Date:   Wed, 1 Sep 2021 16:14:30 +0800
From:   moudy ho <moudy.ho@...iatek.com>
To:     Rob Herring <robh@...nel.org>
CC:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        "Jernej Skrabec" <jernej.skrabec@...l.net>,
        Maoguang Meng <maoguang.meng@...iatek.com>,
        daoyuan huang <daoyuan.huang@...iatek.com>,
        Ping-Hsun Wu <ping-hsun.wu@...iatek.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Rob Landley <rob@...dley.net>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Tomasz Figa <tfiga@...omium.org>,
        Nicolas Boichat <drinkcat@...omium.org>,
        "Alexandre Courbot" <acourbot@...omium.org>,
        Pi-Hsun Shih <pihsun@...omium.org>, <menghui.lin@...iatek.com>,
        Sj Huang <sj.huang@...iatek.com>, <ben.lok@...iatek.com>,
        <randy.wu@...iatek.com>,
        srv_heupstream <srv_heupstream@...iatek.com>,
        Hsin-Yi Wang <hsinyi@...gle.com>
Subject: Re: [PATCH v7 3/5] dt-binding: mt8183: Add Mediatek MDP3 dt-bindings

On Mon, 2021-08-30 at 10:05 -0500, Rob Herring wrote:
> On Mon, Aug 30, 2021 at 2:58 AM moudy ho <moudy.ho@...iatek.com>
> wrote:
> > 
> > On Tue, 2021-08-24 at 13:02 -0500, Rob Herring wrote:
> > > On Tue, Aug 24, 2021 at 06:00:25PM +0800, Moudy Ho wrote:
> > > > This patch adds DT binding document for Media Data Path 3
> > > > (MDP3)
> > > > a unit in multimedia system used for scaling and color format
> > > > convert.
> > > > 
> > > > Signed-off-by: Moudy Ho <moudy.ho@...iatek.com>
> > > > ---
> > > >  .../bindings/media/mediatek,mdp3-ccorr.yaml   |  57 +++++
> > > >  .../bindings/media/mediatek,mdp3-rdma.yaml    | 207
> > > > ++++++++++++++++++
> > > >  .../bindings/media/mediatek,mdp3-rsz.yaml     |  65 ++++++
> > > >  .../bindings/media/mediatek,mdp3-wdma.yaml    |  71 ++++++
> > > >  .../bindings/media/mediatek,mdp3-wrot.yaml    |  71 ++++++
> > > >  5 files changed, 471 insertions(+)
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/media/mediatek,mdp3-
> > > > ccorr.yaml
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/media/mediatek,mdp3-rdma.yaml
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/media/mediatek,mdp3-rsz.yaml
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/media/mediatek,mdp3-wdma.yaml
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/media/mediatek,mdp3-wrot.yaml
> > > > 
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/media/mediatek,mdp3-
> > > > ccorr.yaml
> > > > b/Documentation/devicetree/bindings/media/mediatek,mdp3-
> > > > ccorr.yaml
> > > > new file mode 100644
> > > > index 000000000000..59fd68b46022
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/media/mediatek,mdp3-
> > > > ccorr.yaml
> > > > @@ -0,0 +1,57 @@
> > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > > +%YAML 1.2
> > > > +---
> > > > +$id:
> > > > 
https://urldefense.com/v3/__http://devicetree.org/schemas/media/mediatek,mdp3-ccorr.yaml*__;Iw!!CTRNKA9wMg0ARbw!1C0ChLqzi7Zq8D2d4_S4IqCEei4GXdgy3_VCQg8MdsJP7n8TlxbGyajipusfH8hi$
> > > > 
> > > > +$schema:
> > > > 
https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!1C0ChLqzi7Zq8D2d4_S4IqCEei4GXdgy3_VCQg8MdsJP7n8TlxbGyajipi-OInix$
> > > > 
> > > > +
> > > > +title: Mediatek Media Data Path 3 CCORR Device Tree Bindings
> > > > +
> > > > +maintainers:
> > > > +  - Daoyuan Huang <daoyuan.huang@...iatek.com>
> > > > +  - Moudy Ho <moudy.ho@...iatek.com>
> > > > +
> > > > +description: |
> > > > +  One of Media Data Path 3 (MDP3) components used to do color
> > > > correction with 3X3 matrix.
> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    items:
> > > > +      - enum:
> > > > +        - mediatek,mt8183-mdp3-ccorr
> > > > +
> > > > +  mediatek,mdp3-id:
> > > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > > +    maxItems: 1
> > > > +    description: |
> > > > +      HW index to distinguish same functionality modules.
> > > 
> > > If we wanted h/w indexes in DT, we'd have a standard property.
> > > Why
> > > do
> > > you need this?
> > > 
> > 
> > I'm sorry not quite sure what HW indexes means (something like
> > aliases?)
> 
> It means whatever you said in your description.
> 
> And no, I'm not suggesting you use aliases.

Sorry for the inaccuracy described here, the comment i mentioned before
should be "standard property" instead of "HW index".

> > It was originally used to mark multiple identical modules in the
> > MDP
> > data path algorithm, so that appropriate paths can be dynamically
> > dispatched.
> 
> If they are identical, then why do you need to distinguish them in
> DT?
> If there's some difference you need to know about such as connections
> to other blocks, then describe that. Another common example is
> needing
> to know what bits/registers to access in a syscon phandle. For that,
> make the register offset or bits be args to the phandle property.  
>  
> Rob

Integrating the previous discussion, maybe I can revise the description
to the following:
    description: |
      There may be multiple blocks with the same function but different
      addresses in MDP3. In order to distinguish the connection with
      other blocks, a unique ID is needed to dynamically use one or
      more identical blocks to implement multiple pipelines.

Moudy

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