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

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Message-ID: <aR4EEJO_PeXMKF_h@smile.fi.intel.com>
Date: Wed, 19 Nov 2025 19:53:20 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Jisheng Zhang <jszhang@...nel.org>
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>
Subject: Re: [PATCH] gpio: dwapb: Fold dwapb_context into dwapb_gpio_port

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.

-- 
With Best Regards,
Andy Shevchenko