linux-kernel - Re: [PATCH v12 1/2] spi: add loongson spi bindings

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Message-ID: <f6d4ecb5-e9df-346e-4aab-772fd01689c8@loongson.cn>
Date:   Thu, 8 Jun 2023 19:42:49 +0800
From:   zhuyinbo <zhuyinbo@...ngson.cn>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-spi@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Jianmin Lv <lvjianmin@...ngson.cn>, wanghongliang@...ngson.cn,
        Liu Peibao <liupeibao@...ngson.cn>,
        loongson-kernel@...ts.loongnix.cn, zhuyinbo@...ngson.cn
Subject: Re: [PATCH v12 1/2] spi: add loongson spi bindings



在 2023/6/8 下午6:02, Krzysztof Kozlowski 写道:
> On 08/06/2023 12:00, zhuyinbo wrote:
>>
>>
>> 在 2023/6/8 下午4:53, Krzysztof Kozlowski 写道:
>>> On 08/06/2023 10:39, zhuyinbo wrote:
>>>>>>
>>>>>> Signed-off-by: Yinbo Zhu <zhuyinbo@...ngson.cn>
>>>>>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.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..423ee851edd5
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
>>>>>
>>>>> Filename based on compatible.
>>>>
>>>>
>>>> There will be more ls2k series SoC spi device in the future thus I still
>>>> use "loongson,ls2k-spi.yaml" for cover it.
>>>
>>> Add them now.
>>
>>
>> The 2k0500 doesn't support CCF and not use CCF to gain clock and We
>> internally tend to prioritize supporting 2k1000.
> 
> Don't you refer now to drivers? Because how hardware can not support
> clocks if it has them? How CCF is anyhow related to hardware?


The CCF (common clock framework) driver only affects the clock parameter
pass method and isn't related to clock hardware. and if dts pass a
"clock-frequency" that not need a clock driver but if dts pass a
"clocks" that need a clock driver. Currently, only 2k1000 has
implemented a clock driver.

> 
>>
>>>
>>>>
>>>>>
>>>>>> @@ -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@...ngson.cn>
>>>>>> +
>>>>>> +allOf:
>>>>>> +  - $ref: /schemas/spi/spi-controller.yaml#
>>>>>> +
>>>>>> +properties:
>>>>>> +  compatible:
>>>>>> +    enum:
>>>>>> +      - loongson,ls2k1000-spi
>>>>>
>>>>> No compatibles for other devices? Didn't we have big discussion about this?
>>>>>
>>>>> https://elixir.bootlin.com/linux/v6.1-rc1/source/Documentation/devicetree/bindings/writing-bindings.rst#L42
>>>>
>>>>
>>>> There are other ls2k SPI devices compatible, such as,
>>>> "loongson,ls2k0500-spi", "loongson,ls2k2000-spi" but currently I plan to
>>>> add ls2k1000 spi device first, Other ls2k SoC spi device adaptation may
>>>> require some additional work and I will add it later.
>>>
>>> Previously you claimed this serves entire family, so I don't understand
>>> why you need to fix something. Why previously it was working for entire
>>> family but now it does not?
>>
>>
>> It can work was for ls2k1000 and ls2k0500 and it specifically refers to
>> spi driver. but 2k0500 doesn't implementing a clock driver and doesn't
> 
> We do not discuss here drivers, but bindings. Whatever your drivers are
> not supporting, matters less.
> 
>> use CCF to gain clock but can use "clock-frequency".  Is it necessary to
>> obtain a clock based on CCF? If it's necessary, then it seems that it
>> can only added 2k1000 spi first.
> 
> Not related to bindings...


I may understand that what you said, and the dt-bindings only cover 
hardware and not involve the drivers. if so, I will add following:


--- a/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
+++ b/Documentation/devicetree/bindings/spi/loongson,ls2k-spi.yaml
@@ -16,6 +16,7 @@ properties:
    compatible:
      enum:
        - loongson,ls2k1000-spi
+      - loongson,ls2k0500-spi


Thanks,
Yinbo