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

/*
 * Copyright (c) 2015 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#ifndef ZEPHYR_INCLUDE_DRIVERS_I2C_H_
#define ZEPHYR_INCLUDE_DRIVERS_I2C_H_

/**
 * @brief I2C Interface
 * @defgroup i2c_interface I2C Interface
 * @since 1.0
 * @version 1.0.0
 * @ingroup io_interfaces
 * @{
 */

#include <errno.h>

#include <zephyr/types.h>
#include <zephyr/device.h>
#include <zephyr/kernel.h>
#include <zephyr/sys/slist.h>
#include <zephyr/rtio/rtio.h>

#ifdef __cplusplus
extern "C" {
#endif

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

/** I2C Standard Speed: 100 kHz */
#define I2C_SPEED_STANDARD		(0x1U)

/** I2C Fast Speed: 400 kHz */
#define I2C_SPEED_FAST			(0x2U)

/** I2C Fast Plus Speed: 1 MHz */
#define I2C_SPEED_FAST_PLUS		(0x3U)

/** I2C High Speed: 3.4 MHz */
#define I2C_SPEED_HIGH			(0x4U)

/** I2C Ultra Fast Speed: 5 MHz */
#define I2C_SPEED_ULTRA			(0x5U)

/** Device Tree specified speed */
#define I2C_SPEED_DT			(0x7U)

#define I2C_SPEED_SHIFT			(1U)
#define I2C_SPEED_SET(speed)		(((speed) << I2C_SPEED_SHIFT) \
						& I2C_SPEED_MASK)
#define I2C_SPEED_MASK			(0x7U << I2C_SPEED_SHIFT) /* 3 bits */
#define I2C_SPEED_GET(cfg) 		(((cfg) & I2C_SPEED_MASK) \
						>> I2C_SPEED_SHIFT)

/** Use 10-bit addressing. DEPRECATED - Use I2C_MSG_ADDR_10_BITS instead. */
#define I2C_ADDR_10_BITS		BIT(0)

/** Peripheral to act as Controller. */
#define I2C_MODE_CONTROLLER		BIT(4)

/**
 * @brief Complete I2C DT information
 *
 * @param bus is the I2C bus
 * @param addr is the target address
 */
struct i2c_dt_spec {
	const struct device *bus;
	uint16_t addr;
};

/**
 * @brief Structure initializer for i2c_dt_spec from devicetree (on I3C bus)
 *
 * This helper macro expands to a static initializer for a <tt>struct
 * i2c_dt_spec</tt> by reading the relevant bus and address data from
 * the devicetree.
 *
 * @param node_id Devicetree node identifier for the I2C device whose
 *                struct i2c_dt_spec to create an initializer for
 */
#define I2C_DT_SPEC_GET_ON_I3C(node_id)					\
	.bus = DEVICE_DT_GET(DT_BUS(node_id)),				\
	.addr = DT_PROP_BY_IDX(node_id, reg, 0)

/**
 * @brief Structure initializer for i2c_dt_spec from devicetree (on I2C bus)
 *
 * This helper macro expands to a static initializer for a <tt>struct
 * i2c_dt_spec</tt> by reading the relevant bus and address data from
 * the devicetree.
 *
 * @param node_id Devicetree node identifier for the I2C device whose
 *                struct i2c_dt_spec to create an initializer for
 */
#define I2C_DT_SPEC_GET_ON_I2C(node_id)					\
	.bus = DEVICE_DT_GET(DT_BUS(node_id)),				\
	.addr = DT_REG_ADDR(node_id)

/**
 * @brief Structure initializer for i2c_dt_spec from devicetree
 *
 * This helper macro expands to a static initializer for a <tt>struct
 * i2c_dt_spec</tt> by reading the relevant bus and address data from
 * the devicetree.
 *
 * @param node_id Devicetree node identifier for the I2C device whose
 *                struct i2c_dt_spec to create an initializer for
 */
#define I2C_DT_SPEC_GET(node_id)					\
	{								\
		COND_CODE_1(DT_ON_BUS(node_id, i3c),			\
			    (I2C_DT_SPEC_GET_ON_I3C(node_id)),		\
			    (I2C_DT_SPEC_GET_ON_I2C(node_id)))		\
	}

/**
 * @brief Structure initializer for i2c_dt_spec from devicetree instance
 *
 * This is equivalent to
 * <tt>I2C_DT_SPEC_GET(DT_DRV_INST(inst))</tt>.
 *
 * @param inst Devicetree instance number
 */
#define I2C_DT_SPEC_INST_GET(inst) \
	I2C_DT_SPEC_GET(DT_DRV_INST(inst))


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

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

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

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

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

/** RESTART I2C transaction for this message.
 *
 * @note Not all I2C drivers have or require explicit support for this
 * feature. Some drivers require this be present on a read message
 * that follows a write, or vice-versa.  Some drivers will merge
 * adjacent fragments into a single transaction using this flag; some
 * will not. */
#define I2C_MSG_RESTART			BIT(2)

/** Use 10-bit addressing for this message.
 *
 * @note Not all SoC I2C implementations support this feature. */
#define I2C_MSG_ADDR_10_BITS		BIT(3)

/**
 * @brief One I2C Message.
 *
 * This defines one I2C message to transact on the I2C bus.
 *
 * @note Some of the configurations supported by this API may not be
 * supported by specific SoC I2C hardware implementations, in
 * particular features related to bus transactions intended to read or
 * write data from different buffers within a single transaction.
 * Invocations of i2c_transfer() may not indicate an error when an
 * unsupported configuration is encountered.  In some cases drivers
 * will generate separate transactions for each message fragment, with
 * or without presence of @ref I2C_MSG_RESTART in #flags.
 */
struct i2c_msg {
	/** Data buffer in bytes */
	uint8_t		*buf;

	/** Length of buffer in bytes */
	uint32_t	len;

	/** Flags for this message */
	uint8_t		flags;
};

/**
 * @brief I2C callback for asynchronous transfer requests
 *
 * @param dev I2C device which is notifying of transfer completion or error
 * @param result Result code of the transfer request. 0 is success, -errno for failure.
 * @param data Transfer requester supplied data which is passed along to the callback.
 */
typedef void (*i2c_callback_t)(const struct device *dev, int result, void *data);

/**
 * @cond INTERNAL_HIDDEN
 *
 * These are for internal use only, so skip these in
 * public documentation.
 */
struct i2c_target_config;

typedef int (*i2c_api_configure_t)(const struct device *dev,
				   uint32_t dev_config);
typedef int (*i2c_api_get_config_t)(const struct device *dev,
				    uint32_t *dev_config);
typedef int (*i2c_api_full_io_t)(const struct device *dev,
				 struct i2c_msg *msgs,
				 uint8_t num_msgs,
				 uint16_t addr);
typedef int (*i2c_api_target_register_t)(const struct device *dev,
					struct i2c_target_config *cfg);
typedef int (*i2c_api_target_unregister_t)(const struct device *dev,
					  struct i2c_target_config *cfg);
#ifdef CONFIG_I2C_CALLBACK
typedef int (*i2c_api_transfer_cb_t)(const struct device *dev,
				 struct i2c_msg *msgs,
				 uint8_t num_msgs,
				 uint16_t addr,
				 i2c_callback_t cb,
				 void *userdata);
#endif /* CONFIG_I2C_CALLBACK */
#if defined(CONFIG_I2C_RTIO) || defined(__DOXYGEN__)

/**
 * @typedef i2c_api_iodev_submit
 * @brief Callback API for submitting work to a I2C device with RTIO
 */
typedef void (*i2c_api_iodev_submit)(const struct device *dev,
				     struct rtio_iodev_sqe *iodev_sqe);
#endif /* CONFIG_I2C_RTIO */

typedef int (*i2c_api_recover_bus_t)(const struct device *dev);

__subsystem struct i2c_driver_api {
	i2c_api_configure_t configure;
	i2c_api_get_config_t get_config;
	i2c_api_full_io_t transfer;
	i2c_api_target_register_t target_register;
	i2c_api_target_unregister_t target_unregister;
#ifdef CONFIG_I2C_CALLBACK
	i2c_api_transfer_cb_t transfer_cb;
#endif
#ifdef CONFIG_I2C_RTIO
	i2c_api_iodev_submit iodev_submit;
#endif
	i2c_api_recover_bus_t recover_bus;
};

typedef int (*i2c_target_api_register_t)(const struct device *dev);
typedef int (*i2c_target_api_unregister_t)(const struct device *dev);

__subsystem struct i2c_target_driver_api {
	i2c_target_api_register_t driver_register;
	i2c_target_api_unregister_t driver_unregister;
};

/**
 * @endcond
 */

/** Target device responds to 10-bit addressing. */
#define I2C_TARGET_FLAGS_ADDR_10_BITS	BIT(0)

/** @brief Function called when a write to the device is initiated.
 *
 * This function is invoked by the controller when the bus completes a
 * start condition for a write operation to the address associated
 * with a particular device.
 *
 * A success return shall cause the controller to ACK the next byte
 * received.  An error return shall cause the controller to NACK the
 * next byte received.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @return 0 if the write is accepted, or a negative error code.
 */
typedef int (*i2c_target_write_requested_cb_t)(
		struct i2c_target_config *config);

/** @brief Function called when a write to the device is continued.
 *
 * This function is invoked by the controller when it completes
 * reception of a byte of data in an ongoing write operation to the
 * device.
 *
 * A success return shall cause the controller to ACK the next byte
 * received.  An error return shall cause the controller to NACK the
 * next byte received.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @param val the byte received by the controller.
 *
 * @return 0 if more data can be accepted, or a negative error
 * code.
 */
typedef int (*i2c_target_write_received_cb_t)(
		struct i2c_target_config *config, uint8_t val);

/** @brief Function called when a read from the device is initiated.
 *
 * This function is invoked by the controller when the bus completes a
 * start condition for a read operation from the address associated
 * with a particular device.
 *
 * The value returned in @p *val will be transmitted.  A success
 * return shall cause the controller to react to additional read
 * operations.  An error return shall cause the controller to ignore
 * bus operations until a new start condition is received.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @param val pointer to storage for the first byte of data to return
 * for the read request.
 *
 * @return 0 if more data can be requested, or a negative error code.
 */
typedef int (*i2c_target_read_requested_cb_t)(
		struct i2c_target_config *config, uint8_t *val);

/** @brief Function called when a read from the device is continued.
 *
 * This function is invoked by the controller when the bus is ready to
 * provide additional data for a read operation from the address
 * associated with the device device.
 *
 * The value returned in @p *val will be transmitted.  A success
 * return shall cause the controller to react to additional read
 * operations.  An error return shall cause the controller to ignore
 * bus operations until a new start condition is received.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @param val pointer to storage for the next byte of data to return
 * for the read request.
 *
 * @return 0 if data has been provided, or a negative error code.
 */
typedef int (*i2c_target_read_processed_cb_t)(
		struct i2c_target_config *config, uint8_t *val);

#ifdef CONFIG_I2C_TARGET_BUFFER_MODE
/** @brief Function called when a write to the device is completed.
 *
 * This function is invoked by the controller when it completes
 * reception of data from the source buffer to the destination
 * buffer in an ongoing write operation to the device.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @param ptr pointer to the buffer that contains the data to be transferred.
 *
 * @param len the length of the data to be transferred.
 */
typedef void (*i2c_target_buf_write_received_cb_t)(
		struct i2c_target_config *config, uint8_t *ptr, uint32_t len);

/** @brief Function called when a read from the device is initiated.
 *
 * This function is invoked by the controller when the bus is ready to
 * provide additional data by buffer for a read operation from the address
 * associated with the device.
 *
 * The value returned in @p **ptr and @p *len will be transmitted. A success
 * return shall cause the controller to react to additional read operations.
 * An error return shall cause the controller to ignore bus operations until
 * a new start condition is received.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @param ptr pointer to storage for the address of data buffer to return
 * for the read request.
 *
 * @param len pointer to storage for the length of the data to be transferred
 * for the read request.
 *
 * @return 0 if data has been provided, or a negative error code.
 */
typedef int (*i2c_target_buf_read_requested_cb_t)(
		struct i2c_target_config *config, uint8_t **ptr, uint32_t *len);
#endif

/** @brief Function called when a stop condition is observed after a
 * start condition addressed to a particular device.
 *
 * This function is invoked by the controller when the bus is ready to
 * provide additional data for a read operation from the address
 * associated with the device device.  After the function returns the
 * controller shall enter a state where it is ready to react to new
 * start conditions.
 *
 * @param config the configuration structure associated with the
 * device to which the operation is addressed.
 *
 * @return Ignored.
 */
typedef int (*i2c_target_stop_cb_t)(struct i2c_target_config *config);

/** @brief Structure providing callbacks to be implemented for devices
 * that supports the I2C target API.
 *
 * This structure may be shared by multiple devices that implement the
 * same API at different addresses on the bus.
 */
struct i2c_target_callbacks {
	i2c_target_write_requested_cb_t write_requested;
	i2c_target_read_requested_cb_t read_requested;
	i2c_target_write_received_cb_t write_received;
	i2c_target_read_processed_cb_t read_processed;
#ifdef CONFIG_I2C_TARGET_BUFFER_MODE
	i2c_target_buf_write_received_cb_t buf_write_received;
	i2c_target_buf_read_requested_cb_t buf_read_requested;
#endif
	i2c_target_stop_cb_t stop;
};

/** @brief Structure describing a device that supports the I2C
 * target API.
 *
 * Instances of this are passed to the i2c_target_register() and
 * i2c_target_unregister() functions to indicate addition and removal
 * of a target device, respective.
 *
 * Fields other than @c node must be initialized by the module that
 * implements the device behavior prior to passing the object
 * reference to i2c_target_register().
 */
struct i2c_target_config {
	/** Private, do not modify */
	sys_snode_t node;

	/** Flags for the target device defined by I2C_TARGET_FLAGS_* constants */
	uint8_t flags;

	/** Address for this target device */
	uint16_t address;

	/** Callback functions */
	const struct i2c_target_callbacks *callbacks;
};

/**
 * @brief Validate that I2C bus is ready.
 *
 * @param spec I2C specification from devicetree
 *
 * @retval true if the I2C bus is ready for use.
 * @retval false if the I2C bus is not ready for use.
 */
static inline bool i2c_is_ready_dt(const struct i2c_dt_spec *spec)
{
	/* Validate bus is ready */
	return device_is_ready(spec->bus);
}

/**
 * @brief Check if the current message is a read operation
 *
 * @param msg The message to check
 * @return true if the I2C message is a read operation
 * @return false if the I2C message is a write operation
 */
static inline bool i2c_is_read_op(const struct i2c_msg *msg)
{
	return (msg->flags & I2C_MSG_READ) == I2C_MSG_READ;
}

/**
 * @brief Check if the current message includes a stop.
 *
 * @param msg The message to check
 * @return true if the I2C message includes a stop
 * @return false if the I2C message includes a stop
 */
static inline bool i2c_is_stop_op(const struct i2c_msg *msg)
{
	return (msg->flags & I2C_MSG_STOP) == I2C_MSG_STOP;
}

/**
 * @brief Dump out an I2C message
 *
 * Dumps out a list of I2C messages. For any that are writes (W), the data is
 * displayed in hex. Setting dump_read will dump the data for read messages too,
 * which only makes sense when called after the messages have been processed.
 *
 * It looks something like this (with name "testing"):
 *
 * @code
 * D: I2C msg: testing, addr=56
 * D:    W len=01: 06
 * D:    W len=0e:
 * D: contents:
 * D: 00 01 02 03 04 05 06 07 |........
 * D: 08 09 0a 0b 0c 0d       |......
 * D:    W len=01: 0f
 * D:    R len=01: 6c
 * @endcode
 *
 * @param dev Target for the messages being sent. Its name will be printed in the log.
 * @param msgs Array of messages to dump.
 * @param num_msgs Number of messages to dump.
 * @param addr Address of the I2C target device.
 * @param dump_read Dump data from I2C reads, otherwise only writes have data dumped.
 */
void i2c_dump_msgs_rw(const struct device *dev, const struct i2c_msg *msgs, uint8_t num_msgs,
		      uint16_t addr, bool dump_read);

/**
 * @brief Dump out an I2C message, before it is executed.
 *
 * This is equivalent to:
 *
 *     i2c_dump_msgs_rw(dev, msgs, num_msgs, addr, false);
 *
 * The read messages' data isn't dumped.
 *
 * @param dev Target for the messages being sent. Its name will be printed in the log.
 * @param msgs Array of messages to dump.
 * @param num_msgs Number of messages to dump.
 * @param addr Address of the I2C target device.
 */
static inline void i2c_dump_msgs(const struct device *dev, const struct i2c_msg *msgs,
				 uint8_t num_msgs, uint16_t addr)
{
	i2c_dump_msgs_rw(dev, msgs, num_msgs, addr, false);
}

#if defined(CONFIG_I2C_STATS) || defined(__DOXYGEN__)

#include <zephyr/stats/stats.h>

/** @cond INTERNAL_HIDDEN */

STATS_SECT_START(i2c)
STATS_SECT_ENTRY32(bytes_read)
STATS_SECT_ENTRY32(bytes_written)
STATS_SECT_ENTRY32(message_count)
STATS_SECT_ENTRY32(transfer_call_count)
STATS_SECT_END;

STATS_NAME_START(i2c)
STATS_NAME(i2c, bytes_read)
STATS_NAME(i2c, bytes_written)
STATS_NAME(i2c, message_count)
STATS_NAME(i2c, transfer_call_count)
STATS_NAME_END(i2c);

/** @endcond */


/**
 * @brief I2C specific device state which allows for i2c device class specific additions
 */
struct i2c_device_state {
	struct device_state devstate;
	struct stats_i2c stats;
};

/**
 * @brief Updates the i2c stats for i2c transfers
 *
 * @param dev I2C device to update stats for
 * @param msgs Array of struct i2c_msg
 * @param num_msgs Number of i2c_msgs
 */
static inline void i2c_xfer_stats(const struct device *dev, struct i2c_msg *msgs,
				  uint8_t num_msgs)
{
	struct i2c_device_state *state =
		CONTAINER_OF(dev->state, struct i2c_device_state, devstate);
	uint32_t bytes_read = 0U;
	uint32_t bytes_written = 0U;

	STATS_INC(state->stats, transfer_call_count);
	STATS_INCN(state->stats, message_count, num_msgs);
	for (uint8_t i = 0U; i < num_msgs; i++) {
		if (msgs[i].flags & I2C_MSG_READ) {
			bytes_read += msgs[i].len;
		} else {
			bytes_written += msgs[i].len;
		}
	}
	STATS_INCN(state->stats, bytes_read, bytes_read);
	STATS_INCN(state->stats, bytes_written, bytes_written);
}

/** @cond INTERNAL_HIDDEN */

/**
 * @brief Define a statically allocated and section assigned i2c device state
 */
#define Z_I2C_DEVICE_STATE_DEFINE(dev_id)				\
	static struct i2c_device_state Z_DEVICE_STATE_NAME(dev_id)	\
	__attribute__((__section__(".z_devstate")))

/**
 * @brief Define an i2c device init wrapper function
 *
 * This does device instance specific initialization of common data (such as stats)
 * and calls the given init_fn
 */
#define Z_I2C_INIT_FN(dev_id, init_fn)					\
	static inline int UTIL_CAT(dev_id, _init)(const struct device *dev) \
	{								\
		struct i2c_device_state *state =			\
			CONTAINER_OF(dev->state, struct i2c_device_state, devstate); \
		stats_init(&state->stats.s_hdr, STATS_SIZE_32, 4,	\
			   STATS_NAME_INIT_PARMS(i2c));			\
		stats_register(dev->name, &(state->stats.s_hdr));	\
		if (!is_null_no_warn(init_fn)) {			\
			return init_fn(dev);				\
		}							\
									\
		return 0;						\
	}

/** @endcond */

/**
 * @brief Like DEVICE_DT_DEFINE() with I2C specifics.
 *
 * @details Defines a device which implements the I2C API. May
 * generate a custom device_state container struct and init_fn
 * wrapper when needed depending on I2C @kconfig{CONFIG_I2C_STATS}.
 *
 * @param node_id The devicetree node identifier.
 *
 * @param init_fn Name of the init function of the driver. Can be `NULL`.
 *
 * @param pm PM device resources reference (NULL if device does not use PM).
 *
 * @param data Pointer to the device's private data.
 *
 * @param config The address to the structure containing the
 * configuration information for this instance of the driver.
 *
 * @param level The initialization level. See SYS_INIT() for
 * details.
 *
 * @param prio Priority within the selected initialization level. See
 * SYS_INIT() for details.
 *
 * @param api Provides an initial pointer to the API function struct
 * used by the driver. Can be NULL.
 */
#define I2C_DEVICE_DT_DEFINE(node_id, init_fn, pm, data, config, level,	\
			     prio, api, ...)				\
	Z_I2C_DEVICE_STATE_DEFINE(Z_DEVICE_DT_DEV_ID(node_id));		\
	Z_I2C_INIT_FN(Z_DEVICE_DT_DEV_ID(node_id), init_fn)		\
	Z_DEVICE_DEFINE(node_id, Z_DEVICE_DT_DEV_ID(node_id),		\
			DEVICE_DT_NAME(node_id),			\
			&UTIL_CAT(Z_DEVICE_DT_DEV_ID(node_id), _init),	\
			pm, data, config, level, prio, api,	\
			&(Z_DEVICE_STATE_NAME(Z_DEVICE_DT_DEV_ID(node_id)).devstate), \
			__VA_ARGS__)

#else /* CONFIG_I2C_STATS */

static inline void i2c_xfer_stats(const struct device *dev, struct i2c_msg *msgs,
				  uint8_t num_msgs)
{
	ARG_UNUSED(dev);
	ARG_UNUSED(msgs);
	ARG_UNUSED(num_msgs);
}

#define I2C_DEVICE_DT_DEFINE(node_id, init_fn, pm, data, config, level,	\
			     prio, api, ...)				\
	DEVICE_DT_DEFINE(node_id, init_fn, pm, data, config, level,	\
			 prio, api, __VA_ARGS__)

#endif /* CONFIG_I2C_STATS */

/**
 * @brief Like I2C_DEVICE_DT_DEFINE() for an instance of a DT_DRV_COMPAT compatible
 *
 * @param inst instance number. This is replaced by
 * <tt>DT_DRV_COMPAT(inst)</tt> in the call to I2C_DEVICE_DT_DEFINE().
 *
 * @param ... other parameters as expected by I2C_DEVICE_DT_DEFINE().
 */
#define I2C_DEVICE_DT_INST_DEFINE(inst, ...)		\
	I2C_DEVICE_DT_DEFINE(DT_DRV_INST(inst), __VA_ARGS__)


/**
 * @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.
 */
__syscall int i2c_configure(const struct device *dev, uint32_t dev_config);

static inline int z_impl_i2c_configure(const struct device *dev,
				       uint32_t dev_config)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

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

/**
 * @brief Get configuration of a host controller.
 *
 * This routine provides a way to get current configuration. It is allowed to
 * call the function before i2c_configure, because some I2C ports can be
 * configured during init process. However, if the I2C port is not configured,
 * i2c_get_config returns an error.
 *
 * i2c_get_config can return cached config or probe hardware, but it has to be
 * up to date with current configuration.
 *
 * @param dev Pointer to the device structure for the driver instance.
 * @param dev_config Pointer to return bit-packed 32-bit value of
 * the I2C controller configuration.
 *
 * @retval 0 If successful.
 * @retval -EIO General input / output error.
 * @retval -ERANGE Configured I2C frequency is invalid.
 * @retval -ENOSYS If get config is not implemented
 */
__syscall int i2c_get_config(const struct device *dev, uint32_t *dev_config);

static inline int z_impl_i2c_get_config(const struct device *dev, uint32_t *dev_config)
{
	const struct i2c_driver_api *api = (const struct i2c_driver_api *)dev->api;

	if (api->get_config == NULL) {
		return -ENOSYS;
	}

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

/**
 * @brief Perform data transfer to another I2C device in controller mode.
 *
 * 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.
 *
 * @note Not all scatter/gather transactions can be supported by all
 * drivers.  As an example, a gather write (multiple consecutive
 * `i2c_msg` buffers all configured for `I2C_MSG_WRITE`) may be packed
 * into a single transaction by some drivers, but others may emit each
 * fragment as a distinct write transaction, which will not produce
 * the same behavior.  See the documentation of `struct i2c_msg` for
 * limitations on support for multi-message bus transactions.
 *
 * @note The last message in the scatter/gather transaction implies a STOP
 * whether or not it is explicitly set. This ensures the bus is in a good
 * state for the next transaction which may be from a different call context.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @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.
 */
__syscall int i2c_transfer(const struct device *dev,
			   struct i2c_msg *msgs, uint8_t num_msgs,
			   uint16_t addr);

static inline int z_impl_i2c_transfer(const struct device *dev,
				      struct i2c_msg *msgs, uint8_t num_msgs,
				      uint16_t addr)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

	if (!num_msgs) {
		return 0;
	}

	if (!IS_ENABLED(CONFIG_I2C_ALLOW_NO_STOP_TRANSACTIONS)) {
		msgs[num_msgs - 1].flags |= I2C_MSG_STOP;
	}

	int res =  api->transfer(dev, msgs, num_msgs, addr);

	i2c_xfer_stats(dev, msgs, num_msgs);

	if (IS_ENABLED(CONFIG_I2C_DUMP_MESSAGES)) {
		i2c_dump_msgs_rw(dev, msgs, num_msgs, addr, true);
	}

	return res;
}

#if defined(CONFIG_I2C_CALLBACK) || defined(__DOXYGEN__)

/**
 * @brief Perform data transfer to another I2C device in controller mode.
 *
 * This routine provides a generic interface to perform data transfer
 * to another I2C device asynchronously with a callback completion.
 *
 * @see i2c_transfer()
 * @funcprops \isr_ok
 *
 * @param dev Pointer to the device structure for an I2C controller
 *            driver configured in controller mode.
 * @param msgs Array of messages to transfer, must live until callback completes.
 * @param num_msgs Number of messages to transfer.
 * @param addr Address of the I2C target device.
 * @param cb Function pointer for completion callback.
 * @param userdata Userdata passed to callback.
 *
 * @retval 0 If successful.
 * @retval -EIO General input / output error.
 * @retval -ENOSYS If transfer async is not implemented
 * @retval -EWOULDBLOCK If the device is temporarily busy doing another transfer
 */
static inline int i2c_transfer_cb(const struct device *dev,
				  struct i2c_msg *msgs,
				  uint8_t num_msgs,
				  uint16_t addr,
				  i2c_callback_t cb,
				  void *userdata)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

	if (api->transfer_cb == NULL) {
		return -ENOSYS;
	}

	if (!num_msgs) {
		cb(dev, 0, userdata);
		return 0;
	}

	if (!IS_ENABLED(CONFIG_I2C_ALLOW_NO_STOP_TRANSACTIONS)) {
		msgs[num_msgs - 1].flags |= I2C_MSG_STOP;
	}

	return api->transfer_cb(dev, msgs, num_msgs, addr, cb, userdata);
}

/**
 * @brief Perform data transfer to another I2C device in master mode asynchronously.
 *
 * This is equivalent to:
 *
 *     i2c_transfer_cb(spec->bus, msgs, num_msgs, spec->addr, cb, userdata);
 *
 * @param spec I2C specification from devicetree.
 * @param msgs Array of messages to transfer.
 * @param num_msgs Number of messages to transfer.
 * @param cb Function pointer for completion callback.
 * @param userdata Userdata passed to callback.
 *
 * @return a value from i2c_transfer_cb()
 */
static inline int i2c_transfer_cb_dt(const struct i2c_dt_spec *spec,
				struct i2c_msg *msgs,
				uint8_t num_msgs,
				i2c_callback_t cb,
				void *userdata)
{
	return i2c_transfer_cb(spec->bus, msgs, num_msgs, spec->addr, cb, userdata);
}

/**
 * @brief Write then read data from an I2C device asynchronously.
 *
 * This supports the common operation "this is what I want", "now give
 * it to me" transaction pair through a combined write-then-read bus
 * transaction but using i2c_transfer_cb. This helper function expects
 * caller to pass a message pointer with 2 and only 2 size.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in master mode.
 * @param msgs Array of messages to transfer.
 * @param num_msgs Number of messages to transfer.
 * @param addr Address of the I2C device
 * @param write_buf Pointer to the data to be written
 * @param num_write Number of bytes to write
 * @param read_buf Pointer to storage for read data
 * @param num_read Number of bytes to read
 * @param cb Function pointer for completion callback.
 * @param userdata Userdata passed to callback.
 *
 * @retval 0 if successful
 * @retval negative on error.
 */
static inline int i2c_write_read_cb(const struct device *dev, struct i2c_msg *msgs,
				 uint8_t num_msgs, uint16_t addr, const void *write_buf,
				 size_t num_write, void *read_buf, size_t num_read,
				 i2c_callback_t cb, void *userdata)
{
	if ((msgs == NULL) || (num_msgs != 2)) {
		return -EINVAL;
	}

	msgs[0].buf = (uint8_t *)write_buf;
	msgs[0].len = num_write;
	msgs[0].flags = I2C_MSG_WRITE;

	msgs[1].buf = (uint8_t *)read_buf;
	msgs[1].len = num_read;
	msgs[1].flags = I2C_MSG_RESTART | I2C_MSG_READ | I2C_MSG_STOP;

	return i2c_transfer_cb(dev, msgs, num_msgs, addr, cb, userdata);
}

/**
 * @brief Write then read data from an I2C device asynchronously.
 *
 * This is equivalent to:
 *
 *     i2c_write_read_cb(spec->bus, msgs, num_msgs,
 *                    spec->addr, write_buf,
 *                    num_write, read_buf, num_read);
 *
 * @param spec I2C specification from devicetree.
 * @param msgs Array of messages to transfer.
 * @param num_msgs Number of messages to transfer.
 * @param write_buf Pointer to the data to be written
 * @param num_write Number of bytes to write
 * @param read_buf Pointer to storage for read data
 * @param num_read Number of bytes to read
 * @param cb Function pointer for completion callback.
 * @param userdata Userdata passed to callback.
 *
 * @return a value from i2c_write_read_cb()
 */
static inline int i2c_write_read_cb_dt(const struct i2c_dt_spec *spec, struct i2c_msg *msgs,
				       uint8_t num_msgs, const void *write_buf, size_t num_write,
				       void *read_buf, size_t num_read, i2c_callback_t cb,
				       void *userdata)
{
	return i2c_write_read_cb(spec->bus, msgs, num_msgs, spec->addr, write_buf, num_write,
				 read_buf, num_read, cb, userdata);
}

#if defined(CONFIG_POLL) || defined(__DOXYGEN__)

/** @cond INTERNAL_HIDDEN */
void z_i2c_transfer_signal_cb(const struct device *dev, int result, void *userdata);
/** @endcond */

/**
 * @brief Perform data transfer to another I2C device in controller mode.
 *
 * This routine provides a generic interface to perform data transfer
 * to another I2C device asynchronously with a k_poll_signal completion.
 *
 * @see i2c_transfer_cb()
 * @funcprops \isr_ok
 *
 * @param dev Pointer to the device structure for an I2C controller
 *            driver configured in controller mode.
 * @param msgs Array of messages to transfer, must live until callback completes.
 * @param num_msgs Number of messages to transfer.
 * @param addr Address of the I2C target device.
 * @param sig Signal to notify of transfer completion.
 *
 * @retval 0 If successful.
 * @retval -EIO General input / output error.
 * @retval -ENOSYS If transfer async is not implemented
 * @retval -EWOULDBLOCK If the device is temporarily busy doing another transfer
 */
static inline int i2c_transfer_signal(const struct device *dev,
				 struct i2c_msg *msgs,
				 uint8_t num_msgs,
				 uint16_t addr,
				 struct k_poll_signal *sig)
{
	const struct i2c_driver_api *api = (const struct i2c_driver_api *)dev->api;

	if (api->transfer_cb == NULL) {
		return -ENOSYS;
	}

	return api->transfer_cb(dev, msgs, num_msgs, addr, z_i2c_transfer_signal_cb, sig);
}

#endif /* CONFIG_POLL */

#endif /* CONFIG_I2C_CALLBACK */


#if defined(CONFIG_I2C_RTIO) || defined(__DOXYGEN__)

/**
 * @brief Fallback submit implementation
 *
 * This implementation will schedule a blocking I2C transaction on the bus via the RTIO work
 * queue. It is only used if the I2C driver did not implement the iodev_submit function.
 *
 * @param dev Pointer to the device structure for an I2C controller driver.
 * @param iodev_sqe Prepared submissions queue entry connected to an iodev
 *                  defined by I2C_DT_IODEV_DEFINE.
 */
void i2c_iodev_submit_fallback(const struct device *dev, struct rtio_iodev_sqe *iodev_sqe);

/**
 * @brief Submit request(s) to an I2C device with RTIO
 *
 * @param iodev_sqe Prepared submissions queue entry connected to an iodev
 *                  defined by I2C_DT_IODEV_DEFINE.
 */
static inline void i2c_iodev_submit(struct rtio_iodev_sqe *iodev_sqe)
{
	const struct i2c_dt_spec *dt_spec = (const struct i2c_dt_spec *)iodev_sqe->sqe.iodev->data;
	const struct device *dev = dt_spec->bus;
	const struct i2c_driver_api *api = (const struct i2c_driver_api *)dev->api;

	if (api->iodev_submit == NULL) {
		rtio_iodev_sqe_err(iodev_sqe, -ENOSYS);
		return;
	}
	api->iodev_submit(dt_spec->bus, iodev_sqe);
}

extern const struct rtio_iodev_api i2c_iodev_api;

/**
 * @brief Define an iodev for a given dt node on the bus
 *
 * These do not need to be shared globally but doing so
 * will save a small amount of memory.
 *
 * @param name Symbolic name of the iodev to define
 * @param node_id Devicetree node identifier
 */
#define I2C_DT_IODEV_DEFINE(name, node_id)					\
	const struct i2c_dt_spec _i2c_dt_spec_##name =				\
		I2C_DT_SPEC_GET(node_id);					\
	RTIO_IODEV_DEFINE(name, &i2c_iodev_api, (void *)&_i2c_dt_spec_##name)

/**
 * @brief Define an iodev for a given i2c device on a bus
 *
 * These do not need to be shared globally but doing so
 * will save a small amount of memory.
 *
 * @param name Symbolic name of the iodev to define
 * @param _bus Node ID for I2C bus
 * @param _addr I2C target address
 */
#define I2C_IODEV_DEFINE(name, _bus, _addr)                                     \
	const struct i2c_dt_spec _i2c_dt_spec_##name = {                        \
		.bus = DEVICE_DT_GET(_bus),                                     \
		.addr = _addr,                                                  \
	};                                                                      \
	RTIO_IODEV_DEFINE(name, &i2c_iodev_api, (void *)&_i2c_dt_spec_##name)

/**
 * @brief Copy the i2c_msgs into a set of RTIO requests
 *
 * @param r RTIO context
 * @param iodev RTIO IODev to target for the submissions
 * @param msgs Array of messages
 * @param num_msgs Number of i2c msgs in array
 *
 * @retval sqe Last submission in the queue added
 * @retval NULL Not enough memory in the context to copy the requests
 */
struct rtio_sqe *i2c_rtio_copy(struct rtio *r,
			       struct rtio_iodev *iodev,
			       const struct i2c_msg *msgs,
			       uint8_t num_msgs);

#endif /* CONFIG_I2C_RTIO */

/**
 * @brief Perform data transfer to another I2C device in controller mode.
 *
 * This is equivalent to:
 *
 *     i2c_transfer(spec->bus, msgs, num_msgs, spec->addr);
 *
 * @param spec I2C specification from devicetree.
 * @param msgs Array of messages to transfer.
 * @param num_msgs Number of messages to transfer.
 *
 * @return a value from i2c_transfer()
 */
static inline int i2c_transfer_dt(const struct i2c_dt_spec *spec,
				  struct i2c_msg *msgs, uint8_t num_msgs)
{
	return i2c_transfer(spec->bus, msgs, num_msgs, spec->addr);
}

/**
 * @brief Recover the I2C bus
 *
 * Attempt to recover the I2C bus.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @retval 0 If successful
 * @retval -EBUSY If bus is not clear after recovery attempt.
 * @retval -EIO General input / output error.
 * @retval -ENOSYS If bus recovery is not implemented
 */
__syscall int i2c_recover_bus(const struct device *dev);

static inline int z_impl_i2c_recover_bus(const struct device *dev)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

	if (api->recover_bus == NULL) {
		return -ENOSYS;
	}

	return api->recover_bus(dev);
}

/**
 * @brief Registers the provided config as Target device of a controller.
 *
 * Enable I2C target mode for the 'dev' I2C bus driver using the provided
 * 'config' struct containing the functions and parameters to send bus
 * events. The I2C target will be registered at the address provided as 'address'
 * struct member. Addressing mode - 7 or 10 bit - depends on the 'flags'
 * struct member. Any I2C bus events related to the target mode will be passed
 * onto I2C target device driver via a set of callback functions provided in
 * the 'callbacks' struct member.
 *
 * Most of the existing hardware allows simultaneous support for controller
 * and target mode. This is however not guaranteed.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in target mode.
 * @param cfg Config struct with functions and parameters used by the I2C driver
 * to send bus events
 *
 * @retval 0 Is successful
 * @retval -EINVAL If parameters are invalid
 * @retval -EIO General input / output error.
 * @retval -ENOSYS If target mode is not implemented
 */
static inline int i2c_target_register(const struct device *dev,
				     struct i2c_target_config *cfg)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

	if (api->target_register == NULL) {
		return -ENOSYS;
	}

	return api->target_register(dev, cfg);
}

/**
 * @brief Unregisters the provided config as Target device
 *
 * This routine disables I2C target mode for the 'dev' I2C bus driver using
 * the provided 'config' struct containing the functions and parameters
 * to send bus events.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in target mode.
 * @param cfg Config struct with functions and parameters used by the I2C driver
 * to send bus events
 *
 * @retval 0 Is successful
 * @retval -EINVAL If parameters are invalid
 * @retval -ENOSYS If target mode is not implemented
 */
static inline int i2c_target_unregister(const struct device *dev,
				       struct i2c_target_config *cfg)
{
	const struct i2c_driver_api *api =
		(const struct i2c_driver_api *)dev->api;

	if (api->target_unregister == NULL) {
		return -ENOSYS;
	}

	return api->target_unregister(dev, cfg);
}

/**
 * @brief Instructs the I2C Target device to register itself to the I2C Controller
 *
 * This routine instructs the I2C Target device to register itself to the I2C
 * Controller via its parent controller's i2c_target_register() API.
 *
 * @param dev Pointer to the device structure for the I2C target
 * device (not itself an I2C controller).
 *
 * @retval 0 Is successful
 * @retval -EINVAL If parameters are invalid
 * @retval -EIO General input / output error.
 */
__syscall int i2c_target_driver_register(const struct device *dev);

static inline int z_impl_i2c_target_driver_register(const struct device *dev)
{
	const struct i2c_target_driver_api *api =
		(const struct i2c_target_driver_api *)dev->api;

	return api->driver_register(dev);
}

/**
 * @brief Instructs the I2C Target device to unregister itself from the I2C
 * Controller
 *
 * This routine instructs the I2C Target device to unregister itself from the I2C
 * Controller via its parent controller's i2c_target_register() API.
 *
 * @param dev Pointer to the device structure for the I2C target
 * device (not itself an I2C controller).
 *
 * @retval 0 Is successful
 * @retval -EINVAL If parameters are invalid
 */
__syscall int i2c_target_driver_unregister(const struct device *dev);

static inline int z_impl_i2c_target_driver_unregister(const struct device *dev)
{
	const struct i2c_target_driver_api *api =
		(const struct i2c_target_driver_api *)dev->api;

	return api->driver_unregister(dev);
}

/*
 * Derived i2c APIs -- all implemented in terms of i2c_transfer()
 */

/**
 * @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 an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev, const uint8_t *buf,
			    uint32_t num_bytes, uint16_t addr)
{
	struct i2c_msg msg;

	msg.buf = (uint8_t *)buf;
	msg.len = num_bytes;
	msg.flags = I2C_MSG_WRITE | I2C_MSG_STOP;

	return i2c_transfer(dev, &msg, 1, addr);
}

/**
 * @brief Write a set amount of data to an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_write(spec->bus, buf, num_bytes, spec->addr);
 *
 * @param spec I2C specification from devicetree.
 * @param buf Memory pool from which the data is transferred.
 * @param num_bytes Number of bytes to write.
 *
 * @return a value from i2c_write()
 */
static inline int i2c_write_dt(const struct i2c_dt_spec *spec,
			       const uint8_t *buf, uint32_t num_bytes)
{
	return i2c_write(spec->bus, buf, num_bytes, spec->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 an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev, uint8_t *buf,
			   uint32_t num_bytes, uint16_t addr)
{
	struct i2c_msg msg;

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

	return i2c_transfer(dev, &msg, 1, addr);
}

/**
 * @brief Read a set amount of data from an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_read(spec->bus, buf, num_bytes, spec->addr);
 *
 * @param spec I2C specification from devicetree.
 * @param buf Memory pool that stores the retrieved data.
 * @param num_bytes Number of bytes to read.
 *
 * @return a value from i2c_read()
 */
static inline int i2c_read_dt(const struct i2c_dt_spec *spec,
			      uint8_t *buf, uint32_t num_bytes)
{
	return i2c_read(spec->bus, buf, num_bytes, spec->addr);
}

/**
 * @brief Write then read data from an I2C device.
 *
 * This supports the common operation "this is what I want", "now give
 * it to me" transaction pair through a combined write-then-read bus
 * transaction.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @param addr Address of the I2C device
 * @param write_buf Pointer to the data to be written
 * @param num_write Number of bytes to write
 * @param read_buf Pointer to storage for read data
 * @param num_read Number of bytes to read
 *
 * @retval 0 if successful
 * @retval negative on error.
 */
static inline int i2c_write_read(const struct device *dev, uint16_t addr,
				 const void *write_buf, size_t num_write,
				 void *read_buf, size_t num_read)
{
	struct i2c_msg msg[2];

	msg[0].buf = (uint8_t *)write_buf;
	msg[0].len = num_write;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = (uint8_t *)read_buf;
	msg[1].len = num_read;
	msg[1].flags = I2C_MSG_RESTART | I2C_MSG_READ | I2C_MSG_STOP;

	return i2c_transfer(dev, msg, 2, addr);
}

/**
 * @brief Write then read data from an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_write_read(spec->bus, spec->addr,
 *                    write_buf, num_write,
 *                    read_buf, num_read);
 *
 * @param spec I2C specification from devicetree.
 * @param write_buf Pointer to the data to be written
 * @param num_write Number of bytes to write
 * @param read_buf Pointer to storage for read data
 * @param num_read Number of bytes to read
 *
 * @return a value from i2c_write_read()
 */
static inline int i2c_write_read_dt(const struct i2c_dt_spec *spec,
				    const void *write_buf, size_t num_write,
				    void *read_buf, size_t num_read)
{
	return i2c_write_read(spec->bus, spec->addr,
			      write_buf, num_write,
			      read_buf, num_read);
}

/**
 * @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.
 *
 * Instances of this may be replaced by i2c_write_read().
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev,
				 uint16_t dev_addr,
				 uint8_t start_addr,
				 uint8_t *buf,
				 uint32_t num_bytes)
{
	return i2c_write_read(dev, dev_addr,
			      &start_addr, sizeof(start_addr),
			      buf, num_bytes);
}

/**
 * @brief Read multiple bytes from an internal address of an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_burst_read(spec->bus, spec->addr, start_addr, buf, num_bytes);
 *
 * @param spec I2C specification from devicetree.
 * @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 to read.
 *
 * @return a value from i2c_burst_read()
 */
static inline int i2c_burst_read_dt(const struct i2c_dt_spec *spec,
				    uint8_t start_addr,
				    uint8_t *buf,
				    uint32_t num_bytes)
{
	return i2c_burst_read(spec->bus, spec->addr,
			      start_addr, buf, num_bytes);
}

/**
 * @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.
 *
 * @warning The combined write synthesized by this API may not be
 * supported on all I2C devices.  Uses of this API may be made more
 * portable by replacing them with calls to i2c_write() passing a
 * buffer containing the combined address and data.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev,
				  uint16_t dev_addr,
				  uint8_t start_addr,
				  const uint8_t *buf,
				  uint32_t num_bytes)
{
	struct i2c_msg msg[2];

	msg[0].buf = &start_addr;
	msg[0].len = 1U;
	msg[0].flags = I2C_MSG_WRITE;

	msg[1].buf = (uint8_t *)buf;
	msg[1].len = num_bytes;
	msg[1].flags = I2C_MSG_WRITE | I2C_MSG_STOP;

	return i2c_transfer(dev, msg, 2, dev_addr);
}

/**
 * @brief Write multiple bytes to an internal address of an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_burst_write(spec->bus, spec->addr, start_addr, buf, num_bytes);
 *
 * @param spec I2C specification from devicetree.
 * @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.
 *
 * @return a value from i2c_burst_write()
 */
static inline int i2c_burst_write_dt(const struct i2c_dt_spec *spec,
				     uint8_t start_addr,
				     const uint8_t *buf,
				     uint32_t num_bytes)
{
	return i2c_burst_write(spec->bus, spec->addr,
			       start_addr, buf, num_bytes);
}

/**
 * @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 an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev,
				    uint16_t dev_addr,
				    uint8_t reg_addr, uint8_t *value)
{
	return i2c_write_read(dev, dev_addr,
			      &reg_addr, sizeof(reg_addr),
			      value, sizeof(*value));
}

/**
 * @brief Read internal register of an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_reg_read_byte(spec->bus, spec->addr, reg_addr, value);
 *
 * @param spec I2C specification from devicetree.
 * @param reg_addr Address of the internal register being read.
 * @param value Memory pool that stores the retrieved register value.
 *
 * @return a value from i2c_reg_read_byte()
 */
static inline int i2c_reg_read_byte_dt(const struct i2c_dt_spec *spec,
				       uint8_t reg_addr, uint8_t *value)
{
	return i2c_reg_read_byte(spec->bus, spec->addr, reg_addr, value);
}

/**
 * @brief Write internal register of an I2C device.
 *
 * This routine writes a value to an 8-bit internal register of an I2C
 * device synchronously.
 *
 * @note This function internally combines the register and value into
 * a single bus transaction.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @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(const 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 Write internal register of an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_reg_write_byte(spec->bus, spec->addr, reg_addr, value);
 *
 * @param spec I2C specification from devicetree.
 * @param reg_addr Address of the internal register being written.
 * @param value Value to be written to internal register.
 *
 * @return a value from i2c_reg_write_byte()
 */
static inline int i2c_reg_write_byte_dt(const struct i2c_dt_spec *spec,
					uint8_t reg_addr, uint8_t value)
{
	return i2c_reg_write_byte(spec->bus, spec->addr, reg_addr, value);
}

/**
 * @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.
 *
 * @note If the calculated new register value matches the value that
 * was read this function will not generate a write operation.
 *
 * @param dev Pointer to the device structure for an I2C controller
 * driver configured in controller mode.
 * @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(const struct device *dev,
				      uint8_t dev_addr,
				      uint8_t reg_addr, uint8_t mask,
				      uint8_t value)
{
	uint8_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 Update internal register of an I2C device.
 *
 * This is equivalent to:
 *
 *     i2c_reg_update_byte(spec->bus, spec->addr, reg_addr, mask, value);
 *
 * @param spec I2C specification from devicetree.
 * @param reg_addr Address of the internal register being updated.
 * @param mask Bitmask for updating internal register.
 * @param value Value for updating internal register.
 *
 * @return a value from i2c_reg_update_byte()
 */
static inline int i2c_reg_update_byte_dt(const struct i2c_dt_spec *spec,
					 uint8_t reg_addr, uint8_t mask,
					 uint8_t value)
{
	return i2c_reg_update_byte(spec->bus, spec->addr,
				   reg_addr, mask, value);
}

#ifdef __cplusplus
}
#endif

/**
 * @}
 */

#include <zephyr/syscalls/i2c.h>

#endif /* ZEPHYR_INCLUDE_DRIVERS_I2C_H_ */