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From: Johan Hovold <johan@kernel.org>
To: Markus Pargmann <mpa@pengutronix.de>
Cc: "Linus Walleij" <linus.walleij@linaro.org>,
	"Alexandre Courbot" <gnurou@gmail.com>,
	"Arun Bharadwaj" <arun@gumstix.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Johan Hovold" <johan@kernel.org>,
	linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	kernel@pengutronix.de
Subject: Re: [PATCH v3 3/9] gpiolib: Use GPIO name from names array for gpio descriptor
Date: Wed, 23 Sep 2015 15:02:37 -0700	[thread overview]
Message-ID: <20150923220237.GC19608@localhost> (raw)
In-Reply-To: <1439561466-14350-4-git-send-email-mpa@pengutronix.de>

On Fri, Aug 14, 2015 at 04:11:00PM +0200, Markus Pargmann wrote:
> This patch adds GPIO names to the GPIO descriptors when initializing the
> gpiochip. It also introduces a check whether any of the new names will
> conflict with an existing GPIO name.

And this is why we should not do this. I've said it it before: we need
to consider dynamic buses, not just static device trees.

We have USB and Greybus that will soon be exposing gpiochips and their
line-names can not be globally unique.

Before figuring out what a sane userspace interface should look like we
should not make ABI changes that we need to support indefinitely. The
legacy sysfs interface should instead be frozen.

Exposing a name attribute for a not-necessarily globally unique name
could perhaps be ok, but by enforcing uniqueness at this point we will
then need to come up with another mechanism for naming gpios on dynamic
buses (while maintaining this one indefinitely in parallel).

Linus, please consider dropping these changes for now.

Thanks,
Johan

  parent reply	other threads:[~2015-09-23 22:01 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-14 14:10 [PATCH v3 0/9] gpiolib: Add GPIO name support Markus Pargmann
2015-08-14 14:10 ` [PATCH v3 1/9] gpiolib-of: Rename gpio_hog functions to be generic Markus Pargmann
2015-09-22  0:48   ` Linus Walleij
2015-08-14 14:10 ` [PATCH v3 2/9] gpio: Introduce gpio descriptor 'name' Markus Pargmann
2015-09-22  0:51   ` Linus Walleij
2015-08-14 14:11 ` [PATCH v3 3/9] gpiolib: Use GPIO name from names array for gpio descriptor Markus Pargmann
2015-09-22  0:56   ` Linus Walleij
2015-09-23 22:02   ` Johan Hovold [this message]
2015-09-24 21:50     ` Linus Walleij
2015-08-14 14:11 ` [PATCH v3 4/9] gpio-sysfs: Use gpio descriptor name instead of gpiochip names array Markus Pargmann
2015-09-22  0:57   ` Linus Walleij
2015-08-14 14:11 ` [PATCH v3 5/9] gpiolib: Add gpio name information to /sys/kernel/debug/gpio Markus Pargmann
2015-09-22  1:05   ` Linus Walleij
2015-08-14 14:11 ` [PATCH v3 6/9] gpiolib-sysfs: Show gpio-name in /sys/class/gpio/gpio*/name Markus Pargmann
2015-09-22  1:07   ` Linus Walleij
2015-09-24  7:14     ` Markus Pargmann
2015-08-14 14:11 ` [PATCH v3 7/9] gpiolib-sysfs: Add gpio name parsing for sysfs export Markus Pargmann
2015-09-22  1:09   ` Linus Walleij
2015-09-24  7:23     ` Markus Pargmann
2015-08-14 14:11 ` [PATCH v3 8/9] gpiolib-of: Reuse 'line-name' from DT as gpio descriptor name Markus Pargmann
2015-08-14 14:11 ` [PATCH v3 9/9] gpiolib-of: Use dev_warn instead of pr_warn Markus Pargmann
2015-09-21 10:58 ` [PATCH v3 0/9] gpiolib: Add GPIO name support Markus Pargmann

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