linux-kernel - Re: [PATCH 2/2] dt-bindings: serial: sc16is7xx: remove 'clock-frequency' property

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Message-ID: <2c1b47aa-ad4f-4a7b-901c-e0e44cdc31f2@linaro.org>
Date:   Mon, 16 Oct 2023 16:18:41 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Hugo Villeneuve <hugo@...ovil.com>
Cc:     gregkh@...uxfoundation.org, jirislaby@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        conor+dt@...nel.org, hvilleneuve@...onoff.com,
        linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 2/2] dt-bindings: serial: sc16is7xx: remove
 'clock-frequency' property

On 16/10/2023 15:58, Hugo Villeneuve wrote:
> On Mon, 16 Oct 2023 08:09:56 +0200
> Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:
> 
>> On 13/10/2023 16:19, Hugo Villeneuve wrote:
>>> From: Hugo Villeneuve <hvilleneuve@...onoff.com>
>>>
>>> The 'clock-frequency' property is supported but mainly in ACPI-based
>>> configurations, for example.
>>>
>>> This property has therefore no place in the sc16is7xx YAML binding.
>>
>> Please reference commit which you question - 0d447e927. I don't
>> understand why do you remove it. The property was in the original binding.
> 
> Hi,
> in the max310x YAML conversion review (last week), you told me to
> drop the clock-frequency from the binding, even
> if it is supported by the driver, since it is related to ACPI
> configuration, not DT.

Yes, when we talked about max310x.

> 
> The sc16is7xx driver (IC) is very similar to the max310x, and it also
> supports the clock-frequency property, and I just assumed that its
> presence in the original text binding was some kind of error or legacy
> leftover, and would need to be removed based on your comments.

But that is not the same and not accurate. clock-frequency was described
by the binding.

> 
> Just as a reference, here are the original commits in both drivers that
> added support for the clock-frequency property:
> 
> -----------------------
> commit d4d6f03c4fb3a91dadfe147b47edd40e4d7e4d36
> Author: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Date:   Mon May 17 20:29:30 2021 +0300
> 
>     serial: max310x: Try to get crystal clock rate from property
>     
>     In some configurations, mainly ACPI-based, the clock frequency of
> the device is supplied by very well established 'clock-frequency'
> property. Hence, try to get it from the property at last if no other
> providers are available.
> 
> 
> commit 24bc6e68efa00f95034dbef0ba91661dd80bd37d
> Author: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Date:   Mon Mar 18 12:29:15 2019 +0200
> 
>     serial: sc16is7xx: Respect clock-frequency property
>     
>     If the property is provided and there are no other possibilities to
> detect UART clock frequency, use it as a fallback.
> -----------------------

These are driver changes.

Best regards,
Krzysztof