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From: Qian Zhang <qian.zhang@oss.qualcomm.com>
To: Konrad Dybcio <konrad.dybcio@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>
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 20:08:19 +0800	[thread overview]
Message-ID: <a79100cd-0e33-4eb6-9452-c4458ea40bc0@oss.qualcomm.com> (raw)
In-Reply-To: <920223a6-4e4a-4ebc-8a1c-c37d0923a470@oss.qualcomm.com>



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.


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.


So while the pin name is the same, the use case and the timing 
constraints are fundamentally different.

Best regards,
Qian

  reply	other threads:[~2026-05-15 12:08 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 [this message]
2026-05-15 12:22     ` Konrad Dybcio

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