linux-kernel - Re: [PATCH v10 1/2] dt-bindings: mfd: Add MAX5970 and MAX5978

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Date:   Wed, 16 Nov 2022 08:54:39 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Naresh Solanki <naresh.solanki@...ements.com>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Lee Jones <lee@...nel.org>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Patrick Rudolph <patrick.rudolph@...ements.com>
Cc:     Marcello Sylvester Bauer <sylv@...v.io>
Subject: Re: [PATCH v10 1/2] dt-bindings: mfd: Add MAX5970 and MAX5978

On 15/11/2022 21:30, Naresh Solanki wrote:
> Hi Krzysztof,
> 
> On 15-11-2022 07:34 pm, Krzysztof Kozlowski wrote:
>> On 15/11/2022 12:09, Naresh Solanki wrote:
>>> From: Marcello Sylvester Bauer <sylv@...v.io>
>>>
>>> The MAX597x is a hot swap controller with configurable fault protection.
>>> It also has 10bit ADC for current & voltage measurements.
>>>
>>> Signed-off-by: Marcello Sylvester Bauer <sylv@...v.io>
>>> Co-developed-by: Patrick Rudolph <patrick.rudolph@...ements.com>
>>> Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
>>> Co-developed-by: Naresh Solanki <Naresh.Solanki@...ements.com>
>>> Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>
>>> ---
>>>   .../bindings/mfd/maxim,max5970.yaml           | 154 ++++++++++++++++++
>>>   1 file changed, 154 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
>>> new file mode 100644
>>> index 000000000000..edf0c23db4ca
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mfd/maxim,max5970.yaml
>>> @@ -0,0 +1,154 @@
>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/mfd/maxim,max5970.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Regulator for MAX5970 smart switch from Maxim Integrated.
>>> +
>>> +maintainers:
>>> +  - Patrick Rudolph <patrick.rudolph@...ements.com>
>>> +
>>> +description: |
>>> +  The smart switch provides no output regulation, but independent fault protection
>>> +  and voltage and current sensing.
>>> +  Programming is done through I2C bus.
>>> +
>>> +  Datasheets:
>>> +    https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
>>> +    https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - maxim,max5970
>>> +      - maxim,max5978
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    maxItems: 1
>>> +
>>> +  leds:
>>> +    type: object
>>> +    description:
>>> +      Properties for four LEDS.
>>> +
>>> +    properties:
>>> +      "#address-cells":
>>> +        const: 1
>>> +
>>> +      "#size-cells":
>>> +        const: 0
>>> +
>>> +    patternProperties:
>>> +      "^led@[0-3]$":
>>> +        $ref: /schemas/leds/common.yaml#
>>> +        type: object
>>> +
>>> +    additionalProperties: false
>>> +
>>> +  vss1-supply:
>>> +    description: Supply of the first channel.
>>> +
>>> +  vss2-supply:
>>> +    description: Supply of the second channel.
>>> +
>>> +  regulators:
>>> +    type: object
>>> +    description:
>>> +      Properties for both regulators. Also set value for shunt resistor used.
>>
>> You should explain not the syntax,  but what part of hardware this nodes
>> represents. Therefore "Also set value" does not fit at all. Hardware
>> sets value?
> You mean something like: Properties for power switch
>>
>> I looked at datasheets to figure it out but they do not refer to any
>> configurable regulator, LDO nor "sw0/sw1/sw2". Therefore I have no clue
>> what to expect here...
> Yes this is for power switch part of max5970/8

Nothing in max5970 datasheet about "power switch". "switch" fives two
results, not really related/explaining.

Bindings, your naming and explanation use terms not existing in
datasheet, so it does not look like you are describing hardware.

>>
>>> +
>>> +    patternProperties:
>>> +      "^sw[0-1]$":
>>> +        $ref: /schemas/regulator/regulator.yaml#
>>> +        type: object
>>> +        properties:
>>> +          shunt-resistor-micro-ohms:
>>> +            description: |
>>> +              The value of current sense resistor in microohms.
>>> +
>>> +        required:
>>> +          - shunt-resistor-micro-ohms
>>> +
>>> +      unevaluatedProperties: false
>>
>> I don't think it has proper indentation. Did you test the binding?
> Definitely tested the bindings before I push the patch.

Anyway it is wrong. It must be on the level of properties.


Best regards,
Krzysztof