Re: [PATCH V1 08/15] spmi: pmic_arb: use appropriate flow handler

[kgunda]

On 2017-06-01 00:33, Stephen Boyd wrote:
> On 05/30, Kiran Gunda wrote:
> > From: Abhijeet Dharmapurikar <adharmap@xxxxxxxxxxxxxx>
> >
> > The current code uses handle_level_irq flow handler even if the
> > trigger type of the interrupt is edge. This can lead to missing
> > of an edge transition that happens when the interrupt is being
> > handled. The level flow handler masks the interrupt while it is
> > being handled, so if an edge transition happens at that time,
> > that edge is lost.
> >
> > Use an edge flow handler for edge type interrupts which ensures
> > that the interrupt stays enabled while being handled - at least
> > until it triggers at which point the flow handler sets the
> > IRQF_PENDING flag and only then masks the interrupt. That
> > IRQF_PENDING state indicates an edge transition happened while
> > the interrupt was being handled and the handler is called again.
> >
> > Signed-off-by: Abhijeet Dharmapurikar <adharmap@xxxxxxxxxxxxxx>
> > Signed-off-by: Kiran Gunda <kgunda@xxxxxxxxxxxxxx>
>
> Do we have any edge interrupts in the tree right now? At least
> RTC seems to be using edge... This should go back to stable with
> a Fixes tag.
Yes. A bunch of internal drivers use edge interrupts.
> > ---
> >  drivers/spmi/spmi-pmic-arb.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/spmi/spmi-pmic-arb.c 
> > b/drivers/spmi/spmi-pmic-arb.c
> > index 1d23df0..ad34491 100644
> > --- a/drivers/spmi/spmi-pmic-arb.c
> > +++ b/drivers/spmi/spmi-pmic-arb.c
> > @@ -625,6 +625,12 @@ static int qpnpint_irq_set_type(struct irq_data 
> > *d, unsigned int flow_type)
> >  	}
> >
> >  	qpnpint_spmi_write(d, QPNPINT_REG_SET_TYPE, &type, sizeof(type));
> > +
> > +	if (flow_type & IRQ_TYPE_EDGE_BOTH)
>
> IRQ_TYPE_EDGE_BOTH doesn't seem appropriate to use here. We're
> really just testing to see if the type is an edge type, not if
> it's BOTH edges.
Ok. Agree. Will fix in the follow up patch.
> > +		irq_set_handler_locked(d, handle_edge_irq);
> > +	else
> > +		irq_set_handler_locked(d, handle_level_irq);
> > +
>
> And we already have code that does that check:
>
> 	if (flow_type & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING))
>
> so just put the irq_set_handler_locked() calls in those if
> statements please.
Sure. Will fix in the follow up patch.