circuitpython/extmod/machine_signal.c

// Copyright (c) 2017 Paul Sokolovsky
// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
//
// SPDX-License-Identifier: MIT

#include "py/mpconfig.h"
#if MICROPY_PY_MACHINE

#include <string.h>

#include "py/obj.h"
#include "py/runtime.h"
#include "extmod/virtpin.h"
#include "extmod/machine_signal.h"

// Signal class

typedef struct _machine_signal_t {
    mp_obj_base_t base;
    mp_obj_t pin;
    bool invert;
} machine_signal_t;

STATIC mp_obj_t signal_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
    mp_obj_t pin = args[0];
    bool invert = false;

    #if defined(MICROPY_PY_MACHINE_PIN_MAKE_NEW)
    mp_pin_p_t *pin_p = (mp_pin_t *)mp_proto_get(QSTR_pin_protocol, pin);

    if (pin_p == NULL) {
        // If first argument isn't a Pin-like object, we filter out "invert"
        // from keyword arguments and pass them all to the exported Pin
        // constructor to create one.
        mp_obj_t *pin_args = mp_local_alloc((n_args + n_kw * 2) * sizeof(mp_obj_t));
        memcpy(pin_args, args, n_args * sizeof(mp_obj_t));
        const mp_obj_t *src = args + n_args;
        mp_obj_t *dst = pin_args + n_args;
        mp_obj_t *sig_value = NULL;
        for (size_t cnt = n_kw; cnt; cnt--) {
            if (*src == MP_OBJ_NEW_QSTR(MP_QSTR_invert)) {
                invert = mp_obj_is_true(src[1]);
                n_kw--;
            } else {
                *dst++ = *src;
                *dst++ = src[1];
            }
            if (*src == MP_OBJ_NEW_QSTR(MP_QSTR_value)) {
                // Value is pertained to Signal, so we should invert
                // it for Pin if needed, and we should do it only when
                // inversion status is guaranteedly known.
                sig_value = dst - 1;
            }
            src += 2;
        }

        if (invert && sig_value != NULL) {
            *sig_value = mp_obj_is_true(*sig_value) ? MP_OBJ_NEW_SMALL_INT(0) : MP_OBJ_NEW_SMALL_INT(1);
        }

        // Here we pass NULL as a type, hoping that mp_pin_make_new()
        // will just ignore it as set a concrete type. If not, we'd need
        // to expose port's "default" pin type too.
        pin = MICROPY_PY_MACHINE_PIN_MAKE_NEW(NULL, n_args, n_kw, pin_args);

        mp_local_free(pin_args);
    } else
    #endif
    // Otherwise there should be 1 or 2 args
    {
        if (n_args == 1) {
            if (kw_args == NULL || kw_args->used == 0) {
            } else if (kw_args->used == 1 && kw_args->table[0].key == MP_OBJ_NEW_QSTR(MP_QSTR_invert)) {
                invert = mp_obj_is_true(kw_args->table[0].value);
            } else {
                goto error;
            }
        } else {
        error:
            mp_raise_TypeError(NULL);
        }
    }

    machine_signal_t *o = m_new_obj(machine_signal_t);
    o->base.type = type;
    o->pin = pin;
    o->invert = invert;
    return MP_OBJ_FROM_PTR(o);
}

STATIC mp_uint_t signal_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
    (void)errcode;
    machine_signal_t *self = MP_OBJ_TO_PTR(self_in);

    switch (request) {
        case MP_PIN_READ: {
            return mp_virtual_pin_read(self->pin) ^ self->invert;
        }
        case MP_PIN_WRITE: {
            mp_virtual_pin_write(self->pin, arg ^ self->invert);
            return 0;
        }
    }
    return -1;
}

// fast method for getting/setting signal value
STATIC mp_obj_t signal_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
    mp_arg_check_num_kw_array(n_args, n_kw, 0, 1, false);
    if (n_args == 0) {
        // get pin
        return MP_OBJ_NEW_SMALL_INT(mp_virtual_pin_read(self_in));
    } else {
        // set pin
        mp_virtual_pin_write(self_in, mp_obj_is_true(args[0]));
        return mp_const_none;
    }
}

STATIC mp_obj_t signal_value(size_t n_args, const mp_obj_t *args) {
    return signal_call(args[0], n_args - 1, 0, args + 1);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(signal_value_obj, 1, 2, signal_value);

STATIC mp_obj_t signal_on(mp_obj_t self_in) {
    mp_virtual_pin_write(self_in, 1);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(signal_on_obj, signal_on);

STATIC mp_obj_t signal_off(mp_obj_t self_in) {
    mp_virtual_pin_write(self_in, 0);
    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(signal_off_obj, signal_off);

STATIC const mp_rom_map_elem_t signal_locals_dict_table[] = {
    { MP_ROM_QSTR(MP_QSTR_value), MP_ROM_PTR(&signal_value_obj) },
    { MP_ROM_QSTR(MP_QSTR_on), MP_ROM_PTR(&signal_on_obj) },
    { MP_ROM_QSTR(MP_QSTR_off), MP_ROM_PTR(&signal_off_obj) },
};

STATIC MP_DEFINE_CONST_DICT(signal_locals_dict, signal_locals_dict_table);

STATIC const mp_pin_p_t signal_pin_p = {
    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_pin)
    .ioctl = signal_ioctl,
};

const mp_obj_type_t machine_signal_type = {
    { &mp_type_type },
    .name = MP_QSTR_Signal,
    .make_new = signal_make_new,
    .call = signal_call,
    .protocol = &signal_pin_p,
    .locals_dict = (void *)&signal_locals_dict,
};

#endif // MICROPY_PY_MACHINE