驱动代码：
1 #include <linux/module.h> 2 #include <linux/kernel.h> 3 #include <linux/fs.h> 4 #include <linux/init.h> 5 #include <linux/delay.h> 6 #include <linux/device.h> 7 #include <linux/irq.h> 8 #include <linux/gpio.h> 9 10 #include <linux/sched.h> 11 12 #include <linux/interrupt.h> 13 14 #include <asm/uaccess.h> 15 #include <mach/irqs.h> 16 #include <asm/io.h> 17 #include <mach/regs-gpio.h> 18 #include <mach/hardware.h> 19 20 21 #define __IRQT_FALEDGE IRQ_TYPE_EDGE_FALLING 22 #define __IRQT_RISEDGE IRQ_TYPE_EDGE_RISING 23 #define __IRQT_LOWLVL IRQ_TYPE_LEVEL_LOW 24 #define __IRQT_HIGHLVL IRQ_TYPE_LEVEL_HIGH 25 #define IRQT_NOEDGE (0) 26 #define IRQT_RISING (__IRQT_RISEDGE) 27 #define IRQT_FALLING (__IRQT_FALEDGE) 28 #define IRQT_BOTHEDGE (__IRQT_RISEDGE|__IRQT_FALEDGE) 29 #define IRQT_LOW (__IRQT_LOWLVL) 30 #define IRQT_HIGH (__IRQT_HIGHLVL) 31 #define IRQT_PROBE IRQ_TYPE_PROBE 32 33 34 volatile unsigned long *gpgcon; 35 volatile unsigned long *gpgdat; 36 37 static DECLARE_WAIT_QUEUE_HEAD(button_waitq); 38 static volatile int ev_press=0; 39 40 struct pin_desc{ 41 unsigned int pin;//设备号dev_id 42 unsigned int key_val;//read返回值 43 }; 44 45 struct pin_desc pins_desc[6]={ //6个按键 46 {S3C2410_GPG(0),0x01}, 47 {S3C2410_GPG(3),0x02}, 48 {S3C2410_GPG(5),0x03}, 49 {S3C2410_GPG(6),0x04}, 50 {S3C2410_GPG(7),0x05}, 51 {S3C2410_GPG(11),0x06}, 52 }; 53 54 unsigned char keyval; 55 56 static irqreturn_t buttons_irq(int irq,void *dev_id) 57 { 58 struct pin_desc *pindesc=(struct pin_desc *)dev_id; 59 unsigned int pinval; 60 pinval=s3c2410_gpio_getpin(pindesc->pin); 61 if(pinval) 62 { 63 keyval=0x80|pindesc->key_val; 64 } 65 else 66 { 67 keyval=pindesc->key_val; 68 } 69 ev_press=1; 70 wake_up_interruptible(&button_waitq); 71 return 0; 72 } 73 74 static int key_drv_open(struct inode *inode,struct file *file) 75 { 76 printk("key_drv_open\n"); 77 request_irq(IRQ_EINT8,buttons_irq,IRQT_BOTHEDGE,"S1",&pins_desc[0]); 78 request_irq(IRQ_EINT11,buttons_irq,IRQT_BOTHEDGE,"S2",&pins_desc[1]); 79 request_irq(IRQ_EINT13,buttons_irq,IRQT_BOTHEDGE,"S3",&pins_desc[2]); 80 request_irq(IRQ_EINT14,buttons_irq,IRQT_BOTHEDGE,"S4",&pins_desc[3]); 81 request_irq(IRQ_EINT15,buttons_irq,IRQT_BOTHEDGE,"S5",&pins_desc[4]); 82 request_irq(IRQ_EINT19,buttons_irq,IRQT_BOTHEDGE,"S6",&pins_desc[5]); 83 84 return 0; 85 } 86 87 ssize_t key_drv_read(struct file *file,char __user *buf,size_t size,loff_t *ppos) 88 { 89 //unsigned char key_val; 90 if(size!=1) 91 { 92 return -EINVAL; 93 } 94 95 wait_event_interruptible(button_waitq,ev_press); 96 97 copy_to_user(buf,&keyval,1); 98 99 ev_press=0; 100 101 return sizeof(keyval); 102 } 103 104 int key_drv_close(struct inode *inode,struct file *file) 105 { 106 free_irq(IRQ_EINT8,&pins_desc[0]); 107 free_irq(IRQ_EINT11,&pins_desc[1]); 108 free_irq(IRQ_EINT13,&pins_desc[2]); 109 free_irq(IRQ_EINT14,&pins_desc[3]); 110 free_irq(IRQ_EINT15,&pins_desc[4]); 111 free_irq(IRQ_EINT19,&pins_desc[5]); 112 return 0; 113 114 } 115 116 static struct file_operations key_drv_fops={ 117 .owner=THIS_MODULE, 118 .open=key_drv_open, 119 .read=key_drv_read, 120 .release=key_drv_close, 121 }; 122 123 int major; 124 static struct class *key_drv_class; 125 static struct class_device *key_drv_device; 126 127 static int key_drv_init(void) 128 { 129 major=register_chrdev(0,"key_drv",&key_drv_fops); 130 key_drv_class=class_create(THIS_MODULE,"key_drv"); 131 key_drv_device=device_create(key_drv_class,NULL,MKDEV(major,0),NULL,"buttons"); 132 133 gpgcon = (volatile unsigned long *)ioremap(0x56000060,16); 134 gpgdat = gpgcon+1; 135 return 0; 136 } 137 138 static int key_drv_exit(void) 139 { 140 device_unregister(key_drv_device); 141 class_destroy(key_drv_class); 142 unregister_chrdev(major,"key_drv"); 143 iounmap(gpgcon); 144 return 0; 145 } 146 147 module_init(key_drv_init); 148 module_exit(key_drv_exit); 149 150 MODULE_LICENSE("GPL");
测试代码：
1 #include <sys/types.h> 2 #include <sys/stat.h> 3 #include <fcntl.h> 4 #include <stdio.h> 5 6 7 int main(int argc, char **argv) 8 { 9 int fd; 10 unsigned char val; 11 fd = open("/dev/buttons", O_RDWR); 12 if (fd < 0) 13 { 14 printf("cannot open/n"); 15 return 1; 16 } 17 while(1) 18 { 19 read(fd,&val,1); 20 printf("key_val=0x%x\n",val); 21 } 22 23 return 0; 24 }
流程如下：
