Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.32 as permitted sender) client-ip=23.128.96.32;
Message-ID: <dbf4a48e-c808-4611-96b1-563ece1e451a@linaro.org>
Date:   Thu, 2 Nov 2023 18:40:57 +0000
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [RFC 1/8] dt-bindings: usb: qcom,dwc3: Add bindings to enable
 runtime
Content-Language: en-US
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
References: <20231017131851.8299-1-quic_kriskura@quicinc.com>
 <20231017131851.8299-2-quic_kriskura@quicinc.com>
 <272a9764-1cae-4d86-88b1-00175de83333@linaro.org>
 <960101cc-78c0-49cf-ab62-90614eeb9ee2@quicinc.com>
From:   Caleb Connolly <caleb.connolly@linaro.org>
In-Reply-To: <960101cc-78c0-49cf-ab62-90614eeb9ee2@quicinc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

> 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?
> 
> For xhci, we opted to enable runtime from userspace.

>>>         HS/FS/LS modes are supported.
>>>       type: boolean
>>> +  qcom,enable-rt:
>>> +    description:
>>> +      If present, register vendor hooks to facilitate runtime 
>>> suspend/resume
>>> +    type: boolean
>>
>> A Krzysztof pointed out, properties should define the hardware 
>> behaviour, not tot the implementation details. For this case the 
>> hardware isn't wired up to vbus, so maybe something like "qcom,no-vbus"?
>>> +
> 
> On all targets, vbus is not routed to hardware. This vbus toggle 
> indication is given to controller via qscratch only.
> 
> Regards,
> Krishna,

-- 
// Caleb (they/them)