powerpc: Remove all usages of NO_IRQ

NO_IRQ has been == 0 on powerpc for just over ten years (since commit
0ebfff1491ef ("[POWERPC] Add new interrupt mapping core and change
platforms to use it")). It's also 0 on most other arches.

Although it's fairly harmless, every now and then it causes confusion
when a driver is built on powerpc and another arch which doesn't define
NO_IRQ. There's at least 6 definitions of NO_IRQ in drivers/, at least
some of which are to work around that problem.

So we'd like to remove it. This is fairly trivial in the arch code, we
just convert:

    if (irq == NO_IRQ)	to	if (!irq)
    if (irq != NO_IRQ)	to	if (irq)
    irq = NO_IRQ;	to	irq = 0;
    return NO_IRQ;	to	return 0;

And a few other odd cases as well.

At least for now we keep the #define NO_IRQ, because there is driver
code that uses NO_IRQ and the fixes to remove those will go via other
trees.

Note we also change some occurrences in PPC sound drivers, drivers/ps3,
and drivers/macintosh.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
index ed8bba68a162..998316bf2dad 100644
--- a/arch/powerpc/platforms/powernv/opal-irqchip.c
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -222,7 +222,7 @@ int __init opal_event_init(void)
 		/* Get hardware and virtual IRQ */
 		irq = be32_to_cpup(irqs);
 		virq = irq_create_mapping(NULL, irq);
-		if (virq == NO_IRQ) {
+		if (!virq) {
 			pr_warn("Failed to map irq 0x%x\n", irq);
 			continue;
 		}
@@ -260,7 +260,7 @@ machine_arch_initcall(powernv, opal_event_init);
 int opal_event_request(unsigned int opal_event_nr)
 {
 	if (WARN_ON_ONCE(!opal_event_irqchip.domain))
-		return NO_IRQ;
+		return 0;
 
 	return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
 }