Linux 驱动开发 - 编写 (EEPROM)AT24C02 驱动

#include <linux/kernel.h>#include <linux/module.h>#include <linux/platform_device.h>#include <linux/i2c.h>#include <linux/delay.h>#include <linux/interrupt.h>#include <asm/uaccess.h>#include <linux/init.h>#include <linux/module.h>#include <linux/fs.h>#include <linux/cdev.h>#include <linux/device.h>#include <linux/slab.h>#include <asm/uaccess.h>#include <linux/miscdevice.h>static struct work_struct work;static struct i2c_client *eeprom_client;
#define MAX_SIZE 255  //EEPROM大小#define EEPROM_PAGE  16 //页字节大小
static u8 eeprom_buff[255];static int tiny4412_open(struct inode *inode, struct file *file){  printk("tiny4412_open-->ok\n");  return 0;}
static ssize_t tiny4412_read(struct file *file, char __user *buf, size_t size, loff_t *seek){    unsigned long err;  //判断位置是否超出范围  if(*seek+size>MAX_SIZE)  {    size=MAX_SIZE-*seek;  }  //读取数据  i2c_smbus_read_i2c_block_data(eeprom_client,*seek,size,eeprom_buff);  err=copy_to_user(buf,eeprom_buff,size);  if(err!=0)return -1;  *seek+=size;  return size;}
static ssize_t tiny4412_write(struct file *file, const char __user *buf, size_t size, loff_t *seek){  size_t write_ok_cnt=0;  unsigned long err;  err=copy_from_user(eeprom_buff,buf,size);  if(err!=0)return -1;  //判断位置是否超出范围  if(*seek+size>MAX_SIZE)  {    size=MAX_SIZE-*seek;  }    int write_byte=0;  u8 *write_p=eeprom_buff;  while(1)  {    if(size>EEPROM_PAGE)    {      write_byte=EEPROM_PAGE;      size-=EEPROM_PAGE;    }    else    {      write_byte=size;    }        //写数据    i2c_smbus_write_i2c_block_data(eeprom_client,*seek,write_byte,write_p);    *seek+=write_byte;    write_p+=write_byte;    write_ok_cnt+=write_byte;  //记录写成功的字节数    //等待写完成    msleep(10);    if(write_byte==size)break; //写完毕  }  return write_ok_cnt;}
/*filp:待操作的设备文件file结构体指针off:待操作的定位偏移值(可正可负)whence:待操作的定位起始位置返回：返回移位后的新文件读、写位置，并且新位置总为正值定位起始位置  SEEK_SET:0，表示文件开头  SEEK_CUR:1，表示当前位置  SEEK_END:2，表示文件尾*/static loff_t tiny4412_llseek(struct file *filp, loff_t offset, int whence){  loff_t newpos = 0;  switch(whence)  {    case SEEK_SET:      newpos = offset;      break;    case SEEK_CUR:      newpos = filp->f_pos + offset;      break;    case SEEK_END:      if(MAX_SIZE+offset>=MAX_SIZE)      {        newpos=MAX_SIZE;      }      else      {        newpos = MAX_SIZE + offset;      }      break;    default:      return -EINVAL;//无效的参数  }  filp->f_pos = newpos;  return newpos;}
static int tiny4412_release(struct inode *inode, struct file *file){  printk("tiny4412_release-->ok\n");  return 0;}
static struct file_operations fops={  .open=tiny4412_open,  .read=tiny4412_read,  .write=tiny4412_write,  .release=tiny4412_release,  .llseek=tiny4412_llseek};
/*Linux内核管理驱动---设备号设备号是一个unsigned int 的变量--32位。设备号=主设备号+次设备号*/static struct miscdevice misc={  .minor = MISC_DYNAMIC_MINOR,  /*次设备号填255表示自动分配     主设备号固定为10*/  .name = "tiny4412_eeprom",  /*/dev目录下文件名称*/  .fops = &fops, /*文件操作接口*/};

static int tiny4412_probe(struct i2c_client *client, const struct i2c_device_id *device_id){  printk("probe调用成功:%#X\n",client->addr);  eeprom_client=client;    /*1. 杂项设备的注册函数*/  misc_register(&misc);    return 0;}
static int tiny4412_remove(struct i2c_client *client){  /*2. 杂项设备的注销函数*/  misc_deregister(&misc);  printk("remove调用成功.\n");  return 0;}
static struct i2c_device_id id_table[]={  {"tiny4412_eeprom",0},  {}};
static struct i2c_driver drv={  .probe=tiny4412_probe,  .remove=tiny4412_remove,  .driver=  {    .name="eeprom_iic"  },  .id_table=id_table};
static int __init tiny4412_drv_init(void){    /*注册IIC驱动端*/  i2c_add_driver(&drv);    printk("IIC驱动端: 驱动安装成功\n");    return 0;}
static void __exit tiny4412_drv_cleanup(void){  /*注销IIC驱动端*/  i2c_del_driver(&drv);    printk("IIC驱动端: 驱动卸载成功\n");}
module_init(tiny4412_drv_init);    /*驱动入口--安装驱动的时候执行*/module_exit(tiny4412_drv_cleanup); /*驱动出口--卸载驱动的时候执行*/
MODULE_LICENSE("GPL");  /*设置模块的许可证--GPL*/

#include <linux/kernel.h>#include <linux/module.h>#include <linux/platform_device.h>#include <linux/i2c.h>#include <linux/gpio.h>#include <mach/gpio.h>#include <plat/gpio-cfg.h>
static struct i2c_client *i2c_dev=NULL;static struct i2c_adapter *adap=NULL;static struct i2c_board_info info={  .type="tiny4412_eeprom",  .addr=0x50, /*设备地址*/};
static int __init tiny4412_drv_init(void){    /*根据总线编号获取是适配器*/  adap=i2c_get_adapter(0);  /*注册IIC设备端*/  i2c_dev=i2c_new_device(adap,&info);    printk("IIC设备端: 驱动安装成功\n");    return 0;}
static void __exit tiny4412_drv_cleanup(void){  /*注销IIC设备*/  i2c_unregister_device(i2c_dev);  i2c_put_adapter(adap);    printk("IIC设备端: 驱动卸载成功\n");}
module_init(tiny4412_drv_init);    /*驱动入口--安装驱动的时候执行*/module_exit(tiny4412_drv_cleanup); /*驱动出口--卸载驱动的时候执行*/
MODULE_LICENSE("GPL");  /*设置模块的许可证--GPL*/

#include <stdio.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>
#define EEPROM_DEV "/dev/tiny4412_eeprom"
int main(int argc,char **argv){    /*1. 打开设备文件*/    int fd=open(EEPROM_DEV,O_RDWR);    if(fd<0)    {        printf("%s 设备驱动打开失败.\n",EEPROM_DEV);        return 0;  }    /*3.读写数据*/  unsigned char buff[255];  int cnt;  int i;  for(i=0;i<255;i++)buff[i]=i;  cnt=write(fd,buff,255);    printf("write成功:%d Byte\n",cnt);    //偏移文件指针  lseek(fd,SEEK_SET,0);    unsigned char buff_r[255];  cnt=read(fd,buff_r,255);  printf("read成功:%d Byte\n",cnt);  for(i=0;i<cnt;i++)  {    printf("%d ",buff_r[i]);  }  printf("\n");    return 0;}