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
|
|
|
|