Messages in this thread | | | From | Linus Walleij <> | Date | Sat, 16 May 2020 11:41:30 +0200 | Subject | Re: [PATCH] gpiolib: Document that GPIO line names are not globally unique |
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On Tue, May 12, 2020 at 12:43 PM Bartosz Golaszewski <bgolaszewski@baylibre.com> wrote: > pon., 11 maj 2020 o 12:18 Geert Uytterhoeven <geert+renesas@glider.be> > napisał(a): > > > > gpiochip_set_desc_names() no longer rejects GPIO line name collisions. > > Hence GPIO line names are not guaranteed to be globally unique. > > In case of multiple GPIO lines with the same name, gpio_name_to_desc() > > will return the first match found. (...) > This makes me wonder whether I should do something about this in > libgpiod? Looks to me like gpiod_chip_find_line() and the global > gpiod_line_find() are no longer reliable and should probably return > all lines whose names match.
Hm. You probably know how consumers of libgpiod work better than me.
The background is historical and this happens because gpiolib had a mechanism to name lines before I even took over maintenance, and that did not require line names to be unique. So when I created the character device I had to face the fact.
We also had to deal with the fact that when naming lines, the "NULL alternative" (no name on the line at all) is always a valid fallback.
And all lines named NULL are still valid and all have the same name so...
Yours, Linus Walleij
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