Re: [PATCH v7 1/3] dt-bindings: hwmon: Document the LTC4283 Swap Controller

["Nuno Sá" <noname.nuno@gmail.com>]

On Mon, 2026-03-23 at 08:27 -0700, Guenter Roeck wrote:
> On 3/23/26 08:17, Nuno Sá wrote:
> > On Mon, 2026-03-23 at 07:33 -0700, Guenter Roeck wrote:
> > > [ ...]
> > > > > > +  adi,pgio1-func:
> > > > > > +    description: Configures the function of the PGIO1 pin.
> > > > > > +    $ref: /schemas/types.yaml#/definitions/string
> > > > > > +    enum: [inverted_power_good, power_good, gpio]
> > > > > > +    default: inverted_power_good
> > > > > > +
> > > > > > +  adi,pgio2-func:
> > > > > > +    description: Configures the function of the PGIO2 pin.
> > > > > > +    $ref: /schemas/types.yaml#/definitions/string
> > > > > > +    enum: [inverted_power_good, power_good, gpio, active_current_limiting]
> > > > > > +    default: inverted_power_good
> > > > > > +
> > > > > > +  adi,pgio3-func:
> > > > > > +    description: Configures the function of the PGIO3 pin.
> > > > > > +    $ref: /schemas/types.yaml#/definitions/string
> > > > > > +    enum: [inverted_power_good_input, power_good_input, gpio]
> > > > > > +    default: inverted_power_good_input
> > > > > > +
> > > > > > +  adi,pgio4-func:
> > > > > > +    description: Configures the function of the PGIO4 pin.
> > > > > > +    $ref: /schemas/types.yaml#/definitions/string
> > > > > > +    enum: [inverted_external_fault, external_fault, gpio]
> > > > > > +    default: inverted_external_fault
> > > > > > +
> > > > > > +  adi,gpio-on-adio1:
> > > > > > +    description: If set, the ADIO1 pin is used as a GPIO.
> > > > > > +    type: boolean
> > > > > > +
> > > > > > +  adi,gpio-on-adio2:
> > > > > > +    description: If set, the ADIO2 pin is used as a GPIO.
> > > > > > +    type: boolean
> > > > > > +
> > > > > > +  adi,gpio-on-adio3:
> > > > > > +    description: If set, the ADIO3 pin is used as a GPIO.
> > > > > > +    type: boolean
> > > > > > +
> > > > > > +  adi,gpio-on-adio4:
> > > > > > +    description: If set, the ADIO4 pin is used as a GPIO.
> > > > > > +    type: boolean
> > > > > 
> > > > > Does this dependency block force a redundant specification of adi,pgio4-func?
> > > > > The default for adi,pgio4-func is inverted_external_fault, which means the
> > > > > default hardware state already supports external fault features.
> > > > > If a device tree legitimately omits adi,pgio4-func to rely on that default,
> > > > > will it fail schema validation here since the dependencies keyword strictly
> > > > > checks for the literal presence of properties without injecting defaults?
> > > > 
> > > > Fair point. I guess it will fail but the alternative is to not have any constrain at all so
> > > > maybe worth it to be explicit in here?
> > > > 
> > > 
> > > I don't claim to understand how to define devicetree properties, but
> > > 
> > > adi,pgio4-func = <"gpio">
> > > 
> > > and
> > > 
> > > adi,gpio-on-adio4;
> > > 
> > > seem to be equivalent to me, and omitting the first property (because
> > 
> > Not exactly. ADIO4 and PGIO4 are different pins and can be both configured
> > as GPIOs. ADIO is a boolean because they are either monitored by the ADC (default)
> > or configured as GPIOs. PGIOs can have additional configurations and hence the
> > enum.
> > 
> 
> Ah, I didn't realize the small "A" vs. "G" difference (and apparently
> I don't understand what the AI is complaining about ;-). Sorry for the noise.
> 

My understanding about the AI complain is the below dependencies:

+  adi,external-fault-retry-enable:
+    - adi,pgio4-func
+  adi,external-fault-fet-off-enable:
+    - adi,pgio4-func

The default value (omitting the property) is a valid case to use any of the above two
flags but with the above, omitting the property and adding the flag should result in
an error when validating the binding (because of the dependency). That is why I replied
with

"Fair point. I guess it will fail but the alternative is to not have any constrain at all so
maybe worth it to be explicit in here?"


- Nuno Sá