Re: [PATCH 2/3] gpio: zynq: Clear pending interrupt when enabling a IRQ

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Fri, Jul 18, 2014 at 11:52 AM, Lars-Peter Clausen <lars@xxxxxxxxxx> wrote:

> The Zynq GPIO controller does not disable the interrupt detection when the
> interrupt is masked and only disables the propagation of the interrupt. This
> means when the controller detects an interrupt condition while the interrupt is
> logically disabled (and masked) it will propagate the recorded interrupt event
> once the interrupt is enabled. This will cause the interrupt consumer to see
> spurious interrupts to prevent this first make sure that the interrupt is not
> asserted and then enable it.
>
> E.g. when a interrupt is requested with request_irq() it will be configured
> according to the requested type (edge/level triggered, etc.) after that it will
> be enabled. But the detection circuit might have already registered a false
> interrupt before the interrupt type was correctly configured and once the
> interrupt is unmasked this false interrupt will be propagated and the interrupt
> handler for the just request interrupt will called.
>
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>

Seems like you know what you're doing.

Patch tentatively applied unless Harini or Soren protests...

Yours,
Linus Walleij
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