This patch must be CC to devicetree@xxxxxxxxxxxxxxx as it concerns device tree bindings. Please also keep Alexandre Courbot in the loop as he's working on GPIO refactorings. On Fri, Oct 11, 2013 at 12:05 PM, Jiri Prchal <jiri.prchal@xxxxxxxxxxx> wrote: > Add export possibility to sysfs with given name in device tree. > Rebased from older unapplyed patch: [PATCH] owrt: GPIO: add gpio_export_with_name. > > Signed-off-by: Jiri Prchal <jiri.prchal@xxxxxxxxxxx> This is a very terse commit message for something which will have a very drastic impact on the Linux kernel and device tree. > +3) gpio-export > +-------------- > + > +gpio-export will allow you to automatically export gpio What does this mean? You have to define all terms. And also consider the audience. If someone is using device tree on Symbian or Windows, what does "export" mean to them? Not all readers of this document are Linux implementers. > +required properties: > +- compatible: Should be "gpio-export" If this is a Linux-specific concept it should be named "linux-gpio-export" But overall I'm not happy with this *at all* as the sysfs ABI is already enough of a trouble for us. WIth platforms switching to DT-only probing it would be perfect to get rid of this sysfs interface altogether. Two questions: - What do you think of the approach of just not using this for DT boots, instead we create a new userspace ABI, using e.g. a char device for each GPIO chip like /dev/gpio0, /dev/gpio1 etc and access these using ioctl:s? - I guess you have a specific system in mind for this? What is the use case? I have seen *way* too many people trying to reimplement drivers/leds/leds-gpio.c drivers/input/keyboard/gpio_keys.c drivers/input/keyboard/gpio_keys_polled.c drivers/power/gpio-charger.c drivers/i2c/busses/i2c-gpio.c drivers/extcon/extcon-gpio.c drivers/spi/spi-gpio.c IN USERSPACE! JUST BECAUSE THEY CAN! >From a kernel developers point of view the kernel shall handle hardware, so that is why I'm quite picky about this. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
