[PATCH] gpio: TODO: add a task for removing MMIO-specific fields from gpio_chip

[PATCH] gpio: TODO: add a task for removing MMIO-specific fields from gpio_chip

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Currently for CONFIG_GPIO_GENERIC=y each struct gpio_chip object
contains the fields relevant only for gpio-mmio users. It's not an
insignificant number either as it's several pointers and integers.

It makes sense to remove these fields from struct gpio_chip into a
dedicated structure but this is not trivial due to how the bgpio_init()
function is implemented.

Add a task for tracking this rework.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/TODO | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpio/TODO b/drivers/gpio/TODO
index 4a8b349f2483a..ef53892cb44d7 100644
--- a/drivers/gpio/TODO
+++ b/drivers/gpio/TODO
@@ -131,6 +131,11 @@ Work items:
   helpers (x86 inb()/outb()) and convert port-mapped I/O drivers to use
   this with dry-coding and sending to maintainers to test
 
+- Move the MMIO GPIO specific fields out of struct gpio_chip into a
+  dedicated structure. Currently every GPIO chip has them if gpio-mmio is
+  enabled in Kconfig even if it itself doesn't register with the helper
+  library.
+
 -------------------------------------------------------------------------------
 
 Generic regmap GPIO
-- 
2.48.1

Re: [PATCH] gpio: TODO: add a task for removing MMIO-specific fields from gpio_chip

[Linus Walleij]

On Tue, May 27, 2025 at 1:14 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Currently for CONFIG_GPIO_GENERIC=y each struct gpio_chip object
> contains the fields relevant only for gpio-mmio users. It's not an
> insignificant number either as it's several pointers and integers.
>
> It makes sense to remove these fields from struct gpio_chip into a
> dedicated structure but this is not trivial due to how the bgpio_init()
> function is implemented.
>
> Add a task for tracking this rework.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

That's a good TODO.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij

Re: [PATCH] gpio: TODO: add a task for removing MMIO-specific fields from gpio_chip

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Tue, 27 May 2025 13:13:53 +0200, Bartosz Golaszewski wrote:
> Currently for CONFIG_GPIO_GENERIC=y each struct gpio_chip object
> contains the fields relevant only for gpio-mmio users. It's not an
> insignificant number either as it's several pointers and integers.
> 
> It makes sense to remove these fields from struct gpio_chip into a
> dedicated structure but this is not trivial due to how the bgpio_init()
> function is implemented.
> 
> [...]

Applied, thanks!

[1/1] gpio: TODO: add a task for removing MMIO-specific fields from gpio_chip
      https://git.kernel.org/brgl/linux/c/97a7ea2b8f4a9aec1f43435658343e046c2a4983

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>