On Thu, Jul 24, 2014 at 10:12 AM, Markus Niebel <list-09_linux_arm@xxxxxxx> wrote: > Am 23.07.2014 18:14, wrote Linus Walleij: >> So always prepare the hardware and make it ready for action in respective >> callbacks from the GPIO and irqchip APIs. Do not rely on gpiod_to_irq() having >> been called first. >> > > So a gpio driver is responsible to read status of gpio lines and flag any gpio line > currently configured as out (base on the information read from hardware registers) > on driver probe time - correct? I don't think anyone reads that information explicitly to set up these flags. Drivers just leave the pins in their power-on maiden state without trying to figure out how they're set-up. But as you say, if you call gpiod_get_direction() on them, the flag gets set up indeed. So usually these flags are set by code, calling gpiod_[get/set]_direction(). Then they do get flagged as outputs or inputs. > If yes is the driver allowed to call > gpiod_get_direction() to have the FLAG_IS_OUT set in the gpiolib layer? I don't know if it'd be a good idea to loop over all gpios in a new irqchip and fetch the direction just to get the flags right, so far we haven't done that and I don't know what the usecase would be. If we need that we should do it in gpiolib for all drivers don't you think? But then we need a rationale for doing it, other than it's nice :-) It is already called on-the-fly by debugfs when a user needs that info. 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
