led.c

linux2.6 led driver 是非常难的典形的linux2.6驱动。初学者非常适应

#include <linux/config.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>//Please configure your kernel first to use the following headers, because the directory "asm" is a short cut to your arch's "asm" directory.
#include <asm/io.h>  //This header is for ioremap(), iounmap().
#include <asm/uaccess.h>  //This header is for get_user(), put_user().
#include <asm/irq.h>
#include <linux/sched.h>
#define NAME "led_test"
MODULE_AUTHOR("Lu Xianzi <[e-mail]>");  //This line and the following 4 lines can be omitted.
MODULE_DESCRIPTION("LED Test Driver");
MODULE_LICENSE("Dual BSD/GPL");
static int major=231;
module_param(major, int, 0);
MODULE_PARM_DESC(major, "Major device number");
unsigned long * pREG;  //Definition of register base.
void *LED_GPBCON,*LED_GPBDAT,*LED_GPBUP;

static ssize_t led_test_write(struct file *file, const char __user *data, size_t len, loff_t *ppos)
{
 char buf[256];
 size_t i;
 for (i = 0; i < len && i < 254; i++)
  if (get_user(buf[i], data + i))
   return -EFAULT;
   
 buf[i] = '\0';
 printk("LED Test - write: user_data %s\n", buf);
 return (len < 255 ? len : 255);
}

static int led_test_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
 unsigned long tmp;
 printk("LED Test - ioctl: param %u %lu\n", cmd, arg);
 switch (cmd)
 {
  case 0: {   tmp = ioread32(LED_GPBDAT);
              tmp |= 0x002;          
              iowrite32(tmp, LED_GPBDAT);  }
  case 1:{    tmp = ioread32(LED_GPBDAT);
              tmp |= 0x008;          
              iowrite32(tmp, LED_GPBDAT);  }
//   if (arg > 3)
//    return -EINVAL;
//   if (!cmd)
//    * (volatile unsigned long *)(pREG + 1) |= (0x80 << arg);
//   else
//    * (volatile unsigned long *)(pREG + 1) &= ~(0x80 << arg);
//   tmp = * (volatile unsigned long *)pREG;
//   printk("GPBCON = 0x%lx\n", tmp);
//   tmp = * (volatile unsigned long *)(pREG + 1);
//   printk("GPBDAT = 0x%lx\n", tmp);
//   break;
  default:
   return -EINVAL;
 }
 return 1;
}
static int led_test_open(struct inode *inode, struct file *file)
{
 unsigned m = iminor(inode);
 if (m > 63)
  return -EINVAL;
 printk("LED Test driver opened!\n");
 return nonseekable_open(inode, file);
}
static int led_test_release(struct inode *inode, struct file *file)
{
 printk("LED Test driver released!\n");
 return 0;
}

static struct file_operations led_test_fops = {
 .owner   = THIS_MODULE,
 .ioctl   = led_test_ioctl,
 .write   = led_test_write,
 .open    = led_test_open,
 .release = led_test_release,
};
static int __init led_test_init(void)
{
 int ret;
 ret = register_chrdev(major, NAME, &led_test_fops);
 if (ret < 0) {
  printk("Unable to register character device!\n");
  return ret;
 } 
 LED_GPBCON = ioremap(0x56000010,4);
 LED_GPBDAT = ioremap(0x56000014,4);
 LED_GPBUP  = ioremap(0x56000018,4);
 
 unsigned int tmp = ioread32(LED_GPBCON);
              tmp &= ~0x0000C0; 
              tmp |= 0x000040;          
              iowrite32(tmp, LED_GPBCON);
              
//              tmp = ioread32(LED_GPBDAT);
//              tmp |= 0x008;          
//              iowrite32(tmp, LED_GPBDAT);  
 printk("LED Test Driver initiated.\n"); 
 return 0;
}
static void __exit led_test_cleanup(void)
{
 int ret;
 
 iounmap(LED_GPBCON);
 iounmap(LED_GPBDAT);
 iounmap(LED_GPBUP);
 
 ret = unregister_chrdev(major, NAME); 
 if (ret < 0)
  printk("Unable to register character device!\n");
 else
  printk("LED Test Driver unloaded!");
}
module_init(led_test_init);
module_exit(led_test_cleanup);