Am Freitag, 30. August 2013, 14:08:41 schrieb Stephen Warren: > On 08/29/2013 01:00 PM, Linus Walleij wrote: > > On Fri, Aug 23, 2013 at 9:52 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: > >> On 08/23/2013 12:45 PM, Linus Walleij wrote: > >>> This is a perfectly OK thing to do as long as it is done like > >>> this: > >>> > >>> request_gpio(gpio); > >>> gpio_direction_input(gpio); > >>> request_irq(gpio_to_irq(gpio)); > >> > >> But I'm not aware that there's a rule saying it's illegal to: > >> > >> request_irq(gpio_to_irq(gpio)); > >> request_gpio(gpio); > >> gpio_direction_input(gpio); > > > > No but I think there should be one ... maybe I'm an oddball > > but it seems natural to request a GPIO before tying > > IRQs to fire off it. > > What if there is no GPIO? If there is no GPIO there is no gpio-controller and there is no problem. > There are plenty of chips with dedicated IRQ input pins that can't be > read as GPIOs, or treated as GPIOs in any way. > > If a driver only needs IRQ input functionality, it should just request > an IRQ and be done with it. There should be no need at all for the > driver to know that the IRQ might be routed into a GPIO controller, and > hence that the driver may (or may not) need to additionally request the > GPIO before requesting the IRQ. Yes, you're right, but reality is different. Legacy drivers / board-files do: request_gpio(gpio); gpio_direction_input(gpio); request_irq(gpio_to_irq(gpio)); > In other words, request_irq() must do everything necessary for the input > signal to operate as an IRQ input, irrespective of whether it might be > possible to use that input signal as a GPIO. -- 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
