Re: Adding an interrupt locator to the GPIO, I2C and SPI buses

[David Laight <david%l8s.co.uk@localhost>]

On Thu, Apr 18, 2013 at 08:45:27AM +0200, Marc Balmer wrote:
> 
> The main problem, however, is of course that gpio(4) has no interrupt
> capabilities, yet.  Being the maintainer of gpio(4) I feel a bit guilty
> of this, so I will start to change it ;)

You do need to allow for all the interrupt modes: Level high, level low,
rising edge, falling edge and both edges (and maybe some others).

gpio interrupts also tend to get chained - so the 'interrupt out' pin
of one device is connected to a gpio pin on something else.
It is really best if this is handled as transparantly as possible.

I've forgotten how many 'interrupt numbers' I got to on the SA110/SA1101
system, but IIRC there were 16 for a device interrupting through a gpio
pin on the sa1101 - and some of those were just gpio.

        David

-- 
David Laight: david%l8s.co.uk@localhost