RE: [PATCH v8 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI CSI-2 Rx Subsystem

[Vishal Sagar]

Hi Sakari,

Thanks for reviewing this.

> -----Original Message-----
> From: linux-media-owner@xxxxxxxxxxxxxxx [mailto:linux-media-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Sakari Ailus
> Sent: Tuesday, June 04, 2019 8:56 PM
> To: Vishal Sagar <vishal.sagar@xxxxxxxxxx>
> Cc: Hyun Kwon <hyunk@xxxxxxxxxx>; laurent.pinchart@xxxxxxxxxxxxxxxx;
> mchehab@xxxxxxxxxx; robh+dt@xxxxxxxxxx; mark.rutland@xxxxxxx; Michal
> Simek <michals@xxxxxxxxxx>; linux-media@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; hans.verkuil@xxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Dinesh Kumar
> <dineshk@xxxxxxxxxx>; Sandip Kothari <sandipk@xxxxxxxxxx>; Luca Ceresoli
> <luca@xxxxxxxxxxxxxxxx>; Jacopo Mondi <jacopo@xxxxxxxxxx>
> Subject: Re: [PATCH v8 1/2] media: dt-bindings: media: xilinx: Add Xilinx MIPI
> CSI-2 Rx Subsystem
> 
> Hi Vishal,
> 
> Thanks for the update. A few small issues below...
> 
> On Mon, Jun 03, 2019 at 03:29:30PM +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>
> > Reviewed-by: Hyun Kwon <hyun.kwon@xxxxxxxxxx>
> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> > Reviewed-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>
> > ---
> > v8
> > - Added reset-gpios optional property to assert video_aresetn
> >
> > v7
> > - Removed the control name from dt bindings
> > - Updated the example dt node name to csi2rx
> >
> > v6
> > - Added "control" after V4L2_CID_XILINX_MIPICSISS_ACT_LANES as suggested
> by Luca
> > - Added reviewed by Rob Herring
> >
> > v5
> > - Incorporated comments by Luca Cersoli
> > - Removed DPHY clock from description and example
> > - Removed bayer pattern from device tree MIPI CSI IP
> >   doesn't deal with bayer pattern.
> >
> > v4
> > - Added reviewed by Hyun Kwon
> >
> > v3
> > - 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
> >
> > 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        | 119
> +++++++++++++++++++++
> >  1 file changed, 119 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..fef8179
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/xilinx/xlnx,csi2rxss.txt
> > @@ -0,0 +1,119 @@
> > +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 optional 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.
> > +- interrupts: Property with a value describing the interrupt number.
> > +- clocks: List of phandles to AXI Lite and Video clocks.
> > +- clock-names: Must contain "lite_aclk" and "video_aclk" 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
> > +
> > +
> > +Optional properties:
> > +--------------------
> > +- xlnx,vfb: This is present when Video Format Bridge is enabled.
> > +  Without this property the driver won't be loaded as IP won't be able to
> generate
> > +  media bus format compliant stream output.
> > +- 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: present if the number of active lanes can be
> > +  re-configured at runtime in the Protocol Configuration Register.
> > +  Otherwise all lanes, as set in IP configuration, are always active.
> > +- reset-gpios: Optional specifier for a GPIO that asserts video_aresetn.
> > +
> > +Ports
> > +-----
> > +The device node shall contain two 'port' child nodes as defined in
> > +Documentation/devicetree/bindings/media/video-interfaces.txt.
> > +
> > +The port@0 is a sink port and shall connect to CSI2 source like camera.
> > +It must have the data-lanes property.
> 
> Technically this is wrong as data-lanes is an endpoint property. I'd just
> leave it out here.
> 

Ok I will remove it from here.

> > +
> > +The port@1 is a source port and can be connected to any video processing IP
> > +which can work with AXI4 Stream data.
> > +
> > +Required port properties:
> > +--------------------
> > +- reg: 0 - for sink port.
> > +       1 - for source port.
> > +
> > +Optional endpoint property:
> 
> s/Optional/Required/
> 
Noted. I will change it to required.

> > +---------------------------
> > +- data-lanes: specifies MIPI CSI-2 data lanes as covered in video-
> interfaces.txt.
> > +  This should be in the sink port endpoint which connects to MIPI CSI2 source
> > +  like sensor. The possible values are:
> 
> And add here that it's only needed for port 0. Or put it to the heading.

Ok.

> 
> I think this is good with these changes.
> 
> > +  1       - For 1 lane enabled in IP.
> > +  1 2     - For 2 lanes enabled in IP.
> > +  1 2 3   - For 3 lanes enabled in IP.
> > +  1 2 3 4 - For 4 lanes enabled in IP.
> > +
> > +Example:
> > +
> > +	xcsi2rxss_1: csi2rx@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", "video_aclk";
> > +		clocks = <&misc_clk_0>, <&misc_clk_1>;
> > +		reset-gpios = <&gpio 86 GPIO_ACTIVE_LOW>;
> > +
> > +		ports {
> > +			#address-cells = <1>;
> > +			#size-cells = <0>;
> > +
> > +			port@0 {
> > +				/* Sink port */
> > +				reg = <0>;
> > +				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>;
> > +				};
> > +			};
> > +		};
> > +	};
> > --
> > 1.8.3.1
> 
> How old is that? :-)
> 

Found out that version is nearly 6 years old.  :-)
I will update git.

> --
> Kind regards,
> 
> Sakari Ailus
> sakari.ailus@xxxxxxxxxxxxxxx

Regards
Vishal Sagar