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Subject: Re: [PATCH v11 1/2] dt-bindings: spi: add loongson spi
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Conor Dooley <conor.dooley@microchip.com>
Cc:     Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-spi@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jianmin Lv <lvjianmin@loongson.cn>,
        wanghongliang@loongson.cn, Liu Peibao <liupeibao@loongson.cn>,
        loongson-kernel@lists.loongnix.cn, zhuyinbo@loongson.cn
References: <20230522071030.5193-1-zhuyinbo@loongson.cn>
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 <99b362c2-640c-9150-26ee-e9add4483886@loongson.cn>
 <2196dd29-93ee-00f7-65b4-ede73aa8ba77@linaro.org>
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From:   zhuyinbo <zhuyinbo@loongson.cn>
Message-ID: <32af60eb-dc9d-1d3d-3357-4ec7234bd8a2@loongson.cn>
Date:   Fri, 2 Jun 2023 14:46:50 +0800
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在 2023/6/1 下午11:30, Krzysztof Kozlowski 写道:
> On 01/06/2023 11:51, zhuyinbo wrote:
>>>> Yes, it is make sense as it can reduce the workload of the community.
>>>> For the Loongson platform, the versions of spi peripherals are almost
>>>> the same, except for a few  or individual SoCs.  And we have also
>>>> discussed compatible internally, and we tend to define it this way.
>>>
>>> So you have chosen different path than what's clearly recommended by
>>> community, existing experience and documentation:
>>>
>>> https://elixir.bootlin.com/linux/v6.1-rc1/source/Documentation/devicetree/bindings/writing-bindings.rst#L42
>>>
>>> Family names are not accepted as specific compatibles. Whenever they
>>> were accepted, it lead to problems. All the time.
>>
>>
>> Thank you for your documentation and advice and the Loongson platform
>> have loongson-2h (ls2h), loongson-2k (ls2k), loongson-2p (ls2p) or other
>> series SoC, which loongson-2 seems to be the family name you mentioned
>> and the "loongson,ls2k-spi" should be a speific compatible name.
>>
>>>
>>> https://lore.kernel.org/all/20220822181701.GA89665-robh@kernel.org/
>>> https://lore.kernel.org/all/78651e07-6b3e-4243-8e1f-fcd1dfb3ffe1@www.fastmail.com/
>>> https://lore.kernel.org/all/288f56ba9cfad46354203b7698babe91@walle.cc/
>>> https://lore.kernel.org/all/106e443a-e765-51fe-b556-e4e7e2aa771c@linaro.org/
>>> and many many more discussions.
>>>
>>> You should choose carefully, because we will keep NAK-ing adding
>>> properties to circumvent missing compatibles.
>>
>>
>> I have read the documention and patch link that you mentioned and it
>> seems to advice that We don't have wildcard names in the compatible
>> string and use wildcard names that will cause issue. and the compatible
>> "loongson,ls2k-spi" that wasn't a wildcard names, and if the loongson-2k
>> spi controller hardware upgraded or changed the I will use
>> "loongson,ls2k-spi-version" as a compatible, such as,
>> "loongson,ls2k-spi-v1.1", "loongson,ls2k-spi-v1.1a" or other.
> 
> Versions? Why? They received a lot of comments in the past, let me just
> paste to avoid repeating the same:
> 
> https://lore.kernel.org/all/20220926231238.GA3132756-robh@kernel.org/
> 
> (and many more discussions on devicetree mailing list)
> 


I didn't notice the following words earlier about compatible in
documention and I will use "loongson,ls2k1000-spi" as ls2k1000 SoC spi
compatible, which is a very specific compatible.

"For sub-blocks/components of bigger device (e.g. SoC blocks) use rather
device-based compatible (e.g. SoC-based compatible), instead of custom
versioning of that component.For example use "vendor,soc1234-i2c"
instead of "vendor,i2c-v2".

>>
>>>>
>>>>> Or am I misunderstanding and all ls2k SoCs do work with this driver and
>>>>> you were talking about other, future products?
>>>>
>>>> Actually, in 2k500 has one special type spi was only one cs and their's
>>>> register definition was different from common type spi thus this driver
>>>> doesn't support but this driver can support another common type spi in
>>>> 2k500.  for this special type spi I will add support as needed in the
>>>> future.
>>>
>>> Bindings are for hardware, not driver. What does your driver support or
>>> does not, matters less.
>>
>>
>> okay, I got it, and the loongson spi bindings was for loongson spi
>> controller hardware. if the spi controller hardware not changed in
>> different ls2k SoC and the spi compatible should be same thus loongson
>> spi compatible seems to be adhere to the bindings aggrement.
> 
> Specific compatible - yes. Unspecific - not, because you disregard the
> clear message in the guideline.

okay, I got it.

Thanks.