S3C2440按键驱动的设计（内核2.6.30.4）下图为S3C2440的按键连接电路图：在开始设计程序之前介绍一下与Linux设备中断处理程序相关的知识。首先是申请与释放IRQ的APIrequest_irq()和free_irq()，request_irq()的原型为：intrequest_irq(unsignedintirq,void(*handler)(intirq,void*dev_id,structpt_regs*regs),unsignedlongirqflags,constchar*devname,void*dev_id);irq是要申请的硬件中断号；handler是向系统登记的中断处理函数，是一个回调函数，中断发生时，系统调用这个函数，dev_id参数将被传递；irqflags是中断处理的属性，若设置SA_INTERRUPT，表明中断处理程序是快速处理程序，快速处理程序被调用时屏蔽所有中断，而慢速处理程序不屏蔽；若设置SA_SHIRQ,则多个设备共享中断；dev_id在中断共享时会用到，一般设置为这个设备的device结构本身或者NULL。free_irq()的原型为：voidfree_irq(unsignedintirq,void*dev_id);下面我就开始写驱动程序，源码如下（详解在源码后面说明):#include<linux/module.h>#include<linux/kernel.h>#include<linux/fs.h>#include<linux/init.h>#include<linux/delay.h>#include<linux/poll.h>#include<linux/irq.h>#include<asm/irq.h>#include<linux/interrupt.h>#include<asm/uaccess.h>#include<mach/regs-gpio.h>#include<mach/hardware.h>#include<linux/platform_device.h>#include<linux/cdev.h>#include<linux/miscdevice.h>#defineDEVICE_NAME"IRQ-Test"structbutton_irq_desc{intirq;intpin;intpin_setting;intnumber;char*name;};staticstructbutton_irq_descbutton_irqs[]={{IRQ_EINT1,S3C2410_GPF1,S3C2410_GPF1_EINT1,0,"KEY1"},/*K1*/{IRQ_EINT4,S3C2410_GPF4,S3C2410_GPF4_EINT4,1,"KEY2"},/*K2*/{IRQ_EINT2,S3C2410_GPF2,S3C2410_GPF2_EINT2,2,"KEY3"},/*K3*/{IRQ_EINT0,S3C2410_GPF0,S3C2410_GPF0_EINT0,3,"KEY4"},/*K4*/};staticvolatilecharkey_values[]={'0','0','0','0'};staticDECLARE_WAIT_QUEUE_HEAD(button_waitq);staticvolatileintev_press=0;staticirqreturn_tirq_interrupt(intirq,void*dev_id){structbutton_irq_desc*button_irqs=(structbutton_irq_desc*)dev_id;intdown;down=!s3c2410_gpio_getpin(button_irqs->pin);if(down!=(key_values[button_irqs->number]&1)){key_values[button_irqs->number]='0'+down;ev_press=1;wake_up_interruptible(&button_waitq);}returnIRQ_RETVAL(IRQ_HANDLED);}staticinttq2440_irq_open(structinode*inode,structfile*file){inti;interr=0;for(i=0;i<sizeof(button_irqs)/sizeof(button_irq