十、编写LED混杂设备驱动

led.c修改为：

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/miscdevice.h>
 #include <linux/fs.h>
 #include <linux/io.h>

 #define GPMCON    0x7F008820
 #define GPMDAT    0x7F008824

 static int * __gp_gpmdat;

 static int led_open (struct inode *p_inode, struct file *p_file)
 {
     int *p_gpmcon = NULL;

     p_gpmcon = ioremap(GPMCON, );
     writel(0x1111, p_gpmcon);

     __gp_gpmdat = ioremap(GPMDAT, );

     return ;
 }

 static long led_ioctl (struct file *p_file, unsigned int cmd, unsigned long arg)
 {
     switch (cmd) {
     case :
         writel(0x0, __gp_gpmdat);
         break;

     case :
         writel(0xF, __gp_gpmdat);
         break;

     default:
         return -;
     }
     return ;
 }

 static struct file_operations fops = {
     .owner = THIS_MODULE,
     .open = led_open,
     .unlocked_ioctl = led_ioctl,
 };

 static struct miscdevice led_dev = {
     .minor = MISC_DYNAMIC_MINOR,
     .name = "myled",
     .fops = &fops,
 };

 static __init int led_init (void)
 {
     misc_register(&led_dev);

     return ;
 }

 static __exit void led_exit (void)
 {
     misc_deregister(&led_dev);
 }

 module_init(led_init);
 module_exit(led_exit);

 MODULE_LICENSE("GPL");

其他文件同上一章一样，但是使用led时只需要先insmod led.ko，不需要再创建设备节点便可以使用led_app控制led