linux-kernel - Re: [PATCH v2 3/4] arm64: dts: qcom: qcm2290: add LPASS LPI pin controller

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Message-Id: <DDO0LYS7UTEW.3A9WGTAA5DKVO@linaro.org>
Date: Tue, 21 Oct 2025 13:56:09 +0100
From: "Alexey Klimov" <alexey.klimov@...aro.org>
To: "Bjorn Andersson" <andersson@...nel.org>
Cc: "Konrad Dybcio" <konrad.dybcio@....qualcomm.com>, "Linus Walleij"
 <linus.walleij@...aro.org>, "Rob Herring" <robh@...nel.org>, "Krzysztof
 Kozlowski" <krzk+dt@...nel.org>, "Conor Dooley" <conor+dt@...nel.org>,
 "Konrad Dybcio" <konradybcio@...nel.org>, "Srinivas Kandagatla"
 <srini@...nel.org>, "Dmitry Baryshkov" <dmitry.baryshkov@....qualcomm.com>,
 <linux-arm-msm@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-sound@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] arm64: dts: qcom: qcm2290: add LPASS LPI pin
 controller

On Fri Oct 17, 2025 at 11:42 PM BST, Bjorn Andersson wrote:
> On Fri, Oct 10, 2025 at 01:29:38PM +0100, Alexey Klimov wrote:
>> On Tue Oct 7, 2025 at 1:39 PM BST, Konrad Dybcio wrote:
>> > On 10/7/25 4:03 AM, Alexey Klimov wrote:
>> >> Add the Low Power Audio SubSystem Low Power Island (LPASS LPI) pin
>> >> controller device node required for audio subsystem on Qualcomm
>> >> QRB2210 RB1. QRB2210 is based on qcm2290 which is based on sm6115.
>> >> 
>> >> While at this, also add description of lpi_i2s2 pins (active state)
>> >> required for audio playback via HDMI/I2S.
>> >> 
>> >> Cc: Srinivas Kandagatla <srini@...nel.org>
>> >> Signed-off-by: Alexey Klimov <alexey.klimov@...aro.org>
>> >> ---
>> >
>> > [...]
>> >
>> >> +			lpi_i2s2_active: lpi-i2s2-active-state {
>> >> +				data-pins {
>> >> +					pins = "gpio12";
>> >> +					function = "i2s2_data";
>> >> +					bias-disable;
>> >> +					drive-strength = <8>;
>> >> +					output-high;
>> >
>> > I.. doubt output-high is what you want?
>> 
>> Why? Or is it because of some in-kernel gpiod?
>> 
>
> What does "output-high" mean for a non-gpio function?

This is not efficient. It will be more useful to go straight to
the point.

This description of pins was taken from Qualcomm downstream code
and the similar patch was applied (see provided URL in the prev email).

The same problem here and no response:
https://lore.kernel.org/linux-arm-msm/d8e202fb-f494-4b5e-bfb9-c94c1fd3af4d@linaro.org/

After looking at
https://lore.kernel.org/linux-arm-msm/39ebaf4e-e91f-4568-8de6-9fc1f805a1e4@oss.qualcomm.com/
I guess the output-high should removed at all (if it is the case) but it
will be more efficient to provide that as a feedback rather than vague
responses.

Back to your question -- does it matter here if it is gpio or non-gpio
function?

Best regards,
Alexey.