On Thu, 27 Nov 2014, Robert Jarzmik wrote:

When gpio-pxa was moved to drivers/pxa, it became a driver, and its
initialization and probing happen at postcore initcall. The lubbock code
used to install the chained lubbock interrupt handler at init_irq()
time.

The consequence of the gpio-pxa change is that the installed chained irq
handler lubbock_irq_handler() was overwritten in pxa_gpio_probe(_dt)(),
removing :
 - the handler
 - the falling edge detection setting of GPIO0, which revealed the
   interrupt request from the lubbock IO board.

As a fix, move the gpio0 chained handler setup to a place where we have
the guarantee that pxa_gpio_probe() was called before, so that lubbock
handler becomes the true IRQ chained handler of GPIO0, demuxing the
lubbock IO board interrupts.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
For Thomas: as a side note, I'm not very happy with this patch. What
            makes me unhappy is that I don't know how to express the
            dependency between gpio-pxa probe time and
            irq_set_chained_handler(irq, lubbock_irq_handler).

            At the moment I rely on the fact that
            lubbock_irq_device_init() is called as device initcall while
            pxa_gpio_probe() is called as postcore initcall.

Admittedly I'm confused.

So what is the relationship between installing that chained handler
and that gpio-pxa probe stuff?

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?

Thanks,

	tglx