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circuitpython/shared-bindings/bitbangio/I2C.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Scott Shawcroft
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
// This file contains all of the Python API definitions for the
// bitbangio.I2C class.
#include "shared-bindings/bitbangio/I2C.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/util.h"
#include "lib/utils/buffer_helper.h"
#include "lib/utils/context_manager_helpers.h"
#include "py/mperrno.h"
#include "py/runtime.h"
//| .. currentmodule:: bitbangio
//|
//| :class:`I2C` --- Two wire serial protocol
//| ------------------------------------------
//|
//| .. class:: I2C(scl, sda, \*, frequency=400000)
//|
//| I2C is a two-wire protocol for communicating between devices. At the
//| physical level it consists of 2 wires: SCL and SDA, the clock and data
//| lines respectively.
//|
//| :param ~microcontroller.Pin scl: The clock pin
//| :param ~microcontroller.Pin sda: The data pin
//| :param int frequency: The clock frequency of the bus
//| :param int timeout: The maximum clock stretching timeout in microseconds
//|
STATIC mp_obj_t bitbangio_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *pos_args) {
mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, true);
bitbangio_i2c_obj_t *self = m_new_obj(bitbangio_i2c_obj_t);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(self));
self->base.type = &bitbangio_i2c_type;
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, pos_args + n_args);
enum { ARG_scl, ARG_sda, ARG_frequency, ARG_timeout };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_scl, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_sda, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_frequency, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 255} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, &kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
assert_pin(args[ARG_scl].u_obj, false);
assert_pin(args[ARG_sda].u_obj, false);
const mcu_pin_obj_t* scl = MP_OBJ_TO_PTR(args[ARG_scl].u_obj);
const mcu_pin_obj_t* sda = MP_OBJ_TO_PTR(args[ARG_sda].u_obj);
shared_module_bitbangio_i2c_construct(self, scl, sda, args[ARG_frequency].u_int, args[ARG_timeout].u_int);
return (mp_obj_t)self;
}
//| .. method:: I2C.deinit()
//|
//| Releases control of the underlying hardware so other classes can use it.
//|
STATIC mp_obj_t bitbangio_i2c_obj_deinit(mp_obj_t self_in) {
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
shared_module_bitbangio_i2c_deinit(self);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_deinit_obj, bitbangio_i2c_obj_deinit);
//| .. method:: I2C.__enter__()
//|
//| No-op used in Context Managers.
//|
// Provided by context manager helper.
//| .. method:: I2C.__exit__()
//|
//| Automatically deinitializes the hardware on context exit. See
//| :ref:`lifetime-and-contextmanagers` for more info.
//|
STATIC mp_obj_t bitbangio_i2c_obj___exit__(size_t n_args, const mp_obj_t *args) {
(void)n_args;
shared_module_bitbangio_i2c_deinit(args[0]);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bitbangio_i2c_obj___exit___obj, 4, 4, bitbangio_i2c_obj___exit__);
static void check_lock(bitbangio_i2c_obj_t *self) {
if (!shared_module_bitbangio_i2c_has_lock(self)) {
mp_raise_RuntimeError("Function requires lock");
}
}
//| .. method:: I2C.scan()
//|
//| Scan all I2C addresses between 0x08 and 0x77 inclusive and return a list of
//| those that respond. A device responds if it pulls the SDA line low after
//| its address (including a read bit) is sent on the bus.
//|
STATIC mp_obj_t bitbangio_i2c_scan(mp_obj_t self_in) {
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(self));
check_lock(self);
mp_obj_t list = mp_obj_new_list(0, NULL);
// 7-bit addresses 0b0000xxx and 0b1111xxx are reserved
for (int addr = 0x08; addr < 0x78; ++addr) {
bool success = shared_module_bitbangio_i2c_probe(self, addr);
if (success) {
mp_obj_list_append(list, MP_OBJ_NEW_SMALL_INT(addr));
}
}
return list;
}
MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_scan_obj, bitbangio_i2c_scan);
//| .. method:: I2C.try_lock()
//|
//| Attempts to grab the I2C lock. Returns True on success.
//|
STATIC mp_obj_t bitbangio_i2c_obj_try_lock(mp_obj_t self_in) {
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(self));
return mp_obj_new_bool(shared_module_bitbangio_i2c_try_lock(self));
}
MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_try_lock_obj, bitbangio_i2c_obj_try_lock);
//| .. method:: I2C.unlock()
//|
//| Releases the I2C lock.
//|
STATIC mp_obj_t bitbangio_i2c_obj_unlock(mp_obj_t self_in) {
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(self));
shared_module_bitbangio_i2c_unlock(self);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(bitbangio_i2c_unlock_obj, bitbangio_i2c_obj_unlock);
//| .. method:: I2C.readfrom_into(address, buffer, \*, start=0, end=len(buffer))
//|
//| Read into ``buffer`` from the slave specified 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.
//|
//| :param int address: 7-bit device address
//| :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
//|
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[] = {
{ MP_QSTR_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(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("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);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_readfrom_into_obj, 3, bitbangio_i2c_readfrom_into);
//| .. method:: I2C.writeto(address, buffer, \*, start=0, end=len(buffer), stop=True)
//|
//| Write the bytes from ``buffer`` to the slave specified by ``address``.
//| Transmits a stop bit if ``stop`` is set.
//|
//| 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.
//|
//| 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 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
//|
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[] = {
{ MP_QSTR_address, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
{ MP_QSTR_stop, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = true} },
};
bitbangio_i2c_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
raise_error_if_deinited(shared_module_bitbangio_i2c_deinited(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);
// 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);
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bitbangio_i2c_writeto_obj, 1, bitbangio_i2c_writeto);
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) },
{ MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&bitbangio_i2c_obj___exit___obj) },
{ MP_ROM_QSTR(MP_QSTR_scan), MP_ROM_PTR(&bitbangio_i2c_scan_obj) },
{ MP_ROM_QSTR(MP_QSTR_try_lock), MP_ROM_PTR(&bitbangio_i2c_try_lock_obj) },
{ MP_ROM_QSTR(MP_QSTR_unlock), MP_ROM_PTR(&bitbangio_i2c_unlock_obj) },
{ 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) },
};
STATIC MP_DEFINE_CONST_DICT(bitbangio_i2c_locals_dict, bitbangio_i2c_locals_dict_table);
const mp_obj_type_t bitbangio_i2c_type = {
{ &mp_type_type },
.name = MP_QSTR_I2C,
.make_new = bitbangio_i2c_make_new,
.locals_dict = (mp_obj_dict_t*)&bitbangio_i2c_locals_dict,
};
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