linux字元裝置驅動一般模板
阿新 • • 發佈:2019-02-14
#include <linux/miscdevice.h> //標頭檔案有很多,可以根據具體的情況新增刪除,這裡給一個例子。 #include <linux/delay.h> #include <asm/irq.h> #include <mach/regs-gpio.h> #include <mach/hardware.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/mm.h> #include <linux/fs.h> #include <linux/types.h> #include <linux/moduleparam.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/ioctl.h> #include <linux/cdev.h> #include <linux/string.h> #include <linux/list.h> #include <linux/pci.h> #include <linux/gpio.h> #include <asm/uaccess.h> #include <asm/atomic.h> #include <asm/unistd.h> #include <linux/device.h> #include <plat/gpio-cfg.h> #define DEVICE_NAME "devicename" //檔名 static int major = xxx_major; //預定義的主裝置號 struct xxx_dev_t{ //字元裝置結構體 struct cdev cdev; }xxx_dev;//這一段和static struct cdev cdev;表達了一種意思 static struct class *xxx_class; //在驅動初始化的程式碼裡呼叫class_create為該裝置建立一個class,再為每個裝置呼叫device_create建立對應的裝置 static int xxx_open(struct inode *inode, struct file *filp) //檔案節點,僅有一個;file結構體,追蹤檔案執行時的狀態資訊,可為NULL { } /*清理未結束的輸入輸出操作,釋放資源,可為null*/ static int xxx_realease(struct inode *inode, struct file *filp) { } /*目標檔案結構體指標;對應放置資訊的緩衝區(使用者空間);要讀取的資訊長度;讀的位置相對於檔案開頭的偏移*/ static ssize_t xxx_read(struct file *filp, char __user *buf, size_t len, loff_t *offset) { } /*目標檔案結構體指標;要寫入放置資訊的緩衝區;要寫入的資訊長度;寫的位置相對於檔案開頭的偏移*/ static ssize_t xxx_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset) { } static struct file_operations xxx_fops= //檔案操作結構體 { .owner = THIS_MODULE, .read = xxx_read, .write = xxx_writ, .open = xxx_open, .release = xxx_release, .ioctl = xxx_ioctl, }; static int __init xxx_init(void) //裝置驅動模組載入函式 { int result; int ret; dev_t xxx_dev_no = MKDEV(xxx_major,0); //由預定義的主裝置號生成dev_t裝置號 if(xxx_major){ result = register_chrdev_region(xxx_dev_no,1,DEVICE_NAME); //靜態申請裝置號 }else{ result = alloc_chrdev_region(&xxx_dev_no,0,1,DEVICE_NAME); //動態分配裝置號 xxx_major = MAJOR(xxx_dev_no); } if(result<0) return result; cdev_init(&xxx_dev.dev,&xxx_fops); //初始化cdev結構 xxx_dev.cdev.owner = THIS_MODULE; ret = cdev_add(&xxx_dev.cdev,MKDEV(xxx_major,0),1); //註冊字元裝置 if (ret) { printk("cdev add failed\n"); goto fail1; } xxx_class = class_create(THIS_MODULE,"xxx_class"); if(IS_ERR(xxx_class)) { printk("Err: failed in creating class./n"); goto fail2; } device_create(xxx_class, NULL, MKDEV(xxx_major,0), NULL, DEVICE_NAME); return 0; fail2: cdev_del(&xxx_dev.cdev); fail1: unregister_chrdev_region(xxx_dev_no, 1); return result; } static void __exit xxx_exit(void) //裝置驅動模組解除安裝函式 { device_destory(xxx_class,MKDEV(xxx_major,0)); class_destroy(xxx_class); cdev_del(&xxx_dev.cdev); unregister_chrdev_region(MKDEV(xxx_major,0), 1); } module_init(xxx_init); module_exit(xxx_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("your_name");