Re: [PATCH v2 1/8] dt-bindings: mfd: khadas: Add new compatible for Khadas VIM4 MCU

[Ronald Claveau]

On 4/17/26 9:53 AM, Neil Armstrong wrote:
> On 4/16/26 10:25, Ronald Claveau wrote:
>> On 4/15/26 11:48 PM, Rob Herring wrote:
>>> On Fri, Apr 03, 2026 at 06:08:34PM +0200, Ronald Claveau wrote:
>>>> The Khadas VIM4 MCU register is slightly different
>>>> from previous boards' MCU.
>>>> This board also features a switchable power source for its fan.
>>>>
>>>> Signed-off-by: Ronald Claveau <linux-kernel-dev@xxxxxxxx>
>>>> ---
>>>>   Documentation/devicetree/bindings/mfd/khadas,mcu.yaml | 5 +++++
>>>>   1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/mfd/khadas,mcu.yaml
>>>> b/Documentation/devicetree/bindings/mfd/khadas,mcu.yaml
>>>> index 084960fd5a1fd..67769ef5d58b1 100644
>>>> --- a/Documentation/devicetree/bindings/mfd/khadas,mcu.yaml
>>>> +++ b/Documentation/devicetree/bindings/mfd/khadas,mcu.yaml
>>>> @@ -18,6 +18,7 @@ properties:
>>>>     compatible:
>>>>       enum:
>>>>         - khadas,mcu # MCU revision is discoverable
>>>
>>> The revision is no longer discoverable as was claimed?
>>>
>>
>> The firmware revision is still discoverable, and via the same register,
>> but the VIM4 MCU has a different register layout (eg: no DEVICE_NO
>> register). The new compatible is needed to describe a different MCU
>> variant, not a different revision of the same MCU.
>> I will remove the comment as it is confusing with new boards.
> 
> Yes basically it was discoverable for earlier MCU version, but is not
> for this particular board version.
> 
> Keep the comment, but add a comment on the vim4 entry saying this variant
> is not discoverable.
> 
> Neil
> 

Ok make sense, I will do that.

>>
>>>> +      - khadas,vim4-mcu
>>>>       "#cooling-cells": # Only needed for boards having FAN control
>>>> feature
>>>>       const: 2
>>>> @@ -25,6 +26,10 @@ properties:
>>>>     reg:
>>>>       maxItems: 1
>>>>   +  fan-supply:
>>>> +    description: Phandle to the regulator that powers the fan.
>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>> +
>>>>   required:
>>>>     - compatible
>>>>     - reg
>>>>
>>>> -- 
>>>> 2.49.0
>>>>
>>
>>
> 


-- 
Best regards,
Ronald