Date:   Tue, 12 Mar 2019 11:00:15 +0000
From:   <Eugen.Hristev@...rochip.com>
To:     <vishal.sagar@...inx.com>, <hyunk@...inx.com>,
        <laurent.pinchart@...asonboard.com>, <mchehab@...nel.org>,
        <robh+dt@...nel.org>, <mark.rutland@....com>, <michals@...inx.com>,
        <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <sakari.ailus@...ux.intel.com>, <hans.verkuil@...co.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <dineshk@...inx.com>,
        <sandipk@...inx.com>
Subject: Re: [PATCH v6 0/2] Add support for Xilinx CSI2 Receiver Subsystem



On 12.03.2019 06:35, Vishal Sagar wrote:
> Xilinx MIPI CSI-2 Receiver Subsystem
> ------------------------------------
> 
> The Xilinx MIPI CSI-2 Receiver Subsystem Soft IP consists of a DPHY which
> gets the data, an optional I2C, a CSI-2 Receiver which parses the data and
> converts it into AXIS data.
> This stream output maybe connected to a Xilinx Video Format Bridge.
> The maximum number of lanes supported is fixed in the design.
> The number of active lanes can be programmed.
> For e.g. the design may set maximum lanes as 4 but if the camera sensor has
> only 1 lane then the active lanes shall be set as 1.
> 
> The pixel format set in design acts as a filter allowing only the selected
> data type or RAW8 data packets. The D-PHY register access can be gated in
> the design. The base address of the DPHY depends on whether the internal
> Xilinx I2C controller is enabled or not in design.

Hi Vishal,

Do you also include a driver for the DPHY ? Namely I am interested in 
something which can comply to the PHY subsystem specifications, so it 
can be referenced by possibly other nodes ?

Something like this:

xilinx_dphy: dphy@...00 {
                         compatible = "xlnx,dphy"; 

                         #phy-cells = <0>; 

                         reg = <0x40000 0x100>; 

                 };

 From my understanding your RX system can be referenced as a whole, 
without being able to have the PHY as separate node, and creating 
references maybe like :

phys = <&xilinx_dphy>;


Thanks,

Eugen



> 
> The device driver registers the MIPI CSI2 Rx Subsystem as a V4L2 sub device
> having 2 pads. The sink pad is connected to the MIPI camera sensor and
> output pad is connected to the video node.
> Refer to xlnx,csi2rxss.txt for device tree node details.
> 
> This driver helps configure the number of active lanes to be set, setting
> and handling interrupts and IP core enable. It logs the number of events
> occurring according to their type between streaming ON and OFF.
> It generates a v4l2 event for each short packet data received.
> The application can then dequeue this event and get the requisite data
> from the event structure.
> 
> It adds new V4L2 controls which are used to get the event counter values
> and reset the subsystem.
> 
> The Xilinx CSI-2 Rx Subsystem outputs an AXI4 Stream data which can be
> used for image processing. This data follows the video formats mentioned
> in Xilinx UG934 when the Video Format Bridge is enabled.
> 
> v6
> - 1/2
>    - Added minor comment by Luca
>    - Added Reviewed by Rob Herring
> - 2/2
>    - No change
> 
> v5
> - 1/2
>    - Removed the DPHY clock description and dt node.
>    - removed bayer pattern as CSI doesn't deal with it.
> - 2/2
>    - removed bayer pattern as CSI doesn't deal with it.
>    - add YUV422 10bpc media bus format.
> 
> v4
> - 1/2
>    - Added reviewed by Hyun Kwon
> - 2/2
>    - Removed irq member from core structure
>    - Consolidated IP config prints in xcsi2rxss_log_ipconfig()
>    - Return -EINVAL in case of invalid ioctl
>    - Code formatting
>    - Added reviewed by Hyun Kwon
> 
> v3
> - 1/2
>    - removed interrupt parent as suggested by Rob
>    - removed dphy clock
>    - moved vfb to optional properties
>    - Added required and optional port properties section
>    - Added endpoint property section
> - 2/2
>   - Fixed comments given by Hyun.
>   - Removed DPHY 200 MHz clock. This will be controlled by DPHY driver
>   - Minor code formatting
>   - en_csi_v20 and vfb members removed from struct and made local to dt parsing
>   - lock description updated
>   - changed to ratelimited type for all dev prints in irq handler
>   - Removed YUV 422 10bpc media format
> 
> v2
> - 1/2
>    - updated the compatible string to latest version supported
>    - removed DPHY related parameters
>    - added CSI v2.0 related property (including VCX for supporting upto 16
>      virtual channels).
>    - modified csi-pxl-format from string to unsigned int type where the value
>      is as per the CSI specification
>    - Defined port 0 and port 1 as sink and source ports.
>    - Removed max-lanes property as suggested by Rob and Sakari
> 
> - 2/2
>    - Fixed comments given by Hyun and Sakari.
>    - Made all bitmask using BIT() and GENMASK()
>    - Removed unused definitions
>    - Removed DPHY access. This will be done by separate DPHY PHY driver.
>    - Added support for CSI v2.0 for YUV 422 10bpc, RAW16, RAW20 and extra
>      virtual channels
>    - Fixed the ports as sink and source
>    - Now use the v4l2fwnode API to get number of data-lanes
>    - Added clock framework support
>    - Removed the close() function
>    - updated the set format function
>    - Support only VFB enabled config
> 
> Vishal Sagar (2):
>    media: dt-bindings: media: xilinx: Add Xilinx MIPI CSI-2 Rx Subsystem
>    media: v4l: xilinx: Add Xilinx MIPI CSI-2 Rx Subsystem driver
> 
>   .../bindings/media/xilinx/xlnx,csi2rxss.txt        |  118 ++
>   drivers/media/platform/xilinx/Kconfig              |   10 +
>   drivers/media/platform/xilinx/Makefile             |    1 +
>   drivers/media/platform/xilinx/xilinx-csi2rxss.c    | 1465 ++++++++++++++++++++
>   include/uapi/linux/xilinx-v4l2-controls.h          |   14 +
>   include/uapi/linux/xilinx-v4l2-events.h            |   25 +
>   6 files changed, 1633 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
>   create mode 100644 drivers/media/platform/xilinx/xilinx-csi2rxss.c
>   create mode 100644 include/uapi/linux/xilinx-v4l2-events.h
> 

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