Re: [PATCH v2] gpio: dwapb: Fold dwapb_context into dwapb_gpio_port
From: Andy Shevchenko
Date: Mon Nov 24 2025 - 02:57:17 EST
On Mon, Nov 24, 2025 at 08:32:06AM +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
> 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.
Fold --> fold
Given more thinking on this, I believe the approach with kmalloc() is
preferable, but what should be done is
- making context a global variable
- considering allocation for all ports at once
If this is done, the embedded approach will look less efficient.
So, please try that one instead.
--
With Best Regards,
Andy Shevchenko