#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#define GPIOLED_NAME "gpioled"
#define GPIOLED_CNT 1
#define LEDON 1
#define LEDOFF 0
/*gpioled设备结构体*/
struct gpioled_dev{
       dev_t devid; //dev_t 是一个用于表示设备编号的数据类型,设备号
       int major;//主设备号
       int minor;//次设备号
       struct cdev cdev;//设备关联，字符设备对象
       struct class *class;//设备类
       struct device *device;//设备节点
       struct device_node *nd;//设备树节点指针
       int led_gpio;//GPIO编号(从设备树上获取)
       atomic_t lock; /* 原子变量 */
};
struct gpioled_dev gpioled;//设备

static int led_open(struct inode *inode, struct file *filp)
{
   /*通过判断原子变量的值来检查 LED 有没有被别的应用使用*/
   if(atomic_read(&gpioled.lock) <= 0){
        return -EBUSY; /* LED 被使用，返回忙 */
   }else {
      atomic_dec(&gpioled.lock);//LED没有被使用，就减1，表示现在要用这个原子操作
   }
   filp->private_data = &gpioled;
   return 0;
}

static int led_release(struct inode *inode, struct file *filp)
{
    struct gpioled_dev *dev = filp->private_data;
    /* 关闭驱动文件的时候释放原子变量 */
    atomic_inc(&dev->lock);//加1变成1，表示用完，释放原子变量
   return 0;
}
static ssize_t led_write(struct file *filp, const char __user *buf,
			 size_t count, loff_t *ppos)
{
     int ret;
     unsigned char databuf[1];
     struct gpioled_dev *dev=filp->private_data;
     ret = copy_from_user(databuf,buf,count);
     if(ret < 0){
        return -EINVAL;
     }
     if(databuf[0] == LEDON){
        gpio_set_value(dev->led_gpio,0);//开灯
     }else if(databuf[0] == LEDOFF){
        gpio_set_value(dev->led_gpio,1);//关灯
     }
     return 0;
}

/*操作集*/
static const struct file_operations led_fops = {
	.owner   = THIS_MODULE,
	.write   = led_write,
	.open    = led_open,
	.release = led_release,
};


/*驱动入口函数*/
static int __init led_init(void)
{
    int ret;
    /*1.注册字符设备*/
    gpioled.major = 0;
    if(gpioled.major){//若给定主设备号
         gpioled.devid = MKDEV(gpioled.major,0);//0为次设备号
         ret =  register_chrdev_region(gpioled.devid,GPIOLED_CNT,GPIOLED_NAME);
    }else{//若给定主设备号
         ret =  alloc_chrdev_region(&gpioled.devid,0,GPIOLED_CNT,GPIOLED_NAME);
         //0为次设备号,起始的次设备号
         gpioled.major = MAJOR(gpioled.devid);
         gpioled.minor = MINOR(gpioled.devid);
    }
    if(ret < 0){
        goto fail_devid;
    }
    printk("major=%d minor=%d\r\n",gpioled.major,gpioled.minor);

    /*2.初始化cdev*/
    gpioled.cdev.owner= THIS_MODULE;//模块关联与引用计数管理
    cdev_init(&gpioled.cdev, &led_fops);//字符设备操作函数绑定

    /*3.添加cdev*/
    ret = cdev_add(&gpioled.cdev,gpioled.devid,GPIOLED_CNT);//即后续的./ledApp 可以执行到/dev
    if(ret < 0){
        goto fail_cdev;
    }
    
    /*4.创建类class*/
    gpioled.class = class_create(THIS_MODULE,GPIOLED_NAME);//创建/dev/beep
    if(IS_ERR(gpioled.class)){
        ret = PTR_ERR(gpioled.class);
        goto fail_class;
    }
    
    /*5.创建设备节点device*/
    gpioled.device = device_create(gpioled.class,NULL,gpioled.devid,NULL,GPIOLED_NAME);
    //创建/dev/beep
    if(IS_ERR(gpioled.device)){
        ret = PTR_ERR(gpioled.device);
        goto fail_device;
    }

    /*6.获取设备树节点*/
    gpioled.nd = of_find_node_by_path("/gpioled");//根节点
    if(gpioled.nd ==NULL ){
        ret = -EINVAL;
        goto fail_findnode;
    }

    /*7.获取gpioled根节点下的属性*/
    gpioled.led_gpio = of_get_named_gpio(gpioled.nd,"led-gpio",0);
    if(gpioled.led_gpio < 0){
        printk("can't find led gpio\r\n");
        ret = -EINVAL;
        goto fail_findnode;
       }
       printk("led gpio num = %d\r\n",gpioled.led_gpio);

    /*8.申请IO*/
    ret = gpio_request(gpioled.led_gpio,"led-gpio");
    if(ret){
        printk("Failed to request the led gpio\r\n");
        ret = -EINVAL;
        goto fail_findnode;
    }

    /*9.设置IO口电气属性，设置为输出模式*/
    ret = gpio_direction_output(gpioled.led_gpio,1);//默认高电平
    if (ret < 0) {
        ret = -EINVAL;
        goto fail_setoutput;
    }

    /*10.初始化原子变量*/
    gpioled.lock = (atomic_t)ATOMIC_INIT(0);//gpioled.lock=0
    /*11.原子变量初始值为1*/
    atomic_set(&gpioled.lock, 1);
    
    return 0;
fail_setoutput:/*设置输出失败，释放已申请的IO，避免资源浪费*/
    gpio_free(gpioled.led_gpio);
fail_findnode:
    device_destroy(gpioled.class,gpioled.devid);
fail_device:
    class_destroy(gpioled.class);
fail_class:
    cdev_del(&gpioled.cdev);
fail_cdev:
    unregister_chrdev_region(gpioled.devid,GPIOLED_CNT);
fail_devid:
    return ret;
}

/*驱动出口函数*/
static void __exit led_exit(void)
{
  /*关灯*/
  gpio_set_value(gpioled.led_gpio,1);
  /*释放IO*/
  gpio_free(gpioled.led_gpio);
  /*注销设备节点*/  
  device_destroy(gpioled.class,gpioled.devid);
  /*注销设备类*/
  class_destroy(gpioled.class);
  /*注销字符设备对象驱动*/
  cdev_del(&gpioled.cdev);
  /*注销字符设备驱动*/
  unregister_chrdev_region(gpioled.devid,GPIOLED_CNT);
}

module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("chensir");
MODULE_INFO(intree,"Y");//INFO,信息

#include "stdio.h"
#include "unistd.h"
#include "sys/types.h"  /*open执行所需头文件，根文件目录终端输入man 2 open*/
#include "sys/stat.h"   /*open执行所需头文件，根文件目录终端输入man 2 open*/
#include "fcntl.h"      /*open执行所需头文件，根文件目录终端输入man 2 open*/
#include "stdlib.h"     
#include "string.h"     /*memcpy执行所需头文件，根文件目录终端输入man 3 memcpy*/

/*
*argc:应用程序参数个数
*argv[]：具体的参数内容，字符串形式
*./ledAPP  <fliename>  <0:1>  0表示关灯，1表示开灯
*./ledAPP /dev/gpioled 0   关灯
*./ledAPP /dev/gpioled 1   开灯
*/

#define LEDOFF   0
#define LEDON    1

int main(int argc,char *argv[])
{
  int fd,retvalue;/*fd:类似文件的ID号；retvalue:返回值。*/
  unsigned char databuf[1];/*这种数组可以存储数字或字符*/
  char *filename;
  unsigned char cnt = 0;
  if(argc !=3)
  {
    printf("Error usage!\r\n");
    return -1;
  }
  filename = argv[1];
  /*打开文件*/
  /* int open (const char *pathname,int flags)*/
  fd = open(filename,O_RDWR);/*以读写模式打开文件,fd用于打开文件获取ID号*/
  if(fd<0)
  {
    printf("file %s open failed!\r\n",filename);
    return -1;
  }
  databuf[0] = atoi(argv[2]);/*将字符转换为数字*/
  retvalue=write(fd,databuf,sizeof(databuf));
  if(retvalue<0)
  {
    printf("LED Control Failed!\r\n");
    close(fd);
    
  }
   while(1) {
   sleep(5);
   cnt++;
   printf("App running times:%d\r\n", cnt);
   if(cnt >= 5) break;
 }
  close(fd);
  return 0;
  }