* Re: gpio irq on Beagleboard
2010-04-16 4:59 ` gpio irq on Beagleboard Andrew Tverdohlebov
@ 2010-04-16 5:13 ` Felipe Balbi
0 siblings, 0 replies; 2+ messages in thread
From: Felipe Balbi @ 2010-04-16 5:13 UTC (permalink / raw)
To: ext Andrew Tverdohlebov; +Cc: linux-omap@vger.kernel.org
On Fri, Apr 16, 2010 at 06:59:19AM +0200, ext Andrew Tverdohlebov wrote:
>Dear linux-omap community,
>
>I am writing a simple driver for BeagleBoard
>and trying to get an understanding of how interrupts work.
>
>Could you please answer a small question. What is a difference between irq
> and virtual_irq_start in structure gpio_bank in file
> arch/arm/plat-omap/gpio.c
> As far as I understood irq corresponds to real hardware interrupts while
> virtual_irq_start is completely obscure for me.
> I didn't find a clue in the documentation.
it's where the gpio irqs could be placed (numbering-wise) after the irq
controller. I mean, if the irq controller has 192 irqs, gpio irqs have
to be numbered 193, 194, 195, etc... so virtual_irq_base is that initial
number.
hope I made myself clear enough :-p
if you take a look at the gpio_bank arrays on that same file and look at
the fourth initialization, you can get a clue. Take a look at the
IH_GPIO_BASE define, for example.
--
balbi
^ permalink raw reply [flat|nested] 2+ messages in thread