Re: [PATCH v2 2/3] dt-bindings: hwmon: Add binding for max6639

[Guenter Roeck]

On 10/11/22 09:28, Krzysztof Kozlowski wrote:
> On 11/10/2022 06:47, Naresh Solanki wrote:
> > From: Marcello Sylvester Bauer <sylv@xxxxxxx>
> >
> > Add Devicetree binding documentation for Maxim MAX6639 temperature
> > monitor with PWM fan-speed controller.
> >
> > Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
> > Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> > ---
> >   .../bindings/hwmon/maxim,max6639.yaml         | 116 ++++++++++++++++++
> >   1 file changed, 116 insertions(+)
> >   create mode 100644 Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
> > new file mode 100644
> > index 000000000000..bbefb0a57ab3
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/maxim,max6639.yaml
> > @@ -0,0 +1,116 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +
> > +$id: http://devicetree.org/schemas/hwmon/maxim,max6639.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Maxim max6639
> > +
> > +maintainers:
> > +  - Roland Stigge <stigge@xxxxxxxxx>
> > +
> > +description: |
> > +  The MAX6639 is a 2-channel temperature monitor with dual, automatic, PWM
> > +  fan-speed controller.  It monitors its own temperature and one external
> > +  diode-connected transistor or the temperatures of two external diode-connected
> > +  transistors, typically available in CPUs, FPGAs, or GPUs.
> > +
> > +  Datasheets:
> > +    https://datasheets.maximintegrated.com/en/ds/MAX6639-MAX6639F.pdf
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - maxim,max6639
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +patternProperties:
> > +  "^ot[0-1]_indication$":
>
> No underscores in names.
>
> > +    type: boolean
> > +    default: false
> > +    description:
> > +      If true then enable OT pin indication.
>
> Description copies the name of property. Not really useful. Describe
> that it does.
>
> Why this has 0 and 1 numbers? Isn't it connected with fan?

I had to look up the suggested code to understand what it means.
All the _indication properties actually configure the chip
to enable or disable various alarm output pins (ALERT, OT,
THERM, and FANFAIL). I for my part find the therm "indication"
quite confusing.

Guenter

> > +
> > +  "^therm[0-1]_indication$":
> > +    type: boolean
> > +    default: false
> > +    description:
> > +      If true then enable THERM pin indication.
>
> Ditto
>
> > +
> > +  "^fan@[0-1]$":
>
> [01]
> The same in other cases.
>
> > +    type: object
> > +    description: |
> > +      Represents the two fans and their specific configuration.
> > +
> > +    $ref: fan-common.yaml#
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The fan number.
> > +        items:
> > +          minimum: 0
> > +          maximum: 1
> > +
> > +      maxim,fan-spin-up:
> > +        type: boolean
> > +        description:
> > +          If true then whnever the fan starts up from zero drive, it
>
> whenever
> run spell-check
>
> > +          is driven with 100% duty cycle for 2s to ensure that it
> > +          starts.
> > +
> > +      maxim,full-speed-on-therm:
> > +        type: boolean
> > +        description:
> > +          If true then force fan to full speed if THERM pin goes low.
> > +
> > +      maxim,fanfail_indication:
>
> No underscores
>
> > +        type: boolean
> > +        description:
> > +          If true then enable fanfail pin indication.
>
> Missing blank line
>
> > +    required:
> > +      - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    i2c {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +
> > +      max6639@10 {
>
> Node names should be generic.
> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>
> > +        compatible = "maxim,max6639";
> > +        reg = <0x10>;
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        fan@0 {
> > +          reg = <0x0>;
> > +          pulses-per-revolution = <2>;
> > +          max-rpm = <4000>;
> > +          pwm-frequency = <25000>;
> > +        };
> > +
> > +        fan@1 {
> > +          reg = <0x1>;
> > +          pulses-per-revolution = <2>;
> > +          max-rpm = <32000>;
> > +          pwm-frequency = <25000>;
> > +        };
> > +      };
> > +    };
> > +...
>
> Best regards,
> Krzysztof