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Subject: Re: [PATCH v2 2/4] spi: Add devicetree bindings documentation for
 Loongson SPI
To:     zhangqing <zhangqing@loongson.cn>, Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     linux-spi@vger.kernel.org, Huacai Chen <chenhc@lemote.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        devicetree@vger.kernel.org, linux-mips@vger.kernel.org,
        linux-kernel@vger.kernel.org, gaojuxin@loongson.cn,
        yangtiezhu@loongson.cn
References: <1607413467-17698-1-git-send-email-zhangqing@loongson.cn>
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 <b97c4d59-3279-f67d-d951-1e9436faa640@gmail.com>
 <20e7dafc-8c67-79e4-e64a-a08e21101678@loongson.cn>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Message-ID: <3f5a7d26-e78a-b02e-5fc2-c241547c683d@gmail.com>
Date:   Tue, 8 Dec 2020 17:48:36 +0300
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On 12/8/20 1:47 PM, zhangqing wrote:

>>> Add spi-ls7a binding documentation.
>>>
>>> Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
>>> ---
>>>   Documentation/devicetree/bindings/spi/spi-ls7a.txt | 31 ++++++++++++++++++++++
>>>   1 file changed, 31 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/spi/spi-ls7a.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/spi/spi-ls7a.txt b/Documentation/devicetree/bindings/spi/spi-ls7a.txt
>>> new file mode 100644
>>> index 0000000..56247b5
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/spi/spi-ls7a.txt
>>> @@ -0,0 +1,31 @@
>>> +Binding for LOONGSON LS7A SPI controller
>>> +
>>> +Required properties:
>>> +- compatible: should be "pci0014,7a0b.0","pci0014,7a0b","pciclass088000","pciclass0880".
>>> +- reg: reference IEEE Std 1275-1994.
>>> +- #address-cells: <1>, as required by generic SPI binding.
>>> +- #size-cells: <0>, also as required by generic SPI binding.
>>> +- #interrupts: No hardware interrupt.
>>
>>    You say it's a required prop, yet yuoe example doesn't have it...
>         I want to emphasize here that LS7A SPI has no hardware interrupts, and DT is not actually used.

   The why document the property at all?

>>> +
>>> +Child nodes as per the generic SPI binding.
>>> +
>>> +Example:
>>> +
>>> +            spi@16,0 {
>>> +                compatible = "pci0014,7a0b.0",
>>> +                        "pci0014,7a0b",
>>> +                        "pciclass088000",
>>> +                        "pciclass0880";
>>> +
>>> +                #address-cells = <1>;
>>> +                #size-cells = <0>;
>>> +                reg = <0xb000 0x0 0x0 0x0 0x0>;
>>> +                num-chipselects = <0>;
>>> +                spiflash: s25fl016k@0 {
>>> +                #address-cells = <1>;
>>> +                #size-cells = <1>;
>>
>>    Once more?
>>
>>> +                compatible ="spansion,s25fl016k","jedec,spi-nor";
>>
>>    Once more?
>>
>>> + spi-max-frequency=<50000000>;
>>> +                reg=<0>;
>>
>>    Once more? Did you mean this for a child node?
>        Yes, these are child node attributes, the child node splash is not necessary.

   You should indent the child nodes with 1 more tab...

>>
>>> +                };
>>> +            };
>>
>      Thanks
> 
>      -Qing

MBR, Sergei