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Message-ID: <96b3ebe5-781a-432a-9a73-2217a2a674f4@linaro.org>
Date:   Fri, 3 Nov 2023 14:56:39 +0000
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Subject: Re: [RFC 1/8] dt-bindings: usb: qcom,dwc3: Add bindings to enable
 runtime
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To:     Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     quic_wcheng@quicinc.com, linux-usb@vger.kernel.org,
        Conor Dooley <conor+dt@kernel.org>,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        Andy Gross <agross@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        devicetree@vger.kernel.org, quic_ppratap@quicinc.com,
        quic_jackp@quicinc.com
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From:   Caleb Connolly <caleb.connolly@linaro.org>
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On 03/11/2023 05:34, Krishna Kurapati PSSNV wrote:
> 
> 
> On 11/3/2023 12:10 AM, Caleb Connolly wrote:
>>> Hi Caleb,
>>>
>>>    There are two types of platforms, some use extcon and some use
>>> role-switch to deliver vbus/id notifications. Extcon targets already
>>> have this qscratch modifications present today in vbus and id
>>> handlers. But for role-switch based targets we don't have any way to
>>> get this notification to dwc3-qcom. In this implementation, I wanted
>>> to get those notications from core to glue and for this we
>>> implenented vendor hooks.
>>>
>>> The property added has been used to do two things:
>>>
>>> 1. Register glue's vendor hooks to core driver
>>> 2. Do runtime_allow for glue (and by default for core as the dt is
>>> not flattened)
>>>
>>> In case of extcon, we don't want to register vendor hooks as
>>> notifications are not necessary.
>>
>> Could it just be enabled when role_switch is present then?
>>>
> 
> So we would register vendor hooks when usb-role-switch is present but
> don't do runtime allow, and leave that option to user space right ?
> I think it would work and we can do away with the binding completely.

Can we still enable runtime suspend? Maybe someone else wants to chime
in here, but I'd guess that it's preferable to have it enabled by
default, particularly for devices like phones. Or are there side effects
from this?
> 
> Will wait for comments from other folks as well on this approach.

Sounds good, thanks!
> 
> Thanks for the review,
> Krishna,

-- 
// Caleb (they/them)