CFBD_I2COperations¶

Module: I2C Backend Implementation

Function table that a backend must implement to drive an I2C bus. More...

#include <iic.h>

Public Attributes¶

	Name
int()(CFBD_I2CHandle handle)	init Initialize the I2C hardware/peripheral.
int()(CFBD_I2CHandle handle)	deinit Deinitialize the I2C hardware/peripheral.
int()(CFBD_I2CHandle bus, CFBD_I2C_Message *msgs, int num, uint32_t timeout_ms)	transfer Perform a sequence of I2C messages.
int()(CFBD_I2CHandle bus, uint16_t addr, uint32_t trials, uint32_t timeout_ms)	is_device_ready Check whether a device is ready (acknowledges) within trials.
int()(CFBD_I2CHandle bus)	recover_bus Attempt to recover the I2C bus (clock recovery, toggling lines).
int()(CFBD_I2CHandle bus)	get_error Retrieve the last backend-specific error code.
int()(CFBD_I2CHandle bus, const uint8_t *buf, size_t len)	tx_dma_start Initiate DMA transmission (optional).
int()(CFBD_I2CHandle bus, uint8_t *buf, size_t len)	rx_dma_start Initiate DMA reception (optional).

Detailed Description¶

struct CFBD_I2COperations;

Function table that a backend must implement to drive an I2C bus.

Backends populate this table with pointers to concrete functions that implement initialization, transfers and optional DMA operations. This design enables pluggable I2C backends (STM32, ESP32, etc.) while maintaining a unified public interface.

Public Attributes Documentation¶

variable init¶

int(*)(CFBD_I2CHandle *handle) init;

Initialize the I2C hardware/peripheral.

Return: I2C_OK on success, or negative error code on failure

Called once during system startup to configure clock, pins, and I2C peripheral registers.

variable deinit¶

int(*)(CFBD_I2CHandle *handle) deinit;

Deinitialize the I2C hardware/peripheral.

Return: I2C_OK on success, or negative error code on failure

Clean shutdown: disables interrupts, releases DMA, powers down hardware.

variable transfer¶

int(*)(CFBD_I2CHandle *bus, CFBD_I2C_Message *msgs, int num, uint32_t timeout_ms) transfer;

Perform a sequence of I2C messages.

Parameters:

bus I2C bus handle
msgs Array of messages to transfer
num Number of messages
timeout_ms Operation timeout in milliseconds

Return: I2C_OK on success, or negative error code

Core transfer function. Must support multiple messages in a single transaction (write-read patterns, repeated START, etc.).

variable is_device_ready¶

int(*)(CFBD_I2CHandle *bus, uint16_t addr, uint32_t trials, uint32_t timeout_ms) is_device_ready;

Check whether a device is ready (acknowledges) within trials.

Parameters:

bus I2C bus handle
addr Device address (7-bit)
trials Number of probe attempts
timeout_ms Per-trial timeout

Return: I2C_OK if device acknowledged, negative error otherwise

Probes device presence by attempting multiple transactions. Useful for detecting device hotplug, power-on sequences, etc.

variable recover_bus¶

int(*)(CFBD_I2CHandle *bus) recover_bus;

Attempt to recover the I2C bus (clock recovery, toggling lines).

Return: I2C_OK if recovered, negative error if recovery failed

Handles stuck bus scenarios by toggling SCL, sending dummy clocks, or performing platform-specific recovery procedures.

variable get_error¶

int(*)(CFBD_I2CHandle *bus) get_error;

Retrieve the last backend-specific error code.

Return: Backend-specific error code

Returns additional error details beyond the standard error codes, such as hardware-specific status registers or state flags.

variable tx_dma_start¶

int(*)(CFBD_I2CHandle *bus, const uint8_t *buf, size_t len) tx_dma_start;

Initiate DMA transmission (optional).

Return: I2C_OK if DMA started, error code otherwise

Enables efficient bulk data transmission via DMA. Can return I2C_ERR_INVAL if DMA not supported.

variable rx_dma_start¶

int(*)(CFBD_I2CHandle *bus, uint8_t *buf, size_t len) rx_dma_start;

Initiate DMA reception (optional).

Return: I2C_OK if DMA started, error code otherwise

Enables efficient bulk data reception via DMA.

Updated on 2026-02-03 at 13:21:55 +0000