circuitpython/ports/nrf/common-hal/busio/I2C.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Dan Halbert for Adafruit Industries
* Copyright (c) 2018 Artur Pacholec
* Copyright (c) 2017 hathach
* Copyright (c) 2016 Sandeep Mistry All right reserved.
*
* 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 "shared-bindings/busio/I2C.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "py/mperrno.h"
#include "py/runtime.h"
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#include "supervisor/shared/translate.h"
#include "nrfx_twim.h"
#include "nrfx_spim.h"
#include "nrf_gpio.h"
// all TWI instances have the same max size
// 16 bits for 840, 10 bits for 810, 8 bits for 832
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#define I2C_MAX_XFER_LEN ((1UL << TWIM0_EASYDMA_MAXCNT_SIZE) - 1)
STATIC twim_peripheral_t twim_peripherals[] = {
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#if NRFX_CHECK(NRFX_TWIM0_ENABLED)
// SPIM0 and TWIM0 share an address.
{ .twim = NRFX_TWIM_INSTANCE(0),
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.in_use = false},
#endif
#if NRFX_CHECK(NRFX_TWIM1_ENABLED)
// SPIM1 and TWIM1 share an address.
{ .twim = NRFX_TWIM_INSTANCE(1),
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.in_use = false},
#endif
};
STATIC bool never_reset[MP_ARRAY_SIZE(twim_peripherals)];
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void i2c_reset(void) {
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for (size_t i = 0; i < MP_ARRAY_SIZE(twim_peripherals); i++) {
if (never_reset[i]) {
continue;
}
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nrfx_twim_uninit(&twim_peripherals[i].twim);
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twim_peripherals[i].in_use = false;
}
}
void common_hal_busio_i2c_never_reset(busio_i2c_obj_t *self) {
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for (size_t i = 0; i < MP_ARRAY_SIZE(twim_peripherals); i++) {
if (self->twim_peripheral == &twim_peripherals[i]) {
never_reset[i] = true;
never_reset_pin_number(self->scl_pin_number);
never_reset_pin_number(self->sda_pin_number);
break;
}
}
}
static uint8_t twi_error_to_mp(const nrfx_err_t err) {
switch (err) {
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case NRFX_ERROR_DRV_TWI_ERR_ANACK:
return MP_ENODEV;
case NRFX_ERROR_BUSY:
return MP_EBUSY;
case NRFX_ERROR_DRV_TWI_ERR_DNACK:
case NRFX_ERROR_INVALID_ADDR:
return MP_EIO;
default:
break;
}
return 0;
}
void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
if (scl->number == sda->number) {
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mp_raise_ValueError(translate("Invalid pins"));
}
// Find a free instance.
self->twim_peripheral = NULL;
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for (size_t i = 0; i < MP_ARRAY_SIZE(twim_peripherals); i++) {
if (!twim_peripherals[i].in_use) {
self->twim_peripheral = &twim_peripherals[i];
// Mark it as in_use later after other validation is finished.
break;
}
}
if (self->twim_peripheral == NULL) {
mp_raise_ValueError(translate("All I2C peripherals are in use"));
}
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#if CIRCUITPY_REQUIRE_I2C_PULLUPS
// Test that the pins are in a high state. (Hopefully indicating they are pulled up.)
nrf_gpio_cfg_input(scl->number, NRF_GPIO_PIN_PULLDOWN);
nrf_gpio_cfg_input(sda->number, NRF_GPIO_PIN_PULLDOWN);
common_hal_mcu_delay_us(10);
nrf_gpio_cfg_input(scl->number, NRF_GPIO_PIN_NOPULL);
nrf_gpio_cfg_input(sda->number, NRF_GPIO_PIN_NOPULL);
// We must pull up within 3us to achieve 400khz.
common_hal_mcu_delay_us(3);
if (!nrf_gpio_pin_read(sda->number) || !nrf_gpio_pin_read(scl->number)) {
reset_pin_number(sda->number);
reset_pin_number(scl->number);
mp_raise_RuntimeError(translate("No pull up found on SDA or SCL; check your wiring"));
}
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#endif
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nrfx_twim_config_t config = NRFX_TWIM_DEFAULT_CONFIG(scl->number, sda->number);
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#if defined(TWIM_FREQUENCY_FREQUENCY_K1000)
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if (frequency >= 1000000) {
config.frequency = NRF_TWIM_FREQ_1000K;
} else
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#endif
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if (frequency >= 400000) {
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config.frequency = NRF_TWIM_FREQ_400K;
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} else if (frequency >= 250000) {
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config.frequency = NRF_TWIM_FREQ_250K;
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} else {
config.frequency = NRF_TWIM_FREQ_100K;
}
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self->scl_pin_number = scl->number;
self->sda_pin_number = sda->number;
claim_pin(sda);
claim_pin(scl);
// About to init. If we fail after this point, common_hal_busio_i2c_deinit() will set in_use to false.
self->twim_peripheral->in_use = true;
nrfx_err_t err = nrfx_twim_init(&self->twim_peripheral->twim, &config, NULL, NULL);
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if (err != NRFX_SUCCESS) {
common_hal_busio_i2c_deinit(self);
mp_raise_OSError(MP_EIO);
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}
}
bool common_hal_busio_i2c_deinited(busio_i2c_obj_t *self) {
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return self->sda_pin_number == NO_PIN;
}
void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
if (common_hal_busio_i2c_deinited(self)) {
return;
}
nrfx_twim_uninit(&self->twim_peripheral->twim);
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reset_pin_number(self->sda_pin_number);
reset_pin_number(self->scl_pin_number);
self->sda_pin_number = NO_PIN;
self->scl_pin_number = NO_PIN;
self->twim_peripheral->in_use = false;
}
// nrfx_twim_tx doesn't support 0-length data so we fall back to the hal API
bool common_hal_busio_i2c_probe(busio_i2c_obj_t *self, uint8_t addr) {
NRF_TWIM_Type *reg = self->twim_peripheral->twim.p_twim;
bool found = true;
nrfx_twim_enable(&self->twim_peripheral->twim);
nrf_twim_address_set(reg, addr);
nrf_twim_tx_buffer_set(reg, NULL, 0);
nrf_twim_task_trigger(reg, NRF_TWIM_TASK_RESUME);
nrf_twim_task_trigger(reg, NRF_TWIM_TASK_STARTTX);
while (nrf_twim_event_check(reg, NRF_TWIM_EVENT_TXSTARTED) == 0 &&
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nrf_twim_event_check(reg, NRF_TWIM_EVENT_ERROR) == 0) {
;
}
nrf_twim_event_clear(reg, NRF_TWIM_EVENT_TXSTARTED);
nrf_twim_task_trigger(reg, NRF_TWIM_TASK_STOP);
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while (nrf_twim_event_check(reg, NRF_TWIM_EVENT_STOPPED) == 0) {
;
}
nrf_twim_event_clear(reg, NRF_TWIM_EVENT_STOPPED);
if (nrf_twim_event_check(reg, NRF_TWIM_EVENT_ERROR)) {
nrf_twim_event_clear(reg, NRF_TWIM_EVENT_ERROR);
nrf_twim_errorsrc_get_and_clear(reg);
found = false;
}
nrfx_twim_disable(&self->twim_peripheral->twim);
return found;
}
bool common_hal_busio_i2c_try_lock(busio_i2c_obj_t *self) {
bool grabbed_lock = false;
// NRFX_CRITICAL_SECTION_ENTER();
if (!self->has_lock) {
grabbed_lock = true;
self->has_lock = true;
}
// NRFX_CRITICAL_SECTION_EXIT();
return grabbed_lock;
}
bool common_hal_busio_i2c_has_lock(busio_i2c_obj_t *self) {
return self->has_lock;
}
void common_hal_busio_i2c_unlock(busio_i2c_obj_t *self) {
self->has_lock = false;
}
uint8_t common_hal_busio_i2c_write(busio_i2c_obj_t *self, uint16_t addr, const uint8_t *data, size_t len, bool stopBit) {
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if (len == 0) {
return common_hal_busio_i2c_probe(self, addr) ? 0 : MP_ENODEV;
}
nrfx_err_t err = NRFX_SUCCESS;
nrfx_twim_enable(&self->twim_peripheral->twim);
// break into MAX_XFER_LEN transaction
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while (len) {
const size_t xact_len = MIN(len, I2C_MAX_XFER_LEN);
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nrfx_twim_xfer_desc_t xfer_desc = NRFX_TWIM_XFER_DESC_TX(addr, (uint8_t *)data, xact_len);
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uint32_t const flags = (stopBit ? 0 : NRFX_TWIM_FLAG_TX_NO_STOP);
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if (NRFX_SUCCESS != (err = nrfx_twim_xfer(&self->twim_peripheral->twim, &xfer_desc, flags))) {
break;
}
len -= xact_len;
data += xact_len;
}
nrfx_twim_disable(&self->twim_peripheral->twim);
return twi_error_to_mp(err);
}
uint8_t common_hal_busio_i2c_read(busio_i2c_obj_t *self, uint16_t addr, uint8_t *data, size_t len) {
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if (len == 0) {
return 0;
}
nrfx_err_t err = NRFX_SUCCESS;
nrfx_twim_enable(&self->twim_peripheral->twim);
// break into MAX_XFER_LEN transaction
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while (len) {
const size_t xact_len = MIN(len, I2C_MAX_XFER_LEN);
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nrfx_twim_xfer_desc_t xfer_desc = NRFX_TWIM_XFER_DESC_RX(addr, data, xact_len);
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if (NRFX_SUCCESS != (err = nrfx_twim_xfer(&self->twim_peripheral->twim, &xfer_desc, 0))) {
break;
}
len -= xact_len;
data += xact_len;
}
nrfx_twim_disable(&self->twim_peripheral->twim);
return twi_error_to_mp(err);
}