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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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 <b1e3d199-de5a-f8d5-9159-4965e9e1f5ef@loongson.cn>
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 <99b362c2-640c-9150-26ee-e9add4483886@loongson.cn>
 <69d355ff-90e1-09d2-d4ff-0d7dedc8addb@linaro.org>
From:   zhuyinbo <zhuyinbo@loongson.cn>
Message-ID: <64773170-4cef-9acc-c2d7-f187bc484825@loongson.cn>
Date:   Thu, 1 Jun 2023 19:38:31 +0800
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在 2023/6/1 上午4:06, Krzysztof Kozlowski 写道:
> On 25/05/2023 04:22, zhuyinbo wrote:
>>
>>
>> 在 2023/5/24 下午6:29, Conor Dooley 写道:
>>> On Wed, May 24, 2023 at 05:44:38PM +0800, zhuyinbo wrote:
>>>>
>>>>
>>>> 在 2023/5/24 下午4:56, Conor Dooley 写道:
>>>>> On Mon, May 22, 2023 at 03:10:29PM +0800, Yinbo Zhu wrote:
>>>>>> Add the Loongson platform spi binding with DT schema format using
>>>>>> json-schema.
>>>>>>
>>>>>> Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
>>>>>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>>>>> ---
>>>>>>     .../bindings/spi/loongson,ls2k-spi.yaml       | 41 +++++++++++++++++++
>>>>>>     MAINTAINERS                                   |  6 +++
>>>>>>     2 files changed, 47 insertions(+)
>>>>>>     create mode 100644 Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml b/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
>>>>>> new file mode 100644
>>>>>> index 000000000000..d0be6e5378d7
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
>>>>>> @@ -0,0 +1,41 @@
>>>>>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>>>>>> +%YAML 1.2
>>>>>> +---
>>>>>> +$id: http://devicetree.org/schemas/spi/loongson,ls2k-spi.yaml#
>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>>> +
>>>>>> +title: Loongson SPI controller
>>>>>> +
>>>>>> +maintainers:
>>>>>> +  - Yinbo Zhu <zhuyinbo@loongson.cn>
>>>>>> +
>>>>>> +allOf:
>>>>>> +  - $ref: /schemas/spi/spi-controller.yaml#
>>>>>> +
>>>>>> +properties:
>>>>>> +  compatible:
>>>>>> +    enum:
>>>>>> +      - loongson,ls2k-spi
>>>>>
>>>>> I am sorry to jump in here at such a late stage with a (potentially)
>>>>> trivial question. "ls2k" is the SoC family rather than a specific model
>>>>> as far as I understand.
>>>>> The answer is probably yes, but do all SoCs in the family have an
>>>>> identical version of the IP?
>>>>
>>>>
>>>> No, but the spi supported by this loongson spi driver are all the same
>>>> identical version, and other type or verion spi will be supported as
>>>> needed in the future.
>>>
>>> Does having a catch-all compatible make sense then when not all SoCs in
>>> the ls2k family will actually be able to use this driver?
>>
>>
>> Yes, it is make sense as it can reduce the workload of the community.
> 
> I missed it - that's a great comment. Hm, I don't know... Reviewing
> Loongson patches is quite a work, so I don't see here reduced workload.


If we do not consider the differences in SPI hardware and consider the
differences in SoC, it will result for each new a SoC adaptation, a new
compatible patch needs to be submitted to the community but spi hardware
was same and that will increase the workload of the community, It seems
to be more appropriate that use same compatible when spi hardware was
same and use different compatible when spi hardware was different.

> 
> Please read existing guidelines:
> https://elixir.bootlin.com/linux/v6.1-rc1/source/Documentation/devicetree/bindings/writing-bindings.rst >
> All of them.
> 

okay, I got it.

Thanks.