[PATCH] [RFC] gpiolib: introduce gpio_name() helper

[Geert Uytterhoeven]

Hi Arnd,

On Mon, 29 Jun 2026 at 15:59, Arnd Bergmann <arnd at kernel.org> wrote:
> From: Arnd Bergmann <arnd at arndb.de>
>
> Most remaining users of desc_to_gpio() only call it for printing debug
> information.
>
> Replace this with a new gpiod_name() helper that returns the
> gpio_desc->name string after checking the gpio_desc pointer.
>
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>

Thanks for your patch!

> Not sure if this the way we want to take this, or if the gpio name is
> an appropriate replacement in debug printk.
>
> Since most of the callers of desc_to_gpio() and gpio_to_desc() are
> otherwise in drivers that already depend on CONFIG_GPIOLIB_LEGACY and
> include linux/gpio/legacy.h, only a handful of instances remain that
> are otherwise in files that otherwise only use the descriptor interfaces:

> --- a/drivers/gpio/gpio-aggregator.c
> +++ b/drivers/gpio/gpio-aggregator.c
> @@ -758,8 +758,8 @@ int gpiochip_fwd_desc_add(struct gpiochip_fwd *fwd, struct gpio_desc *desc,
>
>         fwd->descs[offset] = desc;
>
> -       dev_dbg(chip->parent, "%u => gpio %d irq %d\n", offset,
> -               desc_to_gpio(desc), gpiod_to_irq(desc));
> +       dev_dbg(chip->parent, "%u => gpio %s irq %d\n", offset,
> +               gpiod_name(desc), gpiod_to_irq(desc));
>
>         return 0;
>  }

Before, this printed:

    gpio-aggregator gpio-aggregator.1: 0 => gpio 589 irq 188
    gpio-aggregator gpio-aggregator.1: 1 => gpio 590 irq 189

After, this prints:

    gpio-aggregator gpio-aggregator.1: 0 => gpio (null) irq 188
    gpio-aggregator gpio-aggregator.1: 1 => gpio (null) irq 189

Same results for instantiation using sysfs or configfs[1], although
the latter does have optional support for specifying the name.

[1] Documentation/admin-guide/gpio/gpio-aggregator.rst

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds