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From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
To: Qian Zhang <qian.zhang@oss.qualcomm.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>,
	Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Cc: linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] arm64: dts: qcom: arduino-monza: add WLAN enable and rfkill GPIO
Date: Fri, 15 May 2026 14:22:12 +0200	[thread overview]
Message-ID: <b71f7653-78bb-49eb-b4c4-3fa8bca3e705@oss.qualcomm.com> (raw)
In-Reply-To: <a79100cd-0e33-4eb6-9452-c4458ea40bc0@oss.qualcomm.com>

On 5/15/26 2:08 PM, Qian Zhang wrote:
> 
> 
> On 5/15/2026 6:51 PM, Konrad Dybcio wrote:
>> On 5/11/26 10:48 AM, Qian Zhang via B4 Relay wrote:
>>> From: Qian Zhang <qian.zhang@oss.qualcomm.com>
>>>
>>> The QCNFA765 M.2 PCIe WLAN module requires GPIO56 (wlan_en) to be
>>
>> But isn't that just the wlan-en pin that the power sequencing driver
>> takes?
>>
>> ref: drivers/power/sequencing/pwrseq-qcom-wcn.c
>>
>> Konrad
> Thanks for the review.
> It's not the same pin functionally, though they share the same name. There are two key differences:
> 
> 
> Different power topology: The pwrseq-qcom-wcn.c driver targets WLAN
> hips powered by an on-board PMU via the power sequencing framework. In our case (VENTUNO Q), the WLAN module has its own internal PMU, and wlan_en controls the power-on/off of that internal PMU — it is not part of the board-level power sequencing.

I don't believe what you said about the pwrseq driver is true.

> PCIe probe ordering: The WLAN module connects to the PCIe root complex through a PCIe bridge that does not currently support hotplug. If we were to use a similar node configuration as in pwrseq-qcom-wcn.c, there is no guarantee that the WLAN module would be powered on before the PCIe root complex probes, which would cause enumeration failure.

What do you mean by "*currently* does not support hotplug"? Does that
depend on some more code changes?

Konrad

      reply	other threads:[~2026-05-15 12:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-11  8:48 [PATCH v3] arm64: dts: qcom: arduino-monza: add WLAN enable and rfkill GPIO Qian Zhang via B4 Relay
2026-05-12  1:09 ` sashiko-bot
2026-05-15 10:51 ` Konrad Dybcio
2026-05-15 12:08   ` Qian Zhang
2026-05-15 12:22     ` Konrad Dybcio [this message]

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