On Fri, Nov 28, 2014 at 9:30 PM, Robert Jarzmik <robert.jarz...@free.fr> wrote: > Thomas Gleixner <t...@linutronix.de> writes: > >> So what is the relationship between installing that chained handler >> and that gpio-pxa probe stuff? > The relation is in gpio-pxa probe, look at the extract of pxa_gpio_probe() : > pxa_gpio_probe() > irq = gpio_to_irq(0); > irq_set_chip_and_handler(irq, &pxa_muxed_gpio_chip, > handle_edge_irq); > set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); > irq_set_chained_handler(IRQ_GPIO0, pxa_gpio_demux_handler); > > Now look at the extract from the former lubbock_init_irq() : > lubbock_init_irq() > irq = PXA_GPIO_TO_IRQ(0); > irq_set_chained_handler(irq, lubbock_irq_handler); > irq_set_irq_type(irq, IRQ_TYPE_EDGE_FALLING); > > Given that gpio_to_irq(0) = PXA_GPIO_TO_IRQ(0), see how these 2 are fighting > to > install the handler, and how the resulting installed handler depends on the > order of execution of pxa_gpio_to_irq() wrt lubbock_init_irq(). > >> And why is the GPIO0 interrupt handled from arch code rather than from >> a regular driver setup, which depends on the availablity of the GPIO >> driver? > Ah that's a good question. Maybe the answer is that there is no driver in this > case. > When I say "no driver", it's because this interrupt is a consequence of the > IO-Board (or motherboard) wiring topology. > > I think I need to add a bit of context, so pardon my crude ascii-art style, > and > see in the lubbock case, we have this wiring (list of IPs not exhaustive, and > gates to mask each XXX irq not added) : > > IPs on Motherboard Gates on motherboard SoC > > +-------------+ +-------+ > | SMC Lan | --lan irq--- | Latch | - > +-------------+ | | \ > +------PXA-----+ > | | \ | > | > +-------------+ | | |+----------+ > | > | UDC Vbus | --vbus irq-- | Latch | -- NOR gate -- GPIO0 -- ||GPIO block| > | > +-------------+ | | line |+----------+ > | > | | / | > | > +-------------+ | | / > +--------------+ > | SA1111 | --sa11x irq--| Latch | - > +-------------+ +-------+ > > The "gates on motherboard" is what lubbock.c is describing, ie. the > interconnection on the motherboard. I don't see the device/driver model > fitting > to describe these gates, do you ? >
I think that it's a kind of irq muxing, just like lots of PMIC (power management IC). We should move the lubbock board irqs to a mfd driver, and register them as threaded irqs. Best Regards Haojian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
