[PATCH v8 0/8] Add VIM4 MCU/FAN support
linux-kernel-dev at aliel.fr
linux-kernel-dev at aliel.fr
Tue Aug 4 01:30:24 PDT 2026
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
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