RE: [PATCH v3 1/4] dt-bindings: media: platform: visconti: Add Toshiba Visconti Video Input Interface bindings

[yuji2.ishikawa]

Hello Rob,

Thank you for your comments and sorry for this too late reply.

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: Thursday, August 11, 2022 12:38 AM
> To: ishikawa yuji(石川 悠司 ○ＲＤＣ□ＡＩＴＣ○ＥＡ開)
> <yuji2.ishikawa@xxxxxxxxxxxxx>
> Cc: Hans Verkuil <hverkuil@xxxxxxxxx>; Laurent Pinchart
> <laurent.pinchart@xxxxxxxxxxxxxxxx>; Mauro Carvalho Chehab
> <mchehab@xxxxxxxxxx>; iwamatsu nobuhiro(岩松 信洋 □ＳＷＣ◯ＡＣＴ)
> <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>; linux-media@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 1/4] dt-bindings: media: platform: visconti: Add Toshiba
> Visconti Video Input Interface bindings
> 
> On Wed, Aug 10, 2022 at 10:28:19PM +0900, Yuji Ishikawa wrote:
> > Adds the Device Tree binding documentation that allows to describe the
> > Video Input Interface found in Toshiba Visconti SoCs.
> >
> > Signed-off-by: Yuji Ishikawa <yuji2.ishikawa@xxxxxxxxxxxxx>
> > Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> > ---
> > Chengelog v2:
> > - no change
> >
> > Changelog v3:
> > - no change
> > ---
> >  .../bindings/media/toshiba,visconti-viif.yaml | 103
> > ++++++++++++++++++
> >  1 file changed, 103 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/media/toshiba,visconti-viif.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/media/toshiba,visconti-viif.yaml
> > b/Documentation/devicetree/bindings/media/toshiba,visconti-viif.yaml
> > new file mode 100644
> > index 000000000..848ea5019
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/toshiba,visconti-viif.ya
> > +++ ml
> > @@ -0,0 +1,103 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/toshiba,visconti-viif.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Toshiba Visconti5 SoC Video Input Interface Device Tree
> > +Bindings
> > +
> > +maintainers:
> > +  - Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> > +
> > +description: |
> 
> Don't need '|' if no formatting.

I'll remove '|'.

> > +  Toshiba Visconti5 SoC Video Input Interface (VIIF) receives MIPI
> > + CSI2 video stream,  processes the stream with embedded image signal
> processor (L1ISP, L2ISP), then stores pictures to main memory.
> 
> Wrap lines at 80 char.

I'll update the description.

> > +
> > +properties:
> > +  compatible:
> > +    const: toshiba,visconti-viif
> > +
> > +  reg:
> > +    items:
> > +      - description: registers for capture control
> > +      - description: registers for CSI2 receiver control
> > +
> > +  interrupts:
> > +    items:
> > +      - description: Sync Interrupt
> > +      - description: Status (Error) Interrupt
> > +      - description: CSI2 Receiver Interrupt
> > +      - description: L1ISP Interrupt
> > +
> > +  index:
> > +    enum: [0, 1]
> 
> No, we don't do indices in DT. Why do you need this?

The property 'index' can have value <0> or <1>. 
A node with 'index=<0>' corresponds to 0'th VIIF HW instance (VIIF0).
Also, there's 1'st VIIF HW instance (VIIF1) with a bit different operation-mode set.

Sorry for asking question for a comment months ago.
Let me clarify:
* The problem is NOT defining style of 'index' with enum
* The problem is NOT that 'index' is reserved keyword
* The problem is having additional sequential ID for a node, 
  while 'reg' (usually, the base address of registers) can identify instance.
  Therefore, 'index' should be removed, 
  and vendor-specific property can be used to declare each feature only on VIIF1.

Is this correct understanding or am I still missing the point?

> > +
> > +  port:
> > +    $ref: /schemas/graph.yaml#/$defs/port-base
> > +    unevaluatedProperties: false
> > +    description: Input port node, single endpoint describing the CSI-2
> transmitter.
> > +
> > +    properties:
> > +      endpoint:
> > +        $ref: video-interfaces.yaml#
> > +        unevaluatedProperties: false
> > +
> > +        properties:
> > +          data-lanes:
> > +            description: VIIF supports 2 or 4 data lines
> > +            items:
> > +              minItems: 1
> > +              maxItems: 4
> > +              items:
> > +                - const: 1
> > +                - const: 2
> > +                - const: 3
> > +                - const: 4
> 
> blank line

I'll fix this

> 
> > +          clock-lanes:
> > +            description: VIIF supports 1 clock line
> > +            const: 0
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - port
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > +    soc {
> > +        #address-cells = <2>;
> > +        #size-cells = <2>;
> > +
> > +        viif0: viif@1c000000 {
> 
> Drop unused labels.

I'll fix this.

> 
> > +            compatible = "toshiba,visconti-viif";
> > +            reg = <0 0x1c000000 0 0x6000>,
> > +                  <0 0x1c008000 0 0x400>;
> > +            interrupts = <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <GIC_SPI 67 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>,
> > +                         <GIC_SPI 76 IRQ_TYPE_LEVEL_HIGH>;
> > +            index = <0>;
> > +            status = "disabled";
> 
> Why is your example disabled? Don't put 'status' in examples.

I'll remove 'status'.

> 
> > +
> > +            port {
> > +                #address-cells = <1>;
> > +                #size-cells = <0>;
> > +
> > +                csi_in0: endpoint {
> > +                    remote-endpoint = <&imx219_out0>;
> > +                    bus-type = <4>;
> > +                    data-lanes = <1 2>;
> > +                    clock-lanes = <0>;
> > +                    clock-noncontinuous;
> > +                    link-frequencies = /bits/ 64 <456000000>;
> > +                };
> > +            };
> > +        };
> > +    };
> > +
> > --
> > 2.17.1
> >
> >
> >

Regards,
Yuji Ishikawa