Question about shared interrupts in devicetree

[stefan.wahren@i2se.com (Stefan Wahren)]

Hi Geert,

Am 08.04.2015 um 21:20 schrieb Geert Uytterhoeven:
> On Tue, Apr 7, 2015 at 7:06 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
>> [...]
>>
>> thanks for the good explanation. After looking into the reference manual [1] of
>> the i.MX28 i still can't decide if the subsystem generate the interrupts as a
>> whole or
>> as a logical group. I only found this para in chapter 11.11:
>>
>>     The VDDA_BO_IRQ, VDDD_BO_IRQ, VDDIO_BO_IRQ, and BATT_BO_IRQ each
>>     have their own interrupt line back to the interrupt collector.
>>     However, the remaining five interrupts?VDD5V_GT_VDDIO_IRQ, DC_OK_IRQ,
>>     VBUSVALID_IRQ, LINREG_OK_IRQ and PSWITCH_IRQ?all share a single
>>     interrupt line. In this case, software must read the interrupt status
>>     bits to discover which event caused the interrupt.
>>
>> In my case DC_OK_IRQ and PSWITCH_IRQ are relevant.
>>
>> Maybe someone else has a idea?
> Perhaps you can implement an interrupt-controller to handle the multiplexing
> of the 5 remaining interrupts?

Could you please explain the benefit / reason of this approach?

>
> Can they be disabled/enabled individually?

Yes. What are the consequences?

Thanks Stefan

>
>> Thanks Stefan
>>
>> [1] - http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf
>>
>> Document Number: MCIMX28RM
>> Rev 2, 08/2013
>>
>>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds