2013-10-05 实验之LED灯全关，全开

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实验描述：LED灯全关，全开

注意事项：开发板默认已有Led点灯的示例，要将其关闭，否则，看不到效果。

内核版本：Linux 2.6.38

开发板： Mini 6410

电路原理：

驱动程序：

#include <linux/init.h>  #include <linux/module.h>  #include <linux/device.h>#include <asm/uaccess.h>#include <linux/kdev_t.h>#include <linux/fs.h>#include <asm/io.h>/*      Kernel Version: Linux 2.6.38      Arm Version: Mini 6410*/#define MyPrintk  printkstatic dev_t Leds_Major ;static char * DEVICE_NAME = "MyLeds";static struct class *leds_class;volatile unsigned long *gpkcon0 = NULL;volatile unsigned long *gpkdat = NULL;static int   leds_init (struct inode *inode, struct file *file){*gpkcon0 &= ~( (0xF<<4*4) | (0xF<<5*4) | (0xF<<6*4) | (0xF<<7*4));*gpkcon0 |= ( (0x1<<4*4) |(0x1<<5*4) | (0x1<<6*4) | (0x1<<7*4)); *gpkdat |= (1<<4) | (1<<5) | (1<<6) | (1<<7) ;MyPrintk ("Leds Open gpkcon0: %lu\n",*gpkcon0);  MyPrintk ("Leds Open gpkdat: %lu\n",*gpkdat);  return 0;}static ssize_t leds_write (struct file *file, const char __user *buffer, size_t count, loff_t * ppos){ int val; unsigned long ret = copy_from_user(&val,buffer,count);if  (ret != 0){MyPrintk ("value error%lu\n", ret);  return -1;}MyPrintk ("value %d\n", val);  if(val == 1){ *gpkdat &= ~ ((1<<4) | (1<<5) | (1<<6) | (1<<7)) ;  MyPrintk ("Leds On gpkdat:%lu\n",*gpkdat);   }else if(val == 0){*gpkdat |= (1<<4) | (1<<5) | (1<<6) | (1<<7) ;MyPrintk ("Leds Off gpkdat:%lu\n",*gpkdat);  }return 0;}static struct file_operations  s3c64XX_leds_fops = {.owner = THIS_MODULE,.write = leds_write,.open = leds_init,};static int myleds_init(void)  {    Leds_Major = register_chrdev(Leds_Major,DEVICE_NAME , &s3c64XX_leds_fops);if(Leds_Major < 0){MyPrintk (KERN_EMERG "Sorry, Can not register the leds device!\n");    }MyPrintk (KERN_EMERG " Register the leds device\n");    leds_class = class_create(THIS_MODULE, "FirstLeds");  device_create(leds_class, NULL , MKDEV(Leds_Major, 0), NULL, "XYZ");  gpkcon0 = (volatile unsigned long *)ioremap(0x7F008800, 16);  gpkdat = gpkcon0 + 2; return 0;  }  static int myleds_exit(void)  {  unregister_chrdev(Leds_Major, DEVICE_NAME);  device_destroy(leds_class,MKDEV(Leds_Major, 0));  class_destroy(leds_class);  MyPrintk (KERN_EMERG "MyLeds ByeBye\n");    return 0;  }    module_init(myleds_init);  module_exit(myleds_exit);MODULE_LICENSE("GPL");

测试应用程序

#include<stdio.h>#include<fcntl.h>int main(int argc, char **argv){int fd;int val = 1;fd = open("/dev/XYZ", O_RDWR);if (fd < 0){printf("Sorry, can't open!\n");}if (argc != 2){printf("Usage :\n");printf("%s <on|off>\n", argv[0]);return 0;}if (strcmp(argv[1], "on") == 0){val  = 1;}else{val = 0;}write(fd, &val, 4);return 0;}