On Thu, Oct 17, 2013 at 8:04 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > Hello Jiri, > > On Thu, Oct 17, 2013 at 01:08:02PM +0100, Jiri Prchal wrote: >> Add export possibility to sysfs with given name in device tree. It is nice for >> users to have board specific gpios exported at boot-time and with their names. >> It renames some functions in gpiolib and adds name as parameter. If it is passed >> NULL as name everything works like before, export by chip name. >> It can be done by extra function export_with_name without changing original >> export function but I think there would not to be twice almost the same. >> Even if gpio sysfs interface is almost to be deprecated, I would like to add >> this, cause new chardev interface is in farness future. >> Rebased from older unapplyed patch: [PATCH] owrt: GPIO: add gpio_export_with_name. >> v3: >> change to "linux,gpio-export" >> removed arrays of gpios, just one child node -> one GPIO line >> simplified node properties like as it's in gpio-leds >> if not label -> uses child node name >> >> Signed-off-by: Jiri Prchal <jiri.prchal@xxxxxxxxxxx> >> --- >> Documentation/devicetree/bindings/gpio/gpio.txt | 44 ++++++++++++++++++ >> drivers/gpio/gpiolib-of.c | 56 +++++++++++++++++++++++ >> drivers/gpio/gpiolib.c | 27 +++++++---- >> include/asm-generic/gpio.h | 6 ++- >> include/linux/gpio.h | 23 +++++++++- >> 5 files changed, 144 insertions(+), 12 deletions(-) > > As I mentioned on v1 of this patch [1], I do not think that this is the > right way to go about exporting GPIOs to userspace. Why do we need a > binding for a non-device to tell Linux (specifically Linux) whether or > not to represent a device to userspace, and how to do so? > > Why can this policy not be handled within the GPIO framework, or within > GPIO drivers? Pretty much agree with Mark here. There is no reason to limit this naming feature (which I'm not opposed to fundamentally) to the device tree. Besides gpio_export_with_link() does something suspisciously similar, and better-suited in my opinion: the GPIO keeps its hard-coded, predictable name but is also accessible through a link under the device that uses it. Since GPIOs are typically used as functions for devices this seems to make the most sense. But maybe I'm missing your point - could you describe a concrete use-case for this feature that can *not* be achieved using gpio_export_with_link()? Alex. -- 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
