Re: [PATCH v2 2/3] dt-bindings: power: Add mediatek larb definition
From: Krzysztof Kozlowski
Date: Wed Mar 27 2024 - 07:04:39 EST
On 27/03/2024 11:56, Yu-chang Lee (李禹璋) wrote:
> On Wed, 2024-03-27 at 11:43 +0100, Krzysztof Kozlowski wrote:
>>
>> External email : Please do not click links or open attachments until
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>> On 27/03/2024 11:39, Yu-chang Lee (李禹璋) wrote:
>>>>>>
>>>>> Hi,
>>>>>
>>>>> I will double check the format of yaml for the next version,
>> sorry
>>>> for
>>>>> inconvenience. But I did test it on mt8188 chromebook, the reason
>>>> why
>>>>
>>>> How do you test a binding on chromebook?
>>>>
>>>>> power domain need larb node is that when mtcmos power on, signal
>>>> glitch
>>>>> may produce. Power domain driver must reset larb when this happen
>>>> to
>>>>> prevent dummy transaction on bus. That why I need larb node in
>> dts.
>>>>
>>>> No one talks here about larb node...
>>>
>>> Sorry, May you elaborate on what information I need to provide to
>> you
>>> or it is just a syntax problem I need to fix?
>>
>> Please explain the purpose of this property (how is it going to be
>> used by drivers)and what does it represent.
>>
>
> It represent SMI LARB(Local ARBitration). In power domain driver when
> power on power domain, It need to reset LARB to prevent potential power
> glitch which may cause dummy transaction on bus. Without taking care of
> this issue it often leads to camera hang in stress test.
That sounds rather like missing resets... or something else connecting
these devices. Maybe the explanation is just imprecise...
Best regards,
Krzysztof