qt字符设备驱动，简单易学

/** * A demo driver for simple Character device." * * simple_chrdev.c * * Author Tianze Sun * * E-mail [email protected] * * Fri Jun 2th 20:32:43 GMT 2006 * * Current version: 1.1.0 * * All rights reserved. Licensed under dual BSD/GPL license. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/cdev.h> #include <linux/ioctl.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/timer.h> #include <linux/ioport.h> #include <linux/param.h> #include <linux/sched.h> #include <linux/errno.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/signal.h> #define SIMPLE_PHYS_ADDR 0x1FFFFF7C //Address #define SIZE_OF_SIMPLE 2 //2 Bytes #define SIMPLE_TIMER_DELAY 1 // 1 ms #define SIMPLE_IOCTL_MAGIC 'K' //Magic #define CMD1 _IOW(SIMPLE_IOCTL_MAGIC,3,unsigned long) #define CMD2 _IOW(SIMPLE_IOCTL_MAGIC,4,unsigned long) #define CMDn _IOW(SIMPLE_IOCTL_MAGIC,5,unsigned long) #define SIMPLE_NAME "Simple" int SIMPLE_MAJOR = 0; int SIMPLE_MINOR = 0; int SIMPLE_NUMBER = 1; void __iomem *simple_addr_virt = NULL; struct cdev *simple_cdev; dev_t simple_dev; int simple_open(struct inode *inode, struct file *filp); int simple_release(struct inode *inode, struct file *filp); int simple_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg); static ssize_t simple_read(struct file * file, char __user *buf, size_t count, loff_t *ppos); static ssize_t simple_write(struct file *file, const char __user *buf, size_t len, loff_t *ppos); loff_t simple_llseek(struct file *file,loff_t offset, int origin); static struct timer_list simple_timer; static void simple_timer_handler(unsigned long data); extern struct file_operations simple_fops; struct file_operations simple_fops = { .owner = THIS_MODULE, .llseek = simple_llseek, .open = simple_open, .read = simple_read, .write = simple_write, .ioctl = simple_ioctl, .release = simple_release, }; /* Open */ int simple_open(struct inode *inode, struct file *filp) { printk("Simple Device is opened\n"); try_module_get(THIS_MODULE) ; return 0 ; } /* Release */ int simple_release(struct inode *inode, struct file *filp) { printk("Simple Device is released!\n"); module_put(THIS_MODULE) ; return 0 ; } static ssize_t simple_read(struct file *file,char __user *buf,size_t count,loff_t *ppos) { int rv = 0; /* Return Value */ if (count <= 0) return count; printk("Reading Data now...\n"); if (file->f_flags & O_NONBLOCK) { rv = -EAGAIN; return rv; } //Get data from Kernel space. return rv; } /* Write */ static ssize_t simple_write(struct file *file,const char __user *buf,size_t len,loff_t *ppos) { int rv = 0; printk("Writing Data now...\n"); //Get data from User space. return rv; } /* Llseek */ loff_t simple_llseek(struct file *file, loff_t offset, int origin) { long long retval = -EINVAL; switch (origin) { case 1: offset += file->f_pos; retval = offset; case 0: if (offset < 0) break; retval = offset; } return retval; } /* Ioctl */ int simple_ioctl( struct inode *inode, struct file *file,unsigned int cmd, unsigned long arg) { switch( cmd ) { case CMD1: printk("First Command.\n"); //do something... break; case CMD2: printk("Second Command.\n"); //do something... break; case CMDn: printk("Still a Command.\n"); //do something... break; default: return -ENOTTY; } return -EINVAL; } static void simple_timer_handler( unsigned long data) { int Condition = 1; simple_timer.expires = jiffies + SIMPLE_TIMER_DELAY; simple_timer.function = &simple_timer_handler; add_timer (&simple_timer); if(Condition) printk("Everything is fine.\n"); else { printk("We don't need timer anymore...\n"); del_timer(&simple_timer); } return ; } static int __init simple_init(void) { int ret; /* register major and minor */ if(SIMPLE_MAJOR) { simple_dev = MKDEV(SIMPLE_MAJOR, SIMPLE_MINOR); ret = register_chrdev_region(simple_dev,SIMPLE_NUMBER,SIMPLE_NAME); } else { /* Dynamic assign major */ ret = alloc_chrdev_region(&simple_dev, SIMPLE_MINOR,SIMPLE_NUMBER,SIMPLE_NAME); SIMPLE_MAJOR = MAJOR(simple_dev); } if(ret<0) { printk(KERN_ERR "Cannot get major %d!\n",SIMPLE_MAJOR) ; return ret; } /* Register Character Device Driver */ simple_cdev = cdev_alloc() ; if(simple_cdev != NULL) { cdev_init(simple_cdev, &simple_fops) ; simple_cdev->ops = &simple_fops ; simple_cdev->owner = THIS_MODULE ; if(cdev_add(simple_cdev, simple_dev, SIMPLE_NUMBER)) printk(KERN_NOTICE "Someting wrong when adding simple_cdev!\n"); else printk("Success adding simple_cdev!\n"); } else { printk(KERN_ERR "Register simple_dev error!\n") ; return -1 ; } /* Request region */ if(!request_mem_region(SIMPLE_PHYS_ADDR,SIZE_OF_SIMPLE,SIMPLE_NAME)) { printk(KERN_ERR "simple: IO %X is not free.\n", SIMPLE_PHYS_ADDR); return -EBUSY; } /* Memory map */ simple_addr_virt = ioremap(SIMPLE_PHYS_ADDR, SIZE_OF_SIMPLE ); if (!simple_addr_virt) { printk (KERN_ERR "simple: ioremap failed.\n"); iounmap(simple_addr_virt); return -EINVAL; } /* Register timer */ init_timer(&simple_timer); simple_timer.function = &simple_timer_handler; simple_timer.expires = jiffies + SIMPLE_TIMER_DELAY; return 0; } static void __exit simple_exit(void) { dev_t devno = MKDEV(SIMPLE_MAJOR,SIMPLE_MINOR); printk("Unloading simple_cdev now...\n"); unregister_chrdev_region(devno,SIMPLE_NUMBER); release_mem_region(SIMPLE_PHYS_ADDR,SIZE_OF_SIMPLE); iounmap(simple_addr_virt); cdev_del(simple_cdev); } module_init(simple_init); module_exit(simple_exit); MODULE_AUTHOR("Tianze SUN"); MODULE_DESCRIPTION("SIMPLE Character"); MODULE_LICENSE("dual BSD/GPL");