include/i2c.h - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /**
  * @file
  *
  * @brief Public APIs for the I2C drivers.
  */

 /*
  * Copyright (c) 2015 Intel Corporation
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 #ifndef __DRIVERS_I2C_H
 #define __DRIVERS_I2C_H

 /**
  * @brief I2C Interface
  * @defgroup i2c_interface I2C Interface
  * @ingroup io_interfaces
  * @{
  */

 #ifdef __cplusplus
 extern "C" {
 #endif

 #include <zephyr/types.h>
 #include <device.h>

 /*
  * The following #defines are used to configure the I2C controller.
  */

 /** I2C Standard Speed */
 #define I2C_SPEED_STANDARD		(0x1)

 /** I2C Fast Speed */
 #define I2C_SPEED_FAST			(0x2)

 /** I2C Fast Plus Speed */
 #define I2C_SPEED_FAST_PLUS		(0x3)

 /** I2C High Speed */
 #define I2C_SPEED_HIGH			(0x4)

 /** I2C Ultra Fast Speed */
 #define I2C_SPEED_ULTRA			(0x5)

 /** @cond INTERNAL_HIDDEN */
 #define I2C_SPEED_MASK			(0x7 << 1)	/* 3 bits */
 /** @endcond  */

 /** Use 10-bit addressing. */
 #define I2C_ADDR_10_BITS		(1 << 0)

 /** Controller to act as Master. */
 #define I2C_MODE_MASTER			(1 << 4)

 /** Controller to act as Slave. */
 #define I2C_MODE_SLAVE_READ		(1 << 5)


 /*
  * I2C_MSG_* are I2C Message flags.
  */

 /** Write message to I2C bus. */
 #define I2C_MSG_WRITE			(0 << 0)

 /** Read message from I2C bus. */
 #define I2C_MSG_READ			(1 << 0)

 /** @cond INTERNAL_HIDDEN */
 #define I2C_MSG_RW_MASK			(1 << 0)
 /** @endcond  */

 /** Send STOP after this message. */
 #define I2C_MSG_STOP			(1 << 1)

 /** RESTART I2C transaction for this message. */
 #define I2C_MSG_RESTART			(1 << 2)

 /**
  * @brief One I2C Message.
  *
  * This defines one I2C message to transact on the I2C bus.
  */
 struct i2c_msg {
 	/** Data buffer in bytes */
 	u8_t		*buf;

 	/** Length of buffer in bytes */
 	u32_t	len;

 	/** Flags for this message */
 	u8_t		flags;
 };

 union dev_config {
 	u32_t raw;
 	struct __bits {
 		u32_t        use_10_bit_addr : 1;
 		u32_t        speed : 3;
 		u32_t        is_master_device : 1;
 		u32_t        is_slave_read : 1;
 		u32_t        reserved : 26;
 	} bits;
 };

 /**
  * @cond INTERNAL_HIDDEN
  *
  * These are for internal use only, so skip these in
  * public documentation.
  */
 typedef int (*i2c_api_configure_t)(struct device *dev,
 				   u32_t dev_config);
 typedef int (*i2c_api_full_io_t)(struct device *dev,
 				 struct i2c_msg *msgs,
 				 u8_t num_msgs,
 				 u16_t addr);

 struct i2c_driver_api {
 	i2c_api_configure_t configure;
 	i2c_api_full_io_t transfer;
 };
 /**
  * @endcond
  */

 /**
  * @brief Configure operation of a host controller.
  *
  * @param dev Pointer to the device structure for the driver instance.
  * @param dev_config Bit-packed 32-bit value to the device runtime configuration
  * for the I2C controller.
  *
  * @retval 0 If successful.
  * @retval -EIO General input / output error, failed to configure device.
  */
 static inline int i2c_configure(struct device *dev, u32_t dev_config)
 {
 	const struct i2c_driver_api *api = dev->driver_api;

 	return api->configure(dev, dev_config);
 }

 /**
  * @brief Write a set amount of data to an I2C device.
  *
  * This routine writes a set amount of data synchronously.
  *
  * @param dev Pointer to the device structure for the driver instance.
  * @param buf Memory pool from which the data is transferred.
  * @param num_bytes Number of bytes to write.
  * @param addr Address to the target I2C device for writing.
  *
  * @retval 0 If successful.
  * @retval -EIO General input / output error.
  */
 static inline int i2c_write(struct device *dev, u8_t *buf,
 			    u32_t num_bytes, u16_t addr)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	struct i2c_msg msg;

 	msg.buf = buf;
 	msg.len = num_bytes;
 	msg.flags = I2C_MSG_WRITE | I2C_MSG_STOP;

 	return api->transfer(dev, &msg, 1, addr);
 }

 /**
  * @brief Read a set amount of data from an I2C device.
  *
  * This routine reads a set amount of data synchronously.
  *
  * @param dev Pointer to the device structure for the driver instance.
  * @param buf Memory pool that stores the retrieved data.
  * @param num_bytes Number of bytes to read.
  * @param addr Address of the I2C device being read.
  *
  * @retval 0 If successful.
  * @retval -EIO General input / output error.
  */
 static inline int i2c_read(struct device *dev, u8_t *buf,
 			   u32_t num_bytes, u16_t addr)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	struct i2c_msg msg;

 	msg.buf = buf;
 	msg.len = num_bytes;
 	msg.flags = I2C_MSG_READ | I2C_MSG_STOP;

 	return api->transfer(dev, &msg, 1, addr);
 }

 /**
  * @brief Perform data transfer to another I2C device.
  *
  * This routine provides a generic interface to perform data transfer
  * to another I2C device synchronously. Use i2c_read()/i2c_write()
  * for simple read or write.
  *
  * The array of message @a msgs must not be NULL.  The number of
  * message @a num_msgs may be zero,in which case no transfer occurs.
  *
  * @param dev Pointer to the device structure for the driver instance.
  * @param msgs Array of messages to transfer.
  * @param num_msgs Number of messages to transfer.
  * @param addr Address of the I2C target device.
  *
  * @retval 0 If successful.
  * @retval -EIO General input / output error.
  */
 static inline int i2c_transfer(struct device *dev,
 			       struct i2c_msg *msgs, u8_t num_msgs,
 			       u16_t addr)
 {
 	const struct i2c_driver_api *api = dev->driver_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 -EIO General input / output error.
  */
 static inline int i2c_burst_read(struct device *dev, u16_t dev_addr,
 				 u8_t start_addr, u8_t *buf,
 				 u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_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_RESTART | I2C_MSG_READ | I2C_MSG_STOP;

 	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 -EIO General input / output error.
  */
 static inline int i2c_burst_write(struct device *dev, u16_t dev_addr,
 				  u8_t start_addr, u8_t *buf,
 				  u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_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;

 	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 -EIO General input / output error.
  */
 static inline int i2c_reg_read_byte(struct device *dev, u16_t dev_addr,
 				    u8_t reg_addr, u8_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 -EIO General input / output error.
  */
 static inline int i2c_reg_write_byte(struct device *dev, u16_t dev_addr,
 				     u8_t reg_addr, u8_t value)
 {
 	u8_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 mask Bitmask for updating internal register.
  * @param value Value for updating internal register.
  *
  * @retval 0 If successful.
  * @retval -EIO General input / output error.
  */
 static inline int i2c_reg_update_byte(struct device *dev, u8_t dev_addr,
 				      u8_t reg_addr, u8_t mask,
 				      u8_t value)
 {
 	u8_t old_value, new_value;
 	int rc;

 	rc = i2c_reg_read_byte(dev, dev_addr, reg_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 Read multiple bytes from an internal 16 bit address of an I2C device.
  *
  * This routine reads multiple bytes from a 16 bit 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 16 bit 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_read16(struct device *dev, u16_t dev_addr,
 				   u16_t start_addr, u8_t *buf,
 				   u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	u8_t addr_buffer[2];
 	struct i2c_msg msg[2];

 	addr_buffer[1] = start_addr & 0xFF;
 	addr_buffer[0] = start_addr >> 8;
 	msg[0].buf = addr_buffer;
 	msg[0].len = 2;
 	msg[0].flags = I2C_MSG_WRITE;

 	msg[1].buf = buf;
 	msg[1].len = num_bytes;
 	msg[1].flags = I2C_MSG_RESTART | I2C_MSG_READ | I2C_MSG_STOP;

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

 /**
  * @brief Write multiple bytes to a 16 bit internal address of an I2C device.
  *
  * This routine writes multiple bytes to a 16 bit 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 16 bit 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_write16(struct device *dev, u16_t dev_addr,
 				    u16_t start_addr, u8_t *buf,
 				    u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	u8_t addr_buffer[2];
 	struct i2c_msg msg[2];

 	addr_buffer[1] = start_addr & 0xFF;
 	addr_buffer[0] = start_addr >> 8;
 	msg[0].buf = addr_buffer;
 	msg[0].len = 2;
 	msg[0].flags = I2C_MSG_WRITE;

 	msg[1].buf = buf;
 	msg[1].len = num_bytes;
 	msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;

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

 /**
  * @brief Read internal 16 bit address register of an I2C device.
  *
  * This routine reads the value of an 16-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 16 bit 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_read16(struct device *dev, u16_t dev_addr,
 				 u16_t reg_addr, u8_t *value)
 {
 	return i2c_burst_read16(dev, dev_addr, reg_addr, value, 1);
 }

 /**
  * @brief Write internal 16 bit address register of an I2C device.
  *
  * This routine writes a value to an 16-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 16 bit 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_write16(struct device *dev, u16_t dev_addr,
 				  u16_t reg_addr, u8_t value)
 {
 	return i2c_burst_write16(dev, dev_addr, reg_addr, &value, 1);
 }

 /**
  * @brief Update internal 16 bit address register of an I2C device.
  *
  * This routine updates the value of a set of bits from a 16-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 16 bit address of the internal register being updated.
  * @param mask Bitmask for updating internal register.
  * @param value Value for updating internal register.
  *
  * @retval 0 If successful.
  * @retval Negative errno code if failure.
  */
 static inline int i2c_reg_update16(struct device *dev, u16_t dev_addr,
 				   u16_t reg_addr, u8_t mask,
 				   u8_t value)
 {
 	u8_t old_value, new_value;
 	int rc;

 	rc = i2c_reg_read16(dev, dev_addr, reg_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_write16(dev, dev_addr, reg_addr, new_value);
 }

 /**
  * @brief Read multiple bytes from an internal variable byte size
  * address of an I2C device.
  *
  * This routine reads multiple bytes from an addr_size byte 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 Array to an internal register address from which
  *		     the data is being read.
  * @param addr_size Size in bytes of the register address.
  * @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_addr(struct device *dev, u16_t dev_addr,
 				      u8_t *start_addr,
 				      const u8_t addr_size,
 				      u8_t *buf, u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	struct i2c_msg msg[2];

 	msg[0].buf = start_addr;
 	msg[0].len = addr_size;
 	msg[0].flags = I2C_MSG_WRITE;

 	msg[1].buf = buf;
 	msg[1].len = num_bytes;
 	msg[1].flags = I2C_MSG_RESTART | I2C_MSG_READ | I2C_MSG_STOP;

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

 /**
  * @brief Write multiple bytes to an internal variable bytes size
  * address of an I2C device.
  * This routine writes multiple bytes to an addr_size byte 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 Array to an internal register address from which
  *		     the data is being read.
  * @param addr_size Size in bytes of the register address.
  * @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_addr(struct device *dev, u16_t dev_addr,
 				       u8_t *start_addr,
 				       const u8_t addr_size,
 				       u8_t *buf, u8_t num_bytes)
 {
 	const struct i2c_driver_api *api = dev->driver_api;
 	struct i2c_msg msg[2];

 	msg[0].buf = start_addr;
 	msg[0].len = addr_size;
 	msg[0].flags = I2C_MSG_WRITE;

 	msg[1].buf = buf;
 	msg[1].len = num_bytes;
 	msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;

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

 /**
  * @brief Read internal variable byte size address register
  * of an I2C device.
  *
  * This routine reads the value of an addr_size byte 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 Array to an internal register address from which
  *		     the data is being read.
  * @param addr_size Size in bytes of the register address.
  * @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_addr(struct device *dev,
 				    u16_t dev_addr,
 				    u8_t *reg_addr,
 				    const u8_t addr_size,
 				    u8_t *value)
 {
 	return i2c_burst_read_addr(dev, dev_addr, reg_addr,
 				   addr_size, value, 1);
 }

 /**
  * @brief Write internal variable byte size address register
  * of an I2C device.
  *
  * This routine writes a value to an addr_size byte 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 Array to an internal register address from which
  *		     the data is being read.
  * @param addr_size Size in bytes of the register address.
  * @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_addr(struct device *dev,
 				     u16_t dev_addr,
 				     u8_t *reg_addr,
 				     const u8_t addr_size,
 				     u8_t value)
 {
 	return i2c_burst_write_addr(dev, dev_addr, reg_addr,
 				    addr_size, &value, 1);
 }

 /**
  * @brief Update internal variable byte size address register
  * of an I2C device.
  *
  * This routine updates the value of a set of bits from a addr_size byte
  * 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 Array to an internal register address from which
  *		     the data is being read.
  * @param addr_size Size in bytes of the register address.
  * @param mask Bitmask for updating internal register.
  * @param value Value for updating internal register.
  *
  * @retval 0 If successful.
  * @retval Negative errno code if failure.
  */
 static inline int i2c_reg_update_addr(struct device *dev,
 				      u16_t dev_addr,
 				      u8_t *reg_addr,
 				      u8_t addr_size,
 				      u8_t mask,
 				      u8_t value)
 {
 	u8_t old_value, new_value;
 	int rc;

 	rc = i2c_reg_read_addr(dev, dev_addr, reg_addr,
 			       addr_size, &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_addr(dev, dev_addr, reg_addr,
 				  addr_size, new_value);
 }

 struct i2c_client_config {
 	char *i2c_master;
 	u16_t i2c_addr;
 };

 #define I2C_DECLARE_CLIENT_CONFIG	struct i2c_client_config i2c_client

 #define I2C_CLIENT(_master, _addr)		\
 	.i2c_client = {				\
 		.i2c_master = (_master),	\
 		.i2c_addr = (_addr),		\
 	}

 #define I2C_GET_MASTER(_conf)		((_conf)->i2c_client.i2c_master)
 #define I2C_GET_ADDR(_conf)		((_conf)->i2c_client.i2c_addr)

 #ifdef __cplusplus
 }
 #endif

 /**
  * @}
  */


 #endif /* __DRIVERS_I2C_H */
	/**
	* @file
	*
	* @brief Public APIs for the I2C drivers.
	*/

	/*
	* Copyright (c) 2015 Intel Corporation
	*
	* SPDX-License-Identifier: Apache-2.0
	*/
	#ifndef __DRIVERS_I2C_H
	#define __DRIVERS_I2C_H

	/**
	* @brief I2C Interface
	* @defgroup i2c_interface I2C Interface
	* @ingroup io_interfaces
	* @{
	*/

	#ifdef __cplusplus
	extern "C" {
	#endif

	#include <zephyr/types.h>
	#include <device.h>

	/*
	* The following #defines are used to configure the I2C controller.
	*/

	/** I2C Standard Speed */
	#define I2C_SPEED_STANDARD (0x1)

	/** I2C Fast Speed */
	#define I2C_SPEED_FAST (0x2)

	/** I2C Fast Plus Speed */
	#define I2C_SPEED_FAST_PLUS (0x3)

	/** I2C High Speed */
	#define I2C_SPEED_HIGH (0x4)

	/** I2C Ultra Fast Speed */
	#define I2C_SPEED_ULTRA (0x5)

	/** @cond INTERNAL_HIDDEN */
	#define I2C_SPEED_MASK (0x7 << 1) /* 3 bits */
	/** @endcond */

	/** Use 10-bit addressing. */
	#define I2C_ADDR_10_BITS (1 << 0)

	/** Controller to act as Master. */
	#define I2C_MODE_MASTER (1 << 4)

	/** Controller to act as Slave. */
	#define I2C_MODE_SLAVE_READ (1 << 5)


	/*
	* I2C_MSG_* are I2C Message flags.
	*/

	/** Write message to I2C bus. */
	#define I2C_MSG_WRITE (0 << 0)

	/** Read message from I2C bus. */
	#define I2C_MSG_READ (1 << 0)

	/** @cond INTERNAL_HIDDEN */
	#define I2C_MSG_RW_MASK (1 << 0)
	/** @endcond */

	/** Send STOP after this message. */
	#define I2C_MSG_STOP (1 << 1)

	/** RESTART I2C transaction for this message. */
	#define I2C_MSG_RESTART (1 << 2)

	/**
	* @brief One I2C Message.
	*
	* This defines one I2C message to transact on the I2C bus.
	*/
	struct i2c_msg {
	/** Data buffer in bytes */
	u8_t *buf;

	/** Length of buffer in bytes */
	u32_t len;

	/** Flags for this message */
	u8_t flags;
	};

	union dev_config {
	u32_t raw;
	struct __bits {
	u32_t use_10_bit_addr : 1;
	u32_t speed : 3;
	u32_t is_master_device : 1;
	u32_t is_slave_read : 1;
	u32_t reserved : 26;
	} bits;
	};

	/**
	* @cond INTERNAL_HIDDEN
	*
	* These are for internal use only, so skip these in
	* public documentation.
	*/
	typedef int (i2c_api_configure_t)(struct device dev,
	u32_t dev_config);
	typedef int (i2c_api_full_io_t)(struct device dev,
	struct i2c_msg *msgs,
	u8_t num_msgs,
	u16_t addr);

	struct i2c_driver_api {
	i2c_api_configure_t configure;
	i2c_api_full_io_t transfer;
	};
	/**
	* @endcond
	*/

	/**
	* @brief Configure operation of a host controller.
	*
	* @param dev Pointer to the device structure for the driver instance.
	* @param dev_config Bit-packed 32-bit value to the device runtime configuration
	* for the I2C controller.
	*
	* @retval 0 If successful.
	* @retval -EIO General input / output error, failed to configure device.
	*/
	static inline int i2c_configure(struct device *dev, u32_t dev_config)
	{
	const struct i2c_driver_api *api = dev->driver_api;

	return api->configure(dev, dev_config);
	}

	/**
	* @brief Write a set amount of data to an I2C device.
	*
	* This routine writes a set amount of data synchronously.
	*
	* @param dev Pointer to the device structure for the driver instance.
	* @param buf Memory pool from which the data is transferred.
	* @param num_bytes Number of bytes to write.
	* @param addr Address to the target I2C device for writing.
	*
	* @retval 0 If successful.
	* @retval -EIO General input / output error.
	*/
	static inline int i2c_write(struct device dev, u8_t buf,
	u32_t num_bytes, u16_t addr)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	struct i2c_msg msg;

	msg.buf = buf;
	msg.len = num_bytes;
	msg.flags = I2C_MSG_WRITE \| I2C_MSG_STOP;

	return api->transfer(dev, &msg, 1, addr);
	}

	/**
	* @brief Read a set amount of data from an I2C device.
	*
	* This routine reads a set amount of data synchronously.
	*
	* @param dev Pointer to the device structure for the driver instance.
	* @param buf Memory pool that stores the retrieved data.
	* @param num_bytes Number of bytes to read.
	* @param addr Address of the I2C device being read.
	*
	* @retval 0 If successful.
	* @retval -EIO General input / output error.
	*/
	static inline int i2c_read(struct device dev, u8_t buf,
	u32_t num_bytes, u16_t addr)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	struct i2c_msg msg;

	msg.buf = buf;
	msg.len = num_bytes;
	msg.flags = I2C_MSG_READ \| I2C_MSG_STOP;

	return api->transfer(dev, &msg, 1, addr);
	}

	/**
	* @brief Perform data transfer to another I2C device.
	*
	* This routine provides a generic interface to perform data transfer
	* to another I2C device synchronously. Use i2c_read()/i2c_write()
	* for simple read or write.
	*
	* The array of message @a msgs must not be NULL. The number of
	* message @a num_msgs may be zero,in which case no transfer occurs.
	*
	* @param dev Pointer to the device structure for the driver instance.
	* @param msgs Array of messages to transfer.
	* @param num_msgs Number of messages to transfer.
	* @param addr Address of the I2C target device.
	*
	* @retval 0 If successful.
	* @retval -EIO General input / output error.
	*/
	static inline int i2c_transfer(struct device *dev,
	struct i2c_msg *msgs, u8_t num_msgs,
	u16_t addr)
	{
	const struct i2c_driver_api *api = dev->driver_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 -EIO General input / output error.
	*/
	static inline int i2c_burst_read(struct device *dev, u16_t dev_addr,
	u8_t start_addr, u8_t *buf,
	u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_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_RESTART \| I2C_MSG_READ \| I2C_MSG_STOP;

	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 -EIO General input / output error.
	*/
	static inline int i2c_burst_write(struct device *dev, u16_t dev_addr,
	u8_t start_addr, u8_t *buf,
	u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_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;

	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 -EIO General input / output error.
	*/
	static inline int i2c_reg_read_byte(struct device *dev, u16_t dev_addr,
	u8_t reg_addr, u8_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 -EIO General input / output error.
	*/
	static inline int i2c_reg_write_byte(struct device *dev, u16_t dev_addr,
	u8_t reg_addr, u8_t value)
	{
	u8_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 mask Bitmask for updating internal register.
	* @param value Value for updating internal register.
	*
	* @retval 0 If successful.
	* @retval -EIO General input / output error.
	*/
	static inline int i2c_reg_update_byte(struct device *dev, u8_t dev_addr,
	u8_t reg_addr, u8_t mask,
	u8_t value)
	{
	u8_t old_value, new_value;
	int rc;

	rc = i2c_reg_read_byte(dev, dev_addr, reg_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 Read multiple bytes from an internal 16 bit address of an I2C device.
	*
	* This routine reads multiple bytes from a 16 bit 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 16 bit 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_read16(struct device *dev, u16_t dev_addr,
	u16_t start_addr, u8_t *buf,
	u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	u8_t addr_buffer[2];
	struct i2c_msg msg[2];

	addr_buffer[1] = start_addr & 0xFF;
	addr_buffer[0] = start_addr >> 8;
	msg[0].buf = addr_buffer;
	msg[0].len = 2;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_RESTART \| I2C_MSG_READ \| I2C_MSG_STOP;

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

	/**
	* @brief Write multiple bytes to a 16 bit internal address of an I2C device.
	*
	* This routine writes multiple bytes to a 16 bit 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 16 bit 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_write16(struct device *dev, u16_t dev_addr,
	u16_t start_addr, u8_t *buf,
	u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	u8_t addr_buffer[2];
	struct i2c_msg msg[2];

	addr_buffer[1] = start_addr & 0xFF;
	addr_buffer[0] = start_addr >> 8;
	msg[0].buf = addr_buffer;
	msg[0].len = 2;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_WRITE \| I2C_MSG_STOP;

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

	/**
	* @brief Read internal 16 bit address register of an I2C device.
	*
	* This routine reads the value of an 16-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 16 bit 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_read16(struct device *dev, u16_t dev_addr,
	u16_t reg_addr, u8_t *value)
	{
	return i2c_burst_read16(dev, dev_addr, reg_addr, value, 1);
	}

	/**
	* @brief Write internal 16 bit address register of an I2C device.
	*
	* This routine writes a value to an 16-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 16 bit 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_write16(struct device *dev, u16_t dev_addr,
	u16_t reg_addr, u8_t value)
	{
	return i2c_burst_write16(dev, dev_addr, reg_addr, &value, 1);
	}

	/**
	* @brief Update internal 16 bit address register of an I2C device.
	*
	* This routine updates the value of a set of bits from a 16-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 16 bit address of the internal register being updated.
	* @param mask Bitmask for updating internal register.
	* @param value Value for updating internal register.
	*
	* @retval 0 If successful.
	* @retval Negative errno code if failure.
	*/
	static inline int i2c_reg_update16(struct device *dev, u16_t dev_addr,
	u16_t reg_addr, u8_t mask,
	u8_t value)
	{
	u8_t old_value, new_value;
	int rc;

	rc = i2c_reg_read16(dev, dev_addr, reg_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_write16(dev, dev_addr, reg_addr, new_value);
	}

	/**
	* @brief Read multiple bytes from an internal variable byte size
	* address of an I2C device.
	*
	* This routine reads multiple bytes from an addr_size byte 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 Array to an internal register address from which
	* the data is being read.
	* @param addr_size Size in bytes of the register address.
	* @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_addr(struct device *dev, u16_t dev_addr,
	u8_t *start_addr,
	const u8_t addr_size,
	u8_t *buf, u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	struct i2c_msg msg[2];

	msg[0].buf = start_addr;
	msg[0].len = addr_size;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_RESTART \| I2C_MSG_READ \| I2C_MSG_STOP;

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

	/**
	* @brief Write multiple bytes to an internal variable bytes size
	* address of an I2C device.
	* This routine writes multiple bytes to an addr_size byte 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 Array to an internal register address from which
	* the data is being read.
	* @param addr_size Size in bytes of the register address.
	* @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_addr(struct device *dev, u16_t dev_addr,
	u8_t *start_addr,
	const u8_t addr_size,
	u8_t *buf, u8_t num_bytes)
	{
	const struct i2c_driver_api *api = dev->driver_api;
	struct i2c_msg msg[2];

	msg[0].buf = start_addr;
	msg[0].len = addr_size;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_WRITE \| I2C_MSG_STOP;

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

	/**
	* @brief Read internal variable byte size address register
	* of an I2C device.
	*
	* This routine reads the value of an addr_size byte 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 Array to an internal register address from which
	* the data is being read.
	* @param addr_size Size in bytes of the register address.
	* @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_addr(struct device *dev,
	u16_t dev_addr,
	u8_t *reg_addr,
	const u8_t addr_size,
	u8_t *value)
	{
	return i2c_burst_read_addr(dev, dev_addr, reg_addr,
	addr_size, value, 1);
	}

	/**
	* @brief Write internal variable byte size address register
	* of an I2C device.
	*
	* This routine writes a value to an addr_size byte 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 Array to an internal register address from which
	* the data is being read.
	* @param addr_size Size in bytes of the register address.
	* @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_addr(struct device *dev,
	u16_t dev_addr,
	u8_t *reg_addr,
	const u8_t addr_size,
	u8_t value)
	{
	return i2c_burst_write_addr(dev, dev_addr, reg_addr,
	addr_size, &value, 1);
	}

	/**
	* @brief Update internal variable byte size address register
	* of an I2C device.
	*
	* This routine updates the value of a set of bits from a addr_size byte
	* 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 Array to an internal register address from which
	* the data is being read.
	* @param addr_size Size in bytes of the register address.
	* @param mask Bitmask for updating internal register.
	* @param value Value for updating internal register.
	*
	* @retval 0 If successful.
	* @retval Negative errno code if failure.
	*/
	static inline int i2c_reg_update_addr(struct device *dev,
	u16_t dev_addr,
	u8_t *reg_addr,
	u8_t addr_size,
	u8_t mask,
	u8_t value)
	{
	u8_t old_value, new_value;
	int rc;

	rc = i2c_reg_read_addr(dev, dev_addr, reg_addr,
	addr_size, &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_addr(dev, dev_addr, reg_addr,
	addr_size, new_value);
	}

	struct i2c_client_config {
	char *i2c_master;
	u16_t i2c_addr;
	};

	#define I2C_DECLARE_CLIENT_CONFIG struct i2c_client_config i2c_client

	#define I2C_CLIENT(_master, _addr) \
	.i2c_client = { \
	.i2c_master = (_master), \
	.i2c_addr = (_addr), \
	}

	#define I2C_GET_MASTER(_conf) ((_conf)->i2c_client.i2c_master)
	#define I2C_GET_ADDR(_conf) ((_conf)->i2c_client.i2c_addr)

	#ifdef __cplusplus
	}
	#endif

	/**
	* @}
	*/


	#endif /* __DRIVERS_I2C_H */