在编写Linux驱动程序时，我想用某一个引脚做外部中断。但是在调用
int request_irq(unsigned int irq,void (*handler)(int irq, void *dev_id, struct pt_regs *regs),unsigned long irqflags,const char * devname,void *dev_id);
这个函数的时候遇到了一个问题，irq是个硬件终端号，但是到底这个引脚对应的终端号是多少呢？
我在网上找资料说的都稀里糊涂的，不是我想要的答案。
于是我便在内核代码里找，下面贴出Linux内核代码的一段arch\arm\mach-s3c64xx\include\mach\Irqs.h，可以解释这个问题：
/* Since the IRQ_EINT(x) are a linear mapping on current s3c64xx series * we just defined them as an IRQ_EINT(x) macro from S3C_IRQ_EINT_BASE * which we place after the pair of VICs. */#define S3C_IRQ_EINT_BASES3C_IRQ(64+5)#define S3C_EINT(x)((x) + S3C_IRQ_EINT_BASE)#define IRQ_EINT(x)S3C_EINT(x)#define IRQ_EINT_BIT(x)((x) – S3C_EINT(0))/* Next the external interrupt groups. These are similar to the IRQ_EINT(x) * that they are sourced from the GPIO pins but with a different scheme for * priority and source indication. * * The IRQ_EINT(x) can be thought of as 'group 0' of the available GPIO * interrupts, but for historical reasons they are kept apart from these * next interrupts. * * Use IRQ_EINT_GROUP(group, offset) to get the number for use in the * machine specific support files. */#define IRQ_EINT_GROUP1_NR(15)#define IRQ_EINT_GROUP2_NR(8)#define IRQ_EINT_GROUP3_NR(5)#define IRQ_EINT_GROUP4_NR(14)#define IRQ_EINT_GROUP5_NR(7)#define IRQ_EINT_GROUP6_NR(10)#define IRQ_EINT_GROUP7_NR(16)#define IRQ_EINT_GROUP8_NR(15)#define IRQ_EINT_GROUP9_NR(9)#define IRQ_EINT_GROUP_BASES3C_EINT(28)#define IRQ_EINT_GROUP1_BASE(IRQ_EINT_GROUP_BASE + 0x00)#define IRQ_EINT_GROUP2_BASE(IRQ_EINT_GROUP1_BASE + IRQ_EINT_GROUP1_NR)#define IRQ_EINT_GROUP3_BASE(IRQ_EINT_GROUP2_BASE + IRQ_EINT_GROUP2_NR)#define IRQ_EINT_GROUP4_BASE(IRQ_EINT_GROUP3_BASE + IRQ_EINT_GROUP3_NR)#define IRQ_EINT_GROUP5_BASE(IRQ_EINT_GROUP4_BASE + IRQ_EINT_GROUP4_NR)#define IRQ_EINT_GROUP6_BASE(IRQ_EINT_GROUP5_BASE + IRQ_EINT_GROUP5_NR)#define IRQ_EINT_GROUP7_BASE(IRQ_EINT_GROUP6_BASE + IRQ_EINT_GROUP6_NR)#define IRQ_EINT_GROUP8_BASE(IRQ_EINT_GROUP7_BASE + IRQ_EINT_GROUP7_NR)#define IRQ_EINT_GROUP9_BASE(IRQ_EINT_GROUP8_BASE + IRQ_EINT_GROUP8_NR)#define IRQ_EINT_GROUP(group, no)(IRQ_EINT_GROUP##group##_BASE + (no))从以上注释以及代码可以看到，，有两个宏来获得终端号，
IRQ_EINT(x) 第0组
IRQ_EINT_GROUP（group,no） 第1-9组
不然你大概会一直好奇和不甘吧——家门前的那条小路，
