micropython/stmhal/machine_i2c.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 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 <stdio.h>
#include <string.h>

#include "py/runtime.h"
#include "py/mphal.h"
#include "extmod/machine_i2c.h"
#include "genhdr/pins.h"

// for now we use the SW I2C implementation for the HW peripheral I2C blocks
typedef mp_machine_soft_i2c_obj_t machine_hard_i2c_obj_t;

STATIC const mp_obj_type_t machine_hard_i2c_type;

STATIC machine_hard_i2c_obj_t machine_hard_i2c_obj[] = {
    #if defined(MICROPY_HW_I2C1_SCL)
    {{&machine_hard_i2c_type}, 1, 500, &MICROPY_HW_I2C1_SCL, &MICROPY_HW_I2C1_SDA},
    #else
    {{NULL}, 0, 0, NULL, NULL},
    #endif
    #if defined(MICROPY_HW_I2C2_SCL)
    {{&machine_hard_i2c_type}, 1, 500, &MICROPY_HW_I2C2_SCL, &MICROPY_HW_I2C2_SDA},
    #else
    {{NULL}, 0, 0, NULL, NULL},
    #endif
    #if defined(MICROPY_HW_I2C3_SCL)
    {{&machine_hard_i2c_type}, 1, 500, &MICROPY_HW_I2C3_SCL, &MICROPY_HW_I2C3_SDA},
    #else
    {{NULL}, 0, 0, NULL, NULL},
    #endif
};

STATIC void machine_hard_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    machine_hard_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
    mp_printf(print, "I2C(%u, scl=%q, sda=%q, freq=%u, timeout=%u)",
        self - &machine_hard_i2c_obj[0] + 1,
        self->scl->name, self->sda->name, 500000 / self->us_delay, self->us_timeout);
}

mp_obj_t machine_hard_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    // parse args
    enum { ARG_id, ARG_scl, ARG_sda, ARG_freq, ARG_timeout };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
        { MP_QSTR_scl, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_sda, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
        { MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
        { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
    };
    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);

    // work out i2c bus
    int i2c_id = 0;
    if (MP_OBJ_IS_STR(args[ARG_id].u_obj)) {
        const char *port = mp_obj_str_get_str(args[ARG_id].u_obj);
        if (0) {
        #ifdef MICROPY_HW_I2C1_NAME
        } else if (strcmp(port, MICROPY_HW_I2C1_NAME) == 0) {
            i2c_id = 1;
        #endif
        #ifdef MICROPY_HW_I2C2_NAME
        } else if (strcmp(port, MICROPY_HW_I2C2_NAME) == 0) {
            i2c_id = 2;
        #endif
        #ifdef MICROPY_HW_I2C3_NAME
        } else if (strcmp(port, MICROPY_HW_I2C3_NAME) == 0) {
            i2c_id = 3;
        #endif
        } else {
            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
                "I2C(%s) does not exist", port));
        }
    } else {
        i2c_id = mp_obj_get_int(args[ARG_id].u_obj);
        if (i2c_id < 1 || i2c_id > MP_ARRAY_SIZE(machine_hard_i2c_obj)
            || machine_hard_i2c_obj[i2c_id - 1].base.type == NULL) {
            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
                "I2C(%d) does not exist", i2c_id));
        }
    }

    // get static peripheral object
    machine_hard_i2c_obj_t *self = &machine_hard_i2c_obj[i2c_id - 1];

    // here we would check the scl/sda pins and configure them, but it's not implemented
    if (args[ARG_scl].u_obj != MP_OBJ_NULL || args[ARG_sda].u_obj != MP_OBJ_NULL) {
        mp_raise_ValueError("explicit choice of scl/sda is not implemented");
    }

    // set parameters
    if (args[ARG_freq].u_int != -1) {
        if (args[ARG_freq].u_int >= 1000000) {
            // allow fastest possible bit-bang rate
            self->us_delay = 0;
        } else {
            self->us_delay = 500000 / args[ARG_freq].u_int;
            if (self->us_delay == 0) {
                self->us_delay = 1;
            }
        }
    }
    if (args[ARG_timeout].u_int != -1) {
        self->us_timeout = args[ARG_timeout].u_int;
    }

    // init pins
    mp_hal_pin_open_drain(self->scl);
    mp_hal_pin_open_drain(self->sda);

    return MP_OBJ_FROM_PTR(self);
}

STATIC const mp_machine_i2c_p_t machine_hard_i2c_p = {
    .readfrom = mp_machine_soft_i2c_readfrom,
    .writeto = mp_machine_soft_i2c_writeto,
};

STATIC const mp_obj_type_t machine_hard_i2c_type = {
    { &mp_type_type },
    .name = MP_QSTR_I2C,
    .print = machine_hard_i2c_print,
    .make_new = machine_hard_i2c_make_new,
    .protocol = &machine_hard_i2c_p,
    .locals_dict = (mp_obj_dict_t*)&mp_machine_soft_i2c_locals_dict,
};