Hi Laurent, Thank you for your comments. On 2023/7/27 18:23, Laurent Pinchart wrote: > On Wed, Jul 26, 2023 at 12:26:18PM +0100, Bryan O'Donoghue wrote: >> 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. > > I'd drop the "mipi" and just write "data", not "MIPI data". > Ok, I will modify it. >> > +- MIPI CSIRx Controller: is responsible for handling and decoding CSI2 protocol > > It's "CSI-2", not "CSI2". Ok, I will modify it. > >> > + 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. > > A block diagram could be nice. Let me give it a try, based on my > understanding: > > Starfive Camera Subsystem hardware > ---------------------------------- > > The Starfive Camera Subsystem hardware consists of:: > > +---------------------------------------------+ > | VIN | > +--------+ | +-------+ +-------+ +-----+ | > | Camera |----->| D-PHY |-->| CSI-2 |-+->| DMA | | > | Sensor | | | RX | | RX | | +-----+ | > +--------+ | +-------+ +-------+ | | > | | +-----+ +-----+ | > | \->| ISP |-->| DMA | | > | +-----+ +-----+ | > +---------------------------------------------+ > > - VIN (Video IN): The top-level module, responsible for controlling > power and clocks, and routing data between modules. > > - D-PHY RX: The MIPI D-PHY receiver, receiving data from a MIPI CSI-2 > camera sensor. > > - CSI-2 RX: The MIPI CSI-2 receiver controller, responsible for decoding > the CSI-2 protocol. > > - ISP: The ISP, processing raw Bayer data from the CSI-2 receiver and > producing YUV frames. > > > I haven't tried compiling this, so please fix formatting if anything is > wrong (and of course feel free to adapt the diagram and text). > Ok, I will add a block diagram. >> > + >> > + >> > +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. > -- Regards, Jack Zhu
