ds18b20驱动程序Linux ARM-linux嵌入式内核驱动——DS18B20的驱动

/************************************************

DS18B20的驱动，在TX2440A开发板上做测试

维护记录：-10-30V1.0

linux内核：2.6.31

硬件接法：

DQ --> GPB5

驱动用法：

设备名称：TX2440-ds18b20

*************************************************/

#include

#include

#include

#include

#include

#include

#include

//#include

#include

//#include

#include

#include

#include

#define DQ_PINS3C2410_GPB(5)

#define DQ_PIN_OUTPS3C2410_GPIO_OUTPUT

#define DQ_PIN_INPS3C2410_GPIO_INPUT

#define HIGH 1

#define LOW 0

//定义DS18B20ROM指令

#defineDS18B20_ReadROM0x33//读ROM

#defineDS18B20_MatchROM0x55//匹配ROM

#defineDS18B20_SkipROM0xCC//跳过ROM

#defineDS18B20_SearchROM0xF0//搜索ROM

#defineDS18B20_AlarmROM0xEC//报警搜索

//定义DS18B20存储器操作命令

#defineDS18B20_WriteSCR0x4E//写暂存存储器

#defineDS18B20_ReadSCR0xBE//读暂存存储器

#defineDS18B20_CopySCR0x48//复制暂存存储器

#defineDS18B20_ConvertTemp0x44//温度变换

#defineDS18B20_RecallEP0xB8//重新调出

#defineDS18B20_ReadPower0xB4//读电源

typedefunsignedcharU8;

typedefunsignedshortU16;

#define DEVICE_NAME"TX2440-ds18b20"/*设备名称*/

staticintDS18B20_Major=0;/*主设备号*/

U16 temp;

U8 DS18B20_ID[8]={0};

U8 DS18B20_Init(void)

{

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_OUTP);

s3c2410_gpio_setpin(DQ_PIN,LOW);

udelay(700);

s3c2410_gpio_setpin(DQ_PIN,HIGH);

udelay(4);

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_INP);

udelay(100);

/*if(s3c2410_gpio_getpin(DQ_PIN)!=0)//测试复位是否成功

{

printk("There are no 18B20 at GPB5! 0x%x\n");

return 1;

}

else

printk("Init 18B20 succeed!\n");

*/

return0;

}

U8 DS18B20_ReadBit(void)

{

U8 dat;

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_OUTP);

s3c2410_gpio_setpin(DQ_PIN,LOW);

udelay(2);

s3c2410_gpio_setpin(DQ_PIN,HIGH);//add

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_INP);

udelay(10);

if(s3c2410_gpio_getpin(DQ_PIN)!=0)

dat=1;

else

dat=0;

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_OUTP);

s3c2410_gpio_setpin(DQ_PIN,HIGH);//add

udelay(50);

return(dat);

}

U8 DS18B20_ReadByte(void)

{

U8 i,j,dat;

dat=0;

for(i=1;i<=8;i++)

{

j=DS18B20_ReadBit();

dat=(j<<7)|(dat>>1);//读出的数据最低位在最前面，这样刚好一个字节在DAT里

}

return(dat);

}

voidDS18B20_WriteByte(U8 dat)

{

U8 j;

U8 testb;

s3c2410_gpio_cfgpin(DQ_PIN,DQ_PIN_OUTP);

for(j=1;j<=8;j++)

{

testb=dat&0x01;

dat=dat>>1;

if(testb)

{

s3c2410_gpio_setpin(DQ_PIN,LOW);

udelay(8);

s3c2410_gpio_setpin(DQ_PIN,HIGH);

udelay(50);

}

else

{

s3c2410_gpio_setpin(DQ_PIN,LOW);

udelay(90);

s3c2410_gpio_setpin(DQ_PIN,HIGH);

udelay(8);

}

}

}

voidDS18B20_ReadID(void)

{

udelay(1);

DS18B20_Init();

DS18B20_WriteByte(DS18B20_ReadROM);

DS18B20_ID[0]=DS18B20_ReadByte();

DS18B20_ID[1]=DS18B20_ReadByte();

DS18B20_ID[2]=DS18B20_ReadByte();

DS18B20_ID[3]=DS18B20_ReadByte();

DS18B20_ID[4]=DS18B20_ReadByte();

DS18B20_ID[5]=DS18B20_ReadByte();

DS18B20_ID[6]=DS18B20_ReadByte();

DS18B20_ID[7]=DS18B20_ReadByte();

}

voidDS18B20_Match(void)

{

DS18B20_WriteByte(DS18B20_MatchROM);

DS18B20_WriteByte(DS18B20_ID[0]);

DS18B20_WriteByte(DS18B20_ID[1]);

DS18B20_WriteByte(DS18B20_ID[2]);

DS18B20_WriteByte(DS18B20_ID[3]);

DS18B20_WriteByte(DS18B20_ID[4]);

DS18B20_WriteByte(DS18B20_ID[5]);

DS18B20_WriteByte(DS18B20_ID[6]);

DS18B20_WriteByte(DS18B20_ID[7]);

}

voidDS18B20_TmpChange(void)

{

while(DS18B20_Init());

udelay(100);/*delay(1);*/

DS18B20_WriteByte(DS18B20_SkipROM);// address all drivers on bus

DS18B20_WriteByte(DS18B20_ConvertTemp);//initiates a single temperature conversion

}

U16 DS18B20_Temperature(void)

{

U8 a,b;

while(DS18B20_Init());

udelay(100);

DS18B20_WriteByte(DS18B20_SkipROM);

DS18B20_WriteByte(DS18B20_ReadSCR);

udelay(4);

a=DS18B20_ReadByte();

b=DS18B20_ReadByte();

temp=b;

temp<<=8;//two bytecompose a int variable

temp=temp|a;

returntemp;

}

staticintTX2440_ds18b20_open(structinode*inode,structfile*file)

{

printk("TX2440-DS18B20 Driver Open is Called!\n");

DS18B20_TmpChange();

mdelay(1000);

DS18B20_Temperature();

DS18B20_TmpChange();

mdelay(1000);

DS18B20_Temperature();

return0;

}

staticintTX2440_ds18b20_release(structinode*inode,structfile*file)

{

printk("TX2440-DS18B20 Driver Release Called!\n");

return0;

}

staticintTX2440_ds18b20_read(structfile*filp,char*buf,size_t count,loff_t*f_pos)

{

U16 ds18b20_val;

DS18B20_TmpChange();

mdelay(500);

ds18b20_val=DS18B20_Temperature();

if(ds18b20_val<10000)

copy_to_user(buf,&ds18b20_val,sizeof(ds18b20_val));

return0;

}

staticstructfile_operations TX2440_ds18b20_fops=

{

.owner=THIS_MODULE,

.open=TX2440_ds18b20_open,

.release=TX2440_ds18b20_release,

//.ioctl=TX2440_ds18b20_ioctl,

.read=TX2440_ds18b20_read,

};

staticstructclass*ds18b20_class;

staticint__init TX2440_ds18b20_init(void)

{

printk("TX2440 DS18B20 DRIVER MODULE INIT\n");

DS18B20_Init();//DS18B20初始化

DS18B20_Major=register_chrdev(0,DEVICE_NAME,&TX2440_ds18b20_fops);

if(DS18B20_Major<0)

{

printk(DEVICE_NAME" can't register major number\n");

returnDS18B20_Major;

}

printk("register TX2440-DS18B20 Driver OK! Major = %d\n",DS18B20_Major);

ds18b20_class=class_create(THIS_MODULE,DEVICE_NAME);

if(IS_ERR(ds18b20_class))

{

printk("Err: failed in TX2440-DS18B20 class. \n");

return-1;

}

device_create(ds18b20_class,NULL,MKDEV(DS18B20_Major,0),NULL,DEVICE_NAME);

printk(DEVICE_NAME" initialized\n");

return0;

}

staticvoid__exit TX2440_ds18b20_exit(void)

{

printk("TX2440 DS18B20 DRIVER MODULE EXIT\n");

unregister_chrdev(DS18B20_Major,DEVICE_NAME);

device_destroy(ds18b20_class,MKDEV(DS18B20_Major,0));

class_destroy(ds18b20_class);

}

module_init(TX2440_ds18b20_init);

module_exit(TX2440_ds18b20_exit);

MODULE_AUTHOR("");

MODULE_DESCRIPTION("TX2440 DS18B20 Driver");

MODULE_LICENSE("GPL");