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

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Message-ID: <8396dd15-9111-4ceb-a561-6ed57727546f@rock-chips.com>
Date: Tue, 23 Sep 2025 11:40:33 +0800
From: Chaoyi Chen <chaoyi.chen@...k-chips.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Chaoyi Chen <kernel@...kyi.com>, 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>,
 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 9/23/2025 11:17 AM, Dmitry Baryshkov wrote:

> On Tue, Sep 23, 2025 at 09:53:06AM +0800, Chaoyi Chen wrote:
>> Hi Dmitry,
>>
>> On 9/23/2025 9:12 AM, Dmitry Baryshkov wrote:
>>> 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.
>> I think this is a difference in practice. In the previous binding, there was already an orientation-switch under the usb-port. I trying to add both an orientation-switch and a mode-switch to the top-level device in v2. And Krzysztof reminded me that adding a mode-switch under the dp-port would be better, so I changed it to the current form :)
> I couldn't find the comment on lore. Could you please point it out?

Sorry, it is v1. I added an orientation-switch and a mode-switch in the top-level PHY [0]. Comment is here: [1]


[0] https://lore.kernel.org/all/20250715112456.101-4-kernel@airkyi.com/

[1] https://lore.kernel.org/all/4dfed94c-665d-4e04-b527-ddd34fd3db8f@kernel.org/



>>
>>
>>>> +        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
>>>>
>> -- 
>> Best,
>> Chaoyi
>>
-- 
Best,
Chaoyi