我的18B20驱动程序去测试，温度总是不变
C/C++ code#include<linux/init.h>#include<linux/kernel.h>#include<linux/module.h>#include<linux/fs.h>#include<asm/uaccess.h>#include<asm/io.h>#include<linux/device.h>#include<asm/gpio.h>#include<linux/poll.h>#include<linux/interrupt.h>#include<linux/irq.h>#include<linux/time.h>#include<linux/delay.h>MODULE_LICENSE("GPL");/* 起点工作室 18B20驱动程序 采用9位精度 时间75ms采样一次*/#define DEVICE_NAME "18B20-drv"#define GPHCON (unsigned long)(0x56000070)#define GPHDAT (unsigned long)(0x56000074)#define GPHUP (unsigned long)(0x56000078)typedef unsigned char BYTE;#define DS18B20_PIN S3C2410_GPH4#define DS18B20_PIN_OUTP S3C2410_GPH4_OUTP#define DS18B20_PIN_INP S3C2410_GPH4_INP#define HIGH 1#define LOW 0static BYTE data[2];//store 18B20rature high and lowstatic int major=0;static int minor=0;static int temp_open(struct inode *, struct file *);static int temp_release(struct inode *, struct file *);static ssize_t temp_read(struct file *, char *, size_t, loff_t *);//static ssize_t temp_write(struct file *, const char *, size_t, loff_t *);//static int temp_ioctl(struct inode *, struct file *, unsigned int cmd, unsigned long arg);static struct file_operations fops = { .owner = THIS_MODULE, //.open = temp_open, //.release = temp_release, .read = temp_read,// .write = temp_write, //.ioctl = temp_ioctl,};static struct class *dev_class;//use this to create device nodestatic int temp_init(void){ major = register_chrdev(0,DEVICE_NAME,&fops); if(major < 0) { printk("register %s error\n",DEVICE_NAME); return 1; } printk("DEV Number:%d,%d\n",major,minor); dev_class = class_create(THIS_MODULE,DEVICE_NAME); if(dev_class == NULL) { printk("18B20 node create error\n"); printk("TODO:mknod /dev/%s c %d %d\n",DEVICE_NAME,major,minor); } else { device_create(dev_class,NULL,MKDEV(major,minor),"%s%d",DEVICE_NAME,minor); printk("/dev/%s%d register sucess\n",DEVICE_NAME,minor); } return 0;}static void temp_exit(void){ if(dev_class) { device_destroy(dev_class,MKDEV(major,minor)); class_destroy(dev_class); } unregister_chrdev(major,DEVICE_NAME);}module_init(temp_init);module_exit(temp_exit);////////////////////////////registerover//////////////////////////////////* DS18B20 RESET*/static int temp_open(struct inode * pnode, struct file * pfile){ printk("18b20 open\n"); return 0;}static int temp_release(struct inode *pnode, struct file *pfile){ printk("18b20 release\n"); return 0;}int DS18B20_reset(void){ printk("hello reset\n"); s3c2410_gpio_cfgpin(DS18B20_PIN,DS18B20_PIN_OUTP); s3c2410_gpio_setpin(DS18B20_PIN,1); udelay(100); s3c2410_gpio_setpin(DS18B20_PIN,0); udelay(600); s3c2410_gpio_setpin(DS18B20_PIN,1); udelay(100); s3c2410_gpio_cfgpin(DS18B20_PIN,DS18B20_PIN_INP); if(s3c2410_gpio_getpin(DS18B20_PIN)==0) { printk("DS18B20 reset sucessfully\n"); return 0; } else { printk("reset failed and please try again\n"); return 1; }}/* DS18B20 WRITEBYTE*/ void DS18B20_WByte(BYTE cmd) { unsigned int i; s3c2410_gpio_cfgpin(DS18B20_PIN,DS18B20_PIN_OUTP); for(i=0;i<8;i++) { s3c2410_gpio_setpin(DS18B20_PIN,LOW); udelay(1); if(cmd & 0x01) { s3c2410_gpio_setpin(DS18B20_PIN,HIGH); } else s3c2410_gpio_setpin(DS18B20_PIN,LOW); udelay(60); s3c2410_gpio_setpin(DS18B20_PIN,HIGH); udelay(15); cmd=cmd>>1; } s3c2410_gpio_setpin(DS18B20_PIN,HIGH); }/* DS18B20 READBYTE*/BYTE DS18B20_RByte(void){ unsigned int i; BYTE status=0; for(i=0;i<8;i++)//九位精度末3位不用 { s3c2410_gpio_cfgpin(DS18B20_PIN,DS18B20_PIN_OUTP); s3c2410_gpio_setpin(DS18B20_PIN,LOW); udelay(1); status>>=1; s3c2410_gpio_setpin(DS18B20_PIN,HIGH); s3c2410_gpio_cfgpin(DS18B20_PIN,DS18B20_PIN_INP); /* if 1 us after LOW translate HIGH read a 1 */ if(s3c2410_gpio_getpin(DS18B20_PIN)) status = status|0x80; udelay(60); } printk("%x\n",status); return status;} /* DS18B20 temp_init*/void DS18B20_start(void){ DS18B20_reset(); udelay(120); DS18B20_WByte(0xcc);//write cmd DS18B20_WByte(0x44);}/* DS18B20 Read temp*/void DS18B20_Read(void){ DS18B20_reset(); mdelay(2); DS18B20_WByte(0xcc);//write cmd DS18B20_WByte(0x44); data[0] = DS18B20_RByte(); data[1] = DS18B20_RByte();} /* DS18B20 PRO*/void DS18B20_PRO(void){ DS18B20_start(); udelay(5); DS18B20_Read();}static ssize_t temp_read(struct file *file, char *buf, size_t len, loff_t *off){ DS18B20_PRO(); buf[0] = data[0]; buf[1] = data[1]; return 0;}