linux-kernel - Re: [PATCH] gpio: dwapb: Fold dwapb_context into dwapb_gpio

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Message-ID: <CAMRc=McJz-omnKZsFLN+us00811bM1Q8Y-jodL5gtCp=OEsEEA@mail.gmail.com>
Date: Thu, 20 Nov 2025 05:19:22 -0800
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andriy.shevchenko@...el.com>
Cc: Hoan Tran <hoan@...amperecomputing.com>, Linus Walleij <linus.walleij@...aro.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Andy Shevchenko <andy@...nel.org>, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org, 
	Michael Büsch <mb@...s.ch>, 
	Jisheng Zhang <jszhang@...nel.org>
Subject: Re: [PATCH] gpio: dwapb: Fold dwapb_context into dwapb_gpio_port

On Wed, 19 Nov 2025 18:53:20 +0100, Andy Shevchenko
<andriy.shevchenko@...el.com> said:
> On Wed, Nov 19, 2025 at 11:00:49PM +0800, Jisheng Zhang wrote:
>> Fold dwapb_context into struct dwapb_gpio_port to further simplify
>> the code. Sure this brings a tiny 36 bytes data overhead for
>> !PM_SLEEP. After grepping the arm/arm64/riscv dts dir, the max dwapb
>> gpio port number is 6(the berlin2q soc family), so this means we will
>
> GPIO
>
> *and I believe this is limitation by Synopsys in HW, but I'm not going to check
> the datasheet right now.
>
>> waste 216 bytes memory in total which is trivial compared to the
>> system memory.
>>
>> From another side, as Michael mentioned:
>> "The driver currently allocates the struct with kzalloc and stores a
>> pointer to it in case of PM=y.
>> So this probably has an overhead in the same order of magnitude
>> (pointer + malloc overhead/alignment/fragmentation) in case of PM=y
>> now."
>>
>> So let's Fold dwapb_context into struct dwapb_gpio_port.
>>
>> Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
>
>> CC: Michael Büsch <mb@...s.ch>
>
> Please, use --cc or move Cc list below...
>
>> ---
>
> ...this cutter line. It will have the same effect on the emails, but it will
> reduce the noise in the commit message.
>
>> NOTE: this patch is applied against the following series:
>> [PATCH v3 00/15] gpio: Use modern PM macros
>
> It's better to just put a link to lore.kernel.org or at least message-id.
>
> ...
>
> I have a mixed feelings about this, but if maintainers go with it,
> let it be then.
>

I don't mind it so please resend it with the issues addressed, Jisheng.

Bart