RE: [PATCH v7 1/5] dt-bindings: media: platform: visconti: Add Toshiba Visconti Video Input Interface

[yuji2.ishikawa]

Hello Krzysztof
Thank you for your review comments.

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Sent: Friday, July 14, 2023 4:50 PM
> To: ishikawa yuji(石川 悠司 ○ＲＤＣ□ＡＩＴＣ○ＥＡ開)
> <yuji2.ishikawa@xxxxxxxxxxxxx>; Hans Verkuil <hverkuil@xxxxxxxxx>; Sakari
> Ailus <sakari.ailus@xxxxxx>; Laurent Pinchart
> <laurent.pinchart@xxxxxxxxxxxxxxxx>; Mauro Carvalho Chehab
> <mchehab@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof
> Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; iwamatsu nobuhiro(岩松 信洋 ○ＤＩＴＣ□ＤＩＴ○
> ＯＳＴ) <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>; Mark Brown
> <broonie@xxxxxxxxxx>
> Cc: linux-media@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v7 1/5] dt-bindings: media: platform: visconti: Add Toshiba
> Visconti Video Input Interface
> 
> On 14/07/2023 03:50, 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>
> > ---
> > Changelog v2:
> 
> Thank you for your patch. There is something to discuss/improve.
> 
> > - no change
> >
> > Changelog v3:
> > - no change
> >
> > Changelog v4:
> > - fix style problems at the v3 patch
> > - remove "index" member
> > - update example
> >
> > Changelog v5:
> > - no change
> >
> > Changelog v6:
> > - add register definition of BUS-IF and MPU
> >
> > Changelog v7:
> > - remove trailing "bindings" from commit header message
> > - remove trailing "Device Tree Bindings" from title
> > - fix text wrapping of description
> > - change compatible to visconti5-viif
> 
> Then the filename should be updated to match it:
> toshiba,visconti5-viif.yaml
> 

I'll change the filename to toshiba,visconti5-viif.yaml

> > - explicitly define allowed properties for port::endpoint
> >
> >  .../bindings/media/toshiba,visconti-viif.yaml | 108
> > ++++++++++++++++++
> >  1 file changed, 108 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/media/toshiba,visconti-viif.yaml
> >
> 
> ...
> 
> > +  port:
> > +    $ref: /schemas/graph.yaml#/$defs/port-base
> > +    unevaluatedProperties: false
> > +    description: Input port, single endpoint describing the CSI-2 transmitter.
> > +
> > +    properties:
> > +      endpoint:
> > +        $ref: video-interfaces.yaml#
> > +        additionalProperties: false
> 
> This should be rather:
> unevaluatedProperties: false

In the previous discussion with Laurent, I believe additionalProperties was preferred in terms of handling properties not explicitly mentioned.

https://lore.kernel.org/all/Y82NtJCtr+CZgS9k@xxxxxxxxxxxxxxxxxxxxxxxxxx/

Do you have concern about defaulting properties in video-interface.yaml to forbidden?
If defaulting to optional (like most of other bindings) is better, I'll use unevaluatedProperties.

> > +
> > +        required: ["bus-type", "clock-noncontinuous",
> > + "link-frequencies", "remote-endpoint"]
> 
> That's not the syntax we try to keep in the bindings. See renesas,rzg2l-csi2.yaml.
> 

I'll use a line for every element.

> > +
> > +        properties:
> > +          data-lanes:
> > +            description: VIIF supports 2 or 4 data lanes
> > +            $ref: /schemas/types.yaml#/definitions/uint32-array
> > +            minItems: 1
> > +            maxItems: 4
> > +            items:
> > +              minimum: 1
> > +              maximum: 4
> > +
> > +          clock-lanes:
> > +            description: VIIF supports 1 clock lane
> > +            const: 0
> 
> Are you sure it must be on position 0?
> 

Because a Visconti5 CSI2RX has only clock-lane0,
there's no need to specify clock-lane with device tree.

I'll drop "clock-lanes".

> > +
> > +          bus-type: true
> > +          clock-noncontinuous: true
> > +          link-frequencies: true
> > +          remote-endpoint: true
> 
> Drop all of these "xxx: true", should not be needed after converting to
> unevaluatedProperties: false
> 

I'll drop "xxx: true" if unevaluatedProperties is chosen instead of additionalProperties.

> > +
> > +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>;
> > +
> > +        viif@1c000000 {
> 
> isp@
> (or video or something else matching this type of the device, but this should be a
> generic name)
> 

I'll use video@1c000000.

> > +            compatible = "toshiba,visconti5-viif";
> > +            reg = <0 0x1c000000 0 0x6000>,
> > +                  <0 0x1c008000 0 0x400>,
> > +                  <0 0x1c00E000 0 0x1000>,
> > +                  <0 0x2417A000 0 0x1000>;
> 
> Lowercase hex, please.
> 

I'll fix them.

> Best regards,
> Krzysztof

Best regards,
Yuji