Re: [PATCH v8 0/8] Add VIM4 MCU/FAN support

[email protected] Tue, 4 Aug 2026 10:30:24 +0200
Newsgroups org.kernel.vger.linux-i2c,org.infradead.lists.linux-amlogic,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pm
Message-ID <[email protected]>
On 7/8/26 3:42 PM, Daniel Lezcano wrote:
> On 7/2/26 11:55, Ronald Claveau via B4 Relay wrote:
>> The Khadas VIM4 board features a different MCU variant compared to
>> previous VIM boards.
>> While it shares the same I2C-based communication model,
>> it differs in some ways:
>>
>>    - A distinct register map with its own volatile/writeable register set
>>    - A fan control with 0–100 levels instead of the 0–3 levels previously
> 
> That means for a eg. 100 ms polling, the first one takes 10s to reach
> the max speed, while the second takes 300ms, right ?
> 

Sorry for the delay.
Yes I defined levels 30-100 in the DT as the MCU register description
stated that:
`Note: the parameter value of fan normally open is 0x1E~0x64`

I didn't find any issue with the stress test, but I will address your
concern with a smaller list.

>>    - A fan power supply gated through a regulator
>>
>> This series adds support for this new variant by:
>>
>>    1. Refactoring the khadas-mcu MFD driver to use per-variant data
>>       structures (regmap config, cells, fan platform data),
>>       and adding the khadas,vim4-mcu compatible string.
>>
>>    2. Extending the fan thermal driver to retrieve the fan register
>>       and maximum level from platform_data,
>>       and to optionally manage a power regulator for the fan supply.
> 
> Through which tree do you expect patch 5/8 to go ?
> 

MFD seems a good candidate as this patch depends on it.

-- 
Best regards,
Ronald