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Message-ID: <272a9764-1cae-4d86-88b1-00175de83333@linaro.org>
Date:   Thu, 2 Nov 2023 16:33:19 +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 <quic_kriskura@quicinc.com>,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>, quic_wcheng@quicinc.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.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>
From:   Caleb Connolly <caleb.connolly@linaro.org>
In-Reply-To: <20231017131851.8299-2-quic_kriskura@quicinc.com>
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On 17/10/2023 14:18, Krishna Kurapati wrote:
> Add enable-rt binding to let the device register vendor hooks to
> core and facilitate runtime suspend and resume.

Hi Krishna,

 From reading through these patches, it's not clear to me why this 
behaviour should be conditional on a new devicetree property. Are there 
some platforms where this behaviour would be undesirable? And if so then 
would it be possible to determine this based on the QSCRATCH registers?
> 
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
>   Documentation/devicetree/bindings/usb/qcom,dwc3.yaml | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml b/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml
> index cb50261c6a36..788d9c510abc 100644
> --- a/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml
> +++ b/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml
> @@ -151,6 +151,11 @@ properties:
>         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"?
> +
>     wakeup-source: true
>   
>   # Required child node:

-- 
// Caleb (they/them)