[2/2] tty/hvc: Use opal irqchip interface if available

[Samuel Mendoza-Jonas]

On Tue, 2016-07-05 at 15:31 +1000, Michael Ellerman wrote:
> On Tue, 2016-28-06 at 03:11:39 UTC, Sam Mendoza-Jonas wrote:
> > diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c
> > index b7cd0ae..8c53f5b 100644
> > --- a/drivers/tty/hvc/hvc_opal.c
> > +++ b/drivers/tty/hvc/hvc_opal.c
> > @@ -214,7 +216,15 @@ static int hvc_opal_probe(struct platform_device *dev)
> >  		dev->dev.of_node->full_name,
> >  		boot ? " (boot console)" : "");
> >  
> > -	irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
> > +	rc = of_property_read_u32(dev->dev.of_node, "interrupts", &prop);
> > +	if (rc) {
> > +		pr_info("hvc%d: No interrupts property, using OPAL event\n",
> > +				termno);
> > +		irq = opal_event_request(ilog2(OPAL_EVENT_CONSOLE_INPUT));
> > +	} else {
> > +		irq = irq_of_parse_and_map(dev->dev.of_node, 0);
> > +	}
> 
> That seems a bit backward.
> 
> Shouldn't we try irq_of_parse_and_map() and if that fails, then we go back to
> opal_event_request() ?
> 
> cheers

I was unsure for a minute so I double checked this;
of_property_read_u32() returns of_property_read_u32_array(), which
returns 0 on success, unlike a bunch of other of_property helpers.

So if the 'interrupts' property does exist we get 0, and try
irq_of_parse_and_map(). But are you suggesting we try
irq_of_parse_and_map() regardless and then fall back to
opal_event_request()?

Cheers,
Sam