linux-kernel - Re: [PATCH v2 2/4] dt-bindings: power: mediatek: Add MT8189 power domain definitions

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Message-ID: <746e10a5-02fe-4f0d-ab86-d674a8fedab0@kernel.org>
Date: Sun, 14 Sep 2025 14:05:49 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: "irving.ch.lin" <irving-ch.lin@...iatek.com>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 Ulf Hansson <ulf.hansson@...aro.org>,
 Richard Cochran <richardcochran@...il.com>
Cc: Qiqi Wang <qiqi.wang@...iatek.com>, linux-clk@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org,
 linux-pm@...r.kernel.org, netdev@...r.kernel.org,
 Project_Global_Chrome_Upstream_Group@...iatek.com, sirius.wang@...iatek.com,
 vince-wl.liu@...iatek.com, jh.hsu@...iatek.com
Subject: Re: [PATCH v2 2/4] dt-bindings: power: mediatek: Add MT8189 power
 domain definitions

On 12/09/2025 14:04, irving.ch.lin wrote:
> From: Irving-ch Lin <irving-ch.lin@...iatek.com>
> 
> Add device tree bindings for the power domains of MediaTek MT8189 SoC.
> These definitions will be used to describe the power domain topology in
> device tree sources.
> 
> Signed-off-by: Irving-ch Lin <irving-ch.lin@...iatek.com>
> ---
>  .../mediatek,mt8189-power-controller.yaml     | 88 +++++++++++++++++++
>  .../dt-bindings/power/mediatek,mt8189-power.h | 38 ++++++++
>  2 files changed, 126 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/power/mediatek,mt8189-power-controller.yaml
>  create mode 100644 include/dt-bindings/power/mediatek,mt8189-power.h
> 
> diff --git a/Documentation/devicetree/bindings/power/mediatek,mt8189-power-controller.yaml b/Documentation/devicetree/bindings/power/mediatek,mt8189-power-controller.yaml
> new file mode 100644
> index 000000000000..71156f7edafe
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/mediatek,mt8189-power-controller.yaml
> @@ -0,0 +1,88 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/mediatek,mt8189-power-controller.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: MediaTek Power Domains Controller for MT8189
> +
> +maintainers:
> +  - Qiqi Wang <qiqi.wang@...iatek.com>
> +
> +description: |
> +  MediaTek processors include support for multiple power domains which can be
> +  powered up/down by software based on different application scenes to save power.
> +
> +  IP cores belonging to a power domain should contain a 'power-domains'
> +  property that is a phandle for SCPSYS node representing the domain.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - mediatek,mt8189-scpsys
> +
> +  reg:
> +    maxItems: 1
> +
> +  '#power-domain-cells':
> +    const: 1
> +
> +  clocks:
> +    description: |
> +      A number of phandles to clocks that need to be enabled during domain
> +      power-up sequencing.

Nothing improved, there is no such code in the bindings.

> +
> +  clock-names:
> +    description: |
> +      List of names of clocks, in order to match the power-up sequencing
> +      for each power domain we need to group the clocks by name. BASIC

Nothing improved here either.

> +      clocks need to be enabled before enabling the corresponding power
> +      domain, and should not have a '-' in their name (i.e mm, mfg, venc).
> +      SUSBYS clocks need to be enabled before releasing the bus protection,
> +      and should contain a '-' in their name (i.e mm-0, isp-0, cam-0).
> +
> +      In order to follow properly the power-up sequencing, the clocks must
> +      be specified by order, adding first the BASIC clocks followed by the
> +      SUSBSYS clocks.
> +
> +patternProperties:
> +  "^mfg[01]-supply$":
> +    description: |
> +      Regulator supply for mfg domain. With this attribute, scpsys can manage
> +      mfg regulator in mtcmos control flow, to achieve low power scenario.
> +
> +required:
> +  - compatible
> +  - reg
> +  - '#power-domain-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/mediatek,mt8189-clk.h>
> +    #include <dt-bindings/power/mediatek,mt8189-power.h>
> +
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +        scpsys: power-controller@...01000 {
> +            compatible = "mediatek,mt8189-scpsys";
> +            reg = <0 0x1c001000 0 0x1000>;
> +            #power-domain-cells = <1>;
> +            clocks = /* MFG */
> +                <&topckgen_clk CLK_TOP_MFG_REF_SEL>,
> +                <&apmixedsys_clk CLK_APMIXED_MFGPLL>;
> +            clock-names = "mfg", "mfg_top";
> +            mfg0-supply = <&mt6359_vproc1_buck_reg>;
> +            mfg1-supply = <&mt6359_vsram_proc1_ldo_reg>;
> +        };
> +
> +        /* Example of module to register power domain */


What do the guidelines speak about this? Don't do this, don't add the
consumers. Drop.

The binding did not improve, so I am not doing full review. Please go
through writing bindings or tutorials/presentations explaining this, so
we won't need to repeat same comments.


Best regards,
Krzysztof