Hi Jonathan, On 09/07/17 19:39, Jonathan Cameron wrote: > On Sun, 9 Jul 2017 18:57:00 +0200 > Lorenzo Bianconi <lorenzo.bianconi83@xxxxxxxxx> wrote: > >> Add support for active low interrupts (IRQF_TRIGGER_LOW and >> IRQF_TRIGGER_FALLING). Configure the device as active high or low >> according to the requested irq line. >> >> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxx> > Hi Lorenzo, > > Sorry, you are getting caught up in a more general question I'd like to > pin down an answer for... > > What should we be doing if we have a part that supports both high and > low interrupts and/or rising and falling? > > We actually have more than one possible thing we are configuring with > one parameter. If we are looking at shared interrupts or level > converters it's more than possible we have an inversion going on between > the two. How is this represented to the two ends? > > What's the right way of doing this? > > I've added a few CCs that I think might chip in on this question! > > My personal gut feeling is that the inverter should have explicit > representation in the kernel. We should be able to instantiate an > irq_chip which is responsible for flipping it's sense. > > You request an active high input on one side and it deals with > the active low that needs to be requested upstream. > > Chances are I'm missing something and this is already well handled! We already have things like that, such as drivers/irqchip/irq-mtk-sysirq.c (whose sole purpose in life is to invert interrupt polarity). Hope this helps, M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
