RE: [PATCH v3 2/5] dt-bindings: hwmon: Add possible new properties to max31827 bindings

[Matyas, Daniel]

> -----Original Message-----
> From: Conor Dooley <conor@xxxxxxxxxx>
> Sent: Thursday, September 14, 2023 5:42 PM
> To: Matyas, Daniel <Daniel.Matyas@xxxxxxxxxx>
> Cc: Jean Delvare <jdelvare@xxxxxxxx>; Guenter Roeck <linux@roeck-
> us.net>; Rob Herring <robh+dt@xxxxxxxxxx>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@xxxxxxxxxx>; Conor Dooley
> <conor+dt@xxxxxxxxxx>; Jonathan Corbet <corbet@xxxxxxx>; linux-
> hwmon@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-doc@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3 2/5] dt-bindings: hwmon: Add possible new
> properties to max31827 bindings
> 
> [External]
> 
> On Thu, Sep 14, 2023 at 10:59:45AM +0300, Daniel Matyas wrote:
> > These modify the corresponding bits in the configuration register.
> >
> > adi,comp-int is a hardware property, because it affects the behavior
> > of the interrupt signal and whatever it is connected to.
> >
> > adi,timeout-enable is a hardware property, because it affects i2c bus
> > operation.
> >
> > Signed-off-by: Daniel Matyas <daniel.matyas@xxxxxxxxxx>
> > ---
> >
> > v2 -> v3: Changed commit subject and message
> >
> > v1 -> v2: Added adi,timeout-enable property to binding. Fixed
> > dt_binding_check errors.
> >
> >  .../bindings/hwmon/adi,max31827.yaml          | 35
> +++++++++++++++++++
> >  1 file changed, 35 insertions(+)
> >
> > diff --git
> a/Documentation/devicetree/bindings/hwmon/adi,max31827.yaml
> > b/Documentation/devicetree/bindings/hwmon/adi,max31827.yaml
> > index 2dc8b07b4d3b..6bde71bdb8dd 100644
> > --- a/Documentation/devicetree/bindings/hwmon/adi,max31827.yaml
> > +++ b/Documentation/devicetree/bindings/hwmon/adi,max31827.yaml
> > @@ -32,6 +32,37 @@ properties:
> >        Must have values in the interval (1.6V; 3.6V) in order for the device
> to
> >        function correctly.
> >
> > +  adi,comp-int:
> > +    description:
> > +      If present interrupt mode is used. If not present comparator mode
> is used
> > +      (default).
> > +    type: boolean
> > +
> > +  adi,alrm-pol:
> 
> Characters are not at a premium, is there a reason not to use the full
> words? "flt-q" in particular would be quite cryptic if I saw it in a dts.
> 
> > +    description:
> > +      Sets the alarms active state.
> > +            - 0 = active low
> > +            - 1 = active high
> > +      For max31827 and max31828 the default alarm polarity is low. For
> max31829
> > +      it is high.
> 
> This constraint can be expressed in the binding, rather than in free form
> text like done here. Ditto below.
> 
> Thanks,
> Conor.
> 

Ok, but how? The default values are different depending on the compatible string. I searched for similar examples, but I found nothing...

Some bindings use 'default: ' to declare the default values, but this is the default for every chip.

Kind regards,
Daniel

> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [0, 1]
> > +
> > +  adi,flt-q:
> > +    description:
> > +      Select how many consecutive temperature faults must occur before
> > +      overtemperature or undertemperature faults are indicated in the
> > +      corresponding status bits.
> > +      For max31827 default fault queue is 1. For max31828 and
> max31829 it is 4.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [1, 2, 4, 8]
> > +
> > +  adi,timeout-enable:
> > +    description:
> > +      Enables timeout. Bus timeout resets the I2C-compatible interface
> when SCL
> > +      is low for more than 30ms (nominal).
> > +    type: boolean
> > +
> >  required:
> >    - compatible
> >    - reg
> > @@ -49,6 +80,10 @@ examples:
> >              compatible = "adi,max31827";
> >              reg = <0x42>;
> >              vref-supply = <&reg_vdd>;
> > +            adi,comp-int;
> > +            adi,alrm-pol = <0>;
> > +            adi,flt-q = <1>;
> > +            adi,timeout-enable;
> >          };
> >      };
> >  ...
> > --
> > 2.34.1
> >