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

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Message-ID: <0f812132-120e-ffb5-002e-3798854a3c8b@9elements.com>
Date:   Thu, 17 Nov 2022 01:09:25 +0530
From:   Naresh Solanki <naresh.solanki@...ements.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        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

Hi Krzystof,

On 16-11-2022 01:24 pm, Krzysztof Kozlowski wrote:
> 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]$":
>>>> +        $ref: /schemas/leds/common.yaml#
>>>> +        type: object
>>>> +
>>>> +    additionalProperties: false
>>>> +
>>>> +  vss1-supply:
>>>> +    description: Supply of the first channel.
>>>> +
>>>> +  vss2-supply:
>>>> +    description: Supply of the second channel.
>>>> +
>>>> +  regulators:
>>>> +    type: object
>>>> +    description:
>>>> +      Properties for both regulators. Also set value for shunt resistor used.
>>>
>>> You should explain not the syntax,  but what part of hardware this nodes
>>> represents. Therefore "Also set value" does not fit at all. Hardware
>>> sets value?
>> You mean something like: Properties for power switch
>>>
>>> I looked at datasheets to figure it out but they do not refer to any
>>> configurable regulator, LDO nor "sw0/sw1/sw2". Therefore I have no clue
>>> what to expect here...
>> Yes this is for power switch part of max5970/8
> 
> Nothing in max5970 datasheet about "power switch". "switch" fives two
> results, not really related/explaining.
In datasheet the term used is hot swap controller & uses external fet.
Although it gives output 1:1 i.e., doesnt steps up/down the input supply.
i.e., regulator driver is used here.
> 
> Bindings, your naming and explanation use terms not existing in
> datasheet, so it does not look like you are describing hardware.
> 
>>>
>>>> +
>>>> +    patternProperties:
>>>> +      "^sw[0-1]$":
>>>> +        $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.
Will update in next version.
> 
> 
> Best regards,
> Krzysztof
> 

Regards,
Naresh