text: /*
   * Copyright (c) 2016 Intel Corporation
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <zephyr.h>
  
  #include <misc/printk.h>
  
  #include <device.h>
  #include <i2c.h>
  
  #define GYRO_I2C_ADDR 0x6A
  #define WHO_AM_I_REG 0x0F
  
  static void read_who_am_i(struct device *dev)
  {
  	uint8_t data;
  
  	data = WHO_AM_I_REG;
  	if (i2c_write(dev, &data, sizeof(data), GYRO_I2C_ADDR) != 0) {
  		printk("Error on i2c_write()\n");
  		return;
  	}
  
  	data = 0;
  	if (i2c_read(dev, &data, sizeof(data), GYRO_I2C_ADDR) != 0) {
  		printk("Error on i2c_read()\n");
  		return;
  	}
  
  	if (data == 0xd4)
  		printk("Register Who am I read successfully\n");
  	else
  		printk("Register Who am I read FAILED\n");
  }
  
  static void read_who_am_i_by_transfer(struct device *dev)
  {
  	struct i2c_msg msg[2];
  	uint8_t write_data = WHO_AM_I_REG;
  	uint8_t read_data = 0;
  
  	msg[0].flags = I2C_MSG_WRITE | I2C_MSG_RESTART;
  	msg[0].buf = &write_data;
  	msg[0].len = sizeof(write_data);
  
  	msg[1].flags = I2C_MSG_READ | I2C_MSG_STOP;
  	msg[1].buf = &read_data;
  	msg[1].len = sizeof(read_data);
  
  	if (i2c_transfer(dev, msg, 2, GYRO_I2C_ADDR) != 0) {
  		printk("Error on i2c_transfer()\n");
  		return;
  	}
  
  	if (read_data == 0xd4)
  		printk("Register Who am I read successfully\n");
  	else
  		printk("Register Who am I read FAILED\n");
  }
  
  void main(void)
  {
  	union dev_config cfg;
  	struct device *dev;
  
  	printk("Start I2C LSM9DS0 sample\n");
  
  	cfg.raw = 0;
  	cfg.bits.use_10_bit_addr = 0;
  	cfg.bits.speed = I2C_SPEED_STANDARD;
  	cfg.bits.is_master_device = 1;
  
  	dev = device_get_binding("I2C0");
  	if (!dev) {
  		printk("I2C0: Device not found.\n");
  		return;
  	}
  
  	if (i2c_configure(dev, cfg.raw) != 0) {
  		printk("Error on i2c_configure()\n");
  		return;
  	}
  
  	read_who_am_i(dev);
  	read_who_am_i_by_transfer(dev);
  }
  