Question about shared interrupts in devicetree
stefan.wahren at i2se.com
Thu Apr 9 03:24:37 EDT 2015
Am 08.04.2015 um 21:20 schrieb Geert Uytterhoeven:
> On Tue, Apr 7, 2015 at 7:06 PM, Stefan Wahren <stefan.wahren at i2se.com> wrote:
>> thanks for the good explanation. After looking into the reference manual  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
>>  - http://cache.freescale.com/files/dsp/doc/ref_manual/MCIMX28RM.pdf
>> Document Number: MCIMX28RM
>> Rev 2, 08/2013
> 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
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