owb.c

/*
 * MIT License
 *
 * Copyright (c) 2017 David Antliff
 * Copyright (c) 2017 Chris Morgan <chmorgan@gmail.com>
 *
 * 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.
 */

/**
 * @file
 */

#include <stddef.h>
#include <stdbool.h>
#include <inttypes.h>
#include <string.h>
#include <stdlib.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "sdkconfig.h"
#include "driver/gpio.h"
#include "rom/gpio.h"       // for gpio_pad_select_gpio()

#include "owb.h"
#include "owb_gpio.h"

static const char * TAG = "owb";

static bool _is_init(const OneWireBus * bus)
{
    bool ok = false;
    if (bus != NULL)
    {
        if (bus->driver)
        {
            // OK
            ok = true;
        }
        else
        {
            ESP_LOGE(TAG, "bus is not initialised");
        }
    }
    else
    {
        ESP_LOGE(TAG, "bus is NULL");
    }
    return ok;
}

/**
 * @brief 1-Wire 8-bit CRC lookup.
 * @param[in] crc Starting CRC value. Pass in prior CRC to accumulate.
 * @param[in] data Byte to feed into CRC.
 * @return Resultant CRC value.
 */
static uint8_t _calc_crc(uint8_t crc, uint8_t data)
{
    // https://www.maximintegrated.com/en/app-notes/index.mvp/id/27
    static const uint8_t table[256] = {
            0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
            157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
            35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
            190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
            70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
            219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
            101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
            248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
            140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
            17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
            175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
            50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
            202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
            87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
            233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
            116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
    };

    return table[crc ^ data];
}

static uint8_t _calc_crc_block(uint8_t crc, const uint8_t * buffer, size_t len)
{
    do
    {
        crc = _calc_crc(crc, *buffer++);
        ESP_LOGD(TAG, "buffer 0x%02x, crc 0x%02x, len %d", (uint8_t)*(buffer - 1), (int)crc, (int)len);
    }
    while (--len > 0);
    return crc;
}

/**
 * @param[out] is_found true if a device was found, false if not
 * @return status
 */
static owb_status _search(const OneWireBus * bus, OneWireBus_SearchState * state, bool * is_found)
{
    // Based on https://www.maximintegrated.com/en/app-notes/index.mvp/id/187

    // initialize for search
    int id_bit_number = 1;
    int last_zero = 0;
    int rom_byte_number = 0;
    uint8_t id_bit = 0;
    uint8_t cmp_id_bit = 0;
    uint8_t rom_byte_mask = 1;
    uint8_t search_direction = 0;
    bool search_result = false;
    uint8_t crc8 = 0;
    owb_status status = OWB_STATUS_NOT_SET;

    // if the last call was not the last one
    if (!state->last_device_flag)
    {
        // 1-Wire reset
        bool is_present;
        bus->driver->reset(bus, &is_present);
        if (!is_present)
        {
            // reset the search
            state->last_discrepancy = 0;
            state->last_device_flag = false;
            state->last_family_discrepancy = 0;
            *is_found = false;
            return OWB_STATUS_OK;
        }

        // issue the search command
        bus->driver->write_bits(bus, OWB_ROM_SEARCH, 8);

        // loop to do the search
        do
        {
            id_bit = cmp_id_bit = 0;

            // read a bit and its complement
            bus->driver->read_bits(bus, &id_bit, 1);
            bus->driver->read_bits(bus, &cmp_id_bit, 1);

            // check for no devices on 1-wire (signal level is high in both bit reads)
            if (id_bit && cmp_id_bit)
            {
                break;
            }
            else
            {
                // all devices coupled have 0 or 1
                if (id_bit != cmp_id_bit)
                {
                    search_direction = (id_bit) ? 1 : 0;  // bit write value for search
                }
                else
                {
                    // if this discrepancy if before the Last Discrepancy
                    // on a previous next then pick the same as last time
                    if (id_bit_number < state->last_discrepancy)
                    {
                        search_direction = ((state->rom_code.bytes[rom_byte_number] & rom_byte_mask) > 0);
                    }
                    else
                    {
                        // if equal to last pick 1, if not then pick 0
                        search_direction = (id_bit_number == state->last_discrepancy);
                    }

                    // if 0 was picked then record its position in LastZero
                    if (search_direction == 0)
                    {
                        last_zero = id_bit_number;

                        // check for Last discrepancy in family
                        if (last_zero < 9)
                        {
                            state->last_family_discrepancy = last_zero;
                        }
                    }
                }

                // set or clear the bit in the ROM byte rom_byte_number
                // with mask rom_byte_mask
                if (search_direction == 1)
                {
                    state->rom_code.bytes[rom_byte_number] |= rom_byte_mask;
                }
                else
                {
                    state->rom_code.bytes[rom_byte_number] &= ~rom_byte_mask;
                }

                // serial number search direction write bit
                bus->driver->write_bits(bus, search_direction, 1);

                // increment the byte counter id_bit_number
                // and shift the mask rom_byte_mask
                id_bit_number++;
                rom_byte_mask <<= 1;

                // if the mask is 0 then go to new SerialNum byte rom_byte_number and reset mask
                if (rom_byte_mask == 0)
                {
                    crc8 = owb_crc8_byte(crc8, state->rom_code.bytes[rom_byte_number]);  // accumulate the CRC
                    rom_byte_number++;
                    rom_byte_mask = 1;
                }
            }
        }
        while (rom_byte_number < 8);  // loop until through all ROM bytes 0-7

        // if the search was successful then
        if (!((id_bit_number < 65) || (crc8 != 0)))
        {
            // search successful so set LastDiscrepancy,LastDeviceFlag,search_result
            state->last_discrepancy = last_zero;

            // check for last device
            if (state->last_discrepancy == 0)
            {
                state->last_device_flag = true;
            }

            search_result = true;
        }
    }

    // if no device found then reset counters so next 'search' will be like a first
    if (!search_result || !state->rom_code.bytes[0])
    {
        state->last_discrepancy = 0;
        state->last_device_flag = false;
        state->last_family_discrepancy = 0;
        search_result = false;
    }

    status = OWB_STATUS_OK;

    *is_found = search_result;

    return status;
}

// Public API

owb_status owb_uninitialize(OneWireBus * bus)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bus->driver->uninitialize(bus);
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_use_crc(OneWireBus * bus, bool use_crc)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bus->use_crc = use_crc;
        ESP_LOGD(TAG, "use_crc %d", bus->use_crc);

        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_use_parasitic_power(OneWireBus * bus, bool use_parasitic_power)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bus->use_parasitic_power = use_parasitic_power;
        ESP_LOGD(TAG, "use_parasitic_power %d", bus->use_parasitic_power);

        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_use_strong_pullup_gpio(OneWireBus * bus, gpio_num_t gpio)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        if (gpio != GPIO_NUM_NC) {
            // The strong GPIO pull-up is only activated if parasitic-power mode is enabled
            if (!bus->use_parasitic_power) {
                ESP_LOGW(TAG, "Strong pull-up GPIO set with parasitic-power disabled");
            }

            gpio_pad_select_gpio(gpio);
            gpio_set_direction(gpio, GPIO_MODE_OUTPUT);
        }
        else
        {
            gpio_reset_pin(bus->strong_pullup_gpio);
        }

        bus->strong_pullup_gpio = gpio;
        ESP_LOGD(TAG, "use_strong_pullup_gpio %d", bus->strong_pullup_gpio);

        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_read_rom(const OneWireBus * bus, OneWireBus_ROMCode *rom_code)
{
    owb_status status = OWB_STATUS_NOT_SET;

    memset(rom_code, 0, sizeof(OneWireBus_ROMCode));

    if (!bus || !rom_code)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bool is_present;
        bus->driver->reset(bus, &is_present);
        if (is_present)
        {
            uint8_t value = OWB_ROM_READ;
            bus->driver->write_bits(bus, value, 8);
            owb_read_bytes(bus, rom_code->bytes, sizeof(OneWireBus_ROMCode));

            if (bus->use_crc)
            {
                if (owb_crc8_bytes(0, rom_code->bytes, sizeof(OneWireBus_ROMCode)) != 0)
                {
                    ESP_LOGE(TAG, "CRC failed");
                    memset(rom_code->bytes, 0, sizeof(OneWireBus_ROMCode));
                    status = OWB_STATUS_CRC_FAILED;
                }
                else
                {
                    status = OWB_STATUS_OK;
                }
            }
            else
            {
                status = OWB_STATUS_OK;
            }
            char rom_code_s[OWB_ROM_CODE_STRING_LENGTH];
            owb_string_from_rom_code(*rom_code, rom_code_s, sizeof(rom_code_s));
            ESP_LOGD(TAG, "rom_code %s", rom_code_s);
        }
        else
        {
            status = OWB_STATUS_DEVICE_NOT_RESPONDING;
            ESP_LOGE(TAG, "ds18b20 device not responding");
        }
    }

    return status;
}

owb_status owb_verify_rom(const OneWireBus * bus, OneWireBus_ROMCode rom_code, bool * is_present)
{
    owb_status status = OWB_STATUS_NOT_SET;
    bool result = false;

    if (!bus || !is_present)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        OneWireBus_SearchState state = {
            .rom_code = rom_code,
            .last_discrepancy = 64,
            .last_device_flag = false,
        };

        bool is_found = false;
        _search(bus, &state, &is_found);
        if (is_found)
        {
            result = true;
            for (int i = 0; i < sizeof(state.rom_code.bytes) && result; ++i)
            {
                result = rom_code.bytes[i] == state.rom_code.bytes[i];
                ESP_LOGD(TAG, "%02x %02x", rom_code.bytes[i], state.rom_code.bytes[i]);
            }
            is_found = result;
        }
        ESP_LOGD(TAG, "state.last_discrepancy %d, state.last_device_flag %d, is_found %d",
                 state.last_discrepancy, state.last_device_flag, is_found);

        ESP_LOGD(TAG, "rom code %sfound", result ? "" : "not ");
        *is_present = result;
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_reset(const OneWireBus * bus, bool * a_device_present)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !a_device_present)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if(!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        status = bus->driver->reset(bus, a_device_present);
    }

    return status;
}

owb_status owb_read_bit(const OneWireBus * bus, uint8_t * out)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !out)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bus->driver->read_bits(bus, out, 1);
        ESP_LOGD(TAG, "owb_read_bit: %02x", *out);
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_read_byte(const OneWireBus * bus, uint8_t * out)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !out)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        bus->driver->read_bits(bus, out, 8);
        ESP_LOGD(TAG, "owb_read_byte: %02x", *out);
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_read_bytes(const OneWireBus * bus, uint8_t * buffer, unsigned int len)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !buffer)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        for (int i = 0; i < len; ++i)
        {
            uint8_t out;
            bus->driver->read_bits(bus, &out, 8);
            buffer[i] = out;
        }

        ESP_LOGD(TAG, "owb_read_bytes, len %d:", len);
        ESP_LOG_BUFFER_HEX_LEVEL(TAG, buffer, len, ESP_LOG_DEBUG);

        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_write_bit(const OneWireBus * bus, const uint8_t bit)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        ESP_LOGD(TAG, "owb_write_bit: %02x", bit);
        bus->driver->write_bits(bus, bit & 0x01u, 1);
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_write_byte(const OneWireBus * bus, uint8_t data)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        ESP_LOGD(TAG, "owb_write_byte: %02x", data);
        bus->driver->write_bits(bus, data, 8);
        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_write_bytes(const OneWireBus * bus, const uint8_t * buffer, size_t len)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !buffer)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        ESP_LOGD(TAG, "owb_write_bytes, len %d:", len);
        ESP_LOG_BUFFER_HEX_LEVEL(TAG, buffer, len, ESP_LOG_DEBUG);

        for (int i = 0; i < len; i++)
        {
            bus->driver->write_bits(bus, buffer[i], 8);
        }

        status = OWB_STATUS_OK;
    }

    return status;
}

owb_status owb_write_rom_code(const OneWireBus * bus, OneWireBus_ROMCode rom_code)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        owb_write_bytes(bus, (uint8_t*)&rom_code, sizeof(rom_code));
        status = OWB_STATUS_OK;
    }

    return status;
}

uint8_t owb_crc8_byte(uint8_t crc, uint8_t data)
{
    return _calc_crc(crc, data);
}

uint8_t owb_crc8_bytes(uint8_t crc, const uint8_t * data, size_t len)
{
    return _calc_crc_block(crc, data, len);
}

owb_status owb_search_first(const OneWireBus * bus, OneWireBus_SearchState * state, bool * found_device)
{
    bool result;
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus || !state || !found_device)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        memset(&state->rom_code, 0, sizeof(state->rom_code));
        state->last_discrepancy = 0;
        state->last_family_discrepancy = 0;
        state->last_device_flag = false;
        _search(bus, state, &result);
        status = OWB_STATUS_OK;

        *found_device = result;
    }

    return status;
}

owb_status owb_search_next(const OneWireBus * bus, OneWireBus_SearchState * state, bool * found_device)
{
    owb_status status = OWB_STATUS_NOT_SET;
    bool result = false;

    if (!bus || !state || !found_device)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        _search(bus, state, &result);
        status = OWB_STATUS_OK;

        *found_device = result;
    }

    return status;
}

char * owb_string_from_rom_code(OneWireBus_ROMCode rom_code, char * buffer, size_t len)
{
    for (int i = sizeof(rom_code.bytes) - 1; i >= 0; i--)
    {
        sprintf(buffer, "%02x", rom_code.bytes[i]);
        buffer += 2;
    }
    return buffer;
}

owb_status owb_set_strong_pullup(const OneWireBus * bus, bool enable)
{
    owb_status status = OWB_STATUS_NOT_SET;

    if (!bus)
    {
        status = OWB_STATUS_PARAMETER_NULL;
    }
    else if (!_is_init(bus))
    {
        status = OWB_STATUS_NOT_INITIALIZED;
    }
    else
    {
        if (bus->use_parasitic_power && bus->strong_pullup_gpio != GPIO_NUM_NC)
        {
            gpio_set_level(bus->strong_pullup_gpio, enable ? 1 : 0);
            ESP_LOGD(TAG, "strong pullup GPIO %d", enable);
        }  // else ignore

        status = OWB_STATUS_OK;
    }

    return status;
}