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

Jonathan Cameron kernel at jic23.retrosnub.co.uk
Sat Jun 19 12:08:07 CEST 2010


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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