/***************************************************************************** i2c读函数，参数1：从设备地址，参数2：寄存器地址，参数3：读取数据缓冲区，参数4：读取数据大小 ******************************************************************************/ unsigned char _i2c_read(unsigned char device_addr, unsigned char sub_addr, unsigned char *buff, int ByteNo) { int fd, ret; unsigned char buftmp[32]; struct i2c_rdwr_ioctl_data i2c_data; const char *i2c_dev = "/dev/i2c-0"; //---------------------------------- device_addr >>= 1; //init fd = open(i2c_dev, O_RDWR); if (fd<0) { printf("not have /dev/i2c-0 t\r\n"); return -1; } i2c_data.nmsgs = 2; i2c_data.msgs = (struct i2c_msg *)malloc(i2c_data.nmsgs *sizeof(struct i2c_msg)); if (i2c_data.msgs == NULL) { printf("malloc error"); close(fd); return -1; } ioctl(fd, I2C_TIMEOUT, 1); ioctl(fd, I2C_RETRIES, 2); //write reg memset(buftmp, 0, 32); buftmp[0] = sub_addr; i2c_data.msgs[0].len = 1; i2c_data.msgs[0].addr = device_addr; i2c_data.msgs[0].flags = 0; // 0: write 1:read i2c_data.msgs[0].buf = buftmp; //read data i2c_data.msgs[1].len = ByteNo; i2c_data.msgs[1].addr = device_addr; i2c_data.msgs[1].flags = 1; // 0: write 1:read i2c_data.msgs[1].buf = buff; ret = ioctl(fd, I2C_RDWR, (unsigned long)&i2c_data); if (ret < 0) { printf("read data %x %x error\r\n", device_addr, sub_addr); close(fd); free(i2c_data.msgs); return 1; } free(i2c_data.msgs); close(fd); #if 1 int i; printf("i2c__read 0x%02x:",buftmp[0]); for (i = 0; i < ByteNo; i++) { printf(" 0x%02x",buff[i]); } printf("\n"); #endif return 0; } /***************************************************************************** i2c写函数，参数1：从设备地址，参数2：寄存器地址，参数3：要写入的数据缓冲区，参数4：写入数据大小 ******************************************************************************/ unsigned char _i2c_write(unsigned char device_addr, unsigned char sub_addr, unsigned char *buff, int ByteNo) { int fd, ret; unsigned char buftmp[32]; struct i2c_rdwr_ioctl_data i2c_data; const char *i2c_dev = "/dev/i2c-0"; //---------------------------------- device_addr >>= 1; //init fd = open(i2c_dev, O_RDWR); if (fd < 0) { printf("not have /dev/i2c-0\r\n"); return -1; } i2c_data.nmsgs = 1; i2c_data.msgs = (struct i2c_msg *)malloc(i2c_data.nmsgs *sizeof(struct i2c_msg)); if (i2c_data.msgs == NULL) { printf("malloc error"); close(fd); return -1; } ioctl(fd, I2C_TIMEOUT, 1); ioctl(fd, I2C_RETRIES, 2); memset(buftmp, 0, 32); buftmp[0] = sub_addr; memcpy(buftmp + 1, buff, ByteNo); i2c_data.msgs[0].len = ByteNo + 1;; i2c_data.msgs[0].addr = device_addr; i2c_data.msgs[0].flags = 0; // 0: write 1:read i2c_data.msgs[0].buf = buftmp; ret = ioctl(fd, I2C_RDWR, (unsigned long)&i2c_data); if (ret < 0) { printf("write reg %x %x error\r\n", device_addr, sub_addr); close(fd); free(i2c_data.msgs); return 1; } free(i2c_data.msgs); close(fd); #if 1 int i; printf("i2c_write 0x%02x:",buftmp[0]); for(i=0; i<ByteNo; i++) { printf(" 0x%02x",buftmp[1+i]); } printf("\n"); #endif _alpu_delay_ms(100); return 0; } /***************************************************************************** 延时函数（ms） ******************************************************************************/ void _alpu_delay_ms(unsigned int i) { usleep(2000 * i); }文章来源: Linux应用层读写i2c从设备（eeprom）