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Message-ID: <bc356f96-600a-64df-c0fe-00c807fa605c@linaro.org>
Date: Wed, 30 Nov 2022 09:35:04 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Xiangsheng Hou (侯祥胜)
<Xiangsheng.Hou@...iatek.com>,
"miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
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"krzysztof.kozlowski+dt@...aro.org"
<krzysztof.kozlowski+dt@...aro.org>,
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"vigneshr@...com" <vigneshr@...com>,
"richard@....at" <richard@....at>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>,
"linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Benliang Zhao (赵本亮)
<Benliang.Zhao@...iatek.com>,
"linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Bin Zhang (章斌) <bin.zhang@...iatek.com>
Subject: Re: [PATCH 7/9] dt-bindings: spi: mtk-snfi: add two timing delay
property
On 30/11/2022 09:18, Xiangsheng Hou (侯祥胜) wrote:
> Hi Krzysztof,
>
> On Tue, 2022-11-29 at 08:47 +0100, Krzysztof Kozlowski wrote:
>> On 29/11/2022 03:50, Xiangsheng Hou (侯祥胜) wrote:
>>
>>>>> --- a/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-
>>>>> snfi.yaml
>>>>> +++ b/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-
>>>>> snfi.yaml
>>>>> @@ -55,6 +55,22 @@ properties:
>>>>> description: device-tree node of the accompanying ECC
>>>>> engine.
>>>>> $ref: /schemas/types.yaml#/definitions/phandle
>>>>>
>>>>> + rx-sample-delay:
>>>>
>>>> No, use existing property, don't invent your own stuff - missing
>>>> unit
>>>> suffix. See spi-peripheral-props.yaml.
>>>
>>> Will change to other private property. The read sample delay with
>>> MediaTek SPI NAND controller can be set with values from 0 to 47.
>>> However, it`s difficult to say the unit of each vaule, because the
>>> unit
>>> value will be difference with different chip process or different
>>> corner IC.
>>
>> Why you cannot use same formula as other SPI drivers for sample-
>> delay?
>> And divide/multiple by some factor specific to SoC, which is taken
>> from
>> driver_data?
>
> Even for specific SoC, the unit of sample delay may be various with
> different corner IC.
Which is easy to achieve with driver_data as I said.
> Besides, whether it`s acceptable by change the property rx-sample-delay
> and rx-latch-latency to mediatek,rx-sample-delay and mediatek,rx-latch-
> latency?
Not for sample delay, because you should use existing properties. Your
driver implementation is not usually argument to duplicate properties in
the bindings.
Best regards,
Krzysztof
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