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Add writeto_then_readfrom to I2C API. Deprecate stop kwarg. 

writeto_then_readfrom has been added to do a write -> no stop ->
repeated start -> read sequence. This is done to match the
capabilities of Blinka on Linux.

Code that uses stop=False will not work correctly on Blinka.
To fix, if stop=False then use writeto_then_readfrom otherwise use
writeto then readfrom_into.

First step in #2082
This commit is contained in:
Scott Shawcroft 2019-07-26 00:18:29 -07:00
parent 18f441ae35
commit 82d436d05e
No known key found for this signature in database
GPG Key ID: 9349BC7E64B1921E
2 changed files with 177 additions and 67 deletions
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124
shared-bindings/bitbangio/I2C.c
View File

@ -175,6 +175,23 @@ MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_unlock_obj, bitbangio_i2c_obj_unlock);
//| :param int start: Index to start writing at
//| :param int end: Index to write up to but not include
//|
// Shared arg parsing for readfrom_into and writeto_then_readfrom.
STATIC void readfrom(bitbangio_i2c_obj_t *self, mp_int_t address, mp_obj_t buffer, int32_t start, mp_int_t end) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_WRITE);
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, end, &length);
if (length == 0) {
mp_raise_ValueError(translate("Buffer must be at least length 1"));
}
uint8_t status = shared_module_bitbangio_i2c_read(self, address, ((uint8_t*)bufinfo.buf) + start, length);
if (status != 0) {
mp_raise_OSError(status);
}
}
STATIC mp_obj_t bitbangio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_start, ARG_end };
static const mp_arg_t allowed_args[] = {
@ -185,33 +202,21 @@ STATIC mp_obj_t bitbangio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_a
};
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(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);
check_lock(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_WRITE);
int32_t start = args[ARG_start].u_int;
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
if (length == 0) {
mp_raise_ValueError(translate("Buffer must be at least length 1"));
}
uint8_t status = shared_module_bitbangio_i2c_read(self,
args[ARG_address].u_int,
((uint8_t*)bufinfo.buf) + start,
length);
if (status != 0) {
mp_raise_OSError(status);
}
readfrom(self, args[ARG_address].u_int, args[ARG_buffer].u_obj, args[ARG_start].u_int,
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);
//| .. method:: writeto(address, buffer, *, start=0, end=None, stop=True)
//|
//| Write the bytes from ``buffer`` to the slave specified by ``address``.
//| Transmits a stop bit if ``stop`` is set.
//| Write the bytes from ``buffer`` to the slave specified by ``address`` and then transmits a
//| stop bit. Use `writeto_then_readfrom` when needing a write, no stop and repeated start
//| 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
@ -224,9 +229,27 @@ MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 3, bitbangio_i2c_rea
//| :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
//| :param bool stop: If true, output an I2C stop condition after the
//| buffer is written
//| :param bool stop: If true, output an I2C stop condition after the buffer is written.
//| Deprecated. Will be removed in 6.x and act as stop=True.
//|
// Shared arg parsing for writeto and writeto_then_readfrom.
STATIC void writeto(bitbangio_i2c_obj_t *self, mp_int_t address, mp_obj_t buffer, int32_t start, mp_int_t end, bool stop) {
// get the buffer to write the data from
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_READ);
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, end, &length);
// do the transfer
uint8_t status = shared_module_bitbangio_i2c_write(self, address,
((uint8_t*) bufinfo.buf) + start, length,
stop);
if (status != 0) {
mp_raise_OSError(status);
}
}
STATIC mp_obj_t bitbangio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_start, ARG_end, ARG_stop };
static const mp_arg_t allowed_args[] = {
@ -242,24 +265,56 @@ STATIC mp_obj_t bitbangio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, m
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);
// get the buffer to write the data from
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_READ);
int32_t start = args[ARG_start].u_int;
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
// do the transfer
uint8_t status = shared_module_bitbangio_i2c_write(self, args[ARG_address].u_int,
((uint8_t*) bufinfo.buf) + start, length, args[ARG_stop].u_bool);
if (status != 0) {
mp_raise_OSError(status);
}
writeto(self, args[ARG_address].u_int, args[ARG_buffer].u_obj, args[ARG_start].u_int,
args[ARG_end].u_int, args[ARG_stop].u_bool);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_writeto);
//| .. method:: writeto_then_readfrom(address, out_buffer, in_buffer, *, out_start=0, out_end=None, in_start=0, in_end=None)
//|
//| Write the bytes from ``out_buffer`` to the slave specified by ``address``, generate no stop
//| bit, generate a repeated start and read into ``in_buffer``.
//|
//| 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.
//|
//| :param int address: 7-bit device address
//| :param bytearray out_buffer: buffer containing the bytes to write
//| :param bytearray 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 in_start: Index to start writing at
//| :param int in_end: Index to write up to but not include. Defaults to ``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 };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ 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} },
{ MP_QSTR_in_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(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);
writeto(self, args[ARG_address].u_int, args[ARG_out_buffer].u_obj, args[ARG_out_start].u_int,
args[ARG_out_end].u_int, false);
readfrom(self, args[ARG_address].u_int, args[ARG_in_buffer].u_obj, args[ARG_in_start].u_int,
args[ARG_in_end].u_int);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_then_readfrom_obj, 3, 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) },
{ MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&default___enter___obj) },
@ -271,6 +326,7 @@ STATIC const mp_rom_map_elem_t bitbangio_i2c_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_writeto), MP_ROM_PTR(&bitbangio_i2c_writeto_obj) },
{ MP_ROM_QSTR(MP_QSTR_readfrom_into), MP_ROM_PTR(&bitbangio_i2c_readfrom_into_obj) },
{ MP_ROM_QSTR(MP_QSTR_writeto_then_readfrom), MP_ROM_PTR(&bitbangio_i2c_writeto_then_readfrom_obj) },
};
STATIC MP_DEFINE_CONST_DICT(bitbangio_i2c_locals_dict, bitbangio_i2c_locals_dict_table);

120
shared-bindings/busio/I2C.c
View File

@ -189,6 +189,23 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_i2c_unlock_obj, busio_i2c_obj_unlock);
//| :param int start: Index to start writing at
//| :param int end: Index to write up to but not include. Defaults to ``len(buffer)``
//|
// Shared arg parsing for readfrom_into and writeto_then_readfrom.
STATIC void readfrom(busio_i2c_obj_t *self, mp_int_t address, mp_obj_t buffer, int32_t start, mp_int_t end) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_WRITE);
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, end, &length);
if (length == 0) {
mp_raise_ValueError(translate("Buffer must be at least length 1"));
}
uint8_t status = common_hal_busio_i2c_read(self, address, ((uint8_t*)bufinfo.buf) + start, length);
if (status != 0) {
mp_raise_OSError(status);
}
}
STATIC mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_start, ARG_end };
static const mp_arg_t allowed_args[] = {
@ -203,21 +220,8 @@ STATIC mp_obj_t busio_i2c_readfrom_into(size_t n_args, const mp_obj_t *pos_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_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_WRITE);
int32_t start = args[ARG_start].u_int;
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
if (length == 0) {
mp_raise_ValueError(translate("Buffer must be at least length 1"));
}
uint8_t status = common_hal_busio_i2c_read(self, args[ARG_address].u_int, ((uint8_t*)bufinfo.buf) + start, length);
if (status != 0) {
mp_raise_OSError(status);
}
readfrom(self, args[ARG_address].u_int, args[ARG_buffer].u_obj, args[ARG_start].u_int,
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);
@ -225,7 +229,9 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 3, busio_i2c_readfrom_in
//| .. method:: writeto(address, buffer, *, start=0, end=None, stop=True)
//|
//| Write the bytes from ``buffer`` to the slave specified by ``address``.
//| Transmits a stop bit if ``stop`` is set.
//| Transmits a stop bit when stop is True. Setting stop=False is deprecated and stop will be
//| removed in CircuitPython 6.x. Use `writeto_then_readfrom` when needing a write, no stop and
//| repeated start 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
@ -238,9 +244,26 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_readfrom_into_obj, 3, busio_i2c_readfrom_in
//| :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. Defaults to ``len(buffer)``
//| :param bool stop: If true, output an I2C stop condition after the
//| buffer is written
//| :param bool stop: If true, output an I2C stop condition after the buffer is written.
//| Deprecated. Will be removed in 6.x and act as stop=True.
//|
// Shared arg parsing for writeto and writeto_then_readfrom.
STATIC void writeto(busio_i2c_obj_t *self, mp_int_t address, mp_obj_t buffer, int32_t start, mp_int_t end, bool stop) {
// get the buffer to write the data from
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_READ);
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, end, &length);
// do the transfer
uint8_t status = common_hal_busio_i2c_write(self, address, ((uint8_t*) bufinfo.buf) + start,
length, stop);
if (status != 0) {
mp_raise_OSError(status);
}
}
STATIC mp_obj_t busio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_address, ARG_buffer, ARG_start, ARG_end, ARG_stop };
static const mp_arg_t allowed_args[] = {
@ -256,25 +279,55 @@ STATIC mp_obj_t busio_i2c_writeto(size_t n_args, const mp_obj_t *pos_args, mp_ma
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);
// get the buffer to write the data from
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_READ);
int32_t start = args[ARG_start].u_int;
uint32_t length = bufinfo.len;
normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
// do the transfer
uint8_t status = common_hal_busio_i2c_write(self, args[ARG_address].u_int,
((uint8_t*) bufinfo.buf) + start, length, args[ARG_stop].u_bool);
if (status != 0) {
mp_raise_OSError(status);
}
writeto(self, args[ARG_address].u_int, args[ARG_buffer].u_obj, args[ARG_start].u_int,
args[ARG_end].u_int, args[ARG_stop].u_bool);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_obj, 1, busio_i2c_writeto);
//| .. method:: writeto_then_readfrom(address, out_buffer, in_buffer, *, out_start=0, out_end=None, in_start=0, in_end=None)
//|
//| Write the bytes from ``out_buffer`` to the slave specified by ``address``, generate no stop
//| bit, generate a repeated start and read into ``in_buffer``.
//|
//| 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.
//|
//| :param int address: 7-bit device address
//| :param bytearray out_buffer: buffer containing the bytes to write
//| :param bytearray 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 in_start: Index to start writing at
//| :param int in_end: Index to write up to but not include. Defaults to ``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) {
enum { ARG_address, 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_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ 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} },
{ 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]);
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);
writeto(self, args[ARG_address].u_int, args[ARG_out_buffer].u_obj, args[ARG_out_start].u_int,
args[ARG_out_end].u_int, false);
readfrom(self, args[ARG_address].u_int, args[ARG_in_buffer].u_obj, args[ARG_in_start].u_int,
args[ARG_in_end].u_int);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(busio_i2c_writeto_then_readfrom_obj, 3, 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) },
{ MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&default___enter___obj) },
@ -286,6 +339,7 @@ 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) },
};
STATIC MP_DEFINE_CONST_DICT(busio_i2c_locals_dict, busio_i2c_locals_dict_table);