On 19/06/2023 12:28, Jack Zhu wrote:
Add starfive_camss.rst file that documents the Starfive Camera
Subsystem driver which is used for handing image sensor data.
Signed-off-by: Jack Zhu <jack.zhu@xxxxxxxxxxxxxxxx>
---
.../admin-guide/media/starfive_camss.rst | 57 +++++++++++++++++++
.../media/starfive_camss_graph.dot | 16 ++++++
.../admin-guide/media/v4l-drivers.rst | 1 +
MAINTAINERS | 1 +
4 files changed, 75 insertions(+)
create mode 100644 Documentation/admin-guide/media/starfive_camss.rst
create mode 100644 Documentation/admin-guide/media/starfive_camss_graph.dot
diff --git a/Documentation/admin-guide/media/starfive_camss.rst b/Documentation/admin-guide/media/starfive_camss.rst
new file mode 100644
index 000000000000..a6378849384f
--- /dev/null
+++ b/Documentation/admin-guide/media/starfive_camss.rst
@@ -0,0 +1,57 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+.. include:: <isonum.txt>
+
+================================
+Starfive Camera Subsystem driver
+================================
+
+Introduction
+------------
+
+This file documents the driver for the Starfive Camera Subsystem found on
+Starfive JH7110 SoC. The driver is located under drivers/media/platform/
+starfive.
+
+The driver implements V4L2, Media controller and v4l2_subdev interfaces.
+Camera sensor using V4L2 subdev interface in the kernel is supported.
+
+The driver has been successfully used on the Gstreamer 1.18.5 with
+v4l2src plugin.
+
+
+Starfive Camera Subsystem hardware
+----------------------------------
+
+The Starfive Camera Subsystem hardware consists of:
+
+- MIPI DPHY Receiver: receives mipi data from a MIPI camera sensor.
Feels like a terribe nit-pick but you have "mipi" and "MIPI" here. I'd
be consistent with one - recommend MIPI throughout your documentation.
+- MIPI CSIRx Controller: is responsible for handling and decoding CSI2 protocol
+ based camera sensor data stream.
+- ISP: handles the image data streams from the MIPI CSIRx Controller.
Maybe you've done this elsewhere but, it would be worthwhile describing
what the ISP does. Debayering ? 3As ? Just raw dumps ?
+- VIN(Video In): a top-level module, is responsible for controlling power
+ and clocks to other modules, dumps the input data to memory or transfers the
+ input data to ISP.
+
+
+Topology
+--------
+
+The media controller pipeline graph is as follows:
+
+.. _starfive_camss_graph:
+
+.. kernel-figure:: starfive_camss_graph.dot
+ :alt: starfive_camss_graph.dot
+ :align: center
+
+The driver has 2 video devices:
+
+- stf_vin0_wr_video0: capture device for images directly from the VIN module.
OK so you can get the raw images.
+- stf_vin0_isp0_video1: capture device for images without scaling.
+
+The driver has 3 subdevices:
+
+- stf_isp0: is responsible for all the isp operations.
+- stf_vin0_wr: used to dump RAW images to memory.
+- stf_vin0_isp0: used to capture images for the stf_vin0_isp0_video1 device.
But what is being output here ? RGB, jpeg, YUV ?
It would be worth adding a few bits of text to describe that so you
don't have to dive into code to understand it.
---
bod
