mini2440 led驱动代码基于kernel2.6.32.2 之led

最新推荐文章于 2021-05-02 23:04:04 发布

原创最新推荐文章于 2021-05-02 23:04:04 发布 · 659 阅读

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#kernel #arm #semaphore

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本文介绍了一个简单的LED模块驱动程序的设计与实现，该程序基于Linux内核，通过注册字符设备来控制LED灯的状态。通过ioctl系统调用，用户空间程序可以控制指定的LED灯亮起或熄灭。

#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/semaphore.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/semaphore.h>

#include <mach/regs-gpio.h>
#include <mach/gpio-fns.h>
#include <asm/uaccess.h>

#define LED_MAJOR 250
#define LED_NAME "leds"

static unsigned long led_table [] = {
   S3C2410_GPB(5),
   S3C2410_GPB(6),
   S3C2410_GPB(7),
   S3C2410_GPB(8),
};

static unsigned int led_cfg_table [] = {
   S3C2410_GPIO_OUTPUT,
   S3C2410_GPIO_OUTPUT,
   S3C2410_GPIO_OUTPUT,
   S3C2410_GPIO_OUTPUT,
};

struct leds_cdev
{
   struct cdev cdev;
   struct semaphore sem;
};

int leds_major = LED_MAJOR;
struct leds_cdev dev;

static int leds_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
   switch(cmd)
   {
       case 0:
       if(arg > 4){
           return -EINVAL;
           }
       down(&dev.sem);
       s3c2410_gpio_setpin(led_table[arg], 0);
       up(&dev.sem);
       return 0;
       case 1:
       if(arg > 4){
       return -EINVAL;
       }
       down(&dev.sem);
       s3c2410_gpio_setpin(led_table[arg], 1);
       up(&dev.sem);
       return 0;
       default:
           return -EINVAL;
   }
}

struct file_operations cdev_fops = {
   .owner = THIS_MODULE,
   .ioctl = leds_ioctl,
};

static void leds_setup(struct leds_cdev *dev, int index)
{
   int err, devno = MKDEV(leds_major, index);
   cdev_init(&dev->cdev, &cdev_fops);
   dev->cdev.owner = THIS_MODULE;
   dev->cdev.ops = &cdev_fops;
   err = cdev_add(&dev->cdev, devno, 1);
   if(err)
       printk(KERN_NOTICE "Error %d adding LED %d\n", err, index);
}

static int __init dev_init(void)
{
   int result;
   int i;
   dev_t devno = MKDEV(leds_major, 0);
   for(i = 0; i < 4; i++ ){
   s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
   s3c2410_gpio_setpin(led_table[i], 1);
   }

   if(leds_major)
   result = register_chrdev_region(devno, 1, "leds");
   else{
   result = alloc_chrdev_region(&devno, 0, 1, "leds");
   leds_major = devno;
   }

   if(result < 0)
   return result;
   leds_setup(&dev, 0);
   sema_init(&dev.sem, 1);
   return 0;

}

void __exit dev_exit(void)
{
   cdev_del(&dev.cdev);
   unregister_chrdev_region(MKDEV(leds_major, 0), 1);
}

module_init(dev_init);
module_exit(dev_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("emperor");
MODULE_DESCRIPTION("LED MODULE");