From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Linus Walleij <linus.walleij@linaro.org>,
linux-gpio <linux-gpio@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] gpiolib: Document that GPIO line names are not globally unique
Date: Tue, 12 May 2020 12:43:16 +0200 [thread overview]
Message-ID: <CAMpxmJXD9WgrFnKvS2a=iOCVuYiqdTGwp+r2BjOv2RJH2R=s1Q@mail.gmail.com> (raw)
In-Reply-To: <20200511101828.30046-1-geert+renesas@glider.be>
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.
>
> Update the comments for gpio_name_to_desc() and
> gpiochip_set_desc_names() to match reality.
>
> Fixes: f881bab038c9667d ("gpio: keep the GPIO line names internal")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> drivers/gpio/gpiolib.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 99533f4cb5d332a9..98822412f565073a 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -296,6 +296,9 @@ static int gpiodev_add_to_list(struct gpio_device *gdev)
>
> /*
> * Convert a GPIO name to its descriptor
> + * Note that there is no guarantee that GPIO names are globally unique!
> + * Hence this function will return, if it exists, a reference to the first GPIO
> + * line found that matches the given name.
> */
> static struct gpio_desc *gpio_name_to_desc(const char * const name)
> {
> @@ -329,10 +332,12 @@ static struct gpio_desc *gpio_name_to_desc(const char * const name)
> }
>
> /*
> - * Takes the names from gc->names and checks if they are all unique. If they
> - * are, they are assigned to their gpio descriptors.
> + * Take the names from gc->names and assign them to their GPIO descriptors.
> + * Warn if a name is already used for a GPIO line on a different GPIO chip.
> *
> - * Warning if one of the names is already used for a different GPIO.
> + * Note that:
> + * 1. Non-unique names are still accepted,
> + * 2. Name collisions within the same GPIO chip are not reported.
> */
> static int gpiochip_set_desc_names(struct gpio_chip *gc)
> {
> --
> 2.17.1
>
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.
Bart
next prev parent reply other threads:[~2020-05-12 10:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 10:18 [PATCH] gpiolib: Document that GPIO line names are not globally unique Geert Uytterhoeven
2020-05-12 10:43 ` Bartosz Golaszewski [this message]
2020-05-16 9:41 ` Linus Walleij
2020-05-16 9:37 ` Linus Walleij
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAMpxmJXD9WgrFnKvS2a=iOCVuYiqdTGwp+r2BjOv2RJH2R=s1Q@mail.gmail.com' \
--to=bgolaszewski@baylibre.com \
--cc=geert+renesas@glider.be \
--cc=linus.walleij@linaro.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).