linux-kernel - Re: [PATCH v3 1/3] dt-bindings: pinctrl: Add support for Amlogic A4 SoCs

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Message-ID: <7c069b82-c31b-45cc-8cf3-a2181a56c2f5@amlogic.com>
Date: Mon, 28 Oct 2024 17:59:07 +0800
From: Xianwei Zhao <xianwei.zhao@...ogic.com>
To: neil.armstrong@...aro.org, Krzysztof Kozlowski <krzk@...nel.org>,
 Jerome Brunet <jbrunet@...libre.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Kevin Hilman <khilman@...libre.com>,
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
 Bartosz Golaszewski <brgl@...ev.pl>, linux-gpio@...r.kernel.org,
 devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/3] dt-bindings: pinctrl: Add support for Amlogic A4
 SoCs



On 2024/10/28 17:46, neil.armstrong@...aro.org wrote:
> [ EXTERNAL EMAIL ]
> 
> On 28/10/2024 10:36, Xianwei Zhao wrote:
>> Hi Neil,
>>     Thanks for your advice.
>>
>> On 2024/10/28 17:09, neil.armstrong@...aro.org wrote:
>>> [ EXTERNAL EMAIL ]
>>>
>>> On 28/10/2024 10:07, Xianwei Zhao wrote:
>>>> Hi Neil,
>>>>      Based on the current discussion results, GPIO index macro 
>>>> definition does not belong to bindings. If so, the pinctrl driver 
>>>> keeps the existing architecture, and use numbers instead in dts 
>>>> file. Or the pinctrl driver use bank mode acess, this may not be 
>>>> compatible with existing frameworks. This is done by adding of_xlate 
>>>> hook functions in pinctrl_chip struct.
>>>>
>>>> What is your advice that I can implement in the next version. Thanks!
>>>
>>> Keep the driver as-is, but move the header file into 
>>> arch/arm64/boot/dts/amlogic like it was done for the last reset 
>>> controller support:
>>> arch/arm64/boot/dts/amlogic/amlogic-t7-reset.h
>>>
>>
>> I don't see examples C file applies dts header file.
>> C file need to be defined once, and this needs to be defined again in 
>> dts header file.
> 
> Sorry could you rephrase, the sentence isn't clear.
> 

I'm sorry I didn't describe it clearly.

The pin index definition is used in driver C file and in DTS files.
It's not like reset definition only used in DTS files.
If the pin definition header file place arch/arm64/boot/dts/amlogic, so 
the driver C file needs to be defined again. I don't see examples of how 
a C file applies a DTS header file.

> Neil
> 
>>
>>> Neil
>>>
>>>>
>>>> On 2024/10/21 23:27, Krzysztof Kozlowski wrote:
>>>>> [ EXTERNAL EMAIL ]
>>>>>
>>>>> On 21/10/2024 12:38, neil.armstrong@...aro.org wrote:
>>>>>>>> ====><=================
>>>>>>>> +/* Standard port */
>>>>>>>> +#define GPIOB_START        0
>>>>>>>> +#define GPIOB_NUM  14
>>>>>>>> +
>>>>>>>> +#define GPIOD_START        (GPIOB_START + GPIOB_NUM)
>>>>>>>> +#define GPIOD_NUM  16
>>>>>>>> +
>>>>>>>> +#define GPIOE_START        (GPIOD_START + GPIOD_NUM)
>>>>>>>> +#define GPIOE_NUM  2
>>>>>>>> +
>>>>>>>> +#define GPIOT_START        (GPIOE_START + GPIOE_NUM)
>>>>>>>> +#define GPIOT_NUM  23
>>>>>>>> +
>>>>>>>> +#define GPIOX_START        (GPIOT_START + GPIOT_NUM)
>>>>>>>> +#define GPIOX_NUM  18
>>>>>>>> +
>>>>>>>> +#define PERIPHS_PIN_NUM    (GPIOX_START + GPIOX_NUM)
>>>>>>>> +
>>>>>>>> +/* Aobus port */
>>>>>>>> +#define GPIOAO_START       0
>>>>>>>> +#define GPIOAO_NUM 7
>>>>>>>> +
>>>>>>>> +/* It's a special definition, put at the end, just 1 num */
>>>>>>>> +#define    GPIO_TEST_N     (GPIOAO_START +  GPIOAO_NUM)
>>>>>>>> +#define    AOBUS_PIN_NUM   (GPIO_TEST_N + 1)
>>>>>>>> +
>>>>>>>> +#define AMLOGIC_GPIO(port, offset) (port##_START + (offset))
>>>>>>>> ====><=================
>>>>>>>>
>>>>>>>> is exactly what rob asked for, and you nacked it.
>>>>>>>
>>>>>>> No, this is not what was asked, at least according to my 
>>>>>>> understanding.
>>>>>>> Number of GPIOs is not an ABI. Neither is their relationship, 
>>>>>>> where one
>>>>>>> starts and other ends.
>>>>>>
>>>>>> I confirm this need some work, but it moved the per-pin define to 
>>>>>> start
>>>>>> and ranges, so what did rob expect ?
>>>>>>
>>>>>>>
>>>>>>> Maybe I missed something, but I could not find any users of these 
>>>>>>> in the
>>>>>>> DTS. Look:
>>>>>>>
>>>>>>> https://lore.kernel.org/all/20241014-a4_pinctrl-v2-3-3e74a65c285e@amlogic.com/
>>>>>>
>>>>>> So you want consumers before the bindings ? strange argument
>>>>>>
>>>>>>>
>>>>>>> Where is any of above defines?
>>>>>>>
>>>>>>> Maybe they will be visible in the consumer code, but I did not 
>>>>>>> imagine
>>>>>>> such use. You expect:
>>>>>>> reset-gpios = <&ctrl GPIOAO_START 1>???
>>>>>>
>>>>>> No I expect:
>>>>>> reset-gpios = <&ctrl AMLOGIC_GPIO(B, 0) 1>;
>>>>>>
>>>>>> but the macro should go along the dts like we did for the reset 
>>>>>> defines,
>>>>>> so perhaps this is the solution ?
>>>>>
>>>>> OK, so I said it was not a binding:
>>>>> https://lore.kernel.org/all/u4afxqc3ludsic4n3hs3r3drg3ftmsbcwfjltic2mb66foo47x@xe57gltl77hq/
>>>>>
>>>>> and you here confirm, if I understood you correctly, that it goes with
>>>>> the DTS like reset defines (I assume non-ID like defines?), so also 
>>>>> not
>>>>> a binding?
>>>>>
>>>>> What are we disagreeing with?
>>>>>
>>>>> Just to recall, Jerome asked whether you have to now use arbitrary
>>>>> numbers in DTS and my answer was: not. It's still the same answer.
>>>>>
>>>>> Best regards,
>>>>> Krzysztof
>>>>>
>>>
>