machine_spi.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013-2018 Damien P. George
 *
 * 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.
 */

#include "py/runtime.h"
#include "extmod/machine_spi.h"
#include "spi.h"

/******************************************************************************/
// Implementation of hard SPI for machine module

STATIC const machine_hard_spi_obj_t machine_hard_spi_obj[] = {
    {{&machine_hard_spi_type}, &spi_obj[0]},
    {{&machine_hard_spi_type}, &spi_obj[1]},
    {{&machine_hard_spi_type}, &spi_obj[2]},
    {{&machine_hard_spi_type}, &spi_obj[3]},
    {{&machine_hard_spi_type}, &spi_obj[4]},
    {{&machine_hard_spi_type}, &spi_obj[5]},
};

STATIC void machine_hard_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    machine_hard_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
    spi_print(print, self->spi, false);
}

mp_obj_t machine_hard_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    enum { ARG_id, ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit, ARG_sck, ARG_mosi, ARG_miso };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_id,       MP_ARG_OBJ, {.u_obj = MP_OBJ_NEW_SMALL_INT(-1)} },
        { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 500000} },
        { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
        { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 8} },
        { MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = SPI_FIRSTBIT_MSB} },
        { MP_QSTR_sck,      MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_mosi,     MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_miso,     MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
    };
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    // get static peripheral object
    int spi_id = spi_find_index(args[ARG_id].u_obj);
    const machine_hard_spi_obj_t *self = &machine_hard_spi_obj[spi_id - 1];

    // here we would check the sck/mosi/miso pins and configure them, but it's not implemented
    if (args[ARG_sck].u_obj != MP_OBJ_NULL
        || args[ARG_mosi].u_obj != MP_OBJ_NULL
        || args[ARG_miso].u_obj != MP_OBJ_NULL) {
        mp_raise_ValueError("explicit choice of sck/mosi/miso is not implemented");
    }

    // set the SPI configuration values
    SPI_InitTypeDef *init = &self->spi->spi->Init;
    init->Mode = SPI_MODE_MASTER;

    // these parameters are not currently configurable
    init->Direction = SPI_DIRECTION_2LINES;
    init->NSS = SPI_NSS_SOFT;
    init->TIMode = SPI_TIMODE_DISABLE;
    init->CRCCalculation = SPI_CRCCALCULATION_DISABLE;
    init->CRCPolynomial = 0;

    // set configurable paramaters
    spi_set_params(self->spi, 0xffffffff, args[ARG_baudrate].u_int,
        args[ARG_polarity].u_int, args[ARG_phase].u_int, args[ARG_bits].u_int,
        args[ARG_firstbit].u_int);

    // init the SPI bus
    spi_init(self->spi, false);

    return MP_OBJ_FROM_PTR(self);
}

STATIC void machine_hard_spi_init(mp_obj_base_t *self_in, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    machine_hard_spi_obj_t *self = (machine_hard_spi_obj_t*)self_in;

    enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_baudrate, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
    };
    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);

    // set the SPI configuration values
    spi_set_params(self->spi, 0xffffffff, args[ARG_baudrate].u_int,
        args[ARG_polarity].u_int, args[ARG_phase].u_int, args[ARG_bits].u_int,
        args[ARG_firstbit].u_int);

    // re-init the SPI bus
    spi_init(self->spi, false);
}

STATIC void machine_hard_spi_deinit(mp_obj_base_t *self_in) {
    machine_hard_spi_obj_t *self = (machine_hard_spi_obj_t*)self_in;
    spi_deinit(self->spi);
}

STATIC void machine_hard_spi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
    machine_hard_spi_obj_t *self = (machine_hard_spi_obj_t*)self_in;
    spi_transfer(self->spi, len, src, dest, SPI_TRANSFER_TIMEOUT(len));
}

STATIC const mp_machine_spi_p_t machine_hard_spi_p = {
    .init = machine_hard_spi_init,
    .deinit = machine_hard_spi_deinit,
    .transfer = machine_hard_spi_transfer,
};

const mp_obj_type_t machine_hard_spi_type = {
    { &mp_type_type },
    .name = MP_QSTR_SPI,
    .print = machine_hard_spi_print,
    .make_new = mp_machine_spi_make_new, // delegate to master constructor
    .protocol = &machine_hard_spi_p,
    .locals_dict = (mp_obj_dict_t*)&mp_machine_spi_locals_dict,
};