On 28/04/21 06:54, Alexander Dahl wrote: > Hello Rodolfo, > > I might have had a similar problem, so if you don't mind me entering > the discussion … Welcome. :) > Am Tue, Apr 27, 2021 at 05:30:34PM +0200 schrieb Rodolfo Giometti: >> at the moment if a developer wishes to use a GPIO as output or input with a well >> defined name from userspace via the sysfs interface he/she can use, >> respectively, the gpio-leds or gpio-uinput devices. However, IMHO, this is not >> the best nor a proper way to do it, that's why I'm here to propose this really >> simple interface named GPIO_LINE. > > What's the reason to use the sysfs interface instead of libgpiod and > the modern character device based interface? This would not replace libgpiod and the associated character devices but just allowing developers to easily access some well defined input/output lines as, for example, sensors, etc. So, the question is: why a lot of devices can be read/written via the /sys/class interface and gpio lines can not? :-D >> Note: This patch has been already discussed on linux-gpio@xxxxxxxxxxxxxxx >> mail-list (that's why RFC "v2") and, as suggested by Linus Walleij, the >> discussion has been moved here to see what you think about this proposal. You >> can see the discussion here: https://www.spinics.net/lists/linux-gpio/msg50482.html > > Then, I think you should still Cc the linux-gpio list. This mail-list has already discussed about this interface and I whould avoid cross-posting on mail-lists. >> # cat /sys/kernel/debug/gpio >> gpiochip1: GPIOs 446-475, parent: platform/d0018800.pinctrl, GPIO2: >> gpio-446 ( |usb3-vbus ) out hi >> gpio-447 ( |usb2-vbus ) out hi >> gpio-448 ( |iso_out2 ) out hi >> >> gpiochip0: GPIOs 476-511, parent: platform/d0013800.pinctrl, GPIO1: >> gpio-488 ( |ftdi ) in hi >> >> The End. :) > > Defining line names for GPIOs is already somewhat possible. We talked > about this few weeks ago, when I tried to set line names for a SAMA5D2 > based board: > https://lore.kernel.org/linux-gpio/946021874.11132.1615900079722@xxxxxxxxxxxxxxxxx/ I see, but my idea is also to easily manage these lines. Ciao, Rodolfo -- GNU/Linux Solutions e-mail: giometti@xxxxxxxxxxxx Linux Device Driver giometti@xxxxxxxx Embedded Systems phone: +39 349 2432127 UNIX programming skype: rodolfo.giometti
