挂接在/proc上的对LED灯控制的驱动

通过一天的学习总结一下挂接在/proc上的对LED灯控制的驱动开发，代码和过程

1.驱动代码

#include <linux/module.h>  #include <linux/init.h>  #include <linux/version.h>  #include <linux/proc_fs.h>  #include <asm/uaccess.h>#include <linux/gpio.h>#include <mach/regs-gpio.h>MODULE_LICENSE("Dual BSD/GPL");         #define USER_ROOT_DIR "led"  #define USER_ENTRY1   "led_entry1" static struct proc_dir_entry *led_root;  static struct proc_dir_entry *led_entry1;static char msg[255];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 proc_read_information(char *page, char **start, off_t off, int count, int *eof, void *data);int proc_write_information(struct file *file, const char *buffer, unsigned long count, void *data);  static int proc_test_init(void)  {  int i;for( i=0;i<4;i++){s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);}// Create user root dir under /proc  led_root = proc_mkdir(USER_ROOT_DIR, NULL);  if (NULL==led_root)  {  printk(KERN_ALERT "Create dir /proc/%s error!\n",USER_ROOT_DIR);  return -1;  }  printk(KERN_INFO "Create dir /proc/%s\n", USER_ROOT_DIR);  // Create a test entry under USER_ROOT_DIR  led_entry1 = create_proc_entry(USER_ENTRY1,0666, led_root);  if (NULL == led_entry1)  {  printk(KERN_ALERT "Create entry %s under /proc/%s error!\n",USER_ENTRY1, USER_ROOT_DIR);  goto err_out;  }  printk(KERN_INFO "Create /proc/%s/%s\n",USER_ROOT_DIR, USER_ENTRY1);  //led_entry1->read_proc  = proc_read_information; led_entry1->write_proc = proc_write_information;return 0;  err_out: remove_proc_entry(USER_ROOT_DIR, led_root);  return -1;  }  static void proc_test_exit(void)  {  // Remove all entries  remove_proc_entry(USER_ENTRY1, led_root);  remove_proc_entry(USER_ROOT_DIR, NULL);  printk(KERN_INFO "All Proc Entry Removed!\n");  }//int proc_read_information(char *page, char **start, off_t off, int count, int *eof, void *data)//{//} int proc_write_information(struct file *file, const char *buffer, unsigned long count, void *data){int  count2=0,i ;if (copy_from_user((void *)msg, (const void __user *)buffer, count))return -EFAULT;count2 = simple_strtoul(msg, NULL, 0);//printk("information %d\n",count2);switch(count2){case 0:case 1:for(i=0; i<4; i++){   s3c2410_gpio_setpin(led_table[i],!count2);}break;default:return -EINVAL;}return count;} module_init(proc_test_init);  module_exit(proc_test_exit);  

2.驱动Makefile

obj-m:=led2.o    CURRENT_PATH:=$(shell pwd)    ARM_LINUX_KERNEL:=/opt/FriendlyARM/mini2440/linux-2.6.32.2    all:       $(MAKE) -C $(ARM_LINUX_KERNEL) SUBDIRS=$(CURRENT_PATH) modules     clean:  rm -rf *.cmd *.o *.ko  *.mod.c *.symvers *.order

3.开发过程

编写好驱动代码和Makefile,在PC机上编译成功后通过FTP把led2.ko文件上传到开发板，加载驱动（insmod led2.ko）,

执行echo 1 >/proc/led/led_entry1，灯全亮

执行echo 0 >/proc/led/led_entry1，灯全灭

注意：开发板缺省的文件系统已经有了led 测试程序，所以在开发板的命令行终端执行：

#/etc/rc.d/init.d/leds stop