arm驱动模块---简易led驱动.docxVIP

//led灯字符设备驱动/*1. 头文件*/#includelinux/init.h#includelinux/module.h#includelinux/fs.h#includelinux/device.h#includelinux/slab.h#includelinux/cdev.h#includeasm/uaccess.h#includeasm/io.hstatic unsigned int led_major=0;volatile unsigned long *gpc0con = NULL;volatile unsigned long *gpc0dat = NULL;struct led_device{struct class *led_class ;//表示一类设备, 存储某些信息struct device *led_device ;//表示一个设备struct cdev *led_cdev;unsigned int val;};struct led_device *s5pv_led_dev;static ssize_t led_read(struct file *file, char __user *buf, size_t count, loff_t *opps){int ret;ret = copy_to_user(buf, s5pv_led_dev-val, count);if(ret0){printk(KERN_ERR copy to user failed!\n);return ret;}printk(KERN_INFO val=%d\n, s5pv_led_dev-val);return ret?0:count;}static ssize_t led_write(struct file *file, const char __user *buf, size_t count, loff_t *opps){int ret;/*拷贝成功,返回0; 拷贝失败, 返回没有被拷贝的字节数*/ret = copy_from_user(s5pv_led_dev-val, buf, count);if(ret0){printk(KERN_ERR copy from user failed!\n);return ret;}if(s5pv_led_dev-val){/*点亮LED*/*gpc0dat |= ((0x13)|(0x14));}else{/*熄灭LED*/*gpc0dat = ~((0x13)|(0x14));}return ret?0:count;}static int led_open(struct inode *inode, struct file *file){/*1. 将物理地址映射为虚拟地址*/gpc0con = ioremap(0xE0200060, 8);gpc0dat = gpc0con +1;/*2. 初始化GPC0_3,4引脚功能为输出*/*gpc0con = ~((0xf12)|(0xf16));*gpc0con |= ((0x112)|(0x116));return 0;}static int led_close(struct inode *inode, struct file *file){*gpc0con = ~((0xf12)|(0xf16));iounmap(gpc0con);}/*硬件操作方法*/struct file_operations led_fops={.owner = THIS_MODULE,//当前模块所用.open = led_open,.write = led_write,.read = led_read,.release = led_close,};static void setup_led_cdev(void){/*1. 为cdev结构体分配空间*/s5pv_led_dev-led_cdev = cdev_alloc();/*2. 初始化cdev结构体*/cdev_init(s5pv_led_dev-led_cdev, led_fops);/*3. 注册cdev,加载到内核哈希表中*/cdev_add(s5pv_led_dev-led_cdev, MKDEV(led_major, 0), 1);}/*2. 实现模块加载函数*/static int __init led_init(void){dev_t devno;int ret;/*1. 新的申请主设备号的方法*/if(led_major){/*静态申请*/devno = MKDEV(led_major, 0);register_chrdev_region(devno, 1, led);}else{/*