Re: [PATCH V3 3/3] mfd: palmas: Add support for optional wakeup

From: Tony Lindgren
Date: Fri Nov 14 2014 - 12:08:58 EST


* Felipe Balbi <balbi@xxxxxx> [141114 08:20]:
> On Thu, Nov 13, 2014 at 09:40:31AM -0800, Tony Lindgren wrote:
> > +/**
> > + * handle_wakeirq_thread - call device runtime pm calls on wake-up interrupt
> > + * @wakeirq: device specific wake-up interrupt
> > + * @dev_id: struct device entry
> > + */
> > +irqreturn_t handle_wakeirq_thread(int wakeirq, void *dev_id)
> > +{
> > + struct device *dev = dev_id;
> > + irqreturn_t ret = IRQ_NONE;
> > +
> > + if (pm_runtime_suspended(dev)) {
> > + pm_runtime_mark_last_busy(dev);
> > + pm_request_resume(dev);
>
> this assumes that every driver's ->resume() callback has a:
>
> if (pending)
> handle_pending_irqs();
>
> which might not be very nice. I'd rather follow what Thomas suggested
> and always pass device irq so this can mark it pending. Keep in mind
> that we *don't* need a pm_runtime_get_sync() in every IRQ handler
> because of that. Adding it is but the easiest way to get things working
> and, quite frankly, very silly.
>
> what we want is rather:
>
> irqreturn_t my_handler(int irq, void *dev_id)
> {
> struct device *dev = dev_id;
>
> if (pm_runtime_suspended(dev)) {
> pending_irqs_to_be_handled_from_runtime_resume = true;
> pm_runtime_get(dev);
> clear_irq_source(dev);
> return IRQ_HANDLED;
> }
> }
>
> or something similar.

Yeah I'll take a look.

> > + ret = IRQ_HANDLED;
> > + }
>
> you're not masking the wake irq here which means that when this handler
> returns, wake irq will be unmasked by core IRQ subsystem leaving it
> unmasked after ->resume().

It currently assumes the consumer driver takes care of it. But I get
your point, we should be able to automate this further.

And right now there's also a dependency on dev->power.irq_safe so
RPM_ASYNC is not set. And this all should ideally work even with runtime
PM not set as it's also needed for resume from suspend.

> you *know* you'll pass a NULL top half handler, why don't you just force
> IRQF_ONESHOT instead of erroring out ? Just add:
>
> wakeflags |= IRQF_ONESHOT;
>
> and get it over with :-)

Good point :)

Regards,

Tony
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