Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO_SUSPEND flag

[Sudeep Holla]

On 03/12/15 18:13, Tony Lindgren wrote:
> * Linus Walleij <linus.walleij@xxxxxxxxxx> [151201 06:07]:
> > On Fri, Nov 27, 2015 at 6:21 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote:
> >
> > > From: Sudeep Holla <Sudeep.Holla@xxxxxxx>
> > >
> > > The IRQF_NO_SUSPEND flag is used to identify the interrupts that should
> > > be left enabled so as to allow them to work as expected during the
> > > suspend-resume cycle, but doesn't guarantee that it will wake the system
> > > from a suspended state, enable_irq_wake is recommended to be used for
> > > the wakeup.
> > >
> > > This patch removes the use of IRQF_NO_SUSPEND flags replacing it with
> > > irq_set_irq_wake instead.
> > >
> > > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > > Cc: linux-gpio@xxxxxxxxxxxxxxx
> > > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> >
> > I need Tony's ACK on this as well.
>
> At least on omaps, this controller is always powered and we never want to
> suspend it as it handles wake-up events for all the IO pins. And that
> usecase sounds exactly like what you're describing above.

Understood, but I assume this is a generic driver that can be used by
any pinmux.

> I don't quite follow what your suggested alternative for an interrupt
> controller is?

Why can't we use enable_irq_wake even for parent/interrupt controller as
they can be considered as parent wakeup irq. I agree the interrupt
controller may not be powered down, but still it's part of wakeup and
the irq core needs to identify that. By just marking IRQF_NO_SUSPEND,
you are saying that you can handle interrupt in the suspend path but not
informing that it's a wakeup interrupt.

With this change, the wakeup handler (including the parent handler) is
called when it's safe as the irq core maintains the state machine.

> At least we need to have the alternative patched in with this chage before
> just removing IRQF_NO_SUSPEND.

I have added irq_set_irq_wake(pcs_soc->irq, state) in pcs_irq_set_wake
which ensures it's marked for wakeup.

> The enable_irq_wake is naturally used for the consumer drivers of this
> interrupt controller and actually mostly done automatically now with the
> dev_pm_set_dedicated_wake_irq.

Agreed, no doubt on that.

--
Regards,
Sudeep
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