data/method/一些思考/系统移植+驱动/字符设备模板/用户空间与内核空间的信息读写/test.c

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define NEWCHRLED_CNT 1
#define NEWCHRLED_NAME "test"

/* newchrled设备结构体 */
struct newchrled_dev{
        dev_t devid;                    /* 设备号        */
        struct cdev cdev;               /* cdev         */
        struct class *class;            /* 类           */
        struct device *device;  /* 设备          */
        int major;                              /* 主设备号       */
        int minor;                              /* 次设备号   */
};
static char read_char[]="readsuccess";
static char write_char[32];

struct newchrled_dev newchrled; /* led设备 */

static int led_open(struct inode *inode, struct file *filp)
{
        filp->private_data = &newchrled; /* 设置私有数据 */
	printk("open success\n");
        return 0;
}

static ssize_t led_read(struct file *filp, char __user *buf, size_t cnt, loff_t *offt)
{
	int ret;
	ret = copy_to_user(buf,read_char,sizeof(read_char));
	if(ret == 0)
		printk("%s\n",read_char);
	else
		printk("readfail\n");
	return 0;
}

static ssize_t led_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offt)
{
	int ret;
	ret = copy_from_user(write_char,buf,sizeof(write_char));
	if(ret == 0)
		printk("%s\n",write_char);
	else
		printk("writefail\n");
	
       	return 0;
}

static int led_release(struct inode *inode, struct file *filp)
{
        return 0;
}

static long led_ioctl(struct file *filp, unsigned int cmd, unsigned long argv)
{

	printk("open success\n");
        return 0;
}
/* 设备操作函数 */
static struct file_operations newchrled_fops = {
        .owner = THIS_MODULE,
        .open = led_open,
        .read = led_read,
        .write = led_write,
        .release = led_release,
	.unlocked_ioctl= led_ioctl,
};

static int __init led_init(void)
{
        if (newchrled.major) {          /*  定义了设备号 */
		printk("newchrled.major ******************\n");
                newchrled.devid = MKDEV(newchrled.major, 0);
                register_chrdev_region(newchrled.devid, NEWCHRLED_CNT, NEWCHRLED_NAME);
        } else {                                                /* 没有定义设备号 */
                alloc_chrdev_region(&newchrled.devid, 0, NEWCHRLED_CNT, NEWCHRLED_NAME);        /* 申请设备号 */
                newchrled.major = MAJOR(newchrled.devid);       /* 获取分配号的主设备号 */
                newchrled.minor = MINOR(newchrled.devid);       /* 获取分配号的次设备号 */
		printk("newchrled.major %d newchrled.minor %d\n",newchrled.major,newchrled.minor);
        }
        newchrled.cdev.owner = THIS_MODULE;
        cdev_init(&newchrled.cdev, &newchrled_fops);
        cdev_add(&newchrled.cdev, newchrled.devid, NEWCHRLED_CNT);
        newchrled.class = class_create(THIS_MODULE, NEWCHRLED_NAME);
        if (IS_ERR(newchrled.class)) {
                return PTR_ERR(newchrled.class);
        }
        newchrled.device = device_create(newchrled.class, NULL,newchrled.devid, NULL, NEWCHRLED_NAME);
        if (IS_ERR(newchrled.device)) {
                return PTR_ERR(newchrled.device);
        }
        printk("init success\n");
        return 0;
}

static void __exit led_exit(void)
{
        cdev_del(&newchrled.cdev);/*  删除cdev */
        unregister_chrdev_region(newchrled.devid, NEWCHRLED_CNT); /* 注销设备号 */
        device_destroy(newchrled.class, newchrled.devid);
        class_destroy(newchrled.class);

        printk("exit success\n");
}

module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("luozhikun");