circuitpython/ports/cxd56/common-hal/analogio/AnalogIn.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright 2019 Sony Semiconductor Solutions Corporation
 *
 * 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 <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>

#include <arch/chip/scu.h>
#include <arch/chip/adc.h>

#include "py/runtime.h"

#include "shared-bindings/analogio/AnalogIn.h"

typedef struct {
    const char *devpath;
    const mcu_pin_obj_t *pin;
    int fd;
} analogin_dev_t;

STATIC analogin_dev_t analogin_dev[] = {
    {"/dev/lpadc0", &pin_LPADC0, -1},
    {"/dev/lpadc1", &pin_LPADC1, -1},
    {"/dev/lpadc2", &pin_LPADC2, -1},
    {"/dev/lpadc3", &pin_LPADC3, -1},
    {"/dev/hpadc0", &pin_HPADC0, -1},
    {"/dev/hpadc1", &pin_HPADC1, -1},
};

void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const mcu_pin_obj_t *pin) {
    if (!pin->analog) {
        mp_raise_ValueError(translate("AnalogIn not supported on given pin"));
    }

    self->number = -1;

    for (int i = 0; i < MP_ARRAY_SIZE(analogin_dev); i++) {
        if (pin->number == analogin_dev[i].pin->number) {
            self->number = i;
            break;
        }
    }

    if (self->number < 0) {
        mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
    }

    if (analogin_dev[self->number].fd < 0) {
        analogin_dev[self->number].fd = open(analogin_dev[self->number].devpath, O_RDONLY);
        if (analogin_dev[self->number].fd < 0) {
            mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
        }
    }

    // SCU FIFO overwrite
    ioctl(analogin_dev[self->number].fd, SCUIOC_SETFIFOMODE, 1);

    // ADC FIFO size
    ioctl(analogin_dev[self->number].fd, ANIOC_CXD56_FIFOSIZE, 2);

    // start ADC
    ioctl(analogin_dev[self->number].fd, ANIOC_CXD56_START, 0);

    self->pin = pin;
}

void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
    if (common_hal_analogio_analogin_deinited(self)) {
        return;
    }

    // stop ADC
    ioctl(analogin_dev[self->number].fd, ANIOC_CXD56_STOP, 0);
    close(analogin_dev[self->number].fd);
    analogin_dev[self->number].fd = -1;

    self->pin = NULL;
}

bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
    return analogin_dev[self->number].fd < 0;
}

uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
    int16_t value = 0;

    read(analogin_dev[self->number].fd, &value, sizeof(value));

    return (uint16_t)32768 + (uint16_t)value;
}

// Reference voltage is a fixed value which is depending on the board.
// e.g.)
// - Reference Voltage of A2 and A3 pins on Main Board is 0.7V.
// - Reference Voltage of A0 ~ A5 pins on External Interface board is 5.0V
float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
    float voltage;

    if (self->number == 2 || self->number == 3) {
        voltage = 0.0f;
    } else {
        voltage = 5.0f;
    }

    return voltage;
}

void analogin_reset(void) {
    for (int i = 0; i < MP_ARRAY_SIZE(analogin_dev); i++) {
        if (analogin_dev[i].fd >= 0) {
            // stop ADC
            ioctl(analogin_dev[i].fd, ANIOC_CXD56_STOP, 0);
            close(analogin_dev[i].fd);
            analogin_dev[i].fd = -1;
        }
    }
}