哪位高手来救救小弟我的PWM程序啊

谁来救救我的PWM程序啊！！
各位****D的大侠们。小弟初学嵌入式。用s3c2410的定时器0产生PWM信号。但是当我结束应用程序后，驱动产生的PWM波还在。这是怎么回事啊？望各位大侠不吝赐教。
我的驱动程序如下：

C/C++ code

#include<linux/kernel.h>
#include<linux/module.h>
#include<linux/init.h>
#include<linux/fs.h>
#include<linux/types.h>
#include<linux/poll.h> 
#include<linux/version.h>
#include<linux/errno.h>
#include <asm/io.h>
#include <linux/clk.h>
#include<asm-arm/arch-s3c2410/regs-gpio.h>
#include <asm-arm/plat-s3c/regs-timer.h> 
#define pwm_device_MAJOR 50
#define DEVICE_NAME "pwm_device"
#define FREQ 50
#define PWM_CLOSE 0
#define PWM_OPEN 1
static int pwm_device_close(struct inode *inode,struct file *file);
static int pwm_device_open(struct inode *inode,struct file *file);
static int pwm_device_ioctl(struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg);
static int __init pwm_device_init(void);
static void __exit pwm_device_cleanup(void);


static struct file_operations pwm_device_fops=
{
    owner:        THIS_MODULE,
    open:        pwm_device_open,
    release:    pwm_device_close,
    ioctl:        pwm_device_ioctl,
};
static void set_pwm_duty(unsigned long duty)
{
    unsigned long tcon;
    unsigned long tcnt;
    unsigned long tcmp;
    unsigned long tcfg0;
    unsigned long tcfg1;

    struct clk *clk_p;
    unsigned long pclk;

    s3c2410_gpio_cfgpin(S3C2410_GPB0,S3C2410_GPB0_TOUT0);

    tcfg0 = __raw_readl(S3C2410_TCFG0);
    tcfg1 = __raw_readl(S3C2410_TCFG1);
    tcfg0 &= ~S3C2410_TCFG_PRESCALER0_MASK;
    tcfg0 |= (256 - 1);
    tcfg1 &= ~S3C2410_TCFG1_MUX0_MASK;
    tcfg1 |= S3C2410_TCFG1_MUX0_DIV16;
    
    __raw_writel(tcfg0, S3C2410_TCFG0);
    __raw_writel(tcfg1, S3C2410_TCFG1);
  
    clk_p = clk_get(NULL, "pclk");
    pclk  = clk_get_rate(clk_p);
    tcnt  = (pclk/256/16)/FREQ;
    tcmp  = (tcnt*duty)/100;    
    __raw_writel(tcnt, S3C2410_TCNTB(0));
    __raw_writel(tcmp, S3C2410_TCMPB(0));
        
    tcon = __raw_readl(S3C2410_TCON);            
    tcon &= ~0x1f;
    tcon |= 0xb;
    __raw_writel(tcon, S3C2410_TCON);
    
    tcon &= ~2;    
    __raw_writel(tcon, S3C2410_TCON);
}
static int __init pwm_device_init(void)
{
    int result;
    result=register_chrdev(pwm_device_MAJOR,DEVICE_NAME,&pwm_device_fops);
    if (result<0)
    {
        printk(KERN_INFO "[FAILED:Cannot register pwm_device Device!]\n");
        return -EIO;
    }
    else
        printk("Initializing pwm_device Device\t----->\t");
        printk("[OK]\n");
        return 0;
}

static int pwm_device_open(struct inode *inode,struct file *file)
{
    printk(KERN_CRIT "DEMO:pwm_device Device Open!\n");
    return 0;
}
static int pwm_device_ioctl(struct inode *inode,struct file *file,unsigned int cmd,unsigned long arg)
{
    switch(cmd)
    {
    case PWM_CLOSE:
        break;
    case PWM_OPEN:
        if (arg == 0)
            return -EINVAL;
        set_pwm_duty(arg);
        break;
    default:
        break;    
    }
    return 0;
}

static int pwm_device_close(struct inode *inode,struct file *file)
{
    printk(KERN_CRIT "DEMO:pwm_device Device close!\n");
    return 0;
}

static void __exit pwm_device_cleanup(void)
{
    unregister_chrdev(pwm_device_MAJOR,DEVICE_NAME);
    printk("DEMO:pwm_device Device Is Cleanup!\n");
}

module_init(pwm_device_init);
modele_exit(pwm_device_cleanup);

MODULE_LICENSE("GPL");

应用程序如下：

C/C++ code

#include<stdlib.h>
#include<sys/ioctl.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<unistd.h>
#include<stdio.h>

#define DEVICE "/dev/pwm_device"

int main()
{
    int fd;
    int on_off;
    int duty;
    fd=open(DEVICE,O_RDWR);
    if(fd<0)
    {
        printf("open device error!\n");
        exit(-1);
    }
    printf("请输入控制信号.0为关闭PWM输出,1为打开PWM输出功能!\n");
    scanf("%d",&on_off);
    printf("您的输入是:%d\n",on_off);
    printf("请输入小于100的占空比值!\n");
    scanf("%d",&duty);
    printf("您的输入是:%d\n",duty);
    ioctl(fd,on_off,duty);
    while(1);
    close(fd);
    return 0;
}

哪位高手来救救小弟我的PWM程序啊

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