Ok6410 Linux DS18B20 driver

// Note that you can use data = Data * 6.25 on bare metal to increase the temperature by 100 times, but not in the kernel, however, data = Data * 625/100 can be used;

// I checked it online. It seems that the kernel does not support floating point. I don't know if this is the case, but I don't need to use a floating point driver to load it. I cannot load it after use.

/*************************************** **************************************** * ********************************** File Name: DS18B20 b20_drive.c * Introduction: ok6410 DS18B20 driver * Author: different spirit yuan (cp1300@139.com) * Creation Time: 092/09/18 20:37 * modification time: 2012/09/18 * Description: ok6410 Development Board (s3c246410) DS18B20 (gpio) *************************************** **************************************** * ******************************* // system header file # include <Linux /Miscdevice. h> # include <Linux/delay. h> # include <ASM/IRQ. h> # include <Mach/hardware. h> # include <Linux/kernel. h> # include <Linux/module. h> # include <Linux/init. h> # include <Linux/mm. h> # include <Linux/Fs. h> # include <Linux/types. h> # include <Linux/delay. h> # include <Linux/moduleparam. h> # include <Linux/slab. h> # include <Linux/errno. h> # include <Linux/IOCTL. h> # include <Linux/cdev. h> # include <Linux/string. h> # Inc Lude <Linux/list. h> # include <Linux/PCI. h> # include <ASM/uaccess. h> # include <ASM/atomic. h> # include <ASM/unistd. h> # include <Linux/delay. h> # include <Linux/Io. h> // -------------------------- // # include <Mach/map. h> # include <Mach/regs-clock.h> # include <Mach/regs-gpio.h> // ------------------------ // # include <plat/gpio-cfg.h> # include <Mach/gpio-bank-e.h> # include <Mach/ gpio-bank-m.h> # define DS18B20 b20_error0xf 000 // initialization failed // system us latency definition # define delay_us (x) udelay (x) // set DS18B20 Io to push-pull output mode void set18b20ioout (void) {unsigned int reg; reg = readl (initi64xx_gpecon); Reg | = 1; writel (Reg, initi64xx_gpecon);} // read iounsigned char read18b20io (void) {unsigned int reg; reg = readl (initi64xx_gpedat); If (REG & 1) return 1; elsereturn 0 ;}// write iovoid write18b20io (unsigned char data) {unsigned int reg; reg = readl (initi64xx_gpedat); If (data) reg | = 1; els Ereg & = ~ 1; writel (Reg, initi64xx_gpedat);} // set it in the DS18B20 Io input mode void set18b20ioin (void) {unsigned int reg; Reg = readl (initi64xx_gpecon); Reg & = (~ 0xf); writel (Reg, initi64xx_gpecon);} // reset DS18B20 b20u8 DS18B20 reset (void) {u8 I = 0; reset (); write18b20io (1); delay_us (1 ); write18b20io (0); delay_us (500); write18b20io (1); delay_us (2); set18b20ioin (); While (read18b20io () {I ++; delay_us (1 ); if (I> 100) return 1;} delay_us (250); Return 0x00;} // read DS18B20 data u8 DS18B20 b20_readdata (void) {u8 I, Data = 0; for (I = 0; I <8; I ++) {set18b20ioout (); write18b20io (0); Data >>=1; Delay _ Us (12); write18b20io (1); set18b20ioin (); delay_us (1); If (read18b20io () Data | = 0x80; delay_us (42 );} return data;} // write the DS18B20 data void DS18B20 b20_writedata (u8 data) {u8 I; set18b20ioout (); for (I = 0; I <8; I ++) {write18b20io (0); delay_us (12); write18b20io (Data & 0x01); delay_us (30); write18b20io (1); data >>= 1; delay_us (2) ;}}// read temperature int DS18B20 (void) {u8 th, Tl; int data; If (DS18B20 b20_reset () {return DS18B20 b20_error ;} Round (0xcc); DS18B20 (0x44); DS18B20 (); DS18B20 (); DS18B20 (0xcc); Round (0xbe); TL = DS18B20 (readdata); Th = DS18B20 (readdata (); data = th; Data <= 8; Data | = TL; Data = Data * 625/100; return data ;} //////////////////////////////////////// //// // Driver Module name # define device_name "ok6410_ds18b20" // function declaration ////////////////// /// // static long ok6410_ds18b20 _ IOCTL (struct file * file, unsigned int cmd, unsigned long Arg); static ssize_t ok6410_ds18b20 b20_write (struct file * file, const char _ User * buff, size_t size, loff_t * Loff); static ssize_t ok6410_ds18b20 b20_read (struct file * file, char _ User * buff, size_t size, loff_t * Loff ); //////////////////////////////////////// //// // * this structure is the core of the character device driver * When the application operates the open provided by the device file, read, write, and other functions * will eventually call the corresponding function in this structure */static struct File _ Operations dev_fops = {. owner = this_module, // This is a macro that points to the _ this_module variable automatically created during compilation. unlocked_ioctl = ok6410_ds18b20 b20_ioctl ,. read = ok6410_ds18b20 _ read ,. write = ok6410_ds18b20 b20_write}; // register the information used by the driver static struct miscdevice MISC = {. minor = misc_dynamic_minor ,. name = device_name, // Driver Module name. foPs = & dev_fops,}; // access semaphores of the DS18B20 device struct semaphore DS18B20 b20_sem; /*************************************** ***************** **************************************** * ***************** Function Name: static int _ init ok6410_ds18b20 b20_init (void) * function: DS18B20 module initialization function * parameter: none * returned: 0: Successful; <0: Failed * dependency: underlying Linux macro definition * Author: abnormal spirit yuan (cp1300@139.com) * Creation Time: * last modification time: * Description: Initialize DS18B20 hardware, register the DS18B20 driver ************************************* **************************************** * **********************************/static int __ init ok6410_ds18 B20_init (void) {int ret; ret = misc_register (& MISC); // register the driver if (Ret <0) {printk (device_name "can't initialized DS18B20! \ N "); return ret;} init_mutex (& DS18B20 _ SEM); // register the semaphore printk (device_name" initialized \ n "); Return 0; // return success }/********************************** **************************************** * ************************************ Function name: static long ok6410_ds18b20 b20_ioctl (struct file * file, unsigned int cmd, unsigned long Arg) * function: send a command to the DS18B20 driver module, without any practical effect, directly return the 0 * parameter: no function * return: 0 * dependency: none * Author: different spirit yuan (cp1300@139.com) * Creation Time: * last modification time: * Note: no *************************************** **************************************** * ******************************/static long ok6410_ds18b20 b20_ioctl (struct File * file, unsigned int cmd, unsigned long Arg) {return 0 ;} /*************************************** **************************************** * ********************************** Function Name: static ssize_t ok6410_ds18b20 b20_write (struct file * file, const char _ User * buff, size_t size, loff_t * Loff) * function: write data to the DS18B20 driver module, invalid function, return 0 * parameter: file pointer (no function); Buff: data buffer pointer; Buff: data quantity; Loff: no function * return: 0: success; <0: failure * dependency: Linux underlying macro * Author: Alien (cp1300@139.com) * Creation Time: * last modification time: * Note: invalid write ************************************** **************************************** * *******************************/static ssize_t ok6410_ds18b20 b20_write (struct file * file, const char _ User * buff, size_t size, loff_t * Loff) {return 0 ;} /*************************************** **************************************** * ********************************** Function Name: static ssize_t ok6410_ds18b20 b20_read (struct file * file, char _ User * buff, size_t size, loff_t * Loff) * function: Read DS18B20 status, low-level light on * parameter: file: file pointer (ineffective); Buff: data buffer pointer; Buff: data quantity; Loff: ineffective * return: 0: Successful; <0: Failed * dependency: linux underlying macro * Author: different spirit yuan (cp1300@139.com) * Creation Time: * last modification time: * Note: it reads a 16-Bit Signed temperature ***************************** **************************************** **************************************** * **/static ssize_t ok6410_ds18b20 b20_read (struct file * file, char _ User * buff, size_t size, loff_t * Loff) {int temp; int * P; If (down_interruptible (& DS18B20 b20_sem) // obtain the semaphore return-erestartsys; temp = DS18B20 b20_readtemper (); // read temperature if (temp = DS18B20 b20_error) // return-1 for DS18B20 initialization failure; // Return Error P = (int *) buff; * P = temp; // write the temperature to the buffer up (& DS18B20 _ SEM); // release the semaphore return 0 ;} /*************************************** **************************************** * ********************************** Function Name: static void _ exit ok6410_ds18b20 b20_exit (void) * function: uninstall the DS18B20 driver * parameter: No * returned: No * dependency: Linux underlying macro * Author: different spirit (cp1300@139.com) * Creation Time: 2012/09/18 20:38 * last modification time: 2012/09/18 20:38 * description: uninstall the driver ************************************** **************************************** * *********************************/static void _ exit ok6410_ds18b20 b20_exit (void) {misc_deregister (& MISC); // uninstall driver} // dynamic loading Driver Interface (required) module_init (ok6410_ds18b20 b20_init); module_exit (ok6410_ds18b20 b20_exit); // other information (not required) module_author ("cp1300@139.com"); // driver author module_description ("ok6410 (initi6410) DS18B20 driver"); // module_license ("GPL "); // The following agreement

Makefile

ARCH=armCROSS_COMPILE=arm-linux-obj-m := ds18b20_drive.o#ds18b20_drive-objs := ds18b20_drive.oKDIR :=/home/cfan/linux/linux-3.0.1 PWD :=$(shell pwd)all:$(MAKE) -C $(KDIR) M=$(PWD) modulesclean:$(MAKE) -C $(KDIR) M=$(PWD) clean

Test

/*************************************** **************************************** * ********************************** File Name: DS18B20 b20_teset.c * Introduction: ok6410 DS18B20 driver test program * Author: different spirit yuan (cp1300@139.com) * Creation Time: * modification time: * Description: ok6410 Development Board (s3c246410) DS18B20 (gpio) ************************************* **************************************** * *********************************/# include <stdi O. h> # include <stdlib. h> # include <unistd. h> # include <fcntl. h> # include <sys/IOCTL. h> # include <unistd. h> int main (void) {int FD; int data; // DS18B20 test printf ("DS18B20 test... \ n "); FD = open ("/dev/ok6410_ds18b20 ", o_rdonly); // open DS18B20 20if (FD =-1) {printf (" Open DS18B20 error! \ N "); exit (-1);} else {printf (" Open DS18B20 OK! \ N ") ;}while (1) {If (read (FD, & data, (size_t) 2) printf (" read error! \ N "); printf (" DS18B20 = % d \ n ", data); usleep (1000*1000); // 1000 ms }}