RE: [PATCH v2 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI CSI-2 Rx Subsystem

From: Vishal Sagar
Date: Thu Jan 31 2019 - 03:07:22 EST

Hi Rob,

Thanks for reviewing.

> -----Original Message-----
> From: Rob Herring [mailto:robh@xxxxxxxxxx]
> Sent: Thursday, January 31, 2019 1:11 AM
> To: Vishal Sagar <vishal.sagar@xxxxxxxxxx>
> Cc: Hyun Kwon <hyunk@xxxxxxxxxx>; laurent.pinchart@xxxxxxxxxxxxxxxx;
> mchehab@xxxxxxxxxx; mark.rutland@xxxxxxx; Michal Simek
> <michals@xxxxxxxxxx>; linux-media@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; sakari.ailus@xxxxxxxxxxxxxxx;
> hans.verkuil@xxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Dinesh Kumar <dineshk@xxxxxxxxxx>; Sandip Kothari
> <sandipk@xxxxxxxxxx>
> Subject: Re: [PATCH v2 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI
> CSI-2 Rx Subsystem
>
> EXTERNAL EMAIL
>
> On Fri, Jan 25, 2019 at 11:22:56PM +0530, Vishal Sagar wrote:
> > Add bindings documentation for Xilinx MIPI CSI-2 Rx Subsystem.
> >
> > The Xilinx MIPI CSI-2 Rx Subsystem consists of a CSI-2 Rx controller, a
> > DPHY in Rx mode, an optional I2C controller and a Video Format Bridge.
> >
> > Signed-off-by: Vishal Sagar <vishal.sagar@xxxxxxxxxx>
> > ---
> > v2
> > - 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
> >
> > .../bindings/media/xilinx/xlnx,csi2rxss.txt | 105
> +++++++++++++++++++++
> > 1 file changed, 105 insertions(+)
> > create mode 100644
> Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> >
> > diff --git a/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> > new file mode 100644
> > index 0000000..98781cf
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> > @@ -0,0 +1,105 @@
> > +Xilinx MIPI CSI2 Receiver Subsystem Device Tree Bindings
> > +--------------------------------------------------------
> > +
> > +The Xilinx MIPI CSI2 Receiver Subsystem is used to capture MIPI CSI2 traffic
> > +from compliant camera sensors and send the output as AXI4 Stream video
> data
> > +for image processing.
> > +
> > +The subsystem consists of a MIPI DPHY in slave mode which captures the
> > +data packets. This is passed along the MIPI CSI2 Rx IP which extracts the
> > +packet data. The Video Format Bridge (VFB) converts this data to AXI4
> Stream
> > +video data.
> > +
> > +For more details, please refer to PG232 Xilinx MIPI CSI-2 Receiver Subsystem.
> > +
> > +Required properties:
> > +--------------------
> > +- compatible: Must contain "xlnx,mipi-csi2-rx-subsystem-4.0".
> > +- reg: Physical base address and length of the registers set for the device.
> > +- interrupt-parent: specifies the phandle to the parent interrupt controller
>
> Don't document this. It is implied.

Ok. I will remove this in next revision.

>
> > +- interrupts: Property with a value describing the interrupt number.
> > +- clocks: List of phandles to AXI Lite, Video and 200 MHz DPHY clocks.
> > +- clock-names: Must contain "lite_aclk", "video_aclk" and "dphy_clk_200M"
> in
> > + the same order as clocks listed in clocks property.
> > +- xlnx,csi-pxl-format: This denotes the CSI Data type selected in hw design.
> > + Packets other than this data type (except for RAW8 and User defined data
> > + types) will be filtered out. Possible values are as below -
> > + 0x1E - YUV4228B
> > + 0x1F - YUV42210B
> > + 0x20 - RGB444
> > + 0x21 - RGB555
> > + 0x22 - RGB565
> > + 0x23 - RGB666
> > + 0x24 - RGB888
> > + 0x28 - RAW6
> > + 0x29 - RAW7
> > + 0x2A - RAW8
> > + 0x2B - RAW10
> > + 0x2C - RAW12
> > + 0x2D - RAW14
> > + 0x2E - RAW16
> > + 0x2F - RAW20
> > +- xlnx,vfb: This is present when Video Format Bridge is enabled.
>
> boolean?
>

Yes this is a Boolean.

> > +
> > +Optional properties:
> > +--------------------
> > +- xlnx,en-csi-v2-0: Present if CSI v2 is enabled in IP configuration.
> > +- xlnx,en-vcx: When present, there are maximum 16 virtual channels, else
> > + only 4. This is present only if xlnx,en-csi-v2-0 is present.
> > +- xlnx,en-active-lanes: Enable Active lanes configuration in Protocol
> > + Configuration Register.
> > +- xlnx,cfa-pattern: This goes in the sink port to indicate bayer pattern.
> > + Valid values are "bggr", "rggb", "gbrg" and "grbg".
>
> This should go in the endpoint with the other properties. I'd also move
> it down below 'Ports' to be clear it goes in a different node.
>

Agree. I will do this in next revision.

> > +
> > +Ports
> > +-----
> > +The device node shall contain two 'port' child nodes as defined in
> > +Documentation/devicetree/bindings/media/video-interfaces.txt.
> > +
> > +The port@0 is sink port and shall connect to CSI2 source like camera.
> > +It must have the data-lanes property. It may have the xlnx,cfa-pattern
> > +property to indicate bayer pattern of source.
> > +
> > +The port@1 is source port could be connected to any video processing IP
> > +which can work with AXI4 Stream data.
> > +
> > +Both ports must have remote-endpoints.
>
> No need to state that. That's implicit for the graph to work...

Ok

Regards
Vishal Sagar

> > +
> > +Example:
> > +
> > + csiss_1: csiss@a0020000 {
> > + compatible = "xlnx,mipi-csi2-rx-subsystem-4.0";
> > + reg = <0x0 0xa0020000 0x0 0x10000>;
> > + interrupt-parent = <&gic>;
> > + interrupts = <0 95 4>;
> > + xlnx,csi-pxl-format = <0x2a>;
> > + xlnx,vfb;
> > + xlnx,en-active-lanes;
> > + xlnx,en-csi-v2-0;
> > + xlnx,en-vcx;
> > + clock-names = "lite_aclk", "dphy_clk_200M", "video_aclk";
> > + clocks = <&misc_clk_0>, <&misc_clk_1>, <&misc_clk_2>;
> > +
> > + ports {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + port@0 {
> > + /* Sink port */
> > + reg = <0>;
> > + xlnx,cfa-pattern = "bggr"
> > + csiss_in: endpoint {
> > + data-lanes = <1 2 3 4>;
> > + /* MIPI CSI2 Camera handle */
> > + remote-endpoint = <&camera_out>;
> > + };
> > + };
> > + port@1 {
> > + /* Source port */
> > + reg = <1>;
> > + csiss_out: endpoint {
> > + remote-endpoint = <&vproc_in>;
> > + };
> > + };
> > + };
> > + };
> > --
> > 2.7.4
> >