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Message-ID: <CAGXv+5GovP7NuG042AwfmtC-sPJMGuFAm6iZ0iqNZgU0VE+qmQ@mail.gmail.com>
Date: Fri, 12 Sep 2025 16:27:45 +0800
From: Chen-Yu Tsai <wenst@...omium.org>
To: Krzysztof Kozlowski <krzk@...nel.org>
Cc: "Ariel D'Alessandro" <ariel.dalessandro@...labora.com>, airlied@...il.com,
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Subject: Re: [PATCH v2 01/12] dt-bindings: media: Convert MediaTek mt8173-mdp
bindings to DT schema
On Fri, Sep 12, 2025 at 2:06 PM Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> On Thu, Sep 11, 2025 at 12:09:50PM -0300, Ariel D'Alessandro wrote:
> > Convert the existing text-based DT bindings for MediaTek MT8173 Media Data
> > Path to a DT schema.
> >
> > Signed-off-by: Ariel D'Alessandro <ariel.dalessandro@...labora.com>
> > ---
> > .../bindings/media/mediatek,mt8173-mdp.yaml | 169 ++++++++++++++++++
> > .../bindings/media/mediatek-mdp.txt | 95 ----------
> > 2 files changed, 169 insertions(+), 95 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/media/mediatek,mt8173-mdp.yaml
> > delete mode 100644 Documentation/devicetree/bindings/media/mediatek-mdp.txt
> >
> > diff --git a/Documentation/devicetree/bindings/media/mediatek,mt8173-mdp.yaml b/Documentation/devicetree/bindings/media/mediatek,mt8173-mdp.yaml
> > new file mode 100644
> > index 0000000000000..8ca33a733c478
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/mediatek,mt8173-mdp.yaml
> > @@ -0,0 +1,169 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/mediatek,mt8173-mdp.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek MT8173 Media Data Path
> > +
> > +maintainers:
> > + - Ariel D'Alessandro <ariel.dalessandro@...labora.com>
> > +
> > +description:
> > + Media Data Path is used for scaling and color space conversion.
> > +
> > +properties:
> > + compatible:
> > + oneOf:
> > + - enum:
> > + - mediatek,mt8173-mdp-rdma
> > + - mediatek,mt8173-mdp-rsz
> > + - mediatek,mt8173-mdp-wdma
> > + - mediatek,mt8173-mdp-wrot
>
> Why there is no mediatek,mt8173-mdp here? What does this compatible
> represent?
>
> > + - items:
> > + - const: mediatek,mt8173-mdp-rdma
>
> Still suspicious. Device cannot be simulatanously: compatible and not
> compatible. This is not a well known cat that has superposition of two
> states, whenenver you look the other way.
>
> Maybe the old binding was incorrect, maybe the in-tree DTS is incorrect.
> Whichever the reason, this must be investigated and documented, because
> by standard rules this is wrong. Each wrong code needs very clear
> explanations (and "someone did it" is not a good enough explanation).
My guess is that "mediatek,mt8173-mdp" is meant to serve as a single
entry point for the implementation to bind the driver to. The MDP is
a Data Pipeline and there could be multiple instances of the same
IP block, as seen in the original example.
The datasheet I have doesn't cover the "RDMA" block specifically, so
I can't say whether there is an actual difference between the two RDMA
blocks.
ChenYu
> > + - const: mediatek,mt8173-mdp
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + clocks:
> > + minItems: 1
> > + maxItems: 2
> > +
> > + power-domains:
> > + maxItems: 1
> > +
> > + iommus:
> > + maxItems: 1
> > +
> > + mediatek,vpu:
> > + $ref: /schemas/types.yaml#/definitions/phandle
> > + description:
> > + phandle to Mediatek Video Processor Unit for HW Codec encode/decode and
> > + image processing.
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - clocks
> > + - power-domains
> > +
> > +allOf:
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: mediatek,mt8173-mdp-rdma
> > + then:
> > + properties:
> > + clocks:
> > + items:
> > + - description: Main clock
> > + - description: Mutex clock
> > + else:
> > + properties:
> > + clocks:
> > + items:
> > + - description: Main clock
> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - mediatek,mt8173-mdp-rdma
> > + - mediatek,mt8173-mdp-wdma
> > + - mediatek,mt8173-mdp-wrot
> > + then:
> > + required:
> > + - iommus
> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + const: mediatek,mt8173-mdp
> > + then:
> > + required:
> > + - mediatek,vpu
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/clock/mt8173-clk.h>
> > + #include <dt-bindings/memory/mt8173-larb-port.h>
> > + #include <dt-bindings/power/mt8173-power.h>
> > +
> > + soc {
> > + #address-cells = <2>;
> > + #size-cells = <2>;
> > +
> > + mdp_rdma0: rdma@...01000 {
> > + compatible = "mediatek,mt8173-mdp-rdma",
> > + "mediatek,mt8173-mdp";
> > + reg = <0 0x14001000 0 0x1000>;
> > + clocks = <&mmsys CLK_MM_MDP_RDMA0>,
> > + <&mmsys CLK_MM_MUTEX_32K>;
> > + power-domains = <&spm MT8173_POWER_DOMAIN_MM>;
> > + iommus = <&iommu M4U_PORT_MDP_RDMA0>;
> > + mediatek,vpu = <&vpu>;
> > + };
> > +
> > + mdp_rdma1: rdma@...02000 {
> > + compatible = "mediatek,mt8173-mdp-rdma";
> > + reg = <0 0x14002000 0 0x1000>;
> > + clocks = <&mmsys CLK_MM_MDP_RDMA1>,
> > + <&mmsys CLK_MM_MUTEX_32K>;
> > + power-domains = <&spm MT8173_POWER_DOMAIN_MM>;
> > + iommus = <&iommu M4U_PORT_MDP_RDMA1>;
> > + };
>
> My previous comment applies.
>
> Keep one or two examples.
>
> Best regards,
> Krzysztof
>
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