From 1acafbf675c4b187908d51005bb8cba566f4afcc Mon Sep 17 00:00:00 2001
From: Dan Halbert <halbert@halwitz.org>
Date: Thu, 7 Oct 2021 16:36:06 -0400
Subject: [PATCH 1/3] Fix n_args_min on many MP_DEFINE_CONST_FUN_OBJ_KW()

---
 locale/circuitpython.pot                      |  2 ++
 shared-bindings/_bleio/Adapter.c              |  4 +--
 shared-bindings/_bleio/Characteristic.c       |  2 +-
 shared-bindings/_bleio/Descriptor.c           |  2 +-
 shared-bindings/_bleio/ScanEntry.c            |  2 +-
 shared-bindings/_bleio/UUID.c                 |  2 +-
 .../adafruit_bus_device/I2CDevice.c           | 28 ++++++++--------
 shared-bindings/bitbangio/I2C.c               |  8 ++---
 shared-bindings/bitbangio/SPI.c               |  8 ++---
 shared-bindings/bitops/__init__.c             |  2 +-
 shared-bindings/busio/I2C.c                   |  4 +--
 shared-bindings/busio/SPI.c                   | 12 +++----
 shared-bindings/camera/Camera.c               |  2 +-
 shared-bindings/displayio/Bitmap.c            |  3 +-
 shared-bindings/displayio/EPaperDisplay.c     |  2 +-
 shared-bindings/displayio/FourWire.c          |  2 +-
 shared-bindings/msgpack/__init__.c            |  4 +--
 shared-bindings/qrio/QRDecoder.c              |  2 +-
 shared-bindings/socketpool/SocketPool.c       | 26 +++++++--------
 shared-bindings/ssl/SSLContext.c              |  2 +-
 shared-bindings/storage/__init__.c            | 32 +++++++++++--------
 shared-bindings/traceback/__init__.c          |  4 +--
 shared-bindings/usb_hid/Device.c              |  2 +-
 23 files changed, 81 insertions(+), 76 deletions(-)

diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index f79a4c7285..2fe63e67d9 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -3943,6 +3943,7 @@ msgstr ""
 #: ports/espressif/boards/adafruit_funhouse/mpconfigboard.h
 #: ports/espressif/boards/adafruit_magtag_2.9_grayscale/mpconfigboard.h
 #: ports/espressif/boards/adafruit_metro_esp32s2/mpconfigboard.h
+#: ports/espressif/boards/ai_thinker_esp32-c3s/mpconfigboard.h
 #: ports/espressif/boards/ai_thinker_esp_12k_nodemcu/mpconfigboard.h
 #: ports/espressif/boards/artisense_rd00/mpconfigboard.h
 #: ports/espressif/boards/atmegazero_esp32s2/mpconfigboard.h
@@ -3961,6 +3962,7 @@ msgstr ""
 #: ports/espressif/boards/gravitech_cucumber_rs/mpconfigboard.h
 #: ports/espressif/boards/lilygo_ttgo_t8_s2_st7789/mpconfigboard.h
 #: ports/espressif/boards/lolin_s2_mini/mpconfigboard.h
+#: ports/espressif/boards/microdev_micro_c3/mpconfigboard.h
 #: ports/espressif/boards/microdev_micro_s2/mpconfigboard.h
 #: ports/espressif/boards/morpheans_morphesp-240/mpconfigboard.h
 #: ports/espressif/boards/muselab_nanoesp32_s2_wroom/mpconfigboard.h
diff --git a/shared-bindings/_bleio/Adapter.c b/shared-bindings/_bleio/Adapter.c
index c126ee79f2..1c65c0327f 100644
--- a/shared-bindings/_bleio/Adapter.c
+++ b/shared-bindings/_bleio/Adapter.c
@@ -271,7 +271,7 @@ STATIC mp_obj_t bleio_adapter_start_advertising(mp_uint_t n_args, const mp_obj_t
 
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_adapter_start_advertising_obj, 2, bleio_adapter_start_advertising);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_adapter_start_advertising_obj, 1, bleio_adapter_start_advertising);
 
 //|     def stop_advertising(self) -> None:
 //|         """Stop sending advertising packets."""
@@ -456,7 +456,7 @@ STATIC mp_obj_t bleio_adapter_connect(mp_uint_t n_args, const mp_obj_t *pos_args
 
     return common_hal_bleio_adapter_connect(self, address, timeout);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_adapter_connect_obj, 2, bleio_adapter_connect);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_adapter_connect_obj, 1, bleio_adapter_connect);
 
 //|     def erase_bonding(self) -> None:
 //|         """Erase all bonding information stored in flash memory."""
diff --git a/shared-bindings/_bleio/Characteristic.c b/shared-bindings/_bleio/Characteristic.c
index b6b6ee69d4..c83645352b 100644
--- a/shared-bindings/_bleio/Characteristic.c
+++ b/shared-bindings/_bleio/Characteristic.c
@@ -156,7 +156,7 @@ STATIC mp_obj_t bleio_characteristic_add_to_service(size_t n_args, const mp_obj_
 
     return MP_OBJ_FROM_PTR(characteristic);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_characteristic_add_to_service_fun_obj, 3, bleio_characteristic_add_to_service);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_characteristic_add_to_service_fun_obj, 1, bleio_characteristic_add_to_service);
 STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(bleio_characteristic_add_to_service_obj, MP_ROM_PTR(&bleio_characteristic_add_to_service_fun_obj));
 
 
diff --git a/shared-bindings/_bleio/Descriptor.c b/shared-bindings/_bleio/Descriptor.c
index c8a1c87149..86e65ca6eb 100644
--- a/shared-bindings/_bleio/Descriptor.c
+++ b/shared-bindings/_bleio/Descriptor.c
@@ -136,7 +136,7 @@ STATIC mp_obj_t bleio_descriptor_add_to_characteristic(size_t n_args, const mp_o
 
     return MP_OBJ_FROM_PTR(descriptor);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_descriptor_add_to_characteristic_fun_obj, 3, bleio_descriptor_add_to_characteristic);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_descriptor_add_to_characteristic_fun_obj, 1, bleio_descriptor_add_to_characteristic);
 STATIC MP_DEFINE_CONST_CLASSMETHOD_OBJ(bleio_descriptor_add_to_characteristic_obj, MP_ROM_PTR(&bleio_descriptor_add_to_characteristic_fun_obj));
 
 //|     uuid: UUID
diff --git a/shared-bindings/_bleio/ScanEntry.c b/shared-bindings/_bleio/ScanEntry.c
index 531986f349..5a0f6eb1be 100644
--- a/shared-bindings/_bleio/ScanEntry.c
+++ b/shared-bindings/_bleio/ScanEntry.c
@@ -72,7 +72,7 @@ STATIC mp_obj_t bleio_scanentry_matches(mp_uint_t n_args, const mp_obj_t *pos_ar
     mp_get_buffer_raise(args[ARG_prefixes].u_obj, &bufinfo, MP_BUFFER_READ);
     return mp_obj_new_bool(common_hal_bleio_scanentry_matches(self, bufinfo.buf, bufinfo.len, match_all));
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_scanentry_matches_obj, 2, bleio_scanentry_matches);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_scanentry_matches_obj, 1, bleio_scanentry_matches);
 
 //|     address: Address
 //|     """The address of the device (read-only), of type `_bleio.Address`."""
diff --git a/shared-bindings/_bleio/UUID.c b/shared-bindings/_bleio/UUID.c
index a575e382cc..90ee0c82b0 100644
--- a/shared-bindings/_bleio/UUID.c
+++ b/shared-bindings/_bleio/UUID.c
@@ -214,7 +214,7 @@ STATIC mp_obj_t bleio_uuid_pack_into(mp_uint_t n_args, const mp_obj_t *pos_args,
     common_hal_bleio_uuid_pack_into(self, bufinfo.buf + offset);
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_uuid_pack_into_obj, 2, bleio_uuid_pack_into);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_uuid_pack_into_obj, 1, bleio_uuid_pack_into);
 
 STATIC const mp_rom_map_elem_t bleio_uuid_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_uuid16), MP_ROM_PTR(&bleio_uuid_uuid16_obj) },
diff --git a/shared-bindings/adafruit_bus_device/I2CDevice.c b/shared-bindings/adafruit_bus_device/I2CDevice.c
index 12c836396d..2d811787b3 100644
--- a/shared-bindings/adafruit_bus_device/I2CDevice.c
+++ b/shared-bindings/adafruit_bus_device/I2CDevice.c
@@ -109,16 +109,16 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_obj___exit__(size_t n_args, const
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(adafruit_bus_device_i2cdevice___exit___obj, 4, 4, adafruit_bus_device_i2cdevice_obj___exit__);
 
-//|     def readinto(self, buf: WriteableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
-//|         """Read into ``buf`` from the device. The number of bytes read will be the
-//|         length of ``buf``.
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
+//|         """Read into ``buffer`` from the device. The number of bytes read will be the
+//|         length of ``buffer``.
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buf[start:end]``. This will not cause an allocation like
-//|         ``buf[start:end]`` will so it saves memory.
+//|         as if ``buffer[start:end]``. This will not cause an allocation like
+//|         ``buffer[start:end]`` will so it saves memory.
 //|
-//|         :param bytearray buf: buffer to write into
+//|         :param bytearray buffer: buffer to write into
 //|         :param int start: Index to start writing at
-//|         :param int end: Index to write up to but not include; if None, use ``len(buf)``"""
+//|         :param int end: Index to write up to but not include; if None, use ``len(buffer)``"""
 //|         ...
 //|
 STATIC mp_obj_t adafruit_bus_device_i2cdevice_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
@@ -152,17 +152,17 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_readinto(size_t n_args, const mp_o
 
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_readinto_obj, 2, adafruit_bus_device_i2cdevice_readinto);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_readinto_obj, 1, adafruit_bus_device_i2cdevice_readinto);
 
-//|     def write(self, buf: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
 //|         """Write the bytes from ``buffer`` to the device, then transmit a stop bit.
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
 //|         as if ``buffer[start:end]``. This will not cause an allocation like
 //|         ``buffer[start:end]`` will so it saves memory.
 //|
-//|         :param bytearray buf: buffer containing the bytes to write
+//|         :param bytearray buffer: buffer containing the bytes to write
 //|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include; if None, use ``len(buf)``
+//|         :param int end: Index to read up to but not include; if None, use ``len(buffer)``
 //|         """
 //|         ...
 //|
@@ -196,10 +196,10 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_write(size_t n_args, const mp_obj_
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_obj, 2, adafruit_bus_device_i2cdevice_write);
+MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_obj, 1, adafruit_bus_device_i2cdevice_write);
 
 
-//|     def write_then_readinto(self, out_buffer: WriteableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) -> None:
+//|     def write_then_readinto(self, out_buffer: WriteableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = len(out_buffer), in_start: int = 0, in_end: int = len(in_buffer)) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device, then immediately
 //|         reads into ``in_buffer`` from the device. The number of bytes read
 //|         will be the length of ``in_buffer``.
@@ -263,7 +263,7 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_write_then_readinto(size_t n_args,
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_then_readinto_obj, 3, adafruit_bus_device_i2cdevice_write_then_readinto);
+MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_then_readinto_obj, 1, adafruit_bus_device_i2cdevice_write_then_readinto);
 
 STATIC const mp_rom_map_elem_t adafruit_bus_device_i2cdevice_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&adafruit_bus_device_i2cdevice___enter___obj) },
diff --git a/shared-bindings/bitbangio/I2C.c b/shared-bindings/bitbangio/I2C.c
index 9f39e84061..f7bb7b3cd4 100644
--- a/shared-bindings/bitbangio/I2C.c
+++ b/shared-bindings/bitbangio/I2C.c
@@ -165,7 +165,7 @@ STATIC mp_obj_t bitbangio_i2c_obj_unlock(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_unlock_obj, bitbangio_i2c_obj_unlock);
 
-//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
 //|         """Read into ``buffer`` from the device selected by ``address``.
 //|         The number of bytes read will be the length of ``buffer``.
 //|         At least one byte must be read.
@@ -215,7 +215,7 @@ STATIC mp_obj_t bitbangio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_a
         args[ARG_end].u_int);
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 3, bitbangio_i2c_readfrom_into);
+MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 1, bitbangio_i2c_readfrom_into);
 
 //|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
 //|         """Write the bytes from ``buffer`` to the device selected by ``address`` and then transmits a
@@ -274,7 +274,7 @@ STATIC mp_obj_t bitbangio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, m
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_writeto);
 
 
-//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) -> None:
+//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = len(out_buffer), in_start: int = 0, in_end: int = len(in_buffer)) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device selected by ``address``, generate no stop
 //|         bit, generate a repeated start and read into ``in_buffer``. ``out_buffer`` and
 //|         ``in_buffer`` can be the same buffer because they are used sequentially.
@@ -315,7 +315,7 @@ STATIC mp_obj_t bitbangio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_then_readfrom_obj, 3, bitbangio_i2c_writeto_then_readfrom);
+MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_then_readfrom_obj, 1, bitbangio_i2c_writeto_then_readfrom);
 
 STATIC const mp_rom_map_elem_t bitbangio_i2c_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&bitbangio_i2c_deinit_obj) },
diff --git a/shared-bindings/bitbangio/SPI.c b/shared-bindings/bitbangio/SPI.c
index 0f8cb59a60..16a20b3353 100644
--- a/shared-bindings/bitbangio/SPI.c
+++ b/shared-bindings/bitbangio/SPI.c
@@ -224,7 +224,7 @@ STATIC mp_obj_t bitbangio_spi_write(mp_obj_t self_in, mp_obj_t wr_buf) {
 MP_DEFINE_CONST_FUN_OBJ_2(bitbangio_spi_write_obj, bitbangio_spi_write);
 
 
-//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: Optional[int] = None, write_value: int = 0) -> None:
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer), write_value: int = 0) -> None:
 //|         """Read into ``buffer`` while writing ``write_value`` for each byte read.
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
@@ -266,9 +266,9 @@ STATIC mp_obj_t bitbangio_spi_readinto(size_t n_args, const mp_obj_t *pos_args,
     }
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_readinto_obj, 2, bitbangio_spi_readinto);
+MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_readinto_obj, 1, bitbangio_spi_readinto);
 
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: ReadableBuffer, *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) -> None:
+//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: ReadableBuffer, *, out_start: int = 0, out_end: int = len(buffer_out), in_start: int = 0, in_end: int = len(buffer_in)) -> None:
 //|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
 //|         The SPI object must be locked.
 //|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
@@ -329,7 +329,7 @@ STATIC mp_obj_t bitbangio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_
     }
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_write_readinto_obj, 2, bitbangio_spi_write_readinto);
+MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_write_readinto_obj, 1, bitbangio_spi_write_readinto);
 
 STATIC const mp_rom_map_elem_t bitbangio_spi_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&bitbangio_spi_deinit_obj) },
diff --git a/shared-bindings/bitops/__init__.c b/shared-bindings/bitops/__init__.c
index d9849da917..5b455dcb0f 100644
--- a/shared-bindings/bitops/__init__.c
+++ b/shared-bindings/bitops/__init__.c
@@ -86,7 +86,7 @@ STATIC mp_obj_t bit_transpose(size_t n_args, const mp_obj_t *pos_args, mp_map_t
     common_hal_bitops_bit_transpose(output_bufinfo.buf, input_bufinfo.buf, inlen, width);
     return args[ARG_output].u_obj;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitops_bit_transpose_obj, 1, bit_transpose);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitops_bit_transpose_obj, 0, bit_transpose);
 
 STATIC const mp_rom_map_elem_t bitops_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_bitops) },
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
index 344dad8acc..65cec9faa5 100644
--- a/shared-bindings/busio/I2C.c
+++ b/shared-bindings/busio/I2C.c
@@ -226,7 +226,7 @@ STATIC mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args,
         args[ARG_end].u_int);
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 3, busio_i2c_readfrom_into);
+MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 1, busio_i2c_readfrom_into);
 
 //|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
 //|         """Write the bytes from ``buffer`` to the device selected by ``address`` and
@@ -324,7 +324,7 @@ STATIC mp_obj_t busio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *p
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_then_readfrom_obj, 3, busio_i2c_writeto_then_readfrom);
+MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_then_readfrom_obj, 1, busio_i2c_writeto_then_readfrom);
 
 STATIC const mp_rom_map_elem_t busio_i2c_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&busio_i2c_deinit_obj) },
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
index a611d8e1d5..8149d81ebf 100644
--- a/shared-bindings/busio/SPI.c
+++ b/shared-bindings/busio/SPI.c
@@ -237,7 +237,7 @@ STATIC mp_obj_t busio_spi_obj_unlock(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(busio_spi_unlock_obj, busio_spi_obj_unlock);
 
-//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
 //|         """Write the data contained in ``buffer``. The SPI object must be locked.
 //|         If the buffer is empty, nothing happens.
 //|
@@ -276,10 +276,10 @@ STATIC mp_obj_t busio_spi_write(size_t n_args, const mp_obj_t *pos_args, mp_map_
     }
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_obj, 2, busio_spi_write);
+MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_obj, 1, busio_spi_write);
 
 
-//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: Optional[int] = None, write_value: int = 0) -> None:
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer), write_value: int = 0) -> None:
 //|         """Read into ``buffer`` while writing ``write_value`` for each byte read.
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
@@ -321,9 +321,9 @@ STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_m
     }
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 2, busio_spi_readinto);
+MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 1, busio_spi_readinto);
 
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: WriteableBuffer, *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) -> None:
+//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: WriteableBuffer, *, out_start: int = 0, out_end: int = len(buffer_out), in_start: int = 0, in_end: int = len(buffer_in)) -> None:
 //|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
 //|         The SPI object must be locked.
 //|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
@@ -384,7 +384,7 @@ STATIC mp_obj_t busio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args
     }
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_readinto_obj, 2, busio_spi_write_readinto);
+MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_readinto_obj, 1, busio_spi_write_readinto);
 
 //|     frequency: int
 //|     """The actual SPI bus frequency. This may not match the frequency requested
diff --git a/shared-bindings/camera/Camera.c b/shared-bindings/camera/Camera.c
index a588965005..2e84f702cf 100644
--- a/shared-bindings/camera/Camera.c
+++ b/shared-bindings/camera/Camera.c
@@ -116,7 +116,7 @@ STATIC mp_obj_t camera_obj_take_picture(size_t n_args, const mp_obj_t *pos_args,
 
     return MP_OBJ_NEW_SMALL_INT(common_hal_camera_take_picture(self, (uint8_t *)bufinfo.buf, bufinfo.len, args[ARG_width].u_int, args[ARG_height].u_int, format));
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(camera_take_picture_obj, 2, camera_obj_take_picture);
+MP_DEFINE_CONST_FUN_OBJ_KW(camera_take_picture_obj, 1, camera_obj_take_picture);
 
 STATIC const mp_rom_map_elem_t camera_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&camera_deinit_obj) },
diff --git a/shared-bindings/displayio/Bitmap.c b/shared-bindings/displayio/Bitmap.c
index b56991c0c2..de2be6d637 100644
--- a/shared-bindings/displayio/Bitmap.c
+++ b/shared-bindings/displayio/Bitmap.c
@@ -285,8 +285,7 @@ STATIC mp_obj_t displayio_bitmap_obj_blit(size_t n_args, const mp_obj_t *pos_arg
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(displayio_bitmap_blit_obj, 4, displayio_bitmap_obj_blit);
-// `displayio_bitmap_obj_blit` requires at least 4 arguments
+MP_DEFINE_CONST_FUN_OBJ_KW(displayio_bitmap_blit_obj, 1, displayio_bitmap_obj_blit);
 
 //|     def fill(self, value: int) -> None:
 //|         """Fills the bitmap with the supplied palette index value."""
diff --git a/shared-bindings/displayio/EPaperDisplay.c b/shared-bindings/displayio/EPaperDisplay.c
index afe1321251..8d9b68f2b0 100644
--- a/shared-bindings/displayio/EPaperDisplay.c
+++ b/shared-bindings/displayio/EPaperDisplay.c
@@ -240,7 +240,7 @@ STATIC mp_obj_t displayio_epaperdisplay_update_refresh_mode(size_t n_args, const
     displayio_epaperdisplay_change_refresh_mode_parameters(self, &start_sequence, seconds_per_frame);
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(displayio_epaperdisplay_update_refresh_mode_obj, 3, displayio_epaperdisplay_update_refresh_mode);
+MP_DEFINE_CONST_FUN_OBJ_KW(displayio_epaperdisplay_update_refresh_mode_obj, 1, displayio_epaperdisplay_update_refresh_mode);
 
 //|     def refresh(self) -> None:
 //|         """Refreshes the display immediately or raises an exception if too soon. Use
diff --git a/shared-bindings/displayio/FourWire.c b/shared-bindings/displayio/FourWire.c
index 2145425342..c065fee551 100644
--- a/shared-bindings/displayio/FourWire.c
+++ b/shared-bindings/displayio/FourWire.c
@@ -149,7 +149,7 @@ STATIC mp_obj_t displayio_fourwire_obj_send(size_t n_args, const mp_obj_t *pos_a
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(displayio_fourwire_send_obj, 3, displayio_fourwire_obj_send);
+MP_DEFINE_CONST_FUN_OBJ_KW(displayio_fourwire_send_obj, 1, displayio_fourwire_obj_send);
 
 STATIC const mp_rom_map_elem_t displayio_fourwire_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&displayio_fourwire_reset_obj) },
diff --git a/shared-bindings/msgpack/__init__.c b/shared-bindings/msgpack/__init__.c
index 65d5558e60..d71ab9a6b9 100644
--- a/shared-bindings/msgpack/__init__.c
+++ b/shared-bindings/msgpack/__init__.c
@@ -112,7 +112,7 @@ STATIC mp_obj_t mod_msgpack_pack(size_t n_args, const mp_obj_t *pos_args, mp_map
     common_hal_msgpack_pack(args[ARG_obj].u_obj, args[ARG_buffer].u_obj, handler);
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(mod_msgpack_pack_obj, 1, mod_msgpack_pack);
+MP_DEFINE_CONST_FUN_OBJ_KW(mod_msgpack_pack_obj, 0, mod_msgpack_pack);
 
 
 //| def unpack(buffer: ReadableBuffer, *, ext_hook: Union[Callable[[int, bytes], object], None] = None, use_list: bool=True) -> object:
@@ -144,7 +144,7 @@ STATIC mp_obj_t mod_msgpack_unpack(size_t n_args, const mp_obj_t *pos_args, mp_m
 
     return common_hal_msgpack_unpack(args[ARG_buffer].u_obj, hook, args[ARG_use_list].u_bool);
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(mod_msgpack_unpack_obj, 1, mod_msgpack_unpack);
+MP_DEFINE_CONST_FUN_OBJ_KW(mod_msgpack_unpack_obj, 0, mod_msgpack_unpack);
 
 
 STATIC const mp_rom_map_elem_t msgpack_module_globals_table[] = {
diff --git a/shared-bindings/qrio/QRDecoder.c b/shared-bindings/qrio/QRDecoder.c
index 73a5d64694..689c1c6884 100644
--- a/shared-bindings/qrio/QRDecoder.c
+++ b/shared-bindings/qrio/QRDecoder.c
@@ -88,7 +88,7 @@ STATIC mp_obj_t qrio_qrdecoder_decode(size_t n_args, const mp_obj_t *pos_args, m
 
     return shared_module_qrio_qrdecoder_decode(self, &bufinfo, policy);
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(qrio_qrdecoder_decode_obj, 2, qrio_qrdecoder_decode);
+MP_DEFINE_CONST_FUN_OBJ_KW(qrio_qrdecoder_decode_obj, 1, qrio_qrdecoder_decode);
 
 //|     width: int
 //|     """The width of image the decoder expects"""
diff --git a/shared-bindings/socketpool/SocketPool.c b/shared-bindings/socketpool/SocketPool.c
index bd6a2b44f9..90f4fb8d75 100644
--- a/shared-bindings/socketpool/SocketPool.c
+++ b/shared-bindings/socketpool/SocketPool.c
@@ -69,19 +69,20 @@ STATIC mp_obj_t socketpool_socketpool_make_new(const mp_obj_type_t *type, size_t
 //|         :param ~int type: SOCK_STREAM, SOCK_DGRAM or SOCK_RAW"""
 //|         ...
 //|
-
 STATIC mp_obj_t socketpool_socketpool_socket(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    mp_arg_check_num(n_args, kw_args, 0, 5, false);
+    enum { ARG_family, ARG_type };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_family, MP_ARG_INT, {.u_int = SOCKETPOOL_AF_INET} },
+        { MP_QSTR_type, MP_ARG_INT, {.u_int = SOCKETPOOL_SOCK_STREAM} },
+    };
+    socketpool_socketpool_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
+
+    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);
+
+    socketpool_socketpool_addressfamily_t family = args[ARG_family].u_int;
+    socketpool_socketpool_sock_t type = args[ARG_type].u_int;
 
-    socketpool_socketpool_obj_t *self = pos_args[0];
-    socketpool_socketpool_addressfamily_t family = SOCKETPOOL_AF_INET;
-    socketpool_socketpool_sock_t type = SOCKETPOOL_SOCK_STREAM;
-    if (n_args >= 2) {
-        family = mp_obj_get_int(pos_args[1]);
-        if (n_args >= 3) {
-            type = mp_obj_get_int(pos_args[2]);
-        }
-    }
     return common_hal_socketpool_socket(self, family, type);
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(socketpool_socketpool_socket_obj, 1, socketpool_socketpool_socket);
@@ -94,7 +95,6 @@ MP_DEFINE_CONST_FUN_OBJ_KW(socketpool_socketpool_socket_obj, 1, socketpool_socke
 //|     as a tuple."""
 //|     ...
 //|
-
 STATIC mp_obj_t socketpool_socketpool_getaddrinfo(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_host, ARG_port, ARG_family, ARG_type, ARG_proto, ARG_flags };
     static const mp_arg_t allowed_args[] = {
@@ -137,7 +137,7 @@ STATIC mp_obj_t socketpool_socketpool_getaddrinfo(size_t n_args, const mp_obj_t
     tuple->items[4] = MP_OBJ_FROM_PTR(sockaddr);
     return mp_obj_new_list(1, (mp_obj_t *)&tuple);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(socketpool_socketpool_getaddrinfo_obj, 3, socketpool_socketpool_getaddrinfo);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(socketpool_socketpool_getaddrinfo_obj, 1, socketpool_socketpool_getaddrinfo);
 
 STATIC const mp_rom_map_elem_t socketpool_socketpool_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_socket), MP_ROM_PTR(&socketpool_socketpool_socket_obj) },
diff --git a/shared-bindings/ssl/SSLContext.c b/shared-bindings/ssl/SSLContext.c
index 4a3dafb981..f90365054a 100644
--- a/shared-bindings/ssl/SSLContext.c
+++ b/shared-bindings/ssl/SSLContext.c
@@ -79,7 +79,7 @@ STATIC mp_obj_t ssl_sslcontext_wrap_socket(size_t n_args, const mp_obj_t *pos_ar
 
     return common_hal_ssl_sslcontext_wrap_socket(self, sock, server_side, server_hostname);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(ssl_sslcontext_wrap_socket_obj, 2, ssl_sslcontext_wrap_socket);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(ssl_sslcontext_wrap_socket_obj, 1, ssl_sslcontext_wrap_socket);
 
 STATIC const mp_rom_map_elem_t ssl_sslcontext_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_wrap_socket), MP_ROM_PTR(&ssl_sslcontext_wrap_socket_obj) },
diff --git a/shared-bindings/storage/__init__.c b/shared-bindings/storage/__init__.c
index ddd2b9a1a9..c5769b56b5 100644
--- a/shared-bindings/storage/__init__.c
+++ b/shared-bindings/storage/__init__.c
@@ -48,26 +48,30 @@
 //|
 //|     This is the CircuitPython analog to the UNIX ``mount`` command.
 //|
-//|     :param bool readonly: True when the filesystem should be readonly to CircuitPython."""
+//|     :param VfsFat filesystem: The filesystem to mount.
+//|     :param str mount_path: Where to mount the filesystem.
+//|     :param bool readonly: True when the filesystem should be readonly to CircuitPython.
+//|     """
 //|     ...
 //|
 mp_obj_t storage_mount(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_readonly };
+    enum { ARG_filesystem, ARG_mount_path, ARG_readonly };
     static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_filesystem, MP_ARG_OBJ | MP_ARG_REQUIRED },
+        { MP_QSTR_mount_path, MP_ARG_OBJ | MP_ARG_REQUIRED },
         { MP_QSTR_readonly, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
     };
 
-    // parse args
     mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
-    mp_arg_parse_all(n_args - 2, pos_args + 2, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
     // get the mount point
-    const char *mnt_str = mp_obj_str_get_str(pos_args[1]);
+    const char *mnt_str = mp_obj_str_get_str(args[ARG_mount_path].u_obj);
 
     // Make sure we're given an object we can mount.
     // TODO(tannewt): Make sure we have all the methods we need to operating it
     // as a file system.
-    mp_obj_t vfs_obj = pos_args[0];
+    mp_obj_t vfs_obj = args[ARG_filesystem].u_obj;
     mp_obj_t dest[2];
     mp_load_method_maybe(vfs_obj, MP_QSTR_mount, dest);
     if (dest[0] == MP_OBJ_NULL) {
@@ -78,7 +82,7 @@ mp_obj_t storage_mount(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_arg
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(storage_mount_obj, 2, storage_mount);
+MP_DEFINE_CONST_FUN_OBJ_KW(storage_mount_obj, 0, storage_mount);
 
 //| def umount(mount: Union[str, VfsFat]) -> None:
 //|     """Unmounts the given filesystem object or if *mount* is a path, then unmount
@@ -101,6 +105,7 @@ MP_DEFINE_CONST_FUN_OBJ_1(storage_umount_obj, storage_umount);
 //| def remount(mount_path: str, readonly: bool = False, *, disable_concurrent_write_protection: bool = False) -> None:
 //|     """Remounts the given path with new parameters.
 //|
+//|       :param str mount_path: The path to remount.
 //|       :param bool readonly: True when the filesystem should be readonly to CircuitPython.
 //|       :param bool disable_concurrent_write_protection: When True, the check that makes sure the
 //|         underlying filesystem data is written by one computer is disabled. Disabling the protection
@@ -109,24 +114,23 @@ MP_DEFINE_CONST_FUN_OBJ_1(storage_umount_obj, storage_umount);
 //|     ...
 //|
 mp_obj_t storage_remount(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_readonly, ARG_disable_concurrent_write_protection };
+    enum { ARG_mount_path, ARG_readonly, ARG_disable_concurrent_write_protection };
     static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_mount_path, MP_ARG_OBJ | MP_ARG_REQUIRED },
         { MP_QSTR_readonly, MP_ARG_BOOL, {.u_bool = false} },
         { MP_QSTR_disable_concurrent_write_protection, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false} },
     };
 
-    // get the mount point
-    const char *mnt_str = mp_obj_str_get_str(pos_args[0]);
-
-    // parse args
     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_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    const char *mnt_str = mp_obj_str_get_str(args[ARG_mount_path].u_obj);
 
     common_hal_storage_remount(mnt_str, args[ARG_readonly].u_bool, args[ARG_disable_concurrent_write_protection].u_bool);
 
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(storage_remount_obj, 1, storage_remount);
+MP_DEFINE_CONST_FUN_OBJ_KW(storage_remount_obj, 0, storage_remount);
 
 //| def getmount(mount_path: str) -> VfsFat:
 //|     """Retrieves the mount object associated with the mount path"""
diff --git a/shared-bindings/traceback/__init__.c b/shared-bindings/traceback/__init__.c
index 37ef921cca..71fe858dfa 100644
--- a/shared-bindings/traceback/__init__.c
+++ b/shared-bindings/traceback/__init__.c
@@ -105,7 +105,7 @@ STATIC mp_obj_t traceback_format_exception(size_t n_args, const mp_obj_t *pos_ar
     return mp_obj_new_str_from_vstr(&mp_type_str, &vstr);
 }
 
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(traceback_format_exception_obj, 3, traceback_format_exception);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(traceback_format_exception_obj, 0, traceback_format_exception);
 
 //| def print_exception(etype: Type[BaseException], value: BaseException, tb: TracebackType,
 //|                     limit: Optional[int] = None, file: Optional[io.FileIO] = None, chain: Optional[bool] = True) -> None:
@@ -155,7 +155,7 @@ STATIC mp_obj_t traceback_print_exception(size_t n_args, const mp_obj_t *pos_arg
     traceback_exception_common(&print, args[ARG_value].u_obj, args[ARG_tb].u_obj, args[ARG_limit].u_obj);
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_KW(traceback_print_exception_obj, 3, traceback_print_exception);
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(traceback_print_exception_obj, 0, traceback_print_exception);
 
 STATIC const mp_rom_map_elem_t traceback_module_globals_table[] = {
     // module name
diff --git a/shared-bindings/usb_hid/Device.c b/shared-bindings/usb_hid/Device.c
index 8095570da8..30379a25e9 100644
--- a/shared-bindings/usb_hid/Device.c
+++ b/shared-bindings/usb_hid/Device.c
@@ -189,7 +189,7 @@ STATIC mp_obj_t usb_hid_device_send_report(size_t n_args, const mp_obj_t *pos_ar
     common_hal_usb_hid_device_send_report(self, ((uint8_t *)bufinfo.buf), bufinfo.len, report_id);
     return mp_const_none;
 }
-MP_DEFINE_CONST_FUN_OBJ_KW(usb_hid_device_send_report_obj, 2, usb_hid_device_send_report);
+MP_DEFINE_CONST_FUN_OBJ_KW(usb_hid_device_send_report_obj, 1, usb_hid_device_send_report);
 
 //|     def get_last_received_report(self, report_id: Optional[int] = None) -> bytes:
 //|         """Get the last received HID OUT report for the given report ID.

From b48bb75e24ca8502a0950626ae80e8c681049da4 Mon Sep 17 00:00:00 2001
From: Dan Halbert <halbert@halwitz.org>
Date: Thu, 7 Oct 2021 18:15:37 -0400
Subject: [PATCH 2/3] change len(buffer) to sys.maxsize; must import sys

---
 shared-bindings/adafruit_bus_device/I2CDevice.c | 13 ++++++++-----
 shared-bindings/bitbangio/I2C.c                 | 15 +++++++++------
 shared-bindings/bitbangio/SPI.c                 | 12 +++++++-----
 shared-bindings/busio/I2C.c                     | 17 ++++++++++-------
 shared-bindings/busio/SPI.c                     | 13 ++++++++-----
 5 files changed, 42 insertions(+), 28 deletions(-)

diff --git a/shared-bindings/adafruit_bus_device/I2CDevice.c b/shared-bindings/adafruit_bus_device/I2CDevice.c
index 2d811787b3..211bde201a 100644
--- a/shared-bindings/adafruit_bus_device/I2CDevice.c
+++ b/shared-bindings/adafruit_bus_device/I2CDevice.c
@@ -109,7 +109,8 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_obj___exit__(size_t n_args, const
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(adafruit_bus_device_i2cdevice___exit___obj, 4, 4, adafruit_bus_device_i2cdevice_obj___exit__);
 
-//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
+//|     import sys
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Read into ``buffer`` from the device. The number of bytes read will be the
 //|         length of ``buffer``.
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
@@ -154,7 +155,8 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_readinto(size_t n_args, const mp_o
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_readinto_obj, 1, adafruit_bus_device_i2cdevice_readinto);
 
-//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
+//|     import sys
+//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``buffer`` to the device, then transmit a stop bit.
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
 //|         as if ``buffer[start:end]``. This will not cause an allocation like
@@ -199,7 +201,8 @@ STATIC mp_obj_t adafruit_bus_device_i2cdevice_write(size_t n_args, const mp_obj_
 MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_obj, 1, adafruit_bus_device_i2cdevice_write);
 
 
-//|     def write_then_readinto(self, out_buffer: WriteableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = len(out_buffer), in_start: int = 0, in_end: int = len(in_buffer)) -> None:
+//|     import sys
+//|     def write_then_readinto(self, out_buffer: WriteableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device, then immediately
 //|         reads into ``in_buffer`` from the device. The number of bytes read
 //|         will be the length of ``in_buffer``.
@@ -215,9 +218,9 @@ MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_obj, 1, adafruit_
 //|         :param bytearray out_buffer: buffer containing the bytes to write
 //|         :param bytearray in_buffer: buffer containing the bytes to read into
 //|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include; if None, use ``len(out_buffer)``
+//|         :param int out_end: Index to read up to but not include; if not specified, use ``len(out_buffer)``
 //|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include; if None, use ``len(in_buffer)``
+//|         :param int in_end: Index to write up to but not include; if not specified, use ``len(in_buffer)``
 //|         """
 //|         ...
 //|
diff --git a/shared-bindings/bitbangio/I2C.c b/shared-bindings/bitbangio/I2C.c
index f7bb7b3cd4..a4de6a35be 100644
--- a/shared-bindings/bitbangio/I2C.c
+++ b/shared-bindings/bitbangio/I2C.c
@@ -165,7 +165,8 @@ STATIC mp_obj_t bitbangio_i2c_obj_unlock(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_unlock_obj, bitbangio_i2c_obj_unlock);
 
-//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
+//|     import sys
+//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Read into ``buffer`` from the device selected by ``address``.
 //|         The number of bytes read will be the length of ``buffer``.
 //|         At least one byte must be read.
@@ -217,7 +218,8 @@ STATIC mp_obj_t bitbangio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_a
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 1, bitbangio_i2c_readfrom_into);
 
-//|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     import sys
+//|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``buffer`` to the device selected by ``address`` and then transmits a
 //|         stop bit. Use `writeto_then_readfrom` when needing a write, no stop and repeated start
 //|         before a read.
@@ -232,7 +234,7 @@ MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 1, bitbangio_i2c_rea
 //|         :param int address: 7-bit device address
 //|         :param ~_typing.ReadableBuffer buffer: buffer containing the bytes to write
 //|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include"""
+//|         :param int end: Index to read up to but not include. If not specified, use ``len(buffer)``"""
 //|         ...
 //|
 // Shared arg parsing for writeto and writeto_then_readfrom.
@@ -274,7 +276,8 @@ STATIC mp_obj_t bitbangio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, m
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_writeto);
 
 
-//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = len(out_buffer), in_start: int = 0, in_end: int = len(in_buffer)) -> None:
+//|     import sys
+//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device selected by ``address``, generate no stop
 //|         bit, generate a repeated start and read into ``in_buffer``. ``out_buffer`` and
 //|         ``in_buffer`` can be the same buffer because they are used sequentially.
@@ -287,9 +290,9 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_wr
 //|         :param ~_typing.ReadableBuffer out_buffer: buffer containing the bytes to write
 //|         :param ~_typing.WriteableBuffer in_buffer: buffer to write into
 //|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include. Defaults to ``len(buffer)``
+//|         :param int out_end: Index to read up to but not include. If not specified, use ``len(buffer)``
 //|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include. Defaults to ``len(buffer)``"""
+//|         :param int in_end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
 //|
 STATIC mp_obj_t bitbangio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_address, ARG_out_buffer, ARG_in_buffer, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
diff --git a/shared-bindings/bitbangio/SPI.c b/shared-bindings/bitbangio/SPI.c
index 16a20b3353..4141a07184 100644
--- a/shared-bindings/bitbangio/SPI.c
+++ b/shared-bindings/bitbangio/SPI.c
@@ -224,14 +224,15 @@ STATIC mp_obj_t bitbangio_spi_write(mp_obj_t self_in, mp_obj_t wr_buf) {
 MP_DEFINE_CONST_FUN_OBJ_2(bitbangio_spi_write_obj, bitbangio_spi_write);
 
 
-//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer), write_value: int = 0) -> None:
+//|     import sys
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize, write_value: int = 0) -> None:
 //|         """Read into ``buffer`` while writing ``write_value`` for each byte read.
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
 //|
 //|         :param bytearray buffer: Read data into this buffer
 //|         :param int start: Start of the slice of ``buffer`` to read into: ``buffer[start:end]``
-//|         :param int end: End of the slice; this index is not included. Defaults to ``len(buffer)``
+//|         :param int end: End of the slice; this index is not included. If not specified, use ``len(buffer)``
 //|         :param int write_value: Value to write while reading."""
 //|         ...
 //|
@@ -268,7 +269,8 @@ STATIC mp_obj_t bitbangio_spi_readinto(size_t n_args, const mp_obj_t *pos_args,
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_readinto_obj, 1, bitbangio_spi_readinto);
 
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: ReadableBuffer, *, out_start: int = 0, out_end: int = len(buffer_out), in_start: int = 0, in_end: int = len(buffer_in)) -> None:
+//|     import sys
+//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: ReadableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
 //|         The SPI object must be locked.
 //|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
@@ -278,9 +280,9 @@ MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_readinto_obj, 1, bitbangio_spi_readinto
 //|         :param ~_typing.ReadableBuffer buffer_out: Write out the data in this buffer
 //|         :param ~_typing.WriteableBuffer buffer_in: Read data into this buffer
 //|         :param int out_start: Start of the slice of buffer_out to write out: ``buffer_out[out_start:out_end]``
-//|         :param int out_end: End of the slice; this index is not included. Defaults to ``len(buffer_out)``
+//|         :param int out_end: End of the slice; this index is not included. If not specified, use ``len(buffer_out)``
 //|         :param int in_start: Start of the slice of ``buffer_in`` to read into: ``buffer_in[in_start:in_end]``
-//|         :param int in_end: End of the slice; this index is not included. Defaults to ``len(buffer_in)``"""
+//|         :param int in_end: End of the slice; this index is not included. If not specified, use ``len(buffer_in)``"""
 //|         ...
 //|
 STATIC mp_obj_t bitbangio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
index 65cec9faa5..d6778e175c 100644
--- a/shared-bindings/busio/I2C.c
+++ b/shared-bindings/busio/I2C.c
@@ -176,7 +176,8 @@ STATIC mp_obj_t busio_i2c_obj_unlock(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_unlock_obj, busio_i2c_obj_unlock);
 
-//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     import sys
+//|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Read into ``buffer`` from the device selected by ``address``.
 //|         The number of bytes read will be the length of ``buffer``.
 //|         At least one byte must be read.
@@ -188,7 +189,7 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_unlock_obj, busio_i2c_obj_unlock);
 //|         :param int address: 7-bit device address
 //|         :param ~_typing.WriteableBuffer buffer: buffer to write into
 //|         :param int start: Index to start writing at
-//|         :param int end: Index to write up to but not include. Defaults to ``len(buffer)``"""
+//|         :param int end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
 //|         ...
 //|
 // Shared arg parsing for readfrom_into and writeto_then_readfrom.
@@ -228,7 +229,8 @@ STATIC mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args,
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 1, busio_i2c_readfrom_into);
 
-//|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
+//|     import sys
+//|     def writeto(self, address: int, buffer: ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``buffer`` to the device selected by ``address`` and
 //|         then transmit a stop bit.
 //|
@@ -242,7 +244,7 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 1, busio_i2c_readfrom_in
 //|         :param int address: 7-bit device address
 //|         :param ~_typing.ReadableBuffer buffer: buffer containing the bytes to write
 //|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include. Defaults to ``len(buffer)``"""
+//|         :param int end: Index to read up to but not include. If not specified, use ``len(buffer)``"""
 //|         ...
 //|
 // Shared arg parsing for writeto and writeto_then_readfrom.
@@ -282,7 +284,8 @@ STATIC mp_obj_t busio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_ma
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_obj, 1, busio_i2c_writeto);
 
-//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: WriteableBuffer, *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) -> None:
+//|     import sys
+//|     def writeto_then_readfrom(self, address: int, out_buffer: ReadableBuffer, in_buffer: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device selected by ``address``, generate no stop
 //|         bit, generate a repeated start and read into ``in_buffer``. ``out_buffer`` and
 //|         ``in_buffer`` can be the same buffer because they are used sequentially.
@@ -295,9 +298,9 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_obj, 1, busio_i2c_writeto);
 //|         :param ~_typing.ReadableBuffer out_buffer: buffer containing the bytes to write
 //|         :param ~_typing.WriteableBuffer in_buffer: buffer to write into
 //|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include. Defaults to ``len(buffer)``
+//|         :param int out_end: Index to read up to but not include. If not specified, use ``len(buffer)``
 //|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include. Defaults to ``len(buffer)``"""
+//|         :param int in_end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
 //|         ...
 //|
 STATIC mp_obj_t busio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
index 8149d81ebf..8aff8f16b8 100644
--- a/shared-bindings/busio/SPI.c
+++ b/shared-bindings/busio/SPI.c
@@ -237,7 +237,8 @@ STATIC mp_obj_t busio_spi_obj_unlock(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(busio_spi_unlock_obj, busio_spi_obj_unlock);
 
-//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = len(buffer)) -> None:
+//|     import sys
+//|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Write the data contained in ``buffer``. The SPI object must be locked.
 //|         If the buffer is empty, nothing happens.
 //|
@@ -279,7 +280,8 @@ STATIC mp_obj_t busio_spi_write(size_t n_args, const mp_obj_t *pos_args, mp_map_
 MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_obj, 1, busio_spi_write);
 
 
-//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = len(buffer), write_value: int = 0) -> None:
+//|     import sys
+//|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize, write_value: int = 0) -> None:
 //|         """Read into ``buffer`` while writing ``write_value`` for each byte read.
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
@@ -323,7 +325,8 @@ STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_m
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 1, busio_spi_readinto);
 
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: WriteableBuffer, *, out_start: int = 0, out_end: int = len(buffer_out), in_start: int = 0, in_end: int = len(buffer_in)) -> None:
+//|     import sys
+//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
 //|         The SPI object must be locked.
 //|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
@@ -333,9 +336,9 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 1, busio_spi_readinto);
 //|         :param ~_typing.ReadableBuffer buffer_out: Write out the data in this buffer
 //|         :param ~_typing.WriteableBuffer buffer_in: Read data into this buffer
 //|         :param int out_start: Start of the slice of buffer_out to write out: ``buffer_out[out_start:out_end]``
-//|         :param int out_end: End of the slice; this index is not included. Defaults to ``len(buffer_out)``
+//|         :param int out_end: End of the slice; this index is not included. If not specified, use ``len(buffer_out)``
 //|         :param int in_start: Start of the slice of ``buffer_in`` to read into: ``buffer_in[in_start:in_end]``
-//|         :param int in_end: End of the slice; this index is not included. Defaults to ``len(buffer_in)``"""
+//|         :param int in_end: End of the slice; this index is not included. If not specified, use ``len(buffer_in)``"""
 //|         ...
 //|
 

From 431e784a7e6f5af72772d37a7ddab50d1e6cd948 Mon Sep 17 00:00:00 2001
From: Dan Halbert <halbert@halwitz.org>
Date: Thu, 7 Oct 2021 21:20:02 -0400
Subject: [PATCH 3/3] big cleanup of SPI and I2C doc; fix arg names on SPI

---
 .../adafruit_bus_device/I2CDevice.c           | 66 ++++++++++---------
 shared-bindings/bitbangio/I2C.c               | 33 ++++++----
 shared-bindings/bitbangio/SPI.c               | 54 +++++++++------
 shared-bindings/busio/I2C.c                   | 41 +++++++-----
 shared-bindings/busio/SPI.c                   | 64 +++++++++++-------
 5 files changed, 153 insertions(+), 105 deletions(-)

diff --git a/shared-bindings/adafruit_bus_device/I2CDevice.c b/shared-bindings/adafruit_bus_device/I2CDevice.c
index 211bde201a..a6ec8a2dfb 100644
--- a/shared-bindings/adafruit_bus_device/I2CDevice.c
+++ b/shared-bindings/adafruit_bus_device/I2CDevice.c
@@ -63,7 +63,8 @@
 //|                     device.readinto(bytes_read)
 //|                 # A second transaction
 //|                 with device:
-//|                     device.write(bytes_read)"""
+//|                     device.write(bytes_read)
+//|     """
 //|     ...
 //|
 STATIC mp_obj_t adafruit_bus_device_i2cdevice_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
@@ -111,15 +112,16 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(adafruit_bus_device_i2cdevice___exit_
 
 //|     import sys
 //|     def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
-//|         """Read into ``buffer`` from the device. The number of bytes read will be the
-//|         length of ``buffer``.
-//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like
-//|         ``buffer[start:end]`` will so it saves memory.
+//|         """Read into ``buffer`` from the device.
 //|
-//|         :param bytearray buffer: buffer to write into
-//|         :param int start: Index to start writing at
-//|         :param int end: Index to write up to but not include; if None, use ``len(buffer)``"""
+//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
+//|         as if ``buffer[start:end]`` were passed.
+//|         The number of bytes read will be the length of ``buffer[start:end]``.
+//|
+//|         :param WriteableBuffer buffer: read bytes into this buffer
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         """
 //|         ...
 //|
 STATIC mp_obj_t adafruit_bus_device_i2cdevice_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
@@ -158,13 +160,14 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_readinto_obj, 1,
 //|     import sys
 //|     def write(self, buffer: ReadableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``buffer`` to the device, then transmit a stop bit.
-//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like
-//|         ``buffer[start:end]`` will so it saves memory.
 //|
-//|         :param bytearray buffer: buffer containing the bytes to write
-//|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include; if None, use ``len(buffer)``
+//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
+//|         as if ``buffer[start:end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``buffer[start:end]``.
+//|
+//|         :param ReadableBuffer buffer: write out bytes from this buffer
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
 //|         """
 //|         ...
 //|
@@ -202,25 +205,24 @@ MP_DEFINE_CONST_FUN_OBJ_KW(adafruit_bus_device_i2cdevice_write_obj, 1, adafruit_
 
 
 //|     import sys
-//|     def write_then_readinto(self, out_buffer: WriteableBuffer, in_buffer: ReadableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
+//|     def write_then_readinto(self, out_buffer: ReadableBuffer, in_buffer: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
 //|         """Write the bytes from ``out_buffer`` to the device, then immediately
-//|         reads into ``in_buffer`` from the device. The number of bytes read
-//|         will be the length of ``in_buffer``.
-//|         If ``out_start`` or ``out_end`` is provided, then the output buffer
-//|         will be sliced as if ``out_buffer[out_start:out_end]``. This will
-//|         not cause an allocation like ``buffer[out_start:out_end]`` will so
-//|         it saves memory.
-//|         If ``in_start`` or ``in_end`` is provided, then the input buffer
-//|         will be sliced as if ``in_buffer[in_start:in_end]``. This will not
-//|         cause an allocation like ``in_buffer[in_start:in_end]`` will so
-//|         it saves memory.
+//|         reads into ``in_buffer`` from the device.
 //|
-//|         :param bytearray out_buffer: buffer containing the bytes to write
-//|         :param bytearray in_buffer: buffer containing the bytes to read into
-//|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include; if not specified, use ``len(out_buffer)``
-//|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include; if not specified, use ``len(in_buffer)``
+//|         If ``out_start`` or ``out_end`` is provided, then the buffer will be sliced
+//|         as if ``out_buffer[out_start:out_end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``out_buffer[out_start:out_end]``.
+//|
+//|         If ``in_start`` or ``in_end`` is provided, then the input buffer will be sliced
+//|         as if ``in_buffer[in_start:in_end]`` were passed,
+//|         The number of bytes read will be the length of ``out_buffer[in_start:in_end]``.
+//|
+//|         :param ReadableBuffer out_buffer: write out bytes from this buffer
+//|         :param WriteableBuffer in_buffer: read bytes into this buffer
+//|         :param int out_start: beginning of ``out_buffer`` slice
+//|         :param int out_end: end of ``out_buffer`` slice; if not specified, use ``len(out_buffer)``
+//|         :param int in_start: beginning of ``in_buffer`` slice
+//|         :param int in_end: end of ``in_buffer slice``; if not specified, use ``len(in_buffer)``
 //|         """
 //|         ...
 //|
diff --git a/shared-bindings/bitbangio/I2C.c b/shared-bindings/bitbangio/I2C.c
index a4de6a35be..3599cad48f 100644
--- a/shared-bindings/bitbangio/I2C.c
+++ b/shared-bindings/bitbangio/I2C.c
@@ -176,7 +176,7 @@ MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_unlock_obj, bitbangio_i2c_obj_unlock);
 //|         ``buf[start:end]`` will so it saves memory.
 //|
 //|         :param int address: 7-bit device address
-//|         :param ~_typing.WriteableBuffer buffer: buffer to write into
+//|         :param WriteableBuffer buffer: buffer to write into
 //|         :param int start: Index to start writing at
 //|         :param int end: Index to write up to but not include"""
 //|         ...
@@ -225,16 +225,17 @@ MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 1, bitbangio_i2c_rea
 //|         before a read.
 //|
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like
-//|         ``buffer[start:end]`` will so it saves memory.
+//|         as if ``buffer[start:end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``buffer[start:end]``.
 //|
 //|         Writing a buffer or slice of length zero is permitted, as it can be used
 //|         to poll for the existence of a device.
 //|
 //|         :param int address: 7-bit device address
-//|         :param ~_typing.ReadableBuffer buffer: buffer containing the bytes to write
-//|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include. If not specified, use ``len(buffer)``"""
+//|         :param ReadableBuffer buffer: buffer containing the bytes to write
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         """
 //|         ...
 //|
 // Shared arg parsing for writeto and writeto_then_readfrom.
@@ -282,17 +283,23 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_wr
 //|         bit, generate a repeated start and read into ``in_buffer``. ``out_buffer`` and
 //|         ``in_buffer`` can be the same buffer because they are used sequentially.
 //|
-//|         If ``start`` or ``end`` is provided, then the corresponding buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like ``buf[start:end]``
-//|         will so it saves memory.
+//|         If ``out_start`` or ``out_end`` is provided, then the buffer will be sliced
+//|         as if ``out_buffer[out_start:out_end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``out_buffer[start:end]``.
 //|
+//|         If ``in_start`` or ``in_end`` is provided, then the input buffer will be sliced
+//|         as if ``in_buffer[in_start:in_end]`` were passed,
+//|         The number of bytes read will be the length of ``out_buffer[in_start:in_end]``.
+
 //|         :param int address: 7-bit device address
 //|         :param ~_typing.ReadableBuffer out_buffer: buffer containing the bytes to write
 //|         :param ~_typing.WriteableBuffer in_buffer: buffer to write into
-//|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include. If not specified, use ``len(buffer)``
-//|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
+//|         :param int out_start: beginning of ``out_buffer`` slice
+//|         :param int out_end: end of ``out_buffer`` slice; if not specified, use ``len(out_buffer)``
+//|         :param int in_start: beginning of ``in_buffer`` slice
+//|         :param int in_end: end of ``in_buffer slice``; if not specified, use ``len(in_buffer)``
+//|         """
+//|         ...
 //|
 STATIC mp_obj_t bitbangio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_address, ARG_out_buffer, ARG_in_buffer, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
diff --git a/shared-bindings/bitbangio/SPI.c b/shared-bindings/bitbangio/SPI.c
index 4141a07184..0f453b3807 100644
--- a/shared-bindings/bitbangio/SPI.c
+++ b/shared-bindings/bitbangio/SPI.c
@@ -230,13 +230,17 @@ MP_DEFINE_CONST_FUN_OBJ_2(bitbangio_spi_write_obj, bitbangio_spi_write);
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
 //|
-//|         :param bytearray buffer: Read data into this buffer
-//|         :param int start: Start of the slice of ``buffer`` to read into: ``buffer[start:end]``
-//|         :param int end: End of the slice; this index is not included. If not specified, use ``len(buffer)``
-//|         :param int write_value: Value to write while reading."""
+//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
+//|         as if ``buffer[start:end]`` were passed.
+//|         The number of bytes read will be the length of ``buffer[start:end]``.
+//|
+//|         :param WriteableBuffer buffer: read bytes into this buffer
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         :param int write_value: value to write while reading
+//|         """
 //|         ...
 //|
-
 STATIC mp_obj_t bitbangio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_buffer, ARG_start, ARG_end, ARG_write_value };
     static const mp_arg_t allowed_args[] = {
@@ -270,26 +274,36 @@ STATIC mp_obj_t bitbangio_spi_readinto(size_t n_args, const mp_obj_t *pos_args,
 MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_spi_readinto_obj, 1, bitbangio_spi_readinto);
 
 //|     import sys
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: ReadableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
-//|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
+//|     def write_readinto(self, out_buffer: ReadableBuffer, in_buffer: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
+//|         """Write out the data in ``out_buffer`` while simultaneously reading data into ``in_buffer``.
 //|         The SPI object must be locked.
-//|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
-//|         must be equal.
+//|
+//|         If ``out_start`` or ``out_end`` is provided, then the buffer will be sliced
+//|         as if ``out_buffer[out_start:out_end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``out_buffer[out_start:out_end]``.
+//|
+//|         If ``in_start`` or ``in_end`` is provided, then the input buffer will be sliced
+//|         as if ``in_buffer[in_start:in_end]`` were passed,
+//|         The number of bytes read will be the length of ``out_buffer[in_start:in_end]``.
+//|
+//|         The lengths of the slices defined by ``out_buffer[out_start:out_end]``
+//|         and ``in_buffer[in_start:in_end]`` must be equal.
 //|         If buffer slice lengths are both 0, nothing happens.
 //|
-//|         :param ~_typing.ReadableBuffer buffer_out: Write out the data in this buffer
-//|         :param ~_typing.WriteableBuffer buffer_in: Read data into this buffer
-//|         :param int out_start: Start of the slice of buffer_out to write out: ``buffer_out[out_start:out_end]``
-//|         :param int out_end: End of the slice; this index is not included. If not specified, use ``len(buffer_out)``
-//|         :param int in_start: Start of the slice of ``buffer_in`` to read into: ``buffer_in[in_start:in_end]``
-//|         :param int in_end: End of the slice; this index is not included. If not specified, use ``len(buffer_in)``"""
+//|         :param ReadableBuffer out_buffer: write out bytes from this buffer
+//|         :param WriteableBuffer in_buffer: read bytes into this buffer
+//|         :param int out_start: beginning of ``out_buffer`` slice
+//|         :param int out_end: end of ``out_buffer`` slice; if not specified, use ``len(out_buffer)``
+//|         :param int in_start: beginning of ``in_buffer`` slice
+//|         :param int in_end: end of ``in_buffer slice``; if not specified, use ``len(in_buffer)``
+//|         """
 //|         ...
 //|
 STATIC mp_obj_t bitbangio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_buffer_out, ARG_buffer_in, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
+    enum { ARG_out_buffer, ARG_in_buffer, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
     static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_buffer_out,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
-        { MP_QSTR_buffer_in,     MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_out_buffer,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_in_buffer,     MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
         { MP_QSTR_out_start,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_out_end,       MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
         { MP_QSTR_in_start,      MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
@@ -303,13 +317,13 @@ STATIC mp_obj_t bitbangio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
     mp_buffer_info_t buf_out_info;
-    mp_get_buffer_raise(args[ARG_buffer_out].u_obj, &buf_out_info, MP_BUFFER_READ);
+    mp_get_buffer_raise(args[ARG_out_buffer].u_obj, &buf_out_info, MP_BUFFER_READ);
     int32_t out_start = args[ARG_out_start].u_int;
     size_t out_length = buf_out_info.len;
     normalize_buffer_bounds(&out_start, args[ARG_out_end].u_int, &out_length);
 
     mp_buffer_info_t buf_in_info;
-    mp_get_buffer_raise(args[ARG_buffer_in].u_obj, &buf_in_info, MP_BUFFER_WRITE);
+    mp_get_buffer_raise(args[ARG_in_buffer].u_obj, &buf_in_info, MP_BUFFER_WRITE);
     int32_t in_start = args[ARG_in_start].u_int;
     size_t in_length = buf_in_info.len;
     normalize_buffer_bounds(&in_start, args[ARG_in_end].u_int, &in_length);
diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
index d6778e175c..740bd7cca4 100644
--- a/shared-bindings/busio/I2C.c
+++ b/shared-bindings/busio/I2C.c
@@ -179,17 +179,16 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_unlock_obj, busio_i2c_obj_unlock);
 //|     import sys
 //|     def readfrom_into(self, address: int, buffer: WriteableBuffer, *, start: int = 0, end: int = sys.maxsize) -> None:
 //|         """Read into ``buffer`` from the device selected by ``address``.
-//|         The number of bytes read will be the length of ``buffer``.
 //|         At least one byte must be read.
 //|
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like
-//|         ``buf[start:end]`` will so it saves memory.
+//|         as if ``buffer[start:end]`` were passed, but without copying the data.
+//|         The number of bytes read will be the length of ``buffer[start:end]``.
 //|
 //|         :param int address: 7-bit device address
-//|         :param ~_typing.WriteableBuffer buffer: buffer to write into
-//|         :param int start: Index to start writing at
-//|         :param int end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
+//|         :param WriteableBuffer buffer: buffer to write into
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``"""
 //|         ...
 //|
 // Shared arg parsing for readfrom_into and writeto_then_readfrom.
@@ -235,16 +234,17 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 1, busio_i2c_readfrom_in
 //|         then transmit a stop bit.
 //|
 //|         If ``start`` or ``end`` is provided, then the buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like
-//|         ``buffer[start:end]`` will so it saves memory.
+//|         as if ``buffer[start:end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``buffer[start:end]``.
 //|
 //|         Writing a buffer or slice of length zero is permitted, as it can be used
 //|         to poll for the existence of a device.
 //|
 //|         :param int address: 7-bit device address
-//|         :param ~_typing.ReadableBuffer buffer: buffer containing the bytes to write
-//|         :param int start: Index to start writing from
-//|         :param int end: Index to read up to but not include. If not specified, use ``len(buffer)``"""
+//|         :param ReadableBuffer buffer: buffer containing the bytes to write
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         """
 //|         ...
 //|
 // Shared arg parsing for writeto and writeto_then_readfrom.
@@ -290,17 +290,22 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_obj, 1, busio_i2c_writeto);
 //|         bit, generate a repeated start and read into ``in_buffer``. ``out_buffer`` and
 //|         ``in_buffer`` can be the same buffer because they are used sequentially.
 //|
-//|         If ``start`` or ``end`` is provided, then the corresponding buffer will be sliced
-//|         as if ``buffer[start:end]``. This will not cause an allocation like ``buf[start:end]``
-//|         will so it saves memory.
+//|         If ``out_start`` or ``out_end`` is provided, then the buffer will be sliced
+//|         as if ``out_buffer[out_start:out_end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``out_buffer[start:end]``.
 //|
+//|         If ``in_start`` or ``in_end`` is provided, then the input buffer will be sliced
+//|         as if ``in_buffer[in_start:in_end]`` were passed,
+//|         The number of bytes read will be the length of ``out_buffer[in_start:in_end]``.
+
 //|         :param int address: 7-bit device address
 //|         :param ~_typing.ReadableBuffer out_buffer: buffer containing the bytes to write
 //|         :param ~_typing.WriteableBuffer in_buffer: buffer to write into
-//|         :param int out_start: Index to start writing from
-//|         :param int out_end: Index to read up to but not include. If not specified, use ``len(buffer)``
-//|         :param int in_start: Index to start writing at
-//|         :param int in_end: Index to write up to but not include. If not specified, use ``len(buffer)``"""
+//|         :param int out_start: beginning of ``out_buffer`` slice
+//|         :param int out_end: end of ``out_buffer`` slice; if not specified, use ``len(out_buffer)``
+//|         :param int in_start: beginning of ``in_buffer`` slice
+//|         :param int in_end: end of ``in_buffer slice``; if not specified, use ``len(in_buffer)``
+//|         """
 //|         ...
 //|
 STATIC mp_obj_t busio_i2c_writeto_then_readfrom(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
diff --git a/shared-bindings/busio/SPI.c b/shared-bindings/busio/SPI.c
index 8aff8f16b8..ceebce974b 100644
--- a/shared-bindings/busio/SPI.c
+++ b/shared-bindings/busio/SPI.c
@@ -242,9 +242,14 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_spi_unlock_obj, busio_spi_obj_unlock);
 //|         """Write the data contained in ``buffer``. The SPI object must be locked.
 //|         If the buffer is empty, nothing happens.
 //|
-//|         :param ~_typing.ReadableBuffer buffer: Write out the data in this buffer
-//|         :param int start: Start of the slice of ``buffer`` to write out: ``buffer[start:end]``
-//|         :param int end: End of the slice; this index is not included. Defaults to ``len(buffer)``"""
+//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
+//|         as if ``buffer[start:end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``buffer[start:end]``.
+//|
+//|         :param ReadableBuffer buffer: write out bytes from this buffer
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         """
 //|         ...
 //|
 
@@ -286,10 +291,15 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_obj, 1, busio_spi_write);
 //|         The SPI object must be locked.
 //|         If the number of bytes to read is 0, nothing happens.
 //|
-//|         :param ~_typing.WriteableBuffer buffer: Read data into this buffer
-//|         :param int start: Start of the slice of ``buffer`` to read into: ``buffer[start:end]``
-//|         :param int end: End of the slice; this index is not included. Defaults to ``len(buffer)``
-//|         :param int write_value: Value to write while reading. (Usually ignored.)"""
+//|         If ``start`` or ``end`` is provided, then the buffer will be sliced
+//|         as if ``buffer[start:end]`` were passed.
+//|         The number of bytes read will be the length of ``buffer[start:end]``.
+//|
+//|         :param WriteableBuffer buffer: read bytes into this buffer
+//|         :param int start: beginning of buffer slice
+//|         :param int end: end of buffer slice; if not specified, use ``len(buffer)``
+//|         :param int write_value: value to write while reading
+//|         """
 //|         ...
 //|
 
@@ -326,27 +336,37 @@ STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_m
 MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 1, busio_spi_readinto);
 
 //|     import sys
-//|     def write_readinto(self, buffer_out: ReadableBuffer, buffer_in: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
-//|         """Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
+//|     def write_readinto(self, out_buffer: ReadableBuffer, in_buffer: WriteableBuffer, *, out_start: int = 0, out_end: int = sys.maxsize, in_start: int = 0, in_end: int = sys.maxsize) -> None:
+//|         """Write out the data in ``out_buffer`` while simultaneously reading data into ``in_buffer``.
 //|         The SPI object must be locked.
-//|         The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
-//|         must be equal.
+//|
+//|         If ``out_start`` or ``out_end`` is provided, then the buffer will be sliced
+//|         as if ``out_buffer[out_start:out_end]`` were passed, but without copying the data.
+//|         The number of bytes written will be the length of ``out_buffer[out_start:out_end]``.
+//|
+//|         If ``in_start`` or ``in_end`` is provided, then the input buffer will be sliced
+//|         as if ``in_buffer[in_start:in_end]`` were passed,
+//|         The number of bytes read will be the length of ``out_buffer[in_start:in_end]``.
+//|
+//|         The lengths of the slices defined by ``out_buffer[out_start:out_end]``
+//|         and ``in_buffer[in_start:in_end]`` must be equal.
 //|         If buffer slice lengths are both 0, nothing happens.
 //|
-//|         :param ~_typing.ReadableBuffer buffer_out: Write out the data in this buffer
-//|         :param ~_typing.WriteableBuffer buffer_in: Read data into this buffer
-//|         :param int out_start: Start of the slice of buffer_out to write out: ``buffer_out[out_start:out_end]``
-//|         :param int out_end: End of the slice; this index is not included. If not specified, use ``len(buffer_out)``
-//|         :param int in_start: Start of the slice of ``buffer_in`` to read into: ``buffer_in[in_start:in_end]``
-//|         :param int in_end: End of the slice; this index is not included. If not specified, use ``len(buffer_in)``"""
+//|         :param ReadableBuffer out_buffer: write out bytes from this buffer
+//|         :param WriteableBuffer in_buffer: read bytes into this buffer
+//|         :param int out_start: beginning of ``out_buffer`` slice
+//|         :param int out_end: end of ``out_buffer`` slice; if not specified, use ``len(out_buffer)``
+//|         :param int in_start: beginning of ``in_buffer`` slice
+//|         :param int in_end: end of ``in_buffer slice``; if not specified, use ``len(in_buffer)``
+//|         """
 //|         ...
 //|
 
 STATIC mp_obj_t busio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    enum { ARG_buffer_out, ARG_buffer_in, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
+    enum { ARG_out_buffer, ARG_in_buffer, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
     static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_buffer_out,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
-        { MP_QSTR_buffer_in,     MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_out_buffer,    MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
+        { MP_QSTR_in_buffer,     MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
         { MP_QSTR_out_start,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
         { MP_QSTR_out_end,       MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
         { MP_QSTR_in_start,      MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
@@ -359,13 +379,13 @@ STATIC mp_obj_t busio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args
     mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
 
     mp_buffer_info_t buf_out_info;
-    mp_get_buffer_raise(args[ARG_buffer_out].u_obj, &buf_out_info, MP_BUFFER_READ);
+    mp_get_buffer_raise(args[ARG_out_buffer].u_obj, &buf_out_info, MP_BUFFER_READ);
     int32_t out_start = args[ARG_out_start].u_int;
     size_t out_length = buf_out_info.len;
     normalize_buffer_bounds(&out_start, args[ARG_out_end].u_int, &out_length);
 
     mp_buffer_info_t buf_in_info;
-    mp_get_buffer_raise(args[ARG_buffer_in].u_obj, &buf_in_info, MP_BUFFER_WRITE);
+    mp_get_buffer_raise(args[ARG_in_buffer].u_obj, &buf_in_info, MP_BUFFER_WRITE);
     int32_t in_start = args[ARG_in_start].u_int;
     size_t in_length = buf_in_info.len;
     normalize_buffer_bounds(&in_start, args[ARG_in_end].u_int, &in_length);