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machine_i2c.c
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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/modmachine.h"
#include CLOCK_CONFIG_H
#include "pin.h"
#include "fsl_iomuxc.h"
#include "fsl_lpi2c.h"
#define DEFAULT_I2C_FREQ (400000)
#define DEFAULT_I2C_DRIVE (6)
typedef struct _machine_i2c_obj_t {
mp_obj_base_t base;
LPI2C_Type *i2c_inst;
uint8_t i2c_id;
uint8_t i2c_hw_id;
bool transfer_busy;
status_t transfer_status;
lpi2c_master_config_t *master_config;
} machine_i2c_obj_t;
typedef struct _iomux_table_t {
uint32_t muxRegister;
uint32_t muxMode;
uint32_t inputRegister;
uint32_t inputDaisy;
uint32_t configRegister;
} iomux_table_t;
static const uint8_t i2c_index_table[] = MICROPY_HW_I2C_INDEX;
static LPI2C_Type *i2c_base_ptr_table[] = LPI2C_BASE_PTRS;
static const iomux_table_t iomux_table[] = { IOMUX_TABLE_I2C };
#define MICROPY_HW_I2C_NUM ARRAY_SIZE(i2c_index_table)
#define SCL (iomux_table[index])
#define SDA (iomux_table[index + 1])
bool lpi2c_set_iomux(int8_t hw_i2c, uint8_t drive) {
int index = (hw_i2c - 1) * 2;
uint16_t pad_config = pin_generate_config(PIN_PULL_UP_100K, PIN_MODE_OPEN_DRAIN, drive, SCL.configRegister);
if (SCL.muxRegister != 0) {
IOMUXC_SetPinMux(SCL.muxRegister, SCL.muxMode, SCL.inputRegister, SCL.inputDaisy, SCL.configRegister, 1U);
IOMUXC_SetPinConfig(SCL.muxRegister, SCL.muxMode, SCL.inputRegister, SCL.inputDaisy, SCL.configRegister, pad_config);
IOMUXC_SetPinMux(SDA.muxRegister, SDA.muxMode, SDA.inputRegister, SDA.inputDaisy, SDA.configRegister, 1U);
IOMUXC_SetPinConfig(SDA.muxRegister, SDA.muxMode, SDA.inputRegister, SDA.inputDaisy, SDA.configRegister, pad_config);
return true;
} else {
return false;
}
}
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)",
self->i2c_id, self->master_config->baudRate_Hz);
}
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_drive};
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_drive, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_I2C_DRIVE} },
};
// 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 >= MICROPY_HW_I2C_NUM || i2c_index_table[i2c_id] == 0) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("I2C(%d) doesn't exist"), i2c_id);
}
// Get I2C Object.
machine_i2c_obj_t *self = mp_obj_malloc(machine_i2c_obj_t, &machine_i2c_type);
self->i2c_id = i2c_id;
self->i2c_hw_id = i2c_index_table[i2c_id]; // the hw i2c number 1..n
self->i2c_inst = i2c_base_ptr_table[self->i2c_hw_id];
uint8_t drive = args[ARG_drive].u_int;
if (drive < 1 || drive > 7) {
drive = DEFAULT_I2C_DRIVE;
}
// Initialise the I2C peripheral if any arguments given, or it was not initialised previously.
lpi2c_set_iomux(self->i2c_hw_id, drive);
self->master_config = m_new_obj(lpi2c_master_config_t);
LPI2C_MasterGetDefaultConfig(self->master_config);
// Initialise the I2C peripheral.
self->master_config->baudRate_Hz = args[ARG_freq].u_int;
LPI2C_MasterInit(self->i2c_inst, self->master_config, BOARD_BOOTCLOCKRUN_LPI2C_CLK_ROOT);
return MP_OBJ_FROM_PTR(self);
}
static void lpi2c_master_callback(LPI2C_Type *base, lpi2c_master_handle_t *handle, status_t status, void *self_in) {
machine_i2c_obj_t *self = (machine_i2c_obj_t *)self_in;
self->transfer_busy = false;
self->transfer_status = status;
}
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;
status_t ret;
lpi2c_master_handle_t g_master_handle;
lpi2c_master_transfer_t masterXfer = {0};
LPI2C_MasterTransferCreateHandle(self->i2c_inst, &g_master_handle, lpi2c_master_callback, self);
if (flags & MP_MACHINE_I2C_FLAG_READ) {
masterXfer.direction = kLPI2C_Read;
} else {
masterXfer.direction = kLPI2C_Write;
}
if (addr < 0x80) { // 7 or 10 bit address?
masterXfer.slaveAddress = addr;
} else {
masterXfer.slaveAddress = 0x78 | ((addr >> 8) & 0x03);
masterXfer.subaddress = addr & 0xff;
masterXfer.subaddressSize = 1;
}
masterXfer.data = buf;
masterXfer.dataSize = len;
if (flags & MP_MACHINE_I2C_FLAG_STOP) {
masterXfer.flags = kLPI2C_TransferDefaultFlag;
} else {
masterXfer.flags = kLPI2C_TransferNoStopFlag;
}
self->transfer_busy = true;
// Send master data to slave in non-blocking mode
ret = LPI2C_MasterTransferNonBlocking(self->i2c_inst, &g_master_handle, &masterXfer);
if (ret != kStatus_Success) {
return -MP_EIO;
}
// Wait for the transfer to complete
while (self->transfer_busy) {
MICROPY_EVENT_POLL_HOOK
}
// Transfer will not send a stop in case of errors like NAK. So it's done here.
if (flags & MP_MACHINE_I2C_FLAG_STOP && self->transfer_status != kStatus_Success) {
LPI2C_MasterStop(self->i2c_inst);
}
if (self->transfer_status == kStatus_Success) {
return len;
} else if (self->transfer_status == kStatus_LPI2C_Nak) {
return -MP_ENODEV;
} else {
return -MP_EIO;
}
}
static const mp_machine_i2c_p_t machine_i2c_p = {
.transfer = mp_machine_i2c_transfer_adaptor,
.transfer_single = machine_i2c_transfer_single,
};
MP_DEFINE_CONST_OBJ_TYPE(
machine_i2c_type,
MP_QSTR_I2C,
MP_TYPE_FLAG_NONE,
make_new, machine_i2c_make_new,
print, machine_i2c_print,
protocol, &machine_i2c_p,
locals_dict, &mp_machine_i2c_locals_dict
);