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

[Ronald Claveau <linux-kernel-dev@aliel.fr>]

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@aliel.fr>
>> ---
>>  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.

>> +      - 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