Hi Dario,

On 23-02-28, Dario Binacchi wrote:

Hi Stefan,

On Mon, Feb 27, 2023 at 6:52 PM Stefan Wahren [off-list ref] wrote:

quoted

Hi Dario,

Am 26.02.23 um 21:53 schrieb Dario Binacchi:

quoted

Since commit 502df79b860563d7 ("gpiolib: Warn on drivers still using static
gpiobase allocation"), one or more warnings are printed during boot on
systems where static allocation of GPIO base is used:

[    0.136834] gpio gpiochip0: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.142753] gpio gpiochip1: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.148452] gpio gpiochip2: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.154341] gpio gpiochip3: Static allocation of GPIO base is deprecated, use dynamic allocation.
[    0.160097] gpio gpiochip4: Static allocation of GPIO base is deprecated, use dynamic allocation.

So let's follow the suggestion and use dynamic allocation.

i understand the motivation of avoiding these warnings.

AFAIK the MXS platform is older than the dynamic allocation of GPIO
base. In the perfect world all applications has been migrated to
libgpiod / chardev GPIO. But i'm really concerned this hasn't happend
yet, at least for this platform. So i believe this change break
applications, since it affects userspace.

Thanks for your explanations.

There was also a lengthly discussion here:

https://lore.kernel.org/all/20230120104647.nwki4silrtd7bt3w@pengutronix.de/ (local)

Do you think it makes sense to use a Kconfig option to enable/disable
the dynamic allocation of GPIO base?

What we could do is to check the GPIO_SYSFS kconfig symbol. If this is
enabled we should keep the current behaviour to not break the uAPI else
we can go with the dynamic numbering. What we should avoid is a new
Kconfig symbol.

Regards,
  Marco

As done, if I'm not mistaken, in commit 80d34260f36c6 ("pinctrl:
renesas: gpio: Use dynamic GPIO base if no function GPIOs")?
With legacy support enabled by default, but the ability to try out the
latest dynamic allocation functionality.

Thanks and regards,
Dario

quoted

Best regards

quoted

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

  drivers/gpio/gpio-mxs.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-mxs.c b/drivers/gpio/gpio-mxs.c
index 7f59e5d936c2..b48a7c1fb7c1 100644
--- a/drivers/gpio/gpio-mxs.c
+++ b/drivers/gpio/gpio-mxs.c

@@ -330,7 +330,7 @@ static int mxs_gpio_probe(struct platform_device *pdev)

      port->gc.to_irq = mxs_gpio_to_irq;
      port->gc.get_direction = mxs_gpio_get_direction;
-     port->gc.base = port->id * 32;
+     port->gc.base = -1;

      err = gpiochip_add_data(&port->gc, port);
      if (err)

-- 

Dario Binacchi

Senior Embedded Linux Developer

dario.binacchi@amarulasolutions.com

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