华清远见上海中心22071班--11.30作业

题目：用IIC总线实现温湿度传感器的数据读取，并根据该数据实现LED灯的亮灭

#ifndef __SI7006_H__
#define __SI7006_H__

#define GET_TEM _IOR('m',0,int)
#define GET_HUM _IOR('m',1,int)

#define LED_ON _IOR('L',0,int)
#define LED_OFF _IOR('L',1,int)
#endif

#include 
#include 
#include 
#include 
#include 
#include 
#include
#include
#include "si7006.h"

int major;
struct class *cls;
struct device *dev;
struct i2c_client *tclient;

struct device_node *node;
struct gpio_desc * gpiono;//用于接收gpio编号

//获取温湿度数据的函数
int i2c_read_hum_tem(unsigned char reg)
{
  int ret;
  //消息的封装
  char r_buf[]={reg};
  unsigned short val;
  struct i2c_msg r_msg[]={
    [0]={
        .addr = tclient->addr,
        .flags = 0,
        .len = 1,
        .buf = r_buf,
    },
    [1]={
      .addr = tclient->addr,
      .flags = 1,
      .len = 2,
      .buf = (char*)&val,
    },
  };
  //消息的传输
  ret = i2c_transfer(tclient->adapter,r_msg,ARRAY_SIZE(r_msg));
  if(ret!=ARRAY_SIZE(r_msg))
  {
    printk("i2c获取温湿度失败\n");
    return EAGAIN;
  }
  return val;
}
int si7006_open(struct inode *inode,struct file *file)
{
  printk("open\n");
  return 0;
}
ssize_t si7006_read(struct file *file,char *ubuf,size_t size,loff_t *off)
{
  printk("read\n");
  return 0;
}
ssize_t si7006_write(struct file *file,const char *ubuf,size_t size,loff_t *off)
{
  printk("read\n");
  return 0;
}
long si7006_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
{
  int tem,hum;
  int ret;
  switch(cmd)
  {
    case GET_HUM:
      hum = i2c_read_hum_tem(0xe5);
      ret = copy_to_user((void*)arg,(void*)&hum,sizeof(int));
      if(ret)
      {
        printk("copy_to_user fail\n");
        return EINVAL;
      }
      break;
    case GET_TEM:
      tem = i2c_read_hum_tem(0xe3);
      ret = copy_to_user((void*)arg,(void*)&tem,sizeof(int));
      if(ret)
      {
        printk("copy_to_user fail\n");
        return EINVAL;
      }
      break;
    case LED_ON:
       gpiod_set_value(gpiono,1);
       break;
    case LED_OFF:
       gpiod_set_value(gpiono,0);
       break;

  }
  return 0;
}
int si7006_close(struct inode *inode,struct file *file)
{
  printk("close\n");
  return 0;
}

struct file_operations fops={
  .open = si7006_open,
  .read = si7006_read,
  .write = si7006_write,
  .unlocked_ioctl = si7006_ioctl,
  .release = si7006_close,
};




//定义probe函数
int si7006_probe(struct i2c_client *client,const struct i2c_device_id *id)
{
  tclient = client;
  //注册字符设备驱动
  major = register_chrdev(0,"si7006",&fops);
  if(major<0)
  {
    printk("字符设备注册失败\n");
    return major;
  }
  printk("字符设备注册成功\n");
  //自动创建节点
  cls = class_create(THIS_MODULE,"si7006");
  if(IS_ERR(cls))
  {
    printk("提交目录失败\n");
    return PTR_ERR(cls);
  }
  printk("提交目录成功\n");
  dev = device_create(cls,NULL,MKDEV(major,0),NULL,"si7006");
  if(IS_ERR(dev))
  {
    printk("提交设备信息失败\n");
    return PTR_ERR(cls);
  }
  printk("提交设备信息成功\n");


//通过名字获取设备树节点信息
  node=of_find_node_by_name(NULL,"myleds");
  if(node==NULL)
  {
      printk("通过名字解析设备树节点失败\n");
      return -EFAULT;
  }
  printk("成功解析到设备树节点\n");
  //获取并申请gpio编号
  gpiono=gpiod_get_from_of_node(node,"myled1",0,GPIOD_OUT_LOW,NULL);
  if(IS_ERR(gpiono))
  {
      printk("获取gpio编号失败\n");
      return PTR_ERR(gpiono);
  }
  printk("获取gpio编号成功\n");
  return 0;
}




//定义re函数
int si7006_remove(struct i2c_client *client)
{
    printk("%s:%d\n",__func__,__LINE__);

    gpiod_set_value(gpiono,0);
    //释放申请得到的gpio编号
    gpiod_put(gpiono);

    device_destroy(cls,MKDEV(major,0));
    //注销目录信息
    class_destroy(cls);
    //注销字符设备驱动
    unregister_chrdev(major,0);

    return 0;
}
//设备树匹配表
struct of_device_id oftable[]={
    {.compatible = "hqyj,si7006"},
    {},
};
MODULE_DEVICE_TABLE(of,oftable);
//给对象初始化
struct i2c_driver si7006={
  .probe = si7006_probe,
  .remove = si7006_remove,
  .driver ={
    .name = "abc",
    .of_match_table=oftable,
  },
};



module_i2c_driver(si7006);
MODULE_LICENSE("GPL");

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "si7006.h"
int main(int argc, char const *argv[])
{
    int hum,tem;
    float hum1,tem1;
    int ret;
    int led;
    int fd = open("/dev/si7006",O_RDWR);
    if(fd<0)
    {
        printf("打开设备文件失败\n");
        exit(1);
    }
    while(1)
    {
        ioctl(fd,GET_TEM,&tem);
        ioctl(fd,GET_HUM,&hum);
        //字节数转换
        hum = ntohs(hum);
        tem = ntohs(tem);
        //温湿度计算
        hum1 = 125.0*hum/65536-6;
        tem1 = 175.72*tem/65536-46.85;
        if(hum1>50)
        {
            ioctl(fd,LED_ON,&led);
        }
        else
            ioctl(fd,LED_OFF,&led);
        printf("tem:%f  hum:%f\n",tem1,hum1);
        sleep(1);
    }
    return 0;
}

测试结果：

        用手捂住温湿度传感器，使得湿度上升，当湿度上升到50以上时，LED1亮；然后手放开，当湿度降到50以下时，LED1灭

当hum>50时，LED1亮；当hum<=50时，LED1灭