linux驱动----驱动程序

设备驱动分类字符设备驱动 -- 数据的访问是字节流(有序访问)块设备驱动 -- 数据可以随机访问(一般访问是按块访问的存储设备网络设备驱动 -- 集成复杂的协议栈网络设备靠名字管理设备驱动程序1. 设备的操作方法(open/read/write/ioctl/close)2. 设备号 ---用于区分不同的设备设备号 高12位主设备号 低20位的次设备号组成主设备号 区分设备类型 (功能)次设备号区分同类的不同设备3. 向系统注册设备驱动4. 创建设备节点 (绑定名字和设备号)设备驱动开发流程设备操作方法的编写open/read/write/ioctl/closestatic int open(struct inode* node, struct file* file) 45 { 46 led_init(); 47 printk(led open...\n); 48 return 0; 49 } 50 51 static ssize_t read(struct file* file, char __user* buf, size_t len, loff_t* offset) 52 { 53 // copy_to_user(); 54 printk(led read...\n); 55 return 0; 56 } 57 58 static ssize_t write(struct file* file, const char __user* buf, size_t len, loff_t* offset) 59 { 60 // ledon on ledoff off 61 unsigned char data[10] {0}; 62 size_t len_cp len sizeof(data) ? len : sizeof data; 63 int size_cp copy_from_user(data, buf, len_cp); 64 if (size_cp 0) 65 return size_cp; 66 67 if (!strcmp(buf, ledon)) 68 led_on(); 69 else if (!(strcmp(buf, ledoff))) 70 led_off(); 71 else 72 return -EINVAL; 73 74 printk(led write...\n); 75 76 return size_cp; 77 } static int close(struct inode* node, struct file* file) 80 { 81 led_off(); 82 printk(led close...\n); 83 return 0; 84 }设备号的编写以及创建设备节点开机启动函数中int ret 0; 103 //dev MKDEV(MAJOR_NUM, MINOR_NUM); //(MAJOR_NUM 20) | MINOR_NUM; 104 ret alloc_chrdev_region(dev,0,1,led_driver); 105 if(ret 0) 106 goto err_alloc; 107 108 cdev_init(cdev, fops); 109 ret cdev_add(cdev, dev, 1); 110 if (ret 0) 111 goto err_cdev; 112 113 #if 0 114 ret register_chrdev_region(dev, 1, DEV_NAME); 115 if (ret 0) 116 goto err_register_chrdev; 117 #endif 118 119 cls class_create(THIS_MODULE,led_class); 120 if(IS_ERR(cls)) 121 { 122 ret PTR_ERR(cls); 123 printk(KERN_ERR class_create failed! ret %d\n,ret); 124 goto err_class; 125 } 126 Dev device_create(cls,NULL,dev,NULL,led); 127 if(IS_ERR(Dev)) 128 { 129 ret PTR_ERR(Dev); 130 printk(KERN_ERR device_create failed! ret %d\n,ret); 131 goto err_device; 132 }卸载清理函数中static void __exit led1_exit(void) 159 { 160 161 device_destroy(led_class, dev); // 销毁设备 162 class_destroy(led_class); // 销毁类 163 164 iounmap(gpio1_gdir); 165 iounmap(gpio1_dr); 166 iounmap(sw_pad); 167 iounmap(sw_mux); 168 169 unregister_chrdev_region(dev, 1); 170 cdev_del(cdev); 171 172 printk(led_exit ##############\n); 173 }总的代码#include asm/io.h #include asm/string.h #include asm/uaccess.h #include linux/cdev.h #include linux/export.h #include linux/fs.h #include linux/init.h #include linux/kdev_t.h #include linux/printk.h #include linux/types.h #include linux/device.h #define MAJOR_NUM 247 #define MINOR_NUM 0 #define DEV_NAME led #define IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03 0x20e0068U #define IOMUXC_SW_PAD_CTL_PAD_GPIO1_IO03 0x20E02F4U #define GPIO1_DR 0x209C000U #define GPIO1_GDIR 0x209C004U static volatile unsigned int* sw_mux; static volatile unsigned int* sw_pad; static volatile unsigned int* gpio1_dr; static volatile unsigned int* gpio1_gdir; static void led_init(void) { *sw_mux 0x05; *sw_pad 0x10b0; *gpio1_gdir | (1 3); *gpio1_dr | (1 3); } static void led_on(void) { *gpio1_dr ~(1 3); } static void led_off(void) { *gpio1_dr | (1 3); } static int open(struct inode* node, struct file* file) { led_init(); printk(led open...\n); return 0; } static ssize_t read(struct file* file, char __user* buf, size_t len, loff_t* offset) { // copy_to_user(); printk(led read...\n); return 0; } static ssize_t write(struct file* file, const char __user* buf, size_t len, loff_t* offset) { // ledon on ledoff off unsigned char data[10] {0}; size_t len_cp len sizeof(data) ? len : sizeof data; int size_cp copy_from_user(data, buf, len_cp); if (size_cp 0) return size_cp; if (!strcmp(buf, ledon)) led_on(); else if (!(strcmp(buf, ledoff))) led_off(); else return -EINVAL; printk(led write...\n); return size_cp; } static int close(struct inode* node, struct file* file) { led_off(); printk(led close...\n); return 0; } static dev_t dev; static struct file_operations fops { .owner THIS_MODULE, .open open, .read read, .write write, .release close }; static struct cdev cdev; static struct class *cls; static struct device *Dev; static int __init led1_init(void) { int ret 0; //dev MKDEV(MAJOR_NUM, MINOR_NUM); //(MAJOR_NUM 20) | MINOR_NUM; ret alloc_chrdev_region(dev,0,1,led_driver); if(ret 0) goto err_alloc; cdev_init(cdev, fops); ret cdev_add(cdev, dev, 1); if (ret 0) goto err_cdev; #if 0 ret register_chrdev_region(dev, 1, DEV_NAME); if (ret 0) goto err_register_chrdev; #endif cls class_create(THIS_MODULE,led_class); if(IS_ERR(cls)) { ret PTR_ERR(cls); printk(KERN_ERR class_create failed! ret %d\n,ret); goto err_class; } Dev device_create(cls,NULL,dev,NULL,led); if(IS_ERR(Dev)) { ret PTR_ERR(Dev); printk(KERN_ERR device_create failed! ret %d\n,ret); goto err_device; } sw_mux ioremap(IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03, 4); sw_pad ioremap(IOMUXC_SW_PAD_CTL_PAD_GPIO1_IO03, 4); gpio1_dr ioremap(GPIO1_DR, 4); gpio1_gdir ioremap(GPIO1_GDIR, 4); printk(led_init ##############\n); return 0; #if 0 err_register_chrdev: unregister_chrdev_region(dev, 1); #endif err_device: class_destroy(cls); err_class: err_cdev: cdev_del(cdev); err_alloc: printk(led_init failed ############## ret %d\n, ret); return ret; } static void __exit led1_exit(void) { iounmap(gpio1_gdir); iounmap(gpio1_dr); iounmap(sw_pad); iounmap(sw_mux); unregister_chrdev_region(dev, 1); cdev_del(cdev); printk(led_exit ##############\n); } module_init(led1_init); module_exit(led1_exit);