linux-kernel - [PATCH v4 7/7] Documentation: add documentation of AMD isp 4 driver

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Message-ID: <20250911100847.277408-8-Bin.Du@amd.com>
Date: Thu, 11 Sep 2025 18:08:47 +0800
From: Bin Du <Bin.Du@....com>
To: <mchehab@...nel.org>, <hverkuil@...all.nl>,
	<laurent.pinchart+renesas@...asonboard.com>, <bryan.odonoghue@...aro.org>,
	<sakari.ailus@...ux.intel.com>, <prabhakar.mahadev-lad.rj@...renesas.com>,
	<linux-media@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<sultan@...neltoast.com>
CC: <pratap.nirujogi@....com>, <benjamin.chan@....com>, <king.li@....com>,
	<gjorgji.rosikopulos@....com>, <Phil.Jawich@....com>,
	<Dominic.Antony@....com>, <mario.limonciello@....com>,
	<richard.gong@....com>, <anson.tsao@....com>, <bin.du@....com>, Bin Du
	<Bin.Du@....com>, Svetoslav Stoilov <Svetoslav.Stoilov@....com>, "Mario
 Limonciello" <superm1@...nel.org>, Alexey Zagorodnikov <xglooom@...il.com>
Subject: [PATCH v4 7/7] 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@....com>
Signed-off-by: Svetoslav Stoilov <Svetoslav.Stoilov@....com>
Signed-off-by: Bin Du <Bin.Du@....com>
Reviewed-by: Mario Limonciello (AMD) <superm1@...nel.org>
Tested-by: Alexey Zagorodnikov <xglooom@...il.com>
---
 Documentation/admin-guide/media/amdisp4-1.rst | 63 +++++++++++++++++++
 Documentation/admin-guide/media/amdisp4.dot   |  6 ++
 .../admin-guide/media/v4l-drivers.rst         |  1 +
 MAINTAINERS                                   |  2 +
 4 files changed, 72 insertions(+)
 create mode 100644 Documentation/admin-guide/media/amdisp4-1.rst
 create mode 100644 Documentation/admin-guide/media/amdisp4.dot

diff --git a/Documentation/admin-guide/media/amdisp4-1.rst b/Documentation/admin-guide/media/amdisp4-1.rst
new file mode 100644
index 000000000000..878141154f96
--- /dev/null
+++ b/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"
diff --git a/Documentation/admin-guide/media/amdisp4.dot b/Documentation/admin-guide/media/amdisp4.dot
new file mode 100644
index 000000000000..978f30c1a31a
--- /dev/null
+++ b/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]
+}
diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst
index 3bac5165b134..6027416e5373 100644
--- a/Documentation/admin-guide/media/v4l-drivers.rst
+++ b/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
diff --git a/MAINTAINERS b/MAINTAINERS
index 8478789ac265..c34137e27b55 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1139,6 +1139,8 @@ M:	Nirujogi Pratap <pratap.nirujogi@....com>
 L:	linux-media@...r.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
-- 
2.34.1