[技术]

【OK210试用体验】之ds18b20驱动

2015-8-11 12:34:16 3296

0 前几天系统已经一直完成，这俩天做了一下温度传感器的实验，在这里与大家分享。版本说明：平台：OK210； os ：Linux2.6.35.7 驱动类型：ds18b20 驱动程序如下 #include #include #include #include #include #include #include #include #include #include #include #define DS18B20_RESET (0x10009) #define DS18B20_REL (0x10011) #define SKIP_ROM 0xcc #define COVERTT 0x44 #define READ_MEM 0xbe #define WRITE_MEM 0x4e #define NINE_BIT 0x1f #define TEN_BIT 0x3f #define ELE_BIT 0x5f #define TWL_BIT 0x7f #define TH 100 #define TL 0 #define TEMP_H 10000 #define TEMP_L -10000 static unsigned long gpio_con; static unsigned long gpio_dat; static void gpio_cfg_out(unsigned char val) { gpio_con &= ~0xf; gpio_con \|= 0x1; if (val == 0) gpio_dat &= ~0x1; else gpio_dat \|= 0x1; } static unsigned char gpio_cfg_in(void) { gpio_con &= ~0xf; return gpio_dat&0x1; } /* 鍙傜湅鏂囨。P16,娉ㄦ剰鍐?鍜?鐨勬椂闅欒姹?/ static void ds18b20_write8(unsigned char data) { int i; for (i = 0; i < 8; i++) { if ((data & 0x1) == 1) { gpio_cfg_out(0); udelay(3); gpio_cfg_out(1); udelay(80); } else { gpio_cfg_out(0); udelay(80); gpio_cfg_out(1); udelay(3); } data >>= 1; } } /* 鍙傜湅鏂囨。P16,娉ㄦ剰璇?鍜?鐨勬椂闅欒姹?/ static unsigned char ds18b20_read8(void) { int i; unsigned char bit; unsigned char data = 0; for (i = 0; i < 8; i++) { gpio_cfg_out(0); udelay(2); gpio_cfg_out(1); udelay(5); bit = gpio_cfg_in(); data \|= (bit << i); udelay(5); gpio_cfg_out(1); udelay(60); } return data; } /* 鍙傜湅鏂囨。P15/ static void ds18b20_reset(void) { unsigned char ret; gpio_cfg_out(0); udelay(500); gpio_cfg_out(1); udelay(30); ret = gpio_cfg_in(); udelay(500); #if 0 if (ret == 0) { printk("reset ok.n"); } else { printk("reset failed.n"); } #endif } static void ds18b20_config_rel(unsigned char rel) { ds18b20_reset(); ds18b20_write8(SKIP_ROM); ds18b20_write8(WRITE_MEM); ds18b20_write8(TH); ds18b20_write8(TL); switch(rel) { case 9: ds18b20_write8(NINE_BIT); break; case 10: ds18b20_write8(TEN_BIT); break; case 11: ds18b20_write8(ELE_BIT); break; case 12: ds18b20_write8(TWL_BIT); break; } } static int ds18b20_open(struct inode inode, struct file file) { return 0; } static int ds18b20_close(struct inode inode, struct file file) { return 0; } void bubbleSort(int arr[], int count) { int i = count, j; int temp; while(i > 0) { for(j = 0; j < i - 1; j++) { if(arr[j] > arr[j + 1]) { temp = arr[j]; arr[j] = arr[j + 1]; arr[j + 1] = temp; } } i--; } } static ssize_t ds18b20_read(struct file file, char buf, size_t count, loff_t pos) { unsigned char h8, l8; int i, temp = 0, tvalsum; int value[12]; ds18b20_reset(); ds18b20_write8(SKIP_ROM); ds18b20_write8(COVERTT); udelay(700); //mdelay(750); for (i = 0; i < 12; ++i) { ds18b20_reset(); ds18b20_write8(SKIP_ROM); ds18b20_write8(READ_MEM); l8 = ds18b20_read8(); h8 = ds18b20_read8(); temp = (h8 << 8) \| l8; if (temp & 0x8000) { temp = ~temp + 1; } temp = 50; temp >>= 3; if ((temp > TEMP_H) \|\| (temp < TEMP_L)) { --i; temp = 0; continue; } value[i] = temp; } bubbleSort(value, 12); for(i = 4, tvalsum = 0;i < 8; ++i) tvalsum+=value[i]; temp = (tvalsum) / 4; copy_to_user(buf, &temp, 4); return count; } static int ds18b20_ioctl(struct inode inode, struct file file, unsigned int cmd, unsigned long arg) { unsigned char rel; copy_from_user(&rel, (unsigned char )arg, 1); switch(cmd) { case DS18B20_RESET: ds18b20_reset(); break; case DS18B20_REL: ds18b20_config_rel(rel); break; default: return -1; } return 0; } static struct file_operations ds18b20_fops = { .owner = THIS_MODULE, .open = ds18b20_open, .release = ds18b20_close, .read = ds18b20_read, .unlocked_ioctl = ds18b20_ioctl, }; static struct miscdevice ds18b20_miscdev = { .minor = MISC_DYNAMIC_MINOR, .name = "ds18b20", .fops = &ds18b20_fops, }; static int ds18b20_init(void) { misc_register(&ds18b20_miscdev); gpio_con = ioremap(0xE0200C40, 8); gpio_dat = gpio_con + 1; return 0; } static void ds18b20_exit(void) { iounmap(gpio_con); misc_deregister(&ds18b20_miscdev); } module_init(ds18b20_init); module_exit(ds18b20_exit); MODULE_LICENSE("GPL"); 复制代码下面是makefile文件 obj-m := ds18b20_drv.o KDIR := /my_dir/linux-smart210/ all: make -C $(KDIR) M=$(PWD) modules CROSS_COMPILE=ARM-linux- ARCH=arm clean: rm -f .ko .o .mod.o .mod.c .symvers .bak .order 复制代码* 下面是测试程序 #include #include #include #include #include #include #include #define DS18B20_RESET 0x10001 #define DS18B20_REL 0x10002 int main(int argc, char argv[]) { int fd; int data; unsigned char relbit; fd = open("/dev/ds18b20", O_RDWR); if (fd < 0) { printf("open ds18b20 failed.n"); exit(-1); } if (argc < 2) { printf("usage:n %s <9\|10\|11\|12>n", argv[0]); exit(-1); } relbit = strtoul(argv[1], NULL, 10); while (1) { ioctl(fd, DS18B20_REL, &relbit); read(fd, &data, sizeof(data)); usleep(200000); printf("%fn", (float)data / 100); } close(fd); return 0; } 复制代码* 水平有限，难免有错误，忘各位大神多多指教。 0
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