[PATCH 1/3] dt-bindings: hwmon: Add maxim max31790 driver bindings

[Chanh Nguyen]

On 18/03/2024 17:00, Krzysztof Kozlowski wrote:
> On 18/03/2024 10:51, Chanh Nguyen wrote:
>>
>>> It does not look like you tested the bindings, at least after quick
>>> look. Please run `make dt_binding_check` (see
>>> Documentation/devicetree/bindings/writing-schema.rst for instructions).
>>> Maybe you need to update your dtschema and yamllint.
>>>
>>
>>
>> I tested the binding, I didn't see any warning/error log. Please review
>> my logs as below
> 
> Hm, I don't remember what brought my attention to possible error. Maybe
> I mistyped my template.
> 
>>
>> => make dt_binding_check DT_SCHEMA_FILES=/hwmon/max31790.yaml
>> make[1]: Entering directory '/DISK4T/work/community/linux/out'
>>     DTEX    Documentation/devicetree/bindings/hwmon/max31790.example.dts
>>     DTC_CHK Documentation/devicetree/bindings/hwmon/max31790.example.dtb
>> make[1]: Leaving directory '/DISK4T/work/community/linux/out'
>>
>>>>
>>>> Signed-off-by: Chanh Nguyen <chanh at os.amperecomputing.com>
>>>> ---
>>>>    .../devicetree/bindings/hwmon/max31790.yaml   | 44 +++++++++++++++++++
>>>>    1 file changed, 44 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/hwmon/max31790.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/hwmon/max31790.yaml b/Documentation/devicetree/bindings/hwmon/max31790.yaml
>>>> new file mode 100644
>>>> index 000000000000..5a93e6bdebda
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/hwmon/max31790.yaml
>>>
>>> Filename like compatible.
>>
>> Yes, I'll update that in v2
>>
>>>
>>>> @@ -0,0 +1,44 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/hwmon/max31790.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: The Maxim MAX31790 Fan Controller
>>>> +
>>>> +maintainers:
>>>> +  - Jean Delvare <jdelvare at suse.com>
>>>> +  - Guenter Roeck <linux at roeck-us.net>
>>>
>>> You should have here someone responsible for hardware, not subsystem
>>> maintainers.
>>>
>>
>> Hi Krzysztof,
>> I checked the history of the drivers/hwmon/max31790.c and see Guenter
>> Roeck <linux at roeck-us.net> as an important maintainer. I saw many
>> commits from him. So, I add him to maintainer list.
> 
> OK
> 
>>
>>>> +
>>>> +description: >
>>>> +  The MAX31790 controls the speeds of up to six fans using six
>>>> +  independent PWM outputs. The desired fan speeds (or PWM duty cycles)
>>>> +  are written through the I2C interface.
>>>> +
>>>> +  Datasheets:
>>>> +    https://datasheets.maximintegrated.com/en/ds/MAX31790.pdf
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    const: maxim,max31790
>>>> +
>>>> +  reg:
>>>> +    maxItems: 1
>>>
>>> That's weirdly empty.
>>>
>>
>> Hi Krzysztof,
>> I have not yet understood your comment here. Please help give more
>> details for my missing! Thank Krzysztof!
> 
> I expect many more properties of a fan controller. Resources (clocks,
> PWMs, supplies) and FAN specific properties.
> 

Hi Krzysztof,

I'm creating a base binding document for the max31790 driver. I'm basing 
it on the drivers/hwmon/max31790.c. Currently, the max31790.c driver has 
not yet implemented other properties, such as clocks, fan-supply, pwms, 
etc. So I just introduced the "compatible" and "reg" properties.

In the near future, if any other properties are necessary, I think we 
will implement them in drivers/hwmon/max31790.c then update this binding 
document.

I look at other binding documents, I also see something similar. They 
just introduce the "compatible" and "reg" properties.

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/devicetree/bindings/hwmon/adi,max31760.yaml 


https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/devicetree/bindings/hwmon/adt7475.yaml

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/Documentation/devicetree/bindings/hwmon/adi,ad741x.yaml

This is only my view. It's a pleasure to hear your advice. Thanks!


> 
>>>> +
>>>> +required:
>>>> +  - compatible
>>>> +  - reg
>>>> +
>>>
>>> You miss allOf: with $ref to fan controller schema.
>>>
>>
>> Thank Krzysztof,
>> I'll add the allOf at v2.
>>
>>>> +additionalProperties: false
>>>> +
>>>> +examples:
>>>> +  - |
>>>> +    i2c {
>>>> +      #address-cells = <1>;
>>>> +      #size-cells = <0>;
>>>> +
>>>> +      max31790 at 20 {
>>>
>>> Node names should be generic. See also an explanation and list of
>>> examples (not exhaustive) in DT specification:
>>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>>>
>>
>> I suggest some node names, such as "i2c-fan" or "fan-controller" . Can
>> you please share your ideas with me!
> 
> Look at recent commits and patches for similar type of a device.
> 

Hi Krzysztof,

I checked on recent commits and found something of a similar type.

adi,max31760.yaml
         fan-controller at 50 {
             reg = <0x50>;
             compatible = "adi,max31760";
         };

hpe,gxp-fan-ctrl.yaml
     fan-controller at 1000c00 {
       compatible = "hpe,gxp-fan-ctrl";
       reg = <0x1000c00 0x200>, <0xd1000000 0xff>, <0x80200000 0x100000>;
       reg-names = "base", "pl", "fn2";
     };


adi,axi-fan-control.yaml
         axi_fan_control: axi-fan-control at 80000000 {
             compatible = "adi,axi-fan-control-1.00.a";
             reg = <0x0 0x80000000 0x10000>;
             clocks = <&clk 71>;
             interrupts = <0 110 0>;
             pulses-per-revolution = <2>;
         };

I think "fan-controller" is a good node name. Do you think so?

> Best regards,
> Krzysztof
>