i2c: add register access API

	return api->transfer(dev, msgs, num_msgs, addr);

}

/**

 * @brief Read multiple bytes from an internal address of an I2C device.

 *

 * This routine reads multiple bytes from an internal address of an

 * I2C device synchronously.

 *

 * @param dev Pointer to the device structure for the driver instance.

 * @param dev_addr Address of the I2C device for reading.

 * @param start_addr Internal address from which the data is being read.

 * @param buf Memory pool that stores the retrieved data.

 * @param num_bytes Number of bytes being read.

 *

 * @retval 0 If successful.

 * @retval Negative errno code if failure.

 */

static inline int i2c_burst_read(struct device *dev, uint16_t dev_addr,

				 uint8_t start_addr, uint8_t *buf,

				 uint8_t num_bytes)

{

	struct i2c_driver_api *api;

	struct i2c_msg msg[2];

	msg[0].buf = &start_addr;

	msg[0].len = 1;

	msg[0].flags = I2C_MSG_WRITE | I2C_MSG_RESTART;

	msg[1].buf = buf;

	msg[1].len = num_bytes;

	msg[1].flags = I2C_MSG_READ | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;

	return api->transfer(dev, msg, 2, dev_addr);

}

/**

 * @brief Write multiple bytes to an internal address of an I2C device.

 *

 * This routine writes multiple bytes to an internal address of an

 * I2C device synchronously.

 *

 * @param dev Pointer to the device structure for the driver instance.

 * @param dev_addr Address of the I2C device for writing.

 * @param start_addr Internal address to which the data is being written.

 * @param buf Memory pool from which the data is transferred.

 * @param num_bytes Number of bytes being written.

 *

 * @retval 0 If successful.

 * @retval Negative errno code if failure.

 */

static inline int i2c_burst_write(struct device *dev, uint16_t dev_addr,

				  uint8_t start_addr, uint8_t *buf,

				  uint8_t num_bytes)

{

	struct i2c_driver_api *api;

	struct i2c_msg msg[2];

	msg[0].buf = &start_addr;

	msg[0].len = 1;

	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;

	msg[1].len = num_bytes;

	msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;

	api = (struct i2c_driver_api *)dev->driver_api;

	return api->transfer(dev, msg, 2, dev_addr);

}

/**

 * @brief Read internal register of an I2C device.

 *

 * This routine reads the value of an 8-bit internal register of an I2C

 * device synchronously.

 *

 * @param dev Pointer to the device structure for the driver instance.

 * @param dev_addr Address of the I2C device for reading.

 * @param reg_addr Address of the internal register being read.

 * @param value Memory pool that stores the retrieved register value.

 *

 * @retval 0 If successful.

 * @retval Negative errno code if failure.

 */

static inline int i2c_reg_read_byte(struct device *dev, uint16_t dev_addr,

				    uint8_t reg_addr, uint8_t *value)

{

	return i2c_burst_read(dev, dev_addr, reg_addr, value, 1);

}

/**

 * @brief Write internal register of an I2C device.

 *

 * This routine writes a value to an 8-bit internal register of an I2C

 * device synchronously.

 *

 * @param dev Pointer to the device structure for the driver instance.

 * @param dev_addr Address of the I2C device for writing.

 * @param reg_addr Address of the internal register being written.

 * @param value Value to be written to internal register.

 *

 * @retval 0 If successful.

 * @retval Negative errno code if failure.

 */

static inline int i2c_reg_write_byte(struct device *dev, uint16_t dev_addr,

				     uint8_t reg_addr, uint8_t value)

{

	uint8_t tx_buf[2] = {reg_addr, value};

	return i2c_write(dev, tx_buf, 2, dev_addr);

}

/**

 * @brief Update internal register of an I2C device.

 *

 * This routine updates the value of a set of bits from an 8-bit internal

 * register of an I2C device synchronously.

 *

 * @param dev Pointer to the device structure for the driver instance.

 * @param dev_addr Address of the I2C device for updating.

 * @param reg_addr Address of the internal register being updated.

 * @param value Value for updating internal register.

 * @param mask Bitmask for updating internal register.

 *

 * @retval 0 If successful.

 * @retval Negative errno code if failure.

 */

static inline int i2c_reg_update_byte(struct device *dev, uint8_t dev_addr,

				      uint8_t reg_addr, uint8_t value,

				      uint8_t mask)

{

	uint8_t old_value, new_value;

	int rc;

	rc = i2c_reg_read_byte(dev, reg_addr, dev_addr, &old_value);

	if (rc != 0) {

		return rc;

	}

	new_value = (old_value & ~mask) | (value & mask);

	if (new_value == old_value) {

		return 0;

	}

	return i2c_reg_write_byte(dev, dev_addr, reg_addr, new_value);

}

/**

 * @brief Suspend an I2C driver.

 * @param dev Pointer to the device structure for the driver instance.