linux-kernel - Re: [PATCH v2 3/5] dt-bindings: phy: qcom,sc8280xp-qmp-usb43dp-phy: Document static lanes mapping

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <slgu2d4iv6ef76f43gvwaelcl5ymymsvhokyunalq7z3l2ht3j@t7pko4rtqvgm>
Date: Tue, 2 Sep 2025 12:30:33 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Neil Armstrong <neil.armstrong@...aro.org>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>, Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.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>,
        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>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-phy@...ts.infradead.org
Subject: Re: [PATCH v2 3/5] dt-bindings: phy: qcom,sc8280xp-qmp-usb43dp-phy:
 Document static lanes mapping

On Tue, Sep 02, 2025 at 11:00:30AM +0200, Neil Armstrong wrote:
> The QMP USB3/DP Combo PHY hosts an USB3 phy and a DP PHY on top
> of a combo glue to route either lanes to the 4 shared physical lanes.
> 
> The routing of the lanes can be:
> - 2 DP + 2 USB3
> - 4 DP
> - 2 USB3
> 
> The layout of the lanes was designed to be mapped and swapped
> related to the USB-C Power Delivery negociation, so it supports
> a finite set of mappings inherited by the USB-C Altmode layouts.
> 
> Nevertheless those QMP Comby PHY can be statically used to
> drive a DisplayPort connector, DP->HDMI bridge, USB3 A Connector,
> etc... without an USB-C connector and no PD events.
> 
> Add a property that documents the static lanes mapping to
> each underlying PHY to allow supporting boards directly
> connecting USB3 and DisplayPort lanes to the QMP Combo
> lanes.
> 
> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
> ---
>  .../phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml         | 29 ++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> index c8bc512df08b5694c8599f475de78679a4438449..12511a462bc6245e0b82726d053d8605148c5047 100644
> --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-usb43dp-phy.yaml
> @@ -76,6 +76,35 @@ properties:
>    mode-switch: true
>    orientation-switch: true
>  
> +  qcom,static-lanes-mapping:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    minItems: 4
> +    items:
> +      enum:
> +        - 0 # Unconnected (PHY_NONE)
> +        - 4 # USB3 (PHY_TYPE_USB3)
> +        - 6 # DisplayPort (PHY_TYPE_DP)
> +    description:
> +      Describes the static mapping of the Combo PHY lanes, when not used
> +      a in a Type-C dynamic setup using USB-C PD Events to change the mapping.
> +      The 4 lanes can either routed to the underlying DP PHY or the USB3 PHY.
> +      Only 2 of the lanes can be connected to the USB3 PHY, but the 4 lanes can
> +      be connected to the DP PHY.

It feels like this significantly duplicates existing data-lanes
definitions. Can we use that property to express the same semantics?


> +      The numbers corresponds to the PHY Type the lanes are connected to.
> +      The possible combinations are
> +        <0 0 0 0> when none are connected
> +        <4 4 0 6> USB3 and DP single lane
> +        <4 4 6 6> USB3 and DP
> +        <6 6 4 4> DP and USB3
> +        <6 0 4 4> DP and USB3 single lane
> +        <4 4 0 0> USB3 Only
> +        <0 0 4 4> USB3 Only
> +        <6 0 0 0> DP single lane
> +        <0 0 0 6> DP single lane
> +        <6 6 0 0> DP 2 lanes
> +        <0 0 6 6> DP 2 lanes
> +        <6 6 6 6> DP 4 lanes
> +
>    ports:
>      $ref: /schemas/graph.yaml#/properties/ports
>      properties:
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry