ARM9260内部中断和外部中断触发方式

1.内部中断（0～31） 

  内部中断可以有4中触发方式

 static struct irq_chip at91_aic_chip = {
         .name           = "AIC",
         .irq_ack        = at91_aic_mask_irq,
         .irq_mask       = at91_aic_mask_irq,
         .irq_unmask     = at91_aic_unmask_irq,
         .irq_set_type   = at91_aic_set_type,
         .irq_set_wake   = at91_aic_set_wake,
 };

 static int at91_aic_set_type(struct irq_data *d, unsigned type)

 {

        unsigned int smr, srctype;

          switch (type) {

        case IRQ_TYPE_LEVEL_HIGH:

                 srctype = AT91_AIC_SRCTYPE_HIGH;

                 break;

         case IRQ_TYPE_EDGE_RISING:

                 srctype = AT91_AIC_SRCTYPE_RISING;

                 break;

         case IRQ_TYPE_LEVEL_LOW:

                 if ((d->irq == AT91_ID_FIQ) || is_extern_irq(d->irq))           /* only supported on external interrupts */

                         srctype = AT91_AIC_SRCTYPE_LOW;

                 else

                         return -EINVAL;

                 break;

         case IRQ_TYPE_EDGE_FALLING:

                 if ((d->irq == AT91_ID_FIQ) || is_extern_irq(d->irq))           /* only supported on external interrupts */

                         srctype = AT91_AIC_SRCTYPE_FALLING;                 else

                         return -EINVAL;

                 break;

         default:

                 return -EINVAL;

         }

          smr = at91_aic_read(AT91_AIC_SMR(d->irq)) & ~AT91_AIC_SRCTYPE;

         at91_aic_write(AT91_AIC_SMR(d->irq), smr | srctype);

         return 0;

 }

2.外部中断（32～224）

 外部中断有2种触发方式

 static struct irq_chip gpio_irqchip = {
         .name           = "GPIO",
         .irq_disable    = gpio_irq_mask,
        .irq_mask       = gpio_irq_mask,
        .irq_unmask     = gpio_irq_unmask,
         .irq_set_type   = gpio_irq_type,
         .irq_set_wake   = gpio_irq_set_wake,
 };

 static int gpio_irq_type(struct irq_data *d, unsigned type)
 {
         switch (type) {
         case IRQ_TYPE_NONE:
         case IRQ_TYPE_EDGE_BOTH:
                return 0;
         default:
                return -EINVAL;
         }
 }