Re: [PATCH 3/8] dt-bindings: hwmon: Allow specifying channels for lm90

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 20/05/2022 15:42, Guenter Roeck wrote:
>>
>>> +          A descriptive name for this channel, like "ambient" or "psu".
>>> +
>>> +      offset:
>>> +        description: |
>>
>> This does not look like standard property, so you need vendor and unit
>> suffix.
>>
> 
> Temperature offset is a standard property for temperature sensor

The original description was strictly connected to registers, so that
one as not a standard. It seems it was just a wording...

> chips with external channels, implemented by a diode or transistor.
> Making it non-standard will mean that we'll have lots of
> "vendor,offset" properties, one each for each vendor selling
> temperature sensor chips with external channels. This gets
> more complicated here because the lm90 driver does support chips
> from several different vendors. Almost all of them support
> this functionality. Which vendor do you select in this case ?
> 
> I would suggest to use temperature-offset-milliseconds, though.

Yes, this sounds good. Just not seconds but millicelsius, I guess?

> 
>>> +          The value (millidegree Celsius) to be programmed in the channel specific offset register
>>> +          (if supported by device).
>>
>> You described programming model which should not be put in the bindings.
>> Please describe the hardware.
>>
> 
> It is a configuration value, which is hardware dependent because
> it depends on the temperature diode or transistor connected to the chip.

Sure, so this could be reworded "Offset against some base value for each
channel temperature", or something similar (you know better than me).
Referring to registers and where exactly this should be programmed in
the device is related to device programming model, not to bindings.

Best regards,
Krzysztof