On Monday 16 April 2007 3:03 am, Francis Moreau wrote: > > Good .. this is more like an IRQ question though. > > ... > > > IRQ logic on that platform must do a few things, like: > > > > - NR_IRQS includes the N interrupts triggered from that chip, > > and their numbers probably fit right sometime after the > > core set of IRQs (which might include SOC GPIO irqs); > > > > - You'll provide an irq_chip for this controller, and it will > > handle the relevant irq operations (set trigger type, mask, > > unmask etc); > > > > - When configuring the IRQ handler for that "same IRQ", you'll > > set it up to use a chained handler that you provide, which > > reads the register to see which gpio(s) triggered the IRQ, > > maybe acks it (if just reading that register isn't enough), > > and then calls whatever handler was instaled for that GPIO. > > > > If that's not familiar to you, look at arch/arm/mach-at91/gpio.c > > or arch/arm/mach-pxa/irq.c or arch/arm/plat-omap/gpio.c or a > > number of other similar files showing how the "toplevel" IRQ > > logic will demux from a "one of these N GPIOs" interrupt down > > to the handler for that particular IRQ. > > > > I think I got the picture now, thanks again. > > Just to be sure I understand, it seems to me that your point 2) and 3) > are 2 different approaches to do the same thing, aren't they ?
No, all of those need to be done. (Plus maybe a few more things, I wasn't trying to be exhaustive.) That last point is what makes the other ones take effect ... without it, the top level IRQ will never get dispatched to the GPIO-specific IRQ. Look at the examples I referenced. > If so I can only implement 2) since it seems to me better than the > last one (it better uses genirq layer). No, implementing all of those points is required. That's how the relevant parts of the IRQ layer connect to each other. - Dave - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/