Re: [PATCH v2 06/13] dt-bindings: serial: atmel,at91-usart: Add SAM9260 compatibles to SAM9x60

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Sergiu.Moga@microchip.com, robh@kernel.org
Cc: devicetree@vger.kernel.org, alexandre.belloni@bootlin.com,
	linux-clk@vger.kernel.org, Kavyasree.Kotagiri@microchip.com,
	Tudor.Ambarus@microchip.com, richard.genoud@gmail.com,
	gregkh@linuxfoundation.org, radu_nicolae.pirea@upb.ro,
	lee@kernel.org, linux-spi@vger.kernel.org,
	linux-kernel@vger.kernel.org, mturquette@baylibre.com,
	broonie@kernel.org, admin@hifiphile.com,
	krzysztof.kozlowski+dt@linaro.org, linux-serial@vger.kernel.org,
	sboyd@kernel.org, jirislaby@kernel.org,
	Claudiu.Beznea@microchip.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 06/13] dt-bindings: serial: atmel,at91-usart: Add SAM9260 compatibles to SAM9x60
Date: Tue, 13 Sep 2022 10:58:28 +0200	[thread overview]
Message-ID: <5f8ca612-5a89-db3a-42f3-a0613c192a87@linaro.org> (raw)
In-Reply-To: <77d38e3f-6d8c-dbb1-2e66-c768d95b5e35@microchip.com>

On 12/09/2022 15:09, Sergiu.Moga@microchip.com wrote:
> On 12.09.2022 13:44, Krzysztof Kozlowski wrote:
>> On 12/09/2022 09:45, Sergiu.Moga@microchip.com wrote:
>>> On 09.09.2022 04:36, Rob Herring wrote:
>>>> On Thu, Sep 08, 2022 at 03:15:44PM +0000, Sergiu.Moga@microchip.com wrote:
>>>>> On 08.09.2022 15:30, Krzysztof Kozlowski wrote:
>>>>>> On 06/09/2022 15:55, Sergiu Moga wrote:
>>>>>>> Add the AT91SAM9260 serial compatibles to the list of SAM9X60 compatibles
>>>>>>> in order to highlight the incremental characteristics of the SAM9X60
>>>>>>> serial IP.
>>>>>>>
>>>>>>> Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com>
>>>>>>> ---
>>>>>>>
>>>>>>>
>>>>>>> v1 -> v2:
>>>>>>> - Nothing, this patch was not here before
>>>>>>>
>>>>>>>
>>>>>>>     Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml | 2 ++
>>>>>>>     1 file changed, 2 insertions(+)
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml
>>>>>>> index b25535b7a4d2..4d80006963c7 100644
>>>>>>> --- a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml
>>>>>>> +++ b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml
>>>>>>> @@ -26,6 +26,8 @@ properties:
>>>>>>>           - items:
>>>>>>>               - const: microchip,sam9x60-dbgu
>>>>>>>               - const: microchip,sam9x60-usart
>>>>>>> +          - const: atmel,at91sam9260-dbgu
>>>>>>> +          - const: atmel,at91sam9260-usart
>>>>>>
>>>>>> This is weird. You say in commit msg to "highlight the incremental
>>>>>> characteristics" but you basically change here existing compatibles.
>>>>>
>>>>>
>>>>> Does "show that they are incremental IP's" sound better then?
>>>>>
>>>>>
>>>>>> This is not enum, but a list.
>>>>>>
>>>>>
>>>>>
>>>>> What do you mean by this? I know it is a list, I specified so in the
>>>>> commit message.
>>>>
>>>> You are saying that compatible must be exactly the 4 strings above in
>>>> the order listed. You need another entry with another 'items' list.
>>>>
>>>> Rob
>>>
>>>
>>> That is what was intended though: a list of the 4 compatibles in that
>>> exact order. The 4th patch of this series also ensures that all 9x60
>>> nodes have that exact list of 4 compatibles.
>>
>> The commit msg suggest otherwise - two options, because it is
>> incremental... But this one is not really incremental - you require this
>> one, only one, configuration. It's in general fine, but commit msg
>> should reflect what you are really intend to do here and why you are
>> doing it.
>>
>>
>> Best regards,
>> Krzysztof
> 
> 
> My apologies, I still do not understand what is wrong with the commit 
> message. My intention was to ensure that every 9x60 usart compatible is 
> followed by the 9260 compatibles because the 9x60 serial IP is an 
> improvement over the 9260 one. Would you prefer it to be just the first 
> part of the commit message: `Add the AT91SAM9260 serial compatibles to 
> the list of SAM9X60 compatibles`? That way it would really only be what 
> the commit does.

Let me rephrase it:

What your commit is doing is requiring additional fallback compatibles.
Therefore the commit msg should answer - why do you require additional
fallback compatibles?

Incremental characteristics sound to me optional. I can increment
sam9x60 with something or I can skip it. But you are not doing it...
sam9x60 was already there and now you require a fallback.

Best regards,
Krzysztof

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