linux-kernel - Re: [PATCH 1/3] spi: s3c64xx: support spi polling mode using devicetree

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Message-ID: <d5627bf6-8cae-f260-f18e-6259a40237c3@samsung.com>
Date:   Wed, 5 Apr 2023 20:42:22 +0900
From:   Jaewon Kim <jaewon02.kim@...sung.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Andi Shyti <andi@...zian.org>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>
Cc:     linux-spi@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Chanho Park <chanho61.park@...sung.com>
Subject: Re: [PATCH 1/3] spi: s3c64xx: support spi polling mode using
 devicetree


On 23. 4. 5. 14:42, Krzysztof Kozlowski wrote:
> On 04/04/2023 08:00, Jaewon Kim wrote:
>> This patch adds new 'samsung,spi-polling' property to support polling mode.
> Do not use "This commit/patch", but imperative mood. See:
> https://protect2.fireeye.com/v1/url?k=3cb451b1-5d3f4488-3cb5dafe-000babffae10-4326e9d41dfad262&q=1&e=1125b69d-6d9e-4c91-a8fd-3470cd2278e4&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv5.17.1%2Fsource%2FDocumentation%2Fprocess%2Fsubmitting-patches.rst%23L95
>
> Also, binding should be before its usage.

thanks.

I will refer to it in next version.

>> In some environments, polling mode is required even if DMA is supported.
> Why? What are these environments? You need to explain all this in commit
> msg.
>

We are providing a VM environment in which several Guest OSs are running.

There are cases where DMA exist only in HostOS and not exist in GuestOS.
In this case, SPI in GuestOS runs with polling mode.

I thought it was correct that the polling mode was supported optional, 
not quirk.
I have plan to change the polling mode if there is no 'dmas' property.

How about your opinion?


>> Changed it to support not only with quick but also optinally with
> typo: optionally
>
>> devicetree.
>>
> Best regards,
> Krzysztof
>
>

Thanks

Jaewon Kim