On 09/03/2013 06:43 AM, Linus Walleij wrote: > On Fri, Aug 30, 2013 at 9:55 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: >> On 08/29/2013 06:24 PM, Javier Martinez Canillas wrote: >> ... >>> We have been trying to solve this issue for a few months by now and Linus' >>> approach seems to be the most sensible solution to me. >>> >>> Drivers that request an IRQ and assume that platform code will request and setup >>> the GPIO have been broken since the boards using these drivers were migrated to >>> DT (e.g: smsc911x on OMAP2+ boards). >> >> That's only true if the driver for the GPIO controller is buggy. >> Whatever request_irq() maps down to in the GPIO/IRQ controller driver >> simply needs to set up the pin as an interrupt input, then it doesn't >> matter which order the driver does things. > > As mentioned it can't do that, because doing that creates a > restriction on which order the driver does things... I am not convinced here. Which driver (GPIO/IRQ controller driver, or the driver which uses GPIOs/IRQs?) Which operations? > But you mentioned that you wanted an API that would account > for the case where the *same driver* requested the same resource > (a GPIO line) to be used for both IRQ and GPIO, through two > different calls. > > I would be happy to see how we could do that, preferably in a > generic way. > > Since the gpio_request() does not contain the signature of the > calling driver I don't see how we could do this without refactoring > the whole world. > > In that case it would probably be easiest to > *first* proceed to complete Alexandre's suggested refactorings for > GPIO descriptors, which tie down GPIOs to be requested like > clocks and regulators and thus tied to a device, so we can from > there proceed to implement such a conditional request, > as we will then have the required information in the GPIO > subsystem. Indeed, that does seem necessary if you want the GPIO/IRQ core to be able to implement this feature. -- 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
