Hi Marc, Thanks for your comment. On Wed, Jun 12, 2019 at 11:17:10AM +0100, Marc Zyngier wrote: > Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> wrote: > > On Tue, Jun 11, 2019 at 10:00:41AM +0100, Marc Zyngier wrote: [..] > > > We already have plenty of that in the tree, the canonical example > > > probably being drivers/irqchip/irq-mtk-sysirq.c. It should be pretty > > > easy to turn this driver into something more generic. > > > > I don't think drivers/irqchip/irq-mtk-sysirq.c can serve the > > use-case/purpose of this patch. The MTK driver seems to be dealing with > > the polarity inversion of on-SoC interrupts which are routed to GiC, > > whereas in this patch we are talking about an off-chip interrupt > > wired to R-Car GPIO controller. > > And how different is that? The location of the interrupt source is > pretty irrelevant here. The main difference which I sense is that a driver like irq-mtk-sysirq mostly (if not exclusively) deals with internal kernel implementation detail (tuned via DT) whilst adding an inverter for GPIO IRQs raises a whole bunch of new questions (e.g. how to arbitrate between kernel-space and user-space IRQ polarity configuration?). > The point is that there is already a general > scheme to deal with these "signal altering widgets", and that we > should try to reuse at least the concept, if not the code. Since Harish Jenny K N might be working on a new driver doing GPIO IRQ inversion, I have CC-ed him as well to avoid any overlapping work. > > > It looks to me that the nice DTS sketch shared by Linus Walleij in [5] > > might come closer to the concept proposed by Geert? FWIW, the > > infrastructure/implementation to make this possible is still not > > ready. > > Which looks like what I'm suggesting. Then we are on the same page. Thanks. > > M. > > -- > Jazz is not dead, it just smells funny. -- Best Regards, Eugeniu.
