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authorMauro Carvalho Chehab <mchehab@osg.samsung.com>2015-12-12 11:59:14 +0100
committerMauro Carvalho Chehab <mchehab@osg.samsung.com>2016-01-11 15:19:11 +0100
commitb7870d692d7b0718f7153aed9e7a32f0119b525d (patch)
treeeefa33cda39f1c900b445a98c49942e07a896282 /Documentation
parent[media] dvbdev: Document the new MC-related fields (diff)
downloadlinux-b7870d692d7b0718f7153aed9e7a32f0119b525d.tar.xz
linux-b7870d692d7b0718f7153aed9e7a32f0119b525d.zip
[media] DocBook: MC: add the concept of interfaces
The Media Controller next generation patches added a new graph element type: interfaces. It also allows links between interfaces and entities. Update the docbook to reflect that. Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/DocBook/media/v4l/media-controller.xml40
1 files changed, 26 insertions, 14 deletions
diff --git a/Documentation/DocBook/media/v4l/media-controller.xml b/Documentation/DocBook/media/v4l/media-controller.xml
index 873ac3a621f0..def4a27aadef 100644
--- a/Documentation/DocBook/media/v4l/media-controller.xml
+++ b/Documentation/DocBook/media/v4l/media-controller.xml
@@ -58,20 +58,32 @@
<title>Media device model</title>
<para>Discovering a device internal topology, and configuring it at runtime,
is one of the goals of the media controller API. To achieve this, hardware
- devices are modelled as an oriented graph of building blocks called entities
- connected through pads.</para>
- <para>An entity is a basic media hardware or software building block. It can
- correspond to a large variety of logical blocks such as physical hardware
- devices (CMOS sensor for instance), logical hardware devices (a building
- block in a System-on-Chip image processing pipeline), DMA channels or
- physical connectors.</para>
- <para>A pad is a connection endpoint through which an entity can interact
- with other entities. Data (not restricted to video) produced by an entity
- flows from the entity's output to one or more entity inputs. Pads should not
- be confused with physical pins at chip boundaries.</para>
- <para>A link is a point-to-point oriented connection between two pads,
- either on the same entity or on different entities. Data flows from a source
- pad to a sink pad.</para>
+ devices and Linux Kernel interfaces are modelled as graph objects on
+ an oriented graph. The object types that constitute the graph are:</para>
+ <itemizedlist>
+ <listitem><para>An <emphasis role="bold">entity</emphasis>
+ is a basic media hardware or software building block. It can correspond to
+ a large variety of logical blocks such as physical hardware devices
+ (CMOS sensor for instance), logical hardware devices (a building block in
+ a System-on-Chip image processing pipeline), DMA channels or physical
+ connectors.</para></listitem>
+ <listitem><para>An <emphasis role="bold">interface</emphasis>
+ is a graph representation of a Linux Kernel userspace API interface,
+ like a device node or a sysfs file that controls one or more entities
+ in the graph.</para></listitem>
+ <listitem><para>A <emphasis role="bold">pad</emphasis>
+ is a data connection endpoint through which an entity can interact with
+ other entities. Data (not restricted to video) produced by an entity
+ flows from the entity's output to one or more entity inputs. Pads should
+ not be confused with physical pins at chip boundaries.</para></listitem>
+ <listitem><para>A <emphasis role="bold">data link</emphasis>
+ is a point-to-point oriented connection between two pads, either on the
+ same entity or on different entities. Data flows from a source pad to a
+ sink pad.</para></listitem>
+ <listitem><para>An <emphasis role="bold">interface link</emphasis>
+ is a point-to-point bidirectional control connection between a Linux
+ Kernel interface and an entity.m</para></listitem>
+ </itemizedlist>
</section>
</chapter>