Skip to content

Busio: Added DMA functions for I2C, SPI, and UART #10854

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
kamocat wants to merge 4 commits into
base: main
Choose a base branch
from
Open

Busio: Added DMA functions for I2C, SPI, and UART #10854

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
1e574aa
Busio: Added DMA functions for I2C, SPI, and UART
kamocat Feb 24, 2026
d907b70
Busio: Refactored asynchronous methods
kamocat Feb 27, 2026
71c7833
Busio: Updated documentation to reflect API changes
kamocat Feb 27, 2026
d59277a
Busio: Added test suite for nonblocking API
kamocat Feb 27, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
396 changes: 396 additions & 0 deletions ports/raspberrypi/common-hal/busio/dma.c
View file
Open in desktop

Large diffs are not rendered by default.

24 changes: 24 additions & 0 deletions ports/raspberrypi/common-hal/busio/dma.h
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
// This file is part of the CircuitPython project: https://circuitpython.org
//
// SPDX-FileCopyrightText: Copyright (c) 2026
//
// SPDX-License-Identifier: MIT

#pragma once

#include "common-hal/busio/I2C.h"
#include "common-hal/busio/SPI.h"
#include "common-hal/busio/UART.h"

uint common_hal_busio_dma_i2c_read(busio_i2c_obj_t *i2c, uint8_t address, uint8_t *data, size_t len, bool nostop);
uint common_hal_busio_dma_i2c_write(busio_i2c_obj_t *i2c, uint8_t address, const uint8_t *data, size_t len, bool nostop);
bool common_hal_busio_dma_i2c_is_busy(uint dma_channel);

uint common_hal_busio_dma_spi_write(busio_spi_obj_t *spi, const uint8_t *data, size_t len);
uint common_hal_busio_dma_spi_read(busio_spi_obj_t *spi, uint8_t write_value, uint8_t *data, size_t len);
uint common_hal_busio_dma_spi_transfer(busio_spi_obj_t *spi, const uint8_t *out_data, uint8_t *in_data, size_t len);
bool common_hal_busio_dma_spi_is_busy(uint dma_channel);

uint common_hal_busio_dma_uart_read(busio_uart_obj_t *uart, uint8_t *data, size_t len);
uint common_hal_busio_dma_uart_write(busio_uart_obj_t *uart, const uint8_t *data, size_t len);
bool common_hal_busio_dma_uart_is_busy(uint dma_channel);
1 change: 1 addition & 0 deletions ports/raspberrypi/mpconfigport.mk
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ CIRCUITPY_AUDIOIO = 0
CIRCUITPY_AUDIOBUSIO ?= 1
CIRCUITPY_AUDIOCORE ?= 1
CIRCUITPY_AUDIOPWMIO ?= 1
CIRCUITPY_BUSIO_DMA ?= 1

CIRCUITPY_AUDIOMIXER ?= 1

Expand Down
1 change: 1 addition & 0 deletions py/circuitpy_defns.mk
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -501,6 +501,7 @@ SRC_COMMON_HAL_ALL = \
audiopwmio/PWMAudioOut.c \
audiopwmio/__init__.c \
board/__init__.c \
busio/dma.c \
busio/I2C.c \
busio/SPI.c \
busio/UART.c \
Expand Down
3 changes: 3 additions & 0 deletions py/circuitpy_mpconfig.mk
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -220,6 +220,9 @@ CFLAGS += -DCIRCUITPY_BUSIO_SPI=$(CIRCUITPY_BUSIO_SPI)
CIRCUITPY_BUSIO_UART ?= $(CIRCUITPY_BUSIO)
CFLAGS += -DCIRCUITPY_BUSIO_UART=$(CIRCUITPY_BUSIO_UART)

CIRCUITPY_BUSIO_DMA ?= 0
CFLAGS += -DCIRCUITPY_BUSIO_DMA=$(CIRCUITPY_BUSIO_DMA)

CIRCUITPY_CAMERA ?= 0
CFLAGS += -DCIRCUITPY_CAMERA=$(CIRCUITPY_CAMERA)

Expand Down
119 changes: 112 additions & 7 deletions shared-bindings/busio/I2C.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@

#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/busio/I2C.h"
#include "shared-bindings/busio/dma.h"
#include "shared-bindings/util.h"

#include "shared/runtime/buffer_helper.h"
Expand Down Expand Up @@ -92,6 +93,14 @@ static void check_for_deinit(busio_i2c_obj_t *self) {
}
}

static busio_i2c_obj_t *native_i2c(mp_obj_t i2c_obj) {
mp_obj_t native_i2c = mp_obj_cast_to_native_base(i2c_obj, MP_OBJ_FROM_PTR(&busio_i2c_type));
if (native_i2c == MP_OBJ_NULL) {
mp_raise_ValueError_varg(MP_ERROR_TEXT("Must be a %q subclass."), MP_QSTR_I2C);
}
return MP_OBJ_TO_PTR(native_i2c);
}

//| def __enter__(self) -> I2C:
//| """No-op used in Context Managers."""
//| ...
Expand All @@ -112,6 +121,97 @@ static void check_lock(busio_i2c_obj_t *self) {
}
}

#if CIRCUITPY_BUSIO_DMA
//| def dma_readinto(self, address: int, buffer: WriteableBuffer, *, end: bool = False) -> int:
//| """Start a DMA I2C read into ``buffer`` and return the DMA channel.
//|
//| The I2C object must be locked before calling.
//|
//| :param int address: 7-bit I2C target address
//| :param ~circuitpython_typing.WriteableBuffer buffer: destination buffer
//| :param bool end: If ``True``, send a STOP condition at the end of the transfer
//| :return: DMA channel used by this transfer
//| :rtype: int
//| """
//|
static mp_obj_t busio_i2c_dma_read(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_end };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
};

busio_i2c_obj_t *self = native_i2c(pos_args[0]);
check_for_deinit(self);
check_lock(self);

mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

mp_int_t address = args[ARG_address].u_int;
mp_arg_validate_int_range(address, 0, 0x7f, MP_QSTR_address);

mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_WRITE);

uint dma_channel = common_hal_busio_dma_i2c_read(self, address, bufinfo.buf, bufinfo.len, args[ARG_end].u_bool);
return mp_obj_new_int_from_uint(dma_channel);
}
MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_dma_read_obj, 1, busio_i2c_dma_read);

//| def dma_write(self, address: int, buffer: ReadableBuffer, *, end: bool = False) -> int:
//| """Start a DMA I2C write from ``buffer`` and return the DMA channel.
//|
//| The I2C object must be locked before calling.
//|
//| :param int address: 7-bit I2C target address
//| :param ~circuitpython_typing.ReadableBuffer buffer: source buffer
//| :param bool end: If ``True``, send a STOP condition at the end of the transfer
//| :return: DMA channel used by this transfer
//| :rtype: int
//| """
//|
static mp_obj_t busio_i2c_dma_write(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_end };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
};

busio_i2c_obj_t *self = native_i2c(pos_args[0]);
check_for_deinit(self);
check_lock(self);

mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

mp_int_t address = args[ARG_address].u_int;
mp_arg_validate_int_range(address, 0, 0x7f, MP_QSTR_address);

mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_READ);

uint dma_channel = common_hal_busio_dma_i2c_write(self, address, bufinfo.buf, bufinfo.len, args[ARG_end].u_bool);
return mp_obj_new_int_from_uint(dma_channel);
}
MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_dma_write_obj, 1, busio_i2c_dma_write);

//| def dma_is_busy(self, dma_channel: int) -> bool:
//| """Return ``True`` while the I2C DMA channel is active.
//|
//| :param int dma_channel: DMA channel returned by `dma_readinto` or `dma_write`
//| """
//|
static mp_obj_t busio_i2c_dma_is_busy(mp_obj_t self_in, mp_obj_t dma_channel_obj) {
busio_i2c_obj_t *self = native_i2c(self_in);
check_for_deinit(self);
return mp_obj_new_bool(common_hal_busio_dma_i2c_is_busy(mp_obj_get_int(dma_channel_obj)));
}
MP_DEFINE_CONST_FUN_OBJ_2(busio_i2c_dma_is_busy_obj, busio_i2c_dma_is_busy);
#endif

//| def probe(self, address: int) -> List[int]:
//| """Check if a device at the specified address responds.
//|
Expand All @@ -121,7 +221,7 @@ static void check_lock(busio_i2c_obj_t *self) {
//| ...
//|
static mp_obj_t busio_i2c_probe(mp_obj_t self_in, mp_obj_t address_obj) {
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
busio_i2c_obj_t *self = native_i2c(self_in);
check_for_deinit(self);
check_lock(self);

Expand All @@ -139,7 +239,7 @@ MP_DEFINE_CONST_FUN_OBJ_2(busio_i2c_probe_obj, busio_i2c_probe);
//| ...
//|
static mp_obj_t busio_i2c_scan(mp_obj_t self_in) {
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
busio_i2c_obj_t *self = native_i2c(self_in);
check_for_deinit(self);
check_lock(self);
mp_obj_t list = mp_obj_new_list(0, NULL);
Expand All @@ -162,7 +262,7 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_scan_obj, busio_i2c_scan);
//| ...
//|
static mp_obj_t busio_i2c_obj_try_lock(mp_obj_t self_in) {
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
busio_i2c_obj_t *self = native_i2c(self_in);
check_for_deinit(self);
return mp_obj_new_bool(common_hal_busio_i2c_try_lock(self));
}
Expand All @@ -173,7 +273,7 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_try_lock_obj, busio_i2c_obj_try_lock);
//| ...
//|
static mp_obj_t busio_i2c_obj_unlock(mp_obj_t self_in) {
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
busio_i2c_obj_t *self = native_i2c(self_in);
check_for_deinit(self);
common_hal_busio_i2c_unlock(self);
return mp_const_none;
Expand Down Expand Up @@ -206,7 +306,7 @@ static mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args,
{ MP_QSTR_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
busio_i2c_obj_t *self = native_i2c(pos_args[0]);
check_for_deinit(self);
check_lock(self);

Expand Down Expand Up @@ -268,7 +368,7 @@ static mp_obj_t busio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_ma
{ MP_QSTR_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
busio_i2c_obj_t *self = native_i2c(pos_args[0]);
check_for_deinit(self);
check_lock(self);
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
Expand Down Expand Up @@ -348,7 +448,7 @@ static mp_obj_t busio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *p
{ MP_QSTR_in_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_in_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
busio_i2c_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
busio_i2c_obj_t *self = native_i2c(pos_args[0]);
check_for_deinit(self);
check_lock(self);
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
Expand Down Expand Up @@ -403,6 +503,11 @@ static const mp_rom_map_elem_t busio_i2c_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_readfrom_into), MP_ROM_PTR(&busio_i2c_readfrom_into_obj) },
{ MP_ROM_QSTR(MP_QSTR_writeto), MP_ROM_PTR(&busio_i2c_writeto_obj) },
{ MP_ROM_QSTR(MP_QSTR_writeto_then_readfrom), MP_ROM_PTR(&busio_i2c_writeto_then_readfrom_obj) },
#if CIRCUITPY_BUSIO_DMA
{ MP_ROM_QSTR(MP_QSTR_dma_readinto), MP_ROM_PTR(&busio_i2c_dma_read_obj) },
{ MP_ROM_QSTR(MP_QSTR_dma_write), MP_ROM_PTR(&busio_i2c_dma_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_dma_is_busy), MP_ROM_PTR(&busio_i2c_dma_is_busy_obj) },
#endif
#endif // CIRCUITPY_BUSIO_I2C
};

Expand Down
Loading
Loading