Message-ID: <2eb90841-f10c-4524-bbf8-10a2095ecde4@gmail.com>
Date: Wed, 23 Apr 2025 15:21:47 +0200
From: Tomasz Maciej Nowak <tmn505@...il.com>
To: Aaron Kling <webgeek1234@...il.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Thierry Reding
 <thierry.reding@...il.com>, Jonathan Hunter <jonathanh@...dia.com>,
 devicetree@...r.kernel.org, linux-tegra@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64: tegra: Enable PWM fan on the Jetson TX1 Devkit

W dniu 23.04.2025 o 06:31, Aaron Kling pisze:
> On Tue, Apr 22, 2025 at 11:19 AM Tomasz Maciej Nowak <tmn505@...il.com> wrote:
>>
>> W dniu 22.04.2025 o 17:58, Aaron Kling pisze:
>>> On Tue, Apr 22, 2025 at 9:52 AM Tomasz Maciej Nowak <tmn505@...il.com> wrote:
>>>>
>>>> Hi.
>>>>
>>>> W dniu 21.04.2025 o 00:42, Aaron Kling via B4 Relay pisze:
>>>>> From: Aaron Kling <webgeek1234@...il.com>
>>>>>
>>>>> This is based on 6f78a94, which enabled added the fan and thermal zones
>>>>> for the Jetson Nano Devkit. The fan and thermal characteristics of the
>>>>> two devkits are similar, so usng the same configuration.
>>>>
>>>> Does this work on Your DevKit? Doesn't on mine, the fan won't budge. Maybe the
>>>> revision difference? What I'm using ATM is [1] and [2]. Because inverted polarity
>>>> of PWM, not submitted since that'll need the driver changes [3],[4].
>>>
>>> I would have sworn I verified this before sending it in. I've had the
>>> patches for some time. But you are correct, this does not work as-is.
>>> Maybe I lost something cleaning up for submission or just plain
>>> misremembered the verification. I will send a v2 once I've fixed and
>>> verified. Apologies to the list for the bad submission.
>>>
>>> For inverted polarity, listing them backwards already has precedence
>>> in mainline, see the Banana Pi R3 dt. This makes me want to double
>>> check the existing Nano pwm-fan entry in mainline, though. Cause I
>>> thought all the t210 devices were the same in regards to pwm fan
>>> inversion. And it doesn't have reversed entries.
>>
>> That Banana Pi R3 reverse levels look ugly, but if it's permitted I'm not against.
>>
>> I would assume they fixed that in Nano, since PWM controller doesn't implement
>> inverted polarity in hardware. Looking at Switch [5] it seems the TX1 DevKit was
>> used for developing, since they replicated the issue.
>>
>> 5. https://github.com/fail0verflow/switch-linux/commit/b23e8b89081415f2a63bc625db041c8092e2a8a2
>>   >
>>> Sincerely,
>>> Aaron Kling
>>>
>>>>
>>>> 1. https://github.com/tmn505/linux/commit/a78c520ec94aeab2c9dc8e1f46597c4174ff957d
>>>> 2. https://github.com/tmn505/linux/commit/99beee4f0cd5d3a6f30e1829d823c11cb8b54bac
>>>> 3. https://libera.irclog.whitequark.org/tegra/2024-07-19#36707118;
>>>> 4. https://libera.irclog.whitequark.org/tegra/2024-10-14#37145211;
>>>>
>>>> Regards
>>>>

[snip]

> Mmm, so this is strange. I am currently unable to get the fan to move
> on any t210 device. But it works just fine on t186, such as the tx2 nx
> setup supported by mainline. Tomasz, does your change work on 6.12 or
> current mainline? Even if I match your changes on the tx1 devkit, I
> get nothing. The pwm duty cycle is changing as expected, per the
> debugfs pwm listing. Gpio state for pin 4 of the tca9539@74 matches
> the 4.9 kernel when the fan is running. Best I can tell, it should be
> working. But it's not.

Maybe some missing driver from thermal framework? I've attached my kernel config
tailored to t210 for comparison (firmwares are built-in in, adjust path to
firmware collection). Currently I'm running 6.15-rc3 and fan is spinning according
to cooling levels with the changes to PWM nodes which I posted previously.

> Sincerely,
> Aaron
Regards

-- 
TMN

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