[patch 24/50] genirq: add SA_TRIGGER support

[patch 24/50] genirq: add SA_TRIGGER support

[Ingo Molnar]

From: Thomas Gleixner <tglx@linutronix.de>

enable drivers to request an IRQ with a given irq-flow (trigger/polarity)
setting.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/irq/manage.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

Index: linux-genirq.q/kernel/irq/manage.c
===================================================================
--- linux-genirq.q.orig/kernel/irq/manage.c
+++ linux-genirq.q/kernel/irq/manage.c
@@ -214,8 +214,14 @@ int setup_irq(unsigned int irq, struct i
 	p = &desc->action;
 	old = *p;
 	if (old) {
-		/* Can't share interrupts unless both agree to */
-		if (!(old->flags & new->flags & SA_SHIRQ))
+		/*
+		 * Can't share interrupts unless both agree to and are
+		 * the same type (level, edge, polarity). So both flag
+		 * fields must have SA_SHIRQ set and the bits which
+		 * set the trigger type must match.
+		 */
+		if (!((old->flags & new->flags) & SA_SHIRQ) ||
+		    ((old->flags ^ new->flags) & SA_TRIGGER_MASK))
 			goto mismatch;
 
 #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
@@ -238,6 +244,11 @@ int setup_irq(unsigned int irq, struct i
 		desc->status |= IRQ_PER_CPU;
 #endif
 	if (!shared) {
+		/* Setup the type (level, edge polarity) if configured: */
+		if (new->flags & SA_TRIGGER_MASK && desc->handler->set_type)
+			desc->handler->set_type(irq,
+						new->flags & SA_TRIGGER_MASK);
+
 		desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
 				  IRQ_INPROGRESS);