circuitpython/shared-module/adafruit_bus_device/spi_device/SPIDevice.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2020 Mark Komus
 *
 * 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/adafruit_bus_device/spi_device/SPIDevice.h"
#include "shared-bindings/busio/SPI.h"
#include "shared-bindings/digitalio/DigitalInOut.h"
#include "py/mperrno.h"
#include "py/nlr.h"
#include "py/runtime.h"

void common_hal_adafruit_bus_device_spidevice_construct(adafruit_bus_device_spidevice_obj_t *self, busio_spi_obj_t *spi,  digitalio_digitalinout_obj_t *cs,
    bool cs_active_value, uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t extra_clocks) {
    self->spi = spi;
    self->baudrate = baudrate;
    self->polarity = polarity;
    self->phase = phase;
    self->extra_clocks = extra_clocks;
    // May be mp_const_none if CS not used.
    self->chip_select = cs;
    self->cs_active_value = cs_active_value;
}

mp_obj_t common_hal_adafruit_bus_device_spidevice_enter(adafruit_bus_device_spidevice_obj_t *self) {
    {
        mp_obj_t dest[2];
        mp_load_method(self->spi, MP_QSTR_try_lock, dest);

        while (!mp_obj_is_true(mp_call_method_n_kw(0, 0, dest))) {
            mp_handle_pending(true);
        }
    }

    {
        mp_obj_t dest[10];
        mp_load_method(self->spi, MP_QSTR_configure, dest);
        dest[2] = MP_OBJ_NEW_QSTR(MP_QSTR_baudrate);
        dest[3] = MP_OBJ_NEW_SMALL_INT(self->baudrate);
        dest[4] = MP_OBJ_NEW_QSTR(MP_QSTR_polarity);
        dest[5] = MP_OBJ_NEW_SMALL_INT(self->polarity);
        dest[6] = MP_OBJ_NEW_QSTR(MP_QSTR_phase);
        dest[7] = MP_OBJ_NEW_SMALL_INT(self->phase);
        dest[8] = MP_OBJ_NEW_QSTR(MP_QSTR_bits);
        dest[9] = MP_OBJ_NEW_SMALL_INT(8);
        mp_call_method_n_kw(0, 4, dest);
    }

    if (self->chip_select != mp_const_none) {
        common_hal_digitalio_digitalinout_set_value(MP_OBJ_TO_PTR(self->chip_select), self->cs_active_value);
    }
    return self->spi;
}

void common_hal_adafruit_bus_device_spidevice_exit(adafruit_bus_device_spidevice_obj_t *self) {
    if (self->chip_select != mp_const_none) {
        common_hal_digitalio_digitalinout_set_value(MP_OBJ_TO_PTR(self->chip_select), !(self->cs_active_value));
    }

    if (self->extra_clocks > 0) {

        mp_buffer_info_t bufinfo;
        mp_obj_t buffer = mp_obj_new_bytearray_of_zeros(1);

        mp_get_buffer_raise(buffer, &bufinfo, MP_BUFFER_WRITE);
        ((uint8_t *)bufinfo.buf)[0] = 0xFF;

        uint8_t clocks = (self->extra_clocks + 7) / 8;

        mp_obj_t dest[3];
        mp_load_method(self->spi, MP_QSTR_write, dest);
        dest[2] = buffer;
        while (clocks > 0) {
            mp_call_method_n_kw(1, 0, dest);
            clocks--;
        }
    }

    mp_obj_t dest[2];
    mp_load_method(self->spi, MP_QSTR_unlock, dest);
    mp_call_method_n_kw(0, 0, dest);
}