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SubjectRe: [lm-sensors] [PATCH 1/3] hwmon: Driver for SMM665 Six-Channel Active DC Output Controller/Monitor
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).

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.

--
Jean Delvare


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