linux-kernel - Re: [PATCH v4 2/5] dt-bindings: media: add mediatek ISP3.0 camsv

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Message-ID: <2792ce50-c95c-41b8-b564-7d1f98361e78@linaro.org>
Date: Fri, 12 Jan 2024 08:49:27 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Julien Stephan <jstephan@...libre.com>,
 Phi-bang Nguyen <pnguyen@...libre.com>, Andy Hsieh
 <andy.hsieh@...iatek.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Conor Dooley <conor+dt@...nel.org>, devicetree@...r.kernel.org,
 Florian Sylvestre <fsylvestre@...libre.com>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-mediatek@...ts.infradead.org, linux-media@...r.kernel.org,
 Louis Kuo <louis.kuo@...iatek.com>, Matthias Brugger
 <matthias.bgg@...il.com>, Mauro Carvalho Chehab <mchehab@...nel.org>,
 Paul Elder <paul.elder@...asonboard.com>, Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH v4 2/5] dt-bindings: media: add mediatek ISP3.0 camsv

On 12/01/2024 08:41, Laurent Pinchart wrote:
> On Fri, Jan 12, 2024 at 08:34:45AM +0100, Krzysztof Kozlowski wrote:
>> On 10/01/2024 15:14, Julien Stephan wrote:
>>> From: Phi-bang Nguyen <pnguyen@...libre.com>
>>>
>>> This adds the bindings, for the ISP3.0 camsv module embedded in
>>> some Mediatek SoC, such as the mt8365
>>>
>>> Signed-off-by: Phi-bang Nguyen <pnguyen@...libre.com>
>>> Signed-off-by: Julien Stephan <jstephan@...libre.com>
>>> Link: https://lore.kernel.org/r/20230807094940.329165-4-jstephan@baylibre.com
>>> ---
>>>  .../bindings/media/mediatek,mt8365-camsv.yaml | 109 ++++++++++++++++++
>>>  MAINTAINERS                                   |   1 +
>>>  2 files changed, 110 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/media/mediatek,mt8365-camsv.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/media/mediatek,mt8365-camsv.yaml b/Documentation/devicetree/bindings/media/mediatek,mt8365-camsv.yaml
>>> new file mode 100644
>>> index 000000000000..097b1ab6bc72
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/media/mediatek,mt8365-camsv.yaml
>>> @@ -0,0 +1,109 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +# Copyright (c) 2023 MediaTek, BayLibre
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/media/mediatek,mt8365-camsv.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek CAMSV 3.0
>>> +
>>> +maintainers:
>>> +  - Laurent Pinchart <laurent.pinchart@...asonboard.com>
>>> +  - Julien Stephan <jstephan@...libre.com>
>>> +  - Andy Hsieh <andy.hsieh@...iatek.com>
>>> +
>>> +description:
>>> +  The CAMSV is a set of DMA engines connected to the SENINF CSI-2
>>> +  receivers. The number of CAMSVs depend on the SoC model.
>>
>> DMA should not go to media, but to dma
> 
> They're not generic DMA engines. The CAMSV is a video capture device
> that includes a DMA engine, much like pretty much all the other video
> capture devices.

OK, some more explanation would be useful in description.

> 
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: mediatek,mt8365-camsv
>>> +
>>> +  reg:
>>> +    items:
>>> +      - description: camsv base
>>> +      - description: img0 base
>>> +      - description: tg base
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +  power-domains:
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    items:
>>> +      - description: cam clock
>>> +      - description: camtg clock
>>> +      - description: camsv clock
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: cam
>>> +      - const: camtg
>>> +      - const: camsv
>>> +
>>> +  iommus:
>>> +    maxItems: 1
>>> +
>>> +  ports:
>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>> +
>>> +    properties:
>>> +      port@0:
>>> +        $ref: /schemas/graph.yaml#/properties/port
>>> +        description: connection point for camsv0
>>
>> This explains me nothing. What type of connection point? How does it fit
>> the pipeline going to the display?
> 
> The description seems wrong, it should state
> 
>         description: Connection to the SENINF output
> 
> or something similar.

I am still not sure whether DMA engine should be connected via graphs.

Best regards,
Krzysztof