Re: [PATCH v2 02/11] dt-bindings: hwmon: Add Apple System Management Controller hwmon schema

[Guenter Roeck <linux@roeck-us.net>]

On 9/27/25 17:36, James Calligeros wrote:
> Hi Rob,
> 
> On Friday, 26 September 2025 7:43:23 am Australian Eastern Standard Time Rob
> Herring wrote:
>> On Thu, Sep 25, 2025 at 3:49 PM Janne Grunau <j@jannau.net> wrote:
>>> On Fri, Aug 29, 2025 at 11:40:57AM -0500, Rob Herring wrote:
>>>>
>>>> This should be something like this:
>>>>
>>>> "^current-[A-Za-z0-9]{4}$":
>>>>    $ref: "#/$defs/sensor"
>>>>    unevaluatedProperties: false
>>>>
>>>> With the $defs/sensor being:
>>>>
>>>> $defs:
>>>>    sensor:
>>>>      type: object
>>>>      
>>>>      properties:
>>>>        apple,key-id:
>>>>          $ref: /schemas/types.yaml#/definitions/string
>>>>          pattern: "^[A-Za-z0-9]{4}$"
>>>>          
>>>>          description:
>>>>            The SMC FourCC key of the desired sensor. Must match the
>>>>            node's suffix.
>>>>        
>>>>        label:
>>>>          description: Human-readable name for the sensor
>>>>      
>>>>      required:
>>>>        - apple,key-id
>>>>        - label
>>>>
>>>> Though in general, 'label' should never be required being just for human
>>>> convenience.
>>>
>>> That does not sound as it would be compatible with skipping nodes in the
>>> driver if the node misses label. The driver could of course fall back
>>> to create a hwmon sensors without labels.
>>
>> The driver absolutely should.
> 
> The original submission (and our downstream version) do this, but I changed
> it for v2 per Sven's feedback [1]. Outside of development/experimentation,
> we will (should) never have a sensor in the Devicetree of uknown utility.
> If we know what a sensor is for, then we should have a label for it.
> 

Label attributes are optional in hwmon drivers. Period.

Guenter