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

From: Dmitry Osipenko <digetx@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>,
	linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org
Subject: Re: [PATCH v1] hwmon: (lm90) Use edge-triggered interrupt
Date: Thu, 17 Jun 2021 18:27:50 +0300	[thread overview]
Message-ID: <b97e3a75-f1aa-95a4-187d-97dc95e57e2b@gmail.com> (raw)
In-Reply-To: <20210617151236.GB2676642@roeck-us.net>

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.