Documentation: add documentation of AMD isp 4 driver

Add documentation for AMD ISP 4 and describe the main components

Co-developed-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@amd.com>
Signed-off-by: Bin Du <Bin.Du@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Reviewed-by: Sultan Alsawaf <sultan@kerneltoast.com>
Tested-by: Alexey Zagorodnikov <xglooom@gmail.com>
Tested-by: Kate Hsuan <hpa@redhat.com>

Author: Bin Du

Documentation/admin-guide/media/amdisp4-1.rst

@@ -0,0 +1,63 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+====================================
+AMD Image Signal Processor (amdisp4)
+====================================
+
+Introduction
+============
+
+This file documents the driver for the AMD ISP4 that is part of
+AMD Ryzen AI Max 300 Series.
+
+The driver is located under drivers/media/platform/amd/isp4 and uses
+the Media-Controller API.
+
+The driver exposes one video capture device to userspace and provide
+web camera like interface. Internally the video device is connected
+to the isp4 sub-device responsible for communication with the CCPU FW.
+
+Topology
+========
+
+.. _amdisp4_topology_graph:
+
+.. kernel-figure:: amdisp4.dot
+     :alt:   Diagram of the media pipeline topology
+     :align: center
+
+
+
+The driver has 1 sub-device: Representing isp4 image signal processor.
+The driver has 1 video device: Capture device for retrieving images.
+
+- ISP4 Image Signal Processing Subdevice Node
+
+---------------------------------------------
+
+The isp4 is represented as a single V4L2 subdev, the sub-device does not
+provide interface to the user space. The sub-device is connected to one video node
+(isp4_capture) with immutable active link. The sub-device represents ISP with
+connected sensor similar to smart cameras (sensors with integrated ISP).
+sub-device has only one link to the video device for capturing the frames.
+The sub-device communicates with CCPU FW for streaming configuration and
+buffer management.
+
+
+- isp4_capture - Frames Capture Video Node
+
+------------------------------------------
+
+Isp4_capture is a capture device to capture frames to memory.
+The entity is connected to isp4 sub-device. The video device
+provides web camera like interface to userspace. It supports
+mmap and dma buf types of memory.
+
+Capturing Video Frames Example
+==============================
+
+.. code-block:: bash
+
+         v4l2-ctl "-d" "/dev/video0" "--set-fmt-video=width=1920,height=1080,pixelformat=NV12" "--stream-mmap" "--stream-count=10"

Documentation/admin-guide/media/amdisp4.dot

@@ -0,0 +1,6 @@
+digraph board {
+	rankdir=TB
+	n00000001 [label="{{} | amd isp4\n | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
+	n00000001:port0 -> n00000003 [style=bold]
+	n00000003 [label="Preview\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
+}

Documentation/admin-guide/media/v4l-drivers.rst

@@ -9,6 +9,7 @@ Video4Linux (V4L) driver-specific documentation
 .. toctree::
 	:maxdepth: 2
 
+	amdisp4-1
 	bttv
 	c3-isp
 	cafe_ccic

MAINTAINERS

@@ -1168,6 +1168,8 @@ M:	Nirujogi Pratap <pratap.nirujogi@amd.com>
 L:	linux-media@vger.kernel.org
 S:	Maintained
 T:	git git://linuxtv.org/media.git
+F:	Documentation/admin-guide/media/amdisp4-1.rst
+F:	Documentation/admin-guide/media/amdisp4.dot
 F:	drivers/media/platform/amd/Kconfig
 F:	drivers/media/platform/amd/Makefile
 F:	drivers/media/platform/amd/isp4/Kconfig