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Message-ID: <acf9dce0-10c3-4ad8-b96a-5f44b6428497@linaro.org>
Date: Thu, 8 Feb 2024 10:13:30 +0100
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Subject: Re: [PATCH 2/3] arm64: dts: qcom: sa8295p: Enable tertiary controller
 and its 4 USB ports
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To: Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>,
 Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
 Konrad Dybcio <konrad.dybcio@linaro.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>, Bjorn Andersson <andersson@kernel.org>,
 Conor Dooley <conor+dt@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: <20240206114745.1388491-1-quic_kriskura@quicinc.com>
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 <fd4f4cc8-3366-485b-b540-b05ef59dd5d4@quicinc.com>
 <CAA8EJppi+3cJqzkhcaDR_3w_Qhy_AzLBJsW7-dtugzE1egM3Kg@mail.gmail.com>
 <7500f1f8-1d97-4fa9-a7cd-7dea0ad52e00@quicinc.com>
 <CAA8EJpoe-gaSgD_HruYSUAPgfBNCw9-G9wnEnvpkiCtmrqFQ7A@mail.gmail.com>
 <62bba89d-97b0-4129-8abe-6025790d9d13@quicinc.com>
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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In-Reply-To: <62bba89d-97b0-4129-8abe-6025790d9d13@quicinc.com>
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On 08/02/2024 10:07, Krishna Kurapati PSSNV wrote:
>>>>
>>>>> One query. If we model it as a regulator, do we need to add it as a
>>>>> supply and call regulator_enable in dwc3_qcom probe again ?
>>>>
>>>> Not in probe(), but yes. It needs to be enabled when the VBUS has to
>>>> be powered up, when the device is initialised or switched to the host
>>>> mode, and disabled when the VBUS has to be powered down, if the device
>>>> is being switched to the device mode.
>>>>
>>>
>>> Actually since we never go to device mode, can't we just stick to this
>>> pinctrl approach and skip turning on regulator in driver ?
>>
>> Scroll several emails back. DT should describe the hardware. Hardware
>> has VBUS regulators.
>>
> 
> Hi Dmitry,
> 
> I dug up the schematic and I see that the gpio's we are using in this 
> patch are actually "Enable Pins" to an external chip that provides vbus 
> to the peripherals connected. So from the perspective of SoC, it is a 
> GPIO and not to be represented as a regulator I believe.

According to such logic nothing is a regulator... sorry, you just
described regulator.

Best regards,
Krzysztof