硬件发生中断过程和软件识别中断过程是相反的  

cpu读取中断控制器是那个模块发生了中断. 

#if 0
/* Interrupt number assignments within Linux */
#define WM831X_IRQ_TEMP_THW 0
#define WM831X_IRQ_GPIO_1   1
#define WM831X_IRQ_GPIO_2   2
#define WM831X_IRQ_GPIO_3   3
#define WM831X_IRQ_GPIO_4   4
#endif
irq：软件中断号  2.6内核以前在irq.h中
request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
     const char *name, void *dev)
现在有设备树:
interrupt-parent = <&gpio1>
interrupt = <5 Rising>  // 5 hw irq  致命parent  domain   5 --->GPIO
irq_domain-----> 转换为软件中断号
// 解析设备树
int (*xlate)(struct irq_domain *d, struct device_node *node,
       const u32 *intspec, unsigned int intsize,
       unsigned long *out_hwirq, unsigned int *out_type);
保存在platform_device
  request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
     const char *name, void *dev)
//  硬件中断和软件中断之间的映射 
 /* reverse map data. The linear map gets appended to the irq_domain */
 irq_hw_number_t hwirq_max;
 unsigned int revmap_direct_max_irq;
 unsigned int revmap_size;
 struct radix_tree_root revmap_tree;
 unsigned int linear_revmap[]; 
一勤天下无难事。