On Wed, Oct 26, 2016 at 4:22 PM, Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote: > On Tue, 2016-10-25 at 20:20 +0200, Linus Walleij wrote: >> However the semantic is such, that it is not necessary to call >> to_irq() >> before using an IRQ: the irqchip and gpiochip abstractions should be >> orthogonal. > > Linus, > > They are orthogonal. You can request an irq from the irqchip controller > without the gpiochip, like any other irq controller. OK good, sorry if I'm stating the obvious. > irq_create_mapping (and irq_create_fwspec_mapping) internally calls > irq_find_mapping. So if the mapping already exist (the irq is already > used before calling to_irq), the existing mapping will be returned. The > mapping will be actually created only if needed. It seems to be in line > with your explanation, no ? Yes, but you want to call irq_create_mapping() in slowpath (irq setup) and irq_find_mapping() in fastpath (irq handler). Else the first IRQ may result in unwelcomed surprises. > There is really a *lot* of gpio drivers which use irq_create_mapping in > the to_irq callback, are these all wrong ? Yes they are all wrong. They should all be using irq_find_mapping(). > If this should not be used, what should we all do instead ? Call irq_create_mapping() in some other place. 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
