linux-kernel - Re: [PATCH v1] hwmon: (lm90) Use edge-triggered interrupt

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Message-ID: <4ae32e69-1d2f-f75b-ad86-10eac15606df@gmail.com>
Date:   Fri, 18 Jun 2021 11:55:13 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Jean Delvare <jdelvare@...e.com>, linux-kernel@...r.kernel.org,
        linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v1] hwmon: (lm90) Use edge-triggered interrupt

18.06.2021 00:42, Guenter Roeck пишет:
> On Thu, Jun 17, 2021 at 06:27:50PM +0300, Dmitry Osipenko wrote:
>> 17.06.2021 18:12, Guenter Roeck пишет:
>>>> For now I see that the rising edge isn't needed, the TEMP_ALERT goes
>>>> HIGH by itself when temperature backs to normal. But I will try to
>>>> double check.
>>>>
>>> The point is that a sysfs event should be sent to userspace on both
>>> edges, not only when an alarm is raised. But, you are correct,
>>> IRQ_TYPE_EDGE_RISING is currently not needed since sysfs events
>>> are not generated.
>>
>> Ok, thank you for the clarification.
>>
>>>>> Anyway, the tegra30 dts files in the upstream kernel either use
>>>>> IRQ_TYPE_LEVEL_LOW or no interrupts for nct1008. The Nexus 7 dts file
>>>>> in the upstream kernel has no interrupt configured (and coincidentally
>>>>> it was you who added that entry). Where do you see IRQ_TYPE_LEVEL_HIGH ?
>>>> I have a patch that will add the interrupt property, it's stashed
>>>> locally for the next kernel release.
>>>>
>>>> IIUC, it's not only the Tegra30 dts, but all the TegraXXX boards that
>>>> use IRQ_TYPE_LEVEL_LOW are in the same position.
>>> I still don't see a IRQ_TYPE_LEVEL_HIGH, though.
>>
>> Could you please clarify why you're looking for HIGH and not for LOW?
>> The TEMP_ALERT is active-low.
> 
> Because you stated earlier:
> 
> "... cargo-culted and wrong because they use IRQ_TYPE_LEVEL_HIGH ..."
>                                              ^^^^^^^^^^^^^^^^^^^

That was a typo, my bad.