i.MX & IRQF_ONESHOT

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

On Thu, Jan 13, 2011 at 10:12:23PM +0100, Eric B?nard wrote:
> On 13/01/2011 19:15, Thomas Gleixner wrote:
> >On Thu, 13 Jan 2011, Nicolas Ferre wrote:
> >>Le 13/01/2011 10:13, Uwe Kleine-K?nig :
> >>>On Thu, Jan 13, 2011 at 09:25:19AM +0100, Eric B?nard wrote:
> >>>>Commenting out this line in the ads7846 driver makes it work again.
> >>>>Am I missing something obvious or is there a reason for IRQF_ONESHOT
> >>>>creating trouble with gpio irq or SPI on i.MX ?
> >>>I don't know.  Is the irq masked?  pending?
> >>
> >>Just to let you know that I have the same issue on my at91sam9g10ek:
> >>atmel_spi + ads7846 (using ADS7843e actually).
> >>... solved by same workaround.
> >
> >Eric, Nicolas: How are the interrupt handlers set for the relevant
> >interrupt lines and how are the interrupt pins configured?
> >
> on the i.MX27 :
> - gpio configured as a plain input (in function ads7846_dev_init()
> in arch/arm/mach-imx/eukrea_mbimx27-baseboard.c)
> - threaded interrupt handler registered with flags
> IRQF_TRIGGER_FALLING | IRQF_ONESHOT (in function ads7846_probe() in
> drivers/input/touchscreen/ads7846.c)
I didn't recheck the hw manual, but adding IRQF_TRIGGER_FALLING calls
gpio_set_irq_type (defined in arch/arm/plat-mxc/gpio.c) which results
into something called GPIO_INT_FALL_EDGE being written into a register.

So I'd say it's configured to be edge sensitive.

> - the gpio's irq is handled by a chained irq handled registered in
> arch/arm/plat-mxc/gpio.c (the CPU has only one real interrupt for
> all the GPIO banks so this real IRQ handles up to 5 x 32 gpio's
> IRQ).

Best reagrds
Uwe

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