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Message-ID: <4C1C9707.3060703@jic23.retrosnub.co.uk>
Date: Sat, 19 Jun 2010 11:08:07 +0100
From: Jonathan Cameron <kernel@...23.retrosnub.co.uk>
To: Jean Delvare <khali@...ux-fr.org>
CC: guenter.roeck@...csson.com, Jonathan Cameron <jic23@....ac.uk>,
Hans de Goede <hdegoede@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Mark Brown <broonie@...nsource.wolfsonmicro.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>
Subject: Re: [lm-sensors] [PATCH 1/3] hwmon: Driver for SMM665 Six-Channel
Active DC Output Controller/Monitor
On 06/19/10 09:27, Jean Delvare wrote:
> On Fri, 18 Jun 2010 12:13:25 -0700, Guenter Roeck wrote:
>> On Fri, 2010-06-18 at 14:10 -0400, Jonathan Cameron wrote:
>>> Another quick query. Are the _min / _max attributes as defined in the
>>> abi meant for alarms? I always thought they were to tell userspace the
>>> limits on measurement?
>>>
>> Good question. I thought it is supposed to refer to alarm limits, but I
>> may be wrong.
>>
>> Browsing through a couple of drivers, it _looks_ like the values are
>> used for alarm limits (eg adm1025 or lm85). Limits are not always set to
>
> Yes, these are alarms. _min and _max are really misnomers, these should
> have been _low and _high but by the time I realized it, _min and _max
> were already de facto standards and it was too late to change this.
>
> Documentation/hwmon/sysfs-interface says:
>
> Usual items are "input" (measured value), "max" (high threshold,
> "min" (low threshold).
Ah, I missed that general defining of terms. It's fine as is unless we end
up with lots of people not reading it properly like me ;)
>
> Specific occurrences are then left without details. If you think this
> document can be improved, I welcome patches.
>
>> useful values, though. This is what my CPU board returns:
>>
>> lm85-i2c-0-2e
>> Adapter: SMBus PIIX4 adapter at 0580
>> V1.5: +1.80 V (min = +0.00 V, max = +3.32 V)
>> VCore: +1.29 V (min = +0.00 V, max = +2.99 V)
>> V3.3: +3.32 V (min = +0.00 V, max = +4.38 V)
>> V5: +5.00 V (min = +0.00 V, max = +6.64 V)
>> V12: +12.12 V (min = +0.00 V, max = +15.94 V)
>>
>> The lm85 datasheet says: "If a voltage input either exceeds the value
>> set in the voltage high limit register or falls below the value set in
>> the voltage low limit register, the corresponding bit will be set
>> automatically by the LM85 in the interrupt status registers (41-42h)."
>>
>>> Either way, one of us has misunderstood so perhaps the documentation needs
>>> to be more specific....
>>
>> Agreed.
>
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