_T_DVB_DVR:
> +		return "DVR";
> +	case MEDIA_INTF_T_DVB_CA:
> +		return  "CA";
> +	case MEDIA_INTF_T_DVB_NET:
> +		return "dvbnet";
> +	case MEDIA_INTF_T_V4L_VIDEO:
> +		return "video";
> +	case MEDIA_INTF_T_V4L_VBI:
> +		return "vbi";
> +	case MEDIA_INTF_T_V4L_RADIO:
> +		return "radio";
> +	case MEDIA_INTF_T_V4L_SUBDEV:
> +		return "v4l2-subdev";
> +	case MEDIA_INTF_T_V4L_SWRADIO:
> +		return "swradio";
> +	default:
> +		return "unknown-intf";
> +	}
> +};
> +
>  static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
>  {
>  #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
> @@ -84,6 +114,19 @@ static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
>  			"%s: id 0x%08x pad#%d: '%s':%d\n",
>  			event_name, gobj->id, media_localid(gobj),
>  			pad->entity->name, pad->index);
> +		break;
> +	}
> +	case MEDIA_GRAPH_INTF_DEVNODE:
> +	{
> +		struct media_interface *intf = gobj_to_intf(gobj);
> +		struct media_intf_devnode *devnode = intf_to_devnode(intf);
> +
> +		dev_dbg(gobj->mdev->dev,
> +			"%s: id 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
> +			event_name, gobj->id, media_localid(gobj),
> +			intf_type(intf),
> +			devnode->major, devnode->minor);
> +		break;
>  	}
>  	}
>  #endif
> @@ -119,6 +162,9 @@ void media_gobj_init(struct media_device *mdev,
>  	case MEDIA_GRAPH_LINK:
>  		gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
>  		break;
> +	case MEDIA_GRAPH_INTF_DEVNODE:
> +		gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
> +		break;
>  	}
>  	dev_dbg_obj(__func__, gobj);
>  }
> @@ -793,3 +839,40 @@ struct media_pad *media_entity_remote_pad(struct media_pad *pad)
>  
>  }
>  EXPORT_SYMBOL_GPL(media_entity_remote_pad);
> +
> +
> +/* Functions related to the media interface via device nodes */
> +
> +struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
> +						u32 type, u32 flags,
> +						u32 major, u32 minor,
> +						gfp_t gfp_flags)
> +{
> +	struct media_intf_devnode *devnode;
> +	struct media_interface *intf;
> +
> +	devnode = kzalloc(sizeof(*devnode), gfp_flags);
> +	if (!devnode)
> +		return NULL;
> +
> +	intf = &devnode->intf;
> +
> +	intf->type = type;
> +	intf->flags = flags;
> +
> +	devnode->major = major;
> +	devnode->minor = minor;
> +
> +	media_gobj_init(mdev, MEDIA_GRAPH_INTF_DEVNODE,
> +		       &devnode->intf.graph_obj);
> +
> +	return devnode;
> +}
> +EXPORT_SYMBOL_GPL(media_devnode_create);
> +
> +void media_devnode_remove(struct media_intf_devnode *devnode)
> +{
> +	media_gobj_remove(&devnode->intf.graph_obj);
> +	kfree(devnode);
> +}
> +EXPORT_SYMBOL_GPL(media_devnode_remove);
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 05414e351f8e..3b14394d5701 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -44,6 +44,7 @@ struct device;
>   * @entity_id:	Unique ID used on the last entity registered
>   * @pad_id:	Unique ID used on the last pad registered
>   * @link_id:	Unique ID used on the last link registered
> + * @intf_devnode_id: Unique ID used on the last interface devnode registered
>   * @entities:	List of registered entities
>   * @lock:	Entities list lock
>   * @graph_mutex: Entities graph operation lock
> @@ -73,6 +74,7 @@ struct media_device {
>  	u32 entity_id;
>  	u32 pad_id;
>  	u32 link_id;
> +	u32 intf_devnode_id;
>  
>  	struct list_head entities;
>  
> diff --git a/include/media/media-entity.h b/include/media/media-entity.h
> index 239c4ec30ef6..7df8836f4eef 100644
> --- a/include/media/media-entity.h
> +++ b/include/media/media-entity.h
> @@ -36,11 +36,14 @@
>   * @MEDIA_GRAPH_ENTITY:		Identify a media entity
>   * @MEDIA_GRAPH_PAD:		Identify a media pad
>   * @MEDIA_GRAPH_LINK:		Identify a media link
> + * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
> + *				a device node
>   */
>  enum media_gobj_type {
>  	MEDIA_GRAPH_ENTITY,
>  	MEDIA_GRAPH_PAD,
>  	MEDIA_GRAPH_LINK,
> +	MEDIA_GRAPH_INTF_DEVNODE,
>  };
>  
>  #define MEDIA_BITS_PER_TYPE		8
> @@ -141,6 +144,34 @@ struct media_entity {
>  	} info;
>  };
>  
> +/**
> + * struct media_intf_devnode - Define a Kernel API interface
> + *
> + * @graph_obj:		embedded graph object
> + * @type:		Type of the interface as defined at the
> + *			uapi/media/media.h header, e. g.
> + *			MEDIA_INTF_T_*
> + * @flags:		Interface flags as defined at uapi/media/media.h
> + */
> +struct media_interface {
> +	struct media_gobj		graph_obj;
> +	u32				type;
> +	u32				flags;
> +};
> +
> +/**
> + * struct media_intf_devnode - Define a Kernel API interface via a device node
> + *
> + * @intf:	embedded interface object
> + * @major:	Major number of a device node
> + * @minor:	Minor number of a device node
> + */
> +struct media_intf_devnode {
> +	struct media_interface		intf;
> +	u32				major;
> +	u32				minor;
> +};
> +
>  static inline u32 media_entity_type(struct media_entity *entity)
>  {
>  	return entity->type & MEDIA_ENT_TYPE_MASK;
> @@ -198,6 +229,18 @@ struct media_entity_graph {
>  #define gobj_to_link(gobj) \
>  		container_of(gobj, struct media_link, graph_obj)
>  
> +#define gobj_to_link(gobj) \
> +		container_of(gobj, struct media_link, graph_obj)
> +
> +#define gobj_to_pad(gobj) \
> +		container_of(gobj, struct media_pad, graph_obj)
> +
> +#define gobj_to_intf(gobj) \
> +		container_of(gobj, struct media_interface, graph_obj)
> +
> +#define intf_to_devnode(intf) \
> +		container_of(intf, struct media_intf_devnode, intf)
> +
>  void media_gobj_init(struct media_device *mdev,
>  		    enum media_gobj_type type,
>  		    struct media_gobj *gobj);
> @@ -229,6 +272,11 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
>  					     struct media_pipeline *pipe);
>  void media_entity_pipeline_stop(struct media_entity *entity);
>  
> +struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
> +						u32 type, u32 flags,
> +						u32 major, u32 minor,
> +						gfp_t gfp_flags);
> +void media_devnode_remove(struct media_intf_devnode *devnode);
>  #define media_entity_call(entity, operation, args...)			\
>  	(((entity)->ops && (entity)->ops->operation) ?			\
>  	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Mauro Carvalho Chehab Aug. 31, 2015, 10:49 a.m. UTC | #2

Em Mon, 31 Aug 2015 12:20:43 +0200
Hans Verkuil <[e-mail]> escreveu:

> On 08/30/2015 05:06 AM, Mauro Carvalho Chehab wrote:
> > Interfaces are different than entities: they represent a
> > Kernel<->userspace interaction, while entities represent a
> > piece of hardware/firmware/software that executes a function.
> > 
> > Let's distinguish them by creating a separate structure to
> > store the interfaces.
> > 
> > Latter patches should change the existing drivers and logic
> 
> s/Latter/Later/
> 
> FYI: you almost never use 'latter' in English texts. The only common use
> of 'latter' is in the phrase "the latter of two options" where 'latter' means
> 'second'.

I did a global replace on the patches, but perhaps the regex
expression I used didn't got this one.

> 
> > to split the current interface embedded inside the entity
> > structure (device nodes) into a separate object of the graph.
> > 
> > Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
> > 
> > diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
> > index a23c93369a04..583666e2cc25 100644
> > --- a/drivers/media/media-entity.c
> > +++ b/drivers/media/media-entity.c
> > @@ -44,11 +44,41 @@ static inline const char *gobj_type(enum media_gobj_type type)
> >  		return "pad";
> >  	case MEDIA_GRAPH_LINK:
> >  		return "link";
> > +	case MEDIA_GRAPH_INTF_DEVNODE:
> > +		return "intf_devnode";
> 
> You use '-' below for 'v4l-subdev' and 'unknown-intf', so I think this too should
> use '-'. My opinion though.

Gah, forgot this one ;)

> 
> It's a nitpick, so I give my Ack anyway:
> 
> Acked-by: Hans Verkuil <[e-mail]>
> 
> Regards,
> 
> 	Hans
> 
> >  	default:
> >  		return "unknown";
> >  	}
> >  }
> >  
> > +static inline const char *intf_type(struct media_interface *intf)
> > +{
> > +	switch (intf->type) {
> > +	case MEDIA_INTF_T_DVB_FE:
> > +		return "frontend";
> > +	case MEDIA_INTF_T_DVB_DEMUX:
> > +		return "demux";
> > +	case MEDIA_INTF_T_DVB_DVR:
> > +		return "DVR";
> > +	case MEDIA_INTF_T_DVB_CA:
> > +		return  "CA";
> > +	case MEDIA_INTF_T_DVB_NET:
> > +		return "dvbnet";
> > +	case MEDIA_INTF_T_V4L_VIDEO:
> > +		return "video";
> > +	case MEDIA_INTF_T_V4L_VBI:
> > +		return "vbi";
> > +	case MEDIA_INTF_T_V4L_RADIO:
> > +		return "radio";
> > +	case MEDIA_INTF_T_V4L_SUBDEV:
> > +		return "v4l2-subdev";
> > +	case MEDIA_INTF_T_V4L_SWRADIO:
> > +		return "swradio";
> > +	default:
> > +		return "unknown-intf";
> > +	}
> > +};
> > +
> >  static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
> >  {
> >  #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
> > @@ -84,6 +114,19 @@ static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
> >  			"%s: id 0x%08x pad#%d: '%s':%d\n",
> >  			event_name, gobj->id, media_localid(gobj),
> >  			pad->entity->name, pad->index);
> > +		break;
> > +	}
> > +	case MEDIA_GRAPH_INTF_DEVNODE:
> > +	{
> > +		struct media_interface *intf = gobj_to_intf(gobj);
> > +		struct media_intf_devnode *devnode = intf_to_devnode(intf);
> > +
> > +		dev_dbg(gobj->mdev->dev,
> > +			"%s: id 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
> > +			event_name, gobj->id, media_localid(gobj),
> > +			intf_type(intf),
> > +			devnode->major, devnode->minor);
> > +		break;
> >  	}
> >  	}
> >  #endif
> > @@ -119,6 +162,9 @@ void media_gobj_init(struct media_device *mdev,
> >  	case MEDIA_GRAPH_LINK:
> >  		gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
> >  		break;
> > +	case MEDIA_GRAPH_INTF_DEVNODE:
> > +		gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
> > +		break;
> >  	}
> >  	dev_dbg_obj(__func__, gobj);
> >  }
> > @@ -793,3 +839,40 @@ struct media_pad *media_entity_remote_pad(struct media_pad *pad)
> >  
> >  }
> >  EXPORT_SYMBOL_GPL(media_entity_remote_pad);
> > +
> > +
> > +/* Functions related to the media interface via device nodes */
> > +
> > +struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
> > +						u32 type, u32 flags,
> > +						u32 major, u32 minor,
> > +						gfp_t gfp_flags)
> > +{
> > +	struct media_intf_devnode *devnode;
> > +	struct media_interface *intf;
> > +
> > +	devnode = kzalloc(sizeof(*devnode), gfp_flags);
> > +	if (!devnode)
> > +		return NULL;
> > +
> > +	intf = &devnode->intf;
> > +
> > +	intf->type = type;
> > +	intf->flags = flags;
> > +
> > +	devnode->major = major;
> > +	devnode->minor = minor;
> > +
> > +	media_gobj_init(mdev, MEDIA_GRAPH_INTF_DEVNODE,
> > +		       &devnode->intf.graph_obj);
> > +
> > +	return devnode;
> > +}
> > +EXPORT_SYMBOL_GPL(media_devnode_create);
> > +
> > +void media_devnode_remove(struct media_intf_devnode *devnode)
> > +{
> > +	media_gobj_remove(&devnode->intf.graph_obj);
> > +	kfree(devnode);
> > +}
> > +EXPORT_SYMBOL_GPL(media_devnode_remove);
> > diff --git a/include/media/media-device.h b/include/media/media-device.h
> > index 05414e351f8e..3b14394d5701 100644
> > --- a/include/media/media-device.h
> > +++ b/include/media/media-device.h
> > @@ -44,6 +44,7 @@ struct device;
> >   * @entity_id:	Unique ID used on the last entity registered
> >   * @pad_id:	Unique ID used on the last pad registered
> >   * @link_id:	Unique ID used on the last link registered
> > + * @intf_devnode_id: Unique ID used on the last interface devnode registered
> >   * @entities:	List of registered entities
> >   * @lock:	Entities list lock
> >   * @graph_mutex: Entities graph operation lock
> > @@ -73,6 +74,7 @@ struct media_device {
> >  	u32 entity_id;
> >  	u32 pad_id;
> >  	u32 link_id;
> > +	u32 intf_devnode_id;
> >  
> >  	struct list_head entities;
> >  
> > diff --git a/include/media/media-entity.h b/include/media/media-entity.h
> > index 239c4ec30ef6..7df8836f4eef 100644
> > --- a/include/media/media-entity.h
> > +++ b/include/media/media-entity.h
> > @@ -36,11 +36,14 @@
> >   * @MEDIA_GRAPH_ENTITY:		Identify a media entity
> >   * @MEDIA_GRAPH_PAD:		Identify a media pad
> >   * @MEDIA_GRAPH_LINK:		Identify a media link
> > + * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
> > + *				a device node
> >   */
> >  enum media_gobj_type {
> >  	MEDIA_GRAPH_ENTITY,
> >  	MEDIA_GRAPH_PAD,
> >  	MEDIA_GRAPH_LINK,
> > +	MEDIA_GRAPH_INTF_DEVNODE,
> >  };
> >  
> >  #define MEDIA_BITS_PER_TYPE		8
> > @@ -141,6 +144,34 @@ struct media_entity {
> >  	} info;
> >  };
> >  
> > +/**
> > + * struct media_intf_devnode - Define a Kernel API interface
> > + *
> > + * @graph_obj:		embedded graph object
> > + * @type:		Type of the interface as defined at the
> > + *			uapi/media/media.h header, e. g.
> > + *			MEDIA_INTF_T_*
> > + * @flags:		Interface flags as defined at uapi/media/media.h
> > + */
> > +struct media_interface {
> > +	struct media_gobj		graph_obj;
> > +	u32				type;
> > +	u32				flags;
> > +};
> > +
> > +/**
> > + * struct media_intf_devnode - Define a Kernel API interface via a device node
> > + *
> > + * @intf:	embedded interface object
> > + * @major:	Major number of a device node
> > + * @minor:	Minor number of a device node
> > + */
> > +struct media_intf_devnode {
> > +	struct media_interface		intf;
> > +	u32				major;
> > +	u32				minor;
> > +};
> > +
> >  static inline u32 media_entity_type(struct media_entity *entity)
> >  {
> >  	return entity->type & MEDIA_ENT_TYPE_MASK;
> > @@ -198,6 +229,18 @@ struct media_entity_graph {
> >  #define gobj_to_link(gobj) \
> >  		container_of(gobj, struct media_link, graph_obj)
> >  
> > +#define gobj_to_link(gobj) \
> > +		container_of(gobj, struct media_link, graph_obj)
> > +
> > +#define gobj_to_pad(gobj) \
> > +		container_of(gobj, struct media_pad, graph_obj)
> > +
> > +#define gobj_to_intf(gobj) \
> > +		container_of(gobj, struct media_interface, graph_obj)
> > +
> > +#define intf_to_devnode(intf) \
> > +		container_of(intf, struct media_intf_devnode, intf)
> > +
> >  void media_gobj_init(struct media_device *mdev,
> >  		    enum media_gobj_type type,
> >  		    struct media_gobj *gobj);
> > @@ -229,6 +272,11 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
> >  					     struct media_pipeline *pipe);
> >  void media_entity_pipeline_stop(struct media_entity *entity);
> >  
> > +struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
> > +						u32 type, u32 flags,
> > +						u32 major, u32 minor,
> > +						gfp_t gfp_flags);
> > +void media_devnode_remove(struct media_intf_devnode *devnode);
> >  #define media_entity_call(entity, operation, args...)			\
> >  	(((entity)->ops && (entity)->ops->operation) ?			\
> >  	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)
> > 
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to [e-mail]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index a23c93369a04..583666e2cc25 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -44,11 +44,41 @@  static inline const char *gobj_type(enum media_gobj_type type)
 		return "pad";
 	case MEDIA_GRAPH_LINK:
 		return "link";
+	case MEDIA_GRAPH_INTF_DEVNODE:
+		return "intf_devnode";
 	default:
 		return "unknown";
 	}
 }
 
+static inline const char *intf_type(struct media_interface *intf)
+{
+	switch (intf->type) {
+	case MEDIA_INTF_T_DVB_FE:
+		return "frontend";
+	case MEDIA_INTF_T_DVB_DEMUX:
+		return "demux";
+	case MEDIA_INTF_T_DVB_DVR:
+		return "DVR";
+	case MEDIA_INTF_T_DVB_CA:
+		return  "CA";
+	case MEDIA_INTF_T_DVB_NET:
+		return "dvbnet";
+	case MEDIA_INTF_T_V4L_VIDEO:
+		return "video";
+	case MEDIA_INTF_T_V4L_VBI:
+		return "vbi";
+	case MEDIA_INTF_T_V4L_RADIO:
+		return "radio";
+	case MEDIA_INTF_T_V4L_SUBDEV:
+		return "v4l2-subdev";
+	case MEDIA_INTF_T_V4L_SWRADIO:
+		return "swradio";
+	default:
+		return "unknown-intf";
+	}
+};
+
 static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 {
 #if defined(DEBUG) || defined (CONFIG_DYNAMIC_DEBUG)
@@ -84,6 +114,19 @@  static void dev_dbg_obj(const char *event_name,  struct media_gobj *gobj)
 			"%s: id 0x%08x pad#%d: '%s':%d\n",
 			event_name, gobj->id, media_localid(gobj),
 			pad->entity->name, pad->index);
+		break;
+	}
+	case MEDIA_GRAPH_INTF_DEVNODE:
+	{
+		struct media_interface *intf = gobj_to_intf(gobj);
+		struct media_intf_devnode *devnode = intf_to_devnode(intf);
+
+		dev_dbg(gobj->mdev->dev,
+			"%s: id 0x%08x intf_devnode#%d: %s - major: %d, minor: %d\n",
+			event_name, gobj->id, media_localid(gobj),
+			intf_type(intf),
+			devnode->major, devnode->minor);
+		break;
 	}
 	}
 #endif
@@ -119,6 +162,9 @@  void media_gobj_init(struct media_device *mdev,
 	case MEDIA_GRAPH_LINK:
 		gobj->id = media_gobj_gen_id(type, ++mdev->link_id);
 		break;
+	case MEDIA_GRAPH_INTF_DEVNODE:
+		gobj->id = media_gobj_gen_id(type, ++mdev->intf_devnode_id);
+		break;
 	}
 	dev_dbg_obj(__func__, gobj);
 }
@@ -793,3 +839,40 @@  struct media_pad *media_entity_remote_pad(struct media_pad *pad)
 
 }
 EXPORT_SYMBOL_GPL(media_entity_remote_pad);
+
+
+/* Functions related to the media interface via device nodes */
+
+struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
+						u32 type, u32 flags,
+						u32 major, u32 minor,
+						gfp_t gfp_flags)
+{
+	struct media_intf_devnode *devnode;
+	struct media_interface *intf;
+
+	devnode = kzalloc(sizeof(*devnode), gfp_flags);
+	if (!devnode)
+		return NULL;
+
+	intf = &devnode->intf;
+
+	intf->type = type;
+	intf->flags = flags;
+
+	devnode->major = major;
+	devnode->minor = minor;
+
+	media_gobj_init(mdev, MEDIA_GRAPH_INTF_DEVNODE,
+		       &devnode->intf.graph_obj);
+
+	return devnode;
+}
+EXPORT_SYMBOL_GPL(media_devnode_create);
+
+void media_devnode_remove(struct media_intf_devnode *devnode)
+{
+	media_gobj_remove(&devnode->intf.graph_obj);
+	kfree(devnode);
+}
+EXPORT_SYMBOL_GPL(media_devnode_remove);
diff --git a/include/media/media-device.h b/include/media/media-device.h
index 05414e351f8e..3b14394d5701 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -44,6 +44,7 @@  struct device;
  * @entity_id:	Unique ID used on the last entity registered
  * @pad_id:	Unique ID used on the last pad registered
  * @link_id:	Unique ID used on the last link registered
+ * @intf_devnode_id: Unique ID used on the last interface devnode registered
  * @entities:	List of registered entities
  * @lock:	Entities list lock
  * @graph_mutex: Entities graph operation lock
@@ -73,6 +74,7 @@  struct media_device {
 	u32 entity_id;
 	u32 pad_id;
 	u32 link_id;
+	u32 intf_devnode_id;
 
 	struct list_head entities;
 
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index 239c4ec30ef6..7df8836f4eef 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -36,11 +36,14 @@ 
  * @MEDIA_GRAPH_ENTITY:		Identify a media entity
  * @MEDIA_GRAPH_PAD:		Identify a media pad
  * @MEDIA_GRAPH_LINK:		Identify a media link
+ * @MEDIA_GRAPH_INTF_DEVNODE:	Identify a media Kernel API interface via
+ *				a device node
  */
 enum media_gobj_type {
 	MEDIA_GRAPH_ENTITY,
 	MEDIA_GRAPH_PAD,
 	MEDIA_GRAPH_LINK,
+	MEDIA_GRAPH_INTF_DEVNODE,
 };
 
 #define MEDIA_BITS_PER_TYPE		8
@@ -141,6 +144,34 @@  struct media_entity {
 	} info;
 };
 
+/**
+ * struct media_intf_devnode - Define a Kernel API interface
+ *
+ * @graph_obj:		embedded graph object
+ * @type:		Type of the interface as defined at the
+ *			uapi/media/media.h header, e. g.
+ *			MEDIA_INTF_T_*
+ * @flags:		Interface flags as defined at uapi/media/media.h
+ */
+struct media_interface {
+	struct media_gobj		graph_obj;
+	u32				type;
+	u32				flags;
+};
+
+/**
+ * struct media_intf_devnode - Define a Kernel API interface via a device node
+ *
+ * @intf:	embedded interface object
+ * @major:	Major number of a device node
+ * @minor:	Minor number of a device node
+ */
+struct media_intf_devnode {
+	struct media_interface		intf;
+	u32				major;
+	u32				minor;
+};
+
 static inline u32 media_entity_type(struct media_entity *entity)
 {
 	return entity->type & MEDIA_ENT_TYPE_MASK;
@@ -198,6 +229,18 @@  struct media_entity_graph {
 #define gobj_to_link(gobj) \
 		container_of(gobj, struct media_link, graph_obj)
 
+#define gobj_to_link(gobj) \
+		container_of(gobj, struct media_link, graph_obj)
+
+#define gobj_to_pad(gobj) \
+		container_of(gobj, struct media_pad, graph_obj)
+
+#define gobj_to_intf(gobj) \
+		container_of(gobj, struct media_interface, graph_obj)
+
+#define intf_to_devnode(intf) \
+		container_of(intf, struct media_intf_devnode, intf)
+
 void media_gobj_init(struct media_device *mdev,
 		    enum media_gobj_type type,
 		    struct media_gobj *gobj);
@@ -229,6 +272,11 @@  __must_check int media_entity_pipeline_start(struct media_entity *entity,
 					     struct media_pipeline *pipe);
 void media_entity_pipeline_stop(struct media_entity *entity);
 
+struct media_intf_devnode *media_devnode_create(struct media_device *mdev,
+						u32 type, u32 flags,
+						u32 major, u32 minor,
+						gfp_t gfp_flags);
+void media_devnode_remove(struct media_intf_devnode *devnode);
 #define media_entity_call(entity, operation, args...)			\
 	(((entity)->ops && (entity)->ops->operation) ?			\
 	 (entity)->ops->operation((entity) , ##args) : -ENOIOCTLCMD)