ra8_io_i2c_bus_riic.c File Reference

RIIC backend for the ra8_io I2C-bus facade – thin shim over ra8_i2c. More...

#include "ra8_io_i2c_bus_riic.h"
#include <stdint.h>
#include "ra8_attributes.h"
#include "ra8_check.h"
#include "ra8_err.h"
#include "ra8_i2c.h"
#include "ra8_i2c_regs.h"
#include "ra8_io_i2c_bus.h"
#include "ra8_io_i2c_bus_internal.h"

Include dependency graph for ra8_io_i2c_bus_riic.c:

Go to the source code of this file.

Functions
static ra8_err_t	internal_riic_write (void *ctx, uint8_t addr, const uint8_t *data, uint32_t len, bool send_stop)
	RIIC backend: controller write.
static ra8_err_t	internal_riic_read (void *ctx, uint8_t addr, uint8_t *data, uint32_t len)
	RIIC backend: controller read.
static ra8_err_t	internal_riic_transfer (void *ctx, uint8_t addr, const uint8_t *wr, uint32_t wr_len, uint8_t *rd, uint32_t rd_len)
	RIIC backend: write-then-RESTART-then-read.
ra8_err_t	ra8_io_i2c_bus_bind_riic (ra8_io_i2c_bus_t *bus, uint8_t channel)
	Bind bus to RIIC channel channel.

Variables
static const char *const	s_tag = "ra8_io_i2c_bus_riic"
	Module log tag.
static const ra8_io_i2c_bus_iface_t	s_riic_iface
	RIIC backend vtable – every row forwards to ra8_i2c_*.

Detailed Description

RIIC backend for the ra8_io I2C-bus facade – thin shim over ra8_i2c.

Tag

[Ring 4 / PAL] {World: NS}

Implements ra8_io_i2c_bus_iface by forwarding to the classic RIIC polling driver (ra8_i2c.h), unmodified. The bound channel index travels in the handle context ((void*)(uintptr_t)channel), so the backend keeps no static state and multiple bound buses coexist. Argument validation (channel range, NULL buffers, zero lengths) stays with the wrapped driver, which also carries every HUM citation – no raw MMIO is touched here.

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Definition in file ra8_io_i2c_bus_riic.c.

Function Documentation

internal_riic_read()

ra8_err_t internal_riic_read ( void * ctx, uint8_t addr, uint8_t * data, uint32_t len )

static

RIIC backend: controller read.

Decodes the channel from the handle context and forwards to ra8_i2c_read, which always ends the transaction with STOP.

Parameters

[in]	ctx	Bound channel index, encoded as (void*)(uintptr_t).
[in]	addr	7-bit peripheral address.
[out]	data	Destination buffer.
[in]	len	Byte count.

Returns

ra8_err_t Error code.

Return values

k_ra8_ok	Bytes received.
k_ra8_err_null_ptr	data NULL or bad channel.
k_ra8_err_invalid_arg	len is zero.
k_ra8_err_nack	Peripheral NACKed the address byte.

Precondition

The channel was initialised via ra8_i2c_init.

ctx carries a channel index bound by ra8_io_i2c_bus_bind_riic.

Postcondition

On success data holds the received bytes.

STOP was issued and the bus released.

Note

Not thread-safe with respect to the same channel.

Since

0.1.0

Definition at line 101 of file ra8_io_i2c_bus_riic.c.

References ra8_i2c_read().

internal_riic_transfer()

ra8_err_t internal_riic_transfer ( void * ctx, uint8_t addr, const uint8_t * wr, uint32_t wr_len, uint8_t * rd, uint32_t rd_len )

static

RIIC backend: write-then-RESTART-then-read.

Decodes the channel from the handle context and forwards to ra8_i2c_transfer, which owns the repeated-START framing.

Parameters

[in]	ctx	Bound channel index, encoded as (void*)(uintptr_t).
[in]	addr	7-bit peripheral address.
[in]	wr	Bytes to send first.
[in]	wr_len	Number of bytes to send.
[out]	rd	Destination buffer.
[in]	rd_len	Number of bytes to read.

Returns

ra8_err_t Error code.

Return values

k_ra8_ok	Both phases completed; STOP issued.
k_ra8_err_null_ptr	A required buffer was NULL or bad channel.
k_ra8_err_invalid_arg	Both lengths zero.
k_ra8_err_nack	Peripheral NACKed.

Precondition

The channel was initialised via ra8_i2c_init.

ctx carries a channel index bound by ra8_io_i2c_bus_bind_riic.

Postcondition

On success both phases completed and STOP was issued.

The bus is released regardless of outcome.

Note

Not thread-safe with respect to the same channel.

Since

0.1.0

Definition at line 136 of file ra8_io_i2c_bus_riic.c.

References ra8_i2c_transfer(), and RA8_INTERNAL.

internal_riic_write()

ra8_err_t internal_riic_write ( void * ctx, uint8_t addr, const uint8_t * data, uint32_t len, bool send_stop )

static

RIIC backend: controller write.

Decodes the channel from the handle context and forwards to ra8_i2c_write, whose send_stop flag matches the facade contract directly.

Parameters

[in]	ctx	Bound channel index, encoded as (void*)(uintptr_t).
[in]	addr	7-bit peripheral address.
[in]	data	Bytes to send.
[in]	len	Byte count.
[in]	send_stop	true = STOP after payload; false = hold the bus.

Returns

ra8_err_t Error code.

Return values

k_ra8_ok	Payload transmitted.
k_ra8_err_null_ptr	data NULL with len > 0 or bad channel.
k_ra8_err_nack	Peripheral NACKed.
k_ra8_err_hw_timeout	TDRE / TEND poll timed out.

Precondition

The channel was initialised via ra8_i2c_init.

ctx carries a channel index bound by ra8_io_i2c_bus_bind_riic.

Postcondition

On success the payload was transmitted per send_stop.

On failure the bus is released where the driver allows.

Note

Not thread-safe with respect to the same channel.

Since

0.1.0

Definition at line 67 of file ra8_io_i2c_bus_riic.c.

References ra8_i2c_write().

ra8_io_i2c_bus_bind_riic()

ra8_err_t ra8_io_i2c_bus_bind_riic ( ra8_io_i2c_bus_t * bus, uint8_t channel )

nodiscard

Bind bus to RIIC channel channel.

Installs the RIIC trampoline vtable and records the channel in the handle context. No hardware is touched: initialise the channel with ra8_i2c_init(channel, ...) (before or after binding) and route the SCL/SDA pins yourself.

Parameters

[in,out]	bus	Caller-owned handle to bind (non-NULL).
[in]	channel	RIIC channel index (0, 1 or 2).

Returns

ra8_err_t Error code.

Return values

k_ra8_ok	bus now dispatches to ra8_i2c_*.
k_ra8_err_null_ptr	bus was NULL.
k_ra8_err_invalid_arg	channel is out of range.

Precondition

bus points to writable storage.

channel < 3 (the RA8D2 has IIC0..IIC2).

Postcondition

On success bus->iface is non-NULL and every ra8_io_i2c_bus_* call forwards to RIIC channel channel.

On failure bus is left unmodified.

Note

Thread-safe (writes only the caller's handle).

See also

ra8_io_i2c_bus_bind_i3c_compat The I3C I2C-compatibility twin.

Since

0.1.0

Definition at line 153 of file ra8_io_i2c_bus_riic.c.

References ra8_io_i2c_bus_t::ctx, ra8_io_i2c_bus_t::iface, k_ra8_err_invalid_arg, k_ra8_i2c_channel_count, k_ra8_ok, RA8_CHECK_NULL_PTR, s_riic_iface, and s_tag.

Variable Documentation

s_riic_iface

const ra8_io_i2c_bus_iface_t s_riic_iface

static

Initial value:

                                                 = {
  .write    = internal_riic_write,
  .read     = internal_riic_read,
  .transfer = internal_riic_transfer,
}

RIIC backend vtable – every row forwards to ra8_i2c_*.

Definition at line 147 of file ra8_io_i2c_bus_riic.c.

Referenced by ra8_io_i2c_bus_bind_riic().

s_tag

const char* const s_tag = "ra8_io_i2c_bus_riic"

static

Module log tag.

Definition at line 34 of file ra8_io_i2c_bus_riic.c.