circuitpython/atmel-samd/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) 2016 Scott Shawcroft
*
* 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 "py/mperrno.h"
#include "py/nlr.h"
#include "py/runtime.h"
#include "asf/sam0/drivers/sercom/i2c/i2c_master.h"
#include "samd21_pins.h"
// We use ENABLE registers below we don't want to treat as a macro.
#undef ENABLE
// Number of times to try to send packet if failed.
#define TIMEOUT 1
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) {
struct i2c_master_config config_i2c_master;
i2c_master_get_config_defaults(&config_i2c_master);
// Struct takes the argument in Khz not Hz.
config_i2c_master.baud_rate = frequency / 1000;
Sercom* sercom = NULL;
uint32_t sda_pinmux = 0;
uint32_t scl_pinmux = 0;
for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
Sercom* potential_sercom = sda->sercom[i].sercom;
if (potential_sercom == NULL ||
potential_sercom->I2CM.CTRLA.bit.ENABLE != 0 ||
sda->sercom[i].pad != 0) {
continue;
}
sda_pinmux = PINMUX(sda->pin, (i == 0) ? MUX_C : MUX_D);
for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
if (potential_sercom == scl->sercom[j].sercom &&
scl->sercom[j].pad == 1) {
scl_pinmux = PINMUX(scl->pin, (j == 0) ? MUX_C : MUX_D);
sercom = potential_sercom;
break;
}
}
if (sercom != NULL) {
break;
}
}
if (sercom == NULL) {
mp_raise_ValueError("Invalid pins");
}
config_i2c_master.pinmux_pad0 = sda_pinmux; // SDA
config_i2c_master.pinmux_pad1 = scl_pinmux; // SCL
config_i2c_master.buffer_timeout = 10000;
self->sda_pin = sda->pin;
self->scl_pin = scl->pin;
claim_pin(sda);
claim_pin(scl);
enum status_code status = i2c_master_init(&self->i2c_master_instance,
sercom, &config_i2c_master);
if (status != STATUS_OK) {
common_hal_busio_i2c_deinit(self);
if (status == STATUS_ERR_BAUDRATE_UNAVAILABLE) {
mp_raise_ValueError("Unsupported baudrate");
} else {
mp_raise_OSError(MP_EIO);
}
}
i2c_master_enable(&self->i2c_master_instance);
}
void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
i2c_master_reset(&self->i2c_master_instance);
reset_pin(self->sda_pin);
reset_pin(self->scl_pin);
}
bool common_hal_busio_i2c_probe(busio_i2c_obj_t *self, uint8_t addr) {
uint8_t buf;
struct i2c_master_packet packet = {
.address = addr,
.data_length = 0,
.data = &buf,
.ten_bit_address = false,
.high_speed = false,
.hs_master_code = 0x0,
};
enum status_code status = i2c_master_write_packet_wait(
&self->i2c_master_instance, &packet);
return status == STATUS_OK;
}
void common_hal_busio_i2c_configure(busio_i2c_obj_t *self,
uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t bits) {
return;
}
bool common_hal_busio_i2c_try_lock(busio_i2c_obj_t *self) {
self->has_lock = i2c_master_lock(&self->i2c_master_instance) == STATUS_OK;
return self->has_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;
i2c_master_unlock(&self->i2c_master_instance);
}
uint8_t common_hal_busio_i2c_write(busio_i2c_obj_t *self, uint16_t addr,
const uint8_t *data, size_t len, bool transmit_stop_bit) {
struct i2c_master_packet packet = {
.address = addr,
.data_length = len,
.data = (uint8_t *) data,
.ten_bit_address = false,
.high_speed = false,
.hs_master_code = 0x0,
};
uint16_t timeout = 0;
enum status_code status = STATUS_BUSY;
while (status != STATUS_OK) {
if (transmit_stop_bit) {
status = i2c_master_write_packet_wait(&self->i2c_master_instance,
&packet);
} else {
status = i2c_master_write_packet_wait_no_stop(
&self->i2c_master_instance, &packet);
}
/* Increment timeout counter and check if timed out. */
if (timeout++ == TIMEOUT) {
break;
}
}
if (status == STATUS_OK) {
return 0;
} else if (status == STATUS_ERR_BAD_ADDRESS) {
return MP_ENODEV;
}
return MP_EIO;
}
uint8_t common_hal_busio_i2c_read(busio_i2c_obj_t *self, uint16_t addr,
uint8_t *data, size_t len) {
struct i2c_master_packet packet = {
.address = addr,
.data_length = len,
.data = data,
.ten_bit_address = false,
.high_speed = false,
.hs_master_code = 0x0,
};
uint16_t timeout = 0;
enum status_code status = STATUS_BUSY;
while (status != STATUS_OK) {
status = i2c_master_read_packet_wait(&self->i2c_master_instance,
&packet);
/* Increment timeout counter and check if timed out. */
if (timeout++ == TIMEOUT) {
break;
}
}
if (status == STATUS_OK) {
return 0;
} else if (status == STATUS_ERR_BAD_ADDRESS) {
return MP_ENODEV;
}
return MP_EIO;
}