Understanding the LED driver

Hi I will like to understand how this driver work, if anyone has the time
can you comments on this driver?

#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <asm/irq.h>
#include <mach/regs-gpio.h>
#include <mach/hardware.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/gpio.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
#include <asm/unistd.h>


#define DEVICE_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,
};

static int sbc2440_leds_ioctl(
  struct inode *inode, 
  struct file *file, 
  unsigned int cmd, 
  unsigned long arg)
{
  switch(cmd) {
  case 0:
  case 1:
    if (arg > 4) {
      return -EINVAL;
    }
    s3c2410_gpio_setpin(led_table[arg], !cmd);
    return 0;
  default:
    return -EINVAL;
  }
}

static struct file_operations dev_fops = {
  .owner  =  THIS_MODULE,
  .ioctl  =  sbc2440_leds_ioctl,
};

static struct miscdevice misc = {
  .minor = MISC_DYNAMIC_MINOR,
  .name = DEVICE_NAME,
  .fops = &dev_fops,
};

static int __init dev_init(void)
{
  int ret;

  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);
  }

  ret = misc_register(&misc);

  printk (DEVICE_NAME"\tinitialized\n");

  return ret;
}

static void __exit dev_exit(void)
{
  misc_deregister(&misc);
}

module_init(dev_init);
module_exit(dev_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("FriendlyARM Inc.");