[转]mini2440的led的驱动 (指针细致+内存管理)

比原来的好，结构体指针指向更细致了 还涉及内存管理，留下有时间好好学习研究一下

转自：http://blog.sina.com.cn/s/blog_5f8665e70100pjtz.html

这段是mini2440的led Linux驱动程序代码

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <asm/irq.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <linux/platform_device.h>
#include <linux/cdev.h>
#include <linux/miscdevice.h>
#include <linux/sched.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#define LED_MAJOR 0
#define LED_ON  1
#define LED_OFF  0
struct led_dev {
 struct cdev cdev;
 unsigned char value;
};
struct led_dev *led_devp;
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,
};
int led_major = LED_MAJOR;
int led_open(struct inode *inode, struct file *filp)
{
 struct led_dev *dev;
 dev = container_of(inode->i_cdev, struct led_dev, cdev);
 filp->private_data = dev;

 return 0;
}
int led_release(struct inode *inode, struct file *filp)
{
 return 0;
}
ssize_t led_read(struct file *filp, char __user *buff, size_t count, loff_t *f_pos)
{
 struct led_dev *dev = filp->private_data;

 if(copy_to_user(buff, &(dev->value), 1))
  return -EFAULT;

 return 1;
}
ssize_t led_write(struct file *filp, const char __user *buff, size_t count, loff_t *f_pos)
{
 struct led_dev *dev = filp->private_data;
 if(copy_from_user(&(dev->value), buff, 1))
  return -EFAULT;
 if(dev->value == 1)
  s3c2410_gpio_setpin(led_table[1], 0);
 else
  s3c2410_gpio_setpin(led_table[1], 1);
 return 1;
}
int led_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
 struct led_dev *dev = filp->private_data;
 switch(cmd) {
 case LED_ON:
  dev->value = 1;
  s3c2410_gpio_setpin(led_table[arg], 0);
  break;
 case LED_OFF:
  dev->value = 0;
  s3c2410_gpio_setpin(led_table[arg], 1);
  break;
 default:
  return -ENOTTY;
 }

 return 0;
}
struct file_operations led_fops = {
 .owner  = THIS_MODULE,
 .read  = led_read,
 .write  = led_write,
 .ioctl   = led_ioctl,
 .open  = led_open,
 .release = led_release,
};
static void led_setup_cdev(struct led_dev *dev, int index)
{
 int err, devno = MKDEV(led_major, index);

 cdev_init(&dev->cdev, &led_fops);
 dev->cdev.owner = THIS_MODULE;
 dev->cdev.ops = &led_fops;

 err = cdev_add(&dev->cdev, devno, 1);
 if(err)
  printk(KERN_NOTICE "Error %d adding LED %d\n", err, index);
}
int led_init(void)
{
 int result;
        int i;
        for (i = 0; i < 4; i++) {
                s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);
                s3c2410_gpio_setpin(led_table[i], 0);
        }
 dev_t dev = MKDEV(led_major, 0);

 if(led_major)
  result = register_chrdev_region(dev, 1, "leds");
 else {
  result = alloc_chrdev_region(&dev, 0, 1, "leds");
  led_major = MAJOR(dev);
 }
 if(result < 0)
  return result;
 led_devp = kmalloc(sizeof(struct led_dev), GFP_KERNEL);
 if(!led_devp) {
  result = -ENOMEM;
  goto fail_malloc;
 }
 memset(led_devp, 0, sizeof(struct led_dev));
 led_setup_cdev(led_devp, 0);
 return 0;
 fail_malloc:
  unregister_chrdev_region(dev, 1);
  return result;
}
void led_exit(void)
{
 cdev_del(&led_devp->cdev);
 kfree(led_devp);
 unregister_chrdev_region(MKDEV(led_major, 0), 1);
}
module_init(led_init);
module_exit(led_exit);
MODULE_AUTHOR("Jackie");
MODULE_LICENSE("Dual BSD/GPL");

============================================================================================

以下是测试程序：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
int main(int argc, char **argv)
{
 int on;
 int led_no;
 int fd;
 if(argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2], "%d", &on) != 1
  || on < 0 || on >1 || led_no < 0 || led_no >3) {
  fprintf(stderr, "Usage: leds led_no 0|1\n");
  exit(1);
 }
 fd = open("/dev/leds0", 0);
 if(fd < 0) {
  fd = open("/dev/leds", 0);
 }
 if(fd < 0) {
  perror("open device leds");
  exit(1);
 }
 ioctl(fd, on, led_no);
 close(fd);
 return 0;
}