Question on setting up external interrupt for P1020 (MPC8xxx) with device tree

[Scott Wood]

On Fri, 11 Feb 2011 14:07:26 -0500
Kenny Ho <kho at belairnetworks.com> wrote:

> Hi,
> 
>  
> 
> I am trying to write a device driver that uses an external interrupt
> (one of the 16 irq lines) for the Freescale P1020 processor and I hope
> some of you can help.  Am I suppose to setup a separate node in the dts
> and look for that node in my driver to setup the interrupt? 

Ideally, yes.  It's good to describe your device with a node even if it
doesn't have interrupts.

> Or does the > dts interrupt declaration belong to the interrupt-controller
> declaration?  I noticed the mpc8xxx_gpio driver defined its own irq_chip
> but I thought that may be because each gpio pin can trigger an
> interrupt.

Right, it's because gpio is an interrupt controller, not just a user of one.

> Do I need to define my own irq_chip structure for my device
> even if I am using one of the hard irq lines?  

No.  If the device's node describes the interrupt correctly, you can use
irq_of_parse_and_map() on the device node to get a virtual irq that you can
pass to request_irq().

-Scott