micropython/ports/rp2/machine_i2c.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 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 "py/mphal.h"
#include "py/mperrno.h"
#include "extmod/machine_i2c.h"
#include "modmachine.h"
#include "hardware/i2c.h"
#define DEFAULT_I2C_FREQ (400000)
#ifndef MICROPY_HW_I2C0_SCL
#define MICROPY_HW_I2C0_SCL (9)
#define MICROPY_HW_I2C0_SDA (8)
#endif
#ifndef MICROPY_HW_I2C1_SCL
#define MICROPY_HW_I2C1_SCL (7)
#define MICROPY_HW_I2C1_SDA (6)
#endif
// SDA/SCL on even/odd pins, I2C0/I2C1 on even/odd pairs of pins.
#define IS_VALID_SCL(i2c, pin) (((pin) & 1) == 1 && (((pin) & 2) >> 1) == (i2c))
#define IS_VALID_SDA(i2c, pin) (((pin) & 1) == 0 && (((pin) & 2) >> 1) == (i2c))
typedef struct _machine_i2c_obj_t {
mp_obj_base_t base;
i2c_inst_t *const i2c_inst;
uint8_t i2c_id;
uint8_t scl;
uint8_t sda;
uint32_t freq;
} machine_i2c_obj_t;
STATIC machine_i2c_obj_t machine_i2c_obj[] = {
{{&machine_hw_i2c_type}, i2c0, 0, MICROPY_HW_I2C0_SCL, MICROPY_HW_I2C0_SDA, 0},
{{&machine_hw_i2c_type}, i2c1, 1, MICROPY_HW_I2C1_SCL, MICROPY_HW_I2C1_SDA, 0},
};
STATIC void machine_i2c_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_i2c_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "I2C(%u, freq=%u, scl=%u, sda=%u)",
self->i2c_id, self->freq, self->scl, self->sda);
}
mp_obj_t machine_i2c_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_freq, ARG_scl, ARG_sda };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_freq, MP_ARG_INT, {.u_int = DEFAULT_I2C_FREQ} },
{ MP_QSTR_scl, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_sda, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
};
// Parse args.
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 I2C bus.
int i2c_id = mp_obj_get_int(args[ARG_id].u_obj);
if (i2c_id < 0 || i2c_id >= MP_ARRAY_SIZE(machine_i2c_obj)) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2C(%d) doesn't exist"), i2c_id);
}
// Get static peripheral object.
machine_i2c_obj_t *self = (machine_i2c_obj_t *)&machine_i2c_obj[i2c_id];
// Set SCL/SDA pins if configured.
if (args[ARG_scl].u_obj != mp_const_none) {
int scl = mp_hal_get_pin_obj(args[ARG_scl].u_obj);
if (!IS_VALID_SCL(self->i2c_id, scl)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad SCL pin"));
}
self->scl = scl;
}
if (args[ARG_sda].u_obj != mp_const_none) {
int sda = mp_hal_get_pin_obj(args[ARG_sda].u_obj);
if (!IS_VALID_SDA(self->i2c_id, sda)) {
mp_raise_ValueError(MP_ERROR_TEXT("bad SDA pin"));
}
self->sda = sda;
}
// Initialise the I2C peripheral if any arguments given, or it was not initialised previously.
if (n_args > 1 || n_kw > 0 || self->freq == 0) {
self->freq = args[ARG_freq].u_int;
i2c_init(self->i2c_inst, self->freq);
self->freq = i2c_set_baudrate(self->i2c_inst, self->freq);
gpio_set_function(self->scl, GPIO_FUNC_I2C);
gpio_set_function(self->sda, GPIO_FUNC_I2C);
gpio_set_pulls(self->scl, true, 0);
gpio_set_pulls(self->sda, true, 0);
}
return MP_OBJ_FROM_PTR(self);
}
STATIC int machine_i2c_transfer_single(mp_obj_base_t *self_in, uint16_t addr, size_t len, uint8_t *buf, unsigned int flags) {
machine_i2c_obj_t *self = (machine_i2c_obj_t *)self_in;
int ret;
bool nostop = !(flags & MP_MACHINE_I2C_FLAG_STOP);
if (flags & MP_MACHINE_I2C_FLAG_READ) {
ret = i2c_read_blocking(self->i2c_inst, addr, buf, len, nostop);
} else {
if (len <= 2) {
// Workaround issue with hardware I2C not accepting short writes.
mp_machine_soft_i2c_obj_t soft_i2c = {
.base = { &mp_machine_soft_i2c_type },
.us_delay = 500000 / self->freq + 1,
.us_timeout = 255,
.scl = self->scl,
.sda = self->sda,
};
mp_machine_i2c_buf_t bufs = {
.len = len,
.buf = buf,
};
mp_hal_pin_open_drain(self->scl);
mp_hal_pin_open_drain(self->sda);
ret = mp_machine_soft_i2c_transfer(&soft_i2c.base, addr, 1, &bufs, flags);
gpio_set_function(self->scl, GPIO_FUNC_I2C);
gpio_set_function(self->sda, GPIO_FUNC_I2C);
} else {
ret = i2c_write_blocking(self->i2c_inst, addr, buf, len, nostop);
}
}
return (ret < 0) ? -MP_EIO : ret;
}
STATIC const mp_machine_i2c_p_t machine_i2c_p = {
.transfer = mp_machine_i2c_transfer_adaptor,
.transfer_single = machine_i2c_transfer_single,
};
const mp_obj_type_t machine_hw_i2c_type = {
{ &mp_type_type },
.name = MP_QSTR_I2C,
.print = machine_i2c_print,
.make_new = machine_i2c_make_new,
.protocol = &machine_i2c_p,
.locals_dict = (mp_obj_dict_t *)&mp_machine_i2c_locals_dict,
};