linux-kernel - Re: [PATCH v4 2/7] dt-bindings: phy: rockchip: rk3399-typec-phy: Support mode-switch

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Message-ID: <eb6ogrepo5acwcj5gpdolxxyg3xrx7kz6zrbizzseqyavvitfd@cnzurelqeh4t>
Date: Tue, 23 Sep 2025 04:12:45 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Chaoyi Chen <kernel@...kyi.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>, Vinod Koul <vkoul@...nel.org>,
        Kishon Vijay Abraham I <kishon@...nel.org>,
        Heiko Stuebner <heiko@...ech.de>, Sandy Huang <hjc@...k-chips.com>,
        Andy Yan <andy.yan@...k-chips.com>,
        Yubing Zhang <yubing.zhang@...k-chips.com>,
        Frank Wang <frank.wang@...k-chips.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Amit Sunil Dhamne <amitsd@...gle.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Chaoyi Chen <chaoyi.chen@...k-chips.com>,
        Dragan Simic <dsimic@...jaro.org>, Johan Jonker <jbx6244@...il.com>,
        Diederik de Haas <didi.debian@...ow.org>,
        Peter Robinson <pbrobinson@...il.com>, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-phy@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v4 2/7] dt-bindings: phy: rockchip: rk3399-typec-phy:
 Support mode-switch

On Mon, Sep 22, 2025 at 09:20:34AM +0800, Chaoyi Chen wrote:
> From: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> 
> The RK3399 SoC integrates two USB/DP combo PHYs, each of which
> supports software-configurable pin mapping and DisplayPort lane
> assignment. These capabilities enable the PHY itself to handle both
> mode switching and orientation switching, based on the Type-C plug
> orientation and USB PD negotiation results.
> 
> While an external Type-C controller is still required to detect cable
> attachment and report USB PD events, the actual mode and orientation
> switching is performed internally by the PHY through software
> configuration. This allows the PHY to act as a Type-C multiplexer for
> both data role and DP altmode configuration.
> 
> To reflect this hardware design, this patch introduces a new
> "mode-switch" property for the dp-port node in the device tree bindings.
> This property indicates that the connected PHY is capable of handling
> Type-C mode switching itself.
> 
> Signed-off-by: Chaoyi Chen <chaoyi.chen@...k-chips.com>
> 
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> ---
> 
> Changes in v4:
> - Remove "|" in description.
> 
> Changes in v3:
> - Add more descriptions to clarify the role of the PHY in switching.
> 
> Changes in v2:
> - Reuse dp-port/usb3-port in rk3399-typec-phy binding.
> 
>  .../devicetree/bindings/phy/rockchip,rk3399-typec-phy.yaml  | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/rockchip,rk3399-typec-phy.yaml b/Documentation/devicetree/bindings/phy/rockchip,rk3399-typec-phy.yaml
> index 91c011f68cd0..83ebcde096ea 100644
> --- a/Documentation/devicetree/bindings/phy/rockchip,rk3399-typec-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/rockchip,rk3399-typec-phy.yaml
> @@ -51,6 +51,12 @@ properties:
>        '#phy-cells':
>          const: 0
>  
> +      mode-switch:

Having the mode-switch here is a bit strange. I think the whole PHY
device should be an orientation-switch and mode-switch. Otherwise it
feels weird to me.

> +        description:
> +          Indicates the PHY can handle altmode switching. In this case,
> +          requires an external USB Type-C controller to report USB PD message.
> +        type: boolean
> +
>        port:
>          $ref: /schemas/graph.yaml#/properties/port
>          description: Connection to USB Type-C connector
> -- 
> 2.49.0
> 

-- 
With best wishes
Dmitry