Re: [PATCH v2 1/3] dt-bindings: serial: Add Loongson UART controller

[Krzysztof Kozlowski <krzk@kernel.org>]

On 09/08/2024 11:55, 郑豪威 wrote:
>>
>>>>> +    description: Enables fractional-N division. Currently,
>>>>> +      only LS2K1500 and LS2K2000 support this feature.
>>>>> +
>>>>> +  rts-invert:
>>>>> +    description: Inverts the RTS value in the MCR register.
>>>>> +      This should be used on Loongson-3 series CPUs, Loongson-2K
>>>>> +      series CPUs, and Loongson LS7A bridge chips.
>>>>> +
>>>>> +  dtr-invert:
>>>>> +    description: Inverts the DTR value in the MCR register.
>>>>> +      This should be used on Loongson-3 series CPUs, Loongson-2K
>>>>> +      series CPUs, and Loongson LS7A bridge chips.
>>>>> +
>>>>> +  cts-invert:
>>>>> +    description: Inverts the CTS value in the MSR register.
>>>>> +      This should be used on Loongson-2K0500, Loongson-2K1000,
>>>>> +      and Loongson LS7A bridge chips.
>>>>> +
>>>>> +  dsr-invert:
>>>>> +    description: Inverts the DSR value in the MSR register.
>>>>> +      This should be used on Loongson-2K0500, Loongson-2K1000,
>>>>> +      and Loongson LS7A bridge chips.
>> Same questions for all these. Why choosing invert is a board level
>> decision? If it "should be used" then why it is not used always?
>>
> Because these features are not applicable to all chips, such as 
> 'fractional-division',

Hm?

> 
> which is currently supported only by 2K1500 and 2K2000, and for 
> Loongson-3 series

These are SoCs. Compatible defines that. Please align with your
colleagues, because *we talked about this* already.

Best regards,
Krzysztof