Re: hwmon: label vs temp%d_label

From: Chris Packham
Date: Tue Apr 02 2024 - 17:23:12 EST



On 3/04/24 09:59, Guenter Roeck wrote:
> On Tue, Apr 02, 2024 at 08:24:37PM +0000, Chris Packham wrote:
>> Hi Guenter, Jean,
>>
>> I've got a requirement to add some meaningful names to some hwmon
>> sensors (LM75 specifically) so that we can provide some indication of
>> where on a board the sensor is located (e.g. "Intake" vs "Exhaust" vs
>> "Near that really hot chip").
>>
>> I see that the sysfs ABI documents both "label" for the chip and
>> "temp[1-*]_label" (as well as similar fan and Vin attributes). The
>> latter seem to be supported by the hwmon core but I don't see anything
>> for the former (I'm struggling to find any driver that supports a
>> chip-wide label).
>>
>> Assuming I want to have a label added in the device tree to a lm75 would
>> something like the following be acceptable
>>
>>       sensor@48 {
>>         compatible = "national,lm75";
>>         reg = <0x48>;
>>         label = "Intake";
>>       };
>>
>> I'd then update the lm75 driver to grab that from the devicetree and use
>> it to provide the hwmon_temp_label attribute.
>>
> Have you tried just declaring the label property as you suggested above
> in your system without doing anything else, and looked at the generated
> sysfs attributes ?

I have not. But in my defense I'm also using an older kernel LTS that
doesn't have commit e1c9d6d61ddf ("hwmon: Add "label" attribute"). But
now that I know it exists I can carry it as a local patch until we next
update.

Thanks,
Chris