[PATCH] genirq: add SA_TRIGGER support

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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 27 insertions, 4 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3ed7aee84865..627d401c2979 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -225,8 +225,14 @@ int setup_irq(unsigned int irq, struct irqaction *new)
         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)
@@ -250,7 +256,22 @@ int setup_irq(unsigned int irq, struct irqaction *new)
 #endif
         if (!shared) {
                 irq_chip_set_defaults(desc->chip);
-                compat_irq_chip_set_default_handler(desc);
+
+                /* Setup the type (level, edge polarity) if configured: */
+                if (new->flags & SA_TRIGGER_MASK) {
+                        if (desc->chip && desc->chip->set_type)
+                                desc->chip->set_type(irq,
+                                                new->flags & SA_TRIGGER_MASK);
+                        else
+                                /*
+                                 * SA_TRIGGER_* but the PIC does not support
+                                 * multiple flow-types?
+                                 */
+                                printk(KERN_WARNING "setup_irq(%d) SA_TRIGGER"
+                                       "set. No set_type function available\n",
+                                       irq);
+                } else
+                        compat_irq_chip_set_default_handler(desc);
 
                 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
                                   IRQ_INPROGRESS);
@@ -262,7 +283,9 @@ int setup_irq(unsigned int irq, struct irqaction *new)
                                 desc->chip->startup(irq);
                         else
                                 desc->chip->enable(irq);
-                }
+                } else
+                        /* Undo nested disables: */
+                        desc->depth = 1;
         }
         spin_unlock_irqrestore(&desc->lock, flags);