Re: [ELDK] GPIO pin in interrupt handler/AMCC processor

Re: [ELDK] GPIO pin in interrupt handler/AMCC processor

[Zoolu R]

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Hi Stefan,

thanks for you reply, as per Amcc 440 ep h/w spec . I can see 10 External
interrupts can be configured !! So can i use the GPIO ping mapped to one of
these external IRQ's ? Or should the h/w deisgn  also support it  or is it
pure s/w configurations. So i would just like to get an indication via
interrupt when status is changed (0/1). I would like to do this is linux.

Are there any reference drivers for this ? how to go about it ?

Thanks & Regards
Zoolu
On Mon, Feb 8, 2010 at 11:43 PM, Stefan Roese <sr@denx.de> wrote:

> Hi Zoolu,
>
> first, this question is not ELDK related. You should send it to Linux-PPC
> mailing list instead <linuxppc-dev@ozlabs.org>. But still here a few quick
> answers/comments.
>
> On Monday 08 February 2010 17:37:20 Zoolu R wrote:
> > We are using a target with AMCC 440ep processor. We need to read the a
> GPIO
> > pin  value in a interrupt mode in linux kernel. Is there some modules
> where
> > i can refer so some generic implementation(configuring gpio pin as
> >  inteerupt pin and handlling the same).
>
> The PPC4xx GPIO support is available in the current Linux kernel. See:
>
> arch/powerpc/sysdev/ppc4xx_gpio.c
>
> for more details. Please note that you also need to write a GPIO device
> node
> in the device tree source (dts) of your Linux port. See this file for
> details
> in the GPIO node:
>
> arch/powerpc/boot/dts/warp.dts
>
> >  I would like to detect the dynamic
> >  value change(0/1) using interrupt and perform isr_call back. Could some
> >  one show me some pointers.
>
> So you don't want to use the GPIO pin functionality, but the external
> interrupt functionality (the pin functions are multiplexed). You need to
> write
> a device driver for your custom device. And you need to configure the pin
> as
> external interrupt and again add a device node including the interrupt
> description into your device tree source (dts).
>
> Cheers,
> Stefan
>
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