// Необходимые заголовочные файлы
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <linux/i2c-dev.h>

///

int main()
{
	int fdev = open("/dev/i2c-1", O_RDWR);  // открываем i2c шину

	if (fdev < 0) {
		fprintf(stderr, "Failed to open I2C interface %s Error: %s\n", dev_path, strerror(errno));
		return -1;
	}

	unsigned char i2c_addr = 0x5A;

	// устанавливаем адрес подчиненного устройства, в нашем случае 0x5A
	if (ioctl(fdev, I2C_SLAVE, i2c_addr) < 0) {
		fprintf(stderr, "Failed to select I2C slave device! Error: %s\n", strerror(errno));
		return -1;
	}

	// включаем проверку контрольных сумм, дабы не было проблем
	if (ioctl(fdev, I2C_PEC, 1) < 0) {
		fprintf(stderr, "Failed to enable SMBus packet error checking, error: %s\n", strerror(errno));
		return -1;
	}


	// пробуем что-нибудь спросить у устройства, отправив SMBus READ запрос

	i2c_data data;
	char command = 0x06; // команда 0x06 означает прочитать значение термопарного датчика.

	struct i2c_smbus_ioctl_data sdat = {
		.read_write = I2C_SMBUS_READ, 
		.command = command,
		.size = I2C_SMBUS_WORD_DATA,
		.data = &data
	};

	if (ioctl(fdev, I2C_SMBUS, &sdat) < 0) {
		fprintf(stderr, "Failed to perfom I2C_SMBUS transaction, error: %s\n", strerror(errno));
		return -1;
	}

	// выполняем вычисление значения температуры, как описано в даташите
	double temp = (double) data.word;
	temp = (temp * 0.02)-0.01;
	temp = temp - 273.15;

	// печатаем результат в цельсиях
	printf("Tamb = %04.2f\n", temp);

	return 0;
}

// RAM
#define MLX90614_RAWIR1 0x04
#define MLX90614_RAWIR2 0x05
#define MLX90614_TA 0x06
#define MLX90614_TOBJ1 0x07
#define MLX90614_TOBJ2 0x08

// EEPROM
#define MLX90614_TOMAX 0x20
#define MLX90614_TOMIN 0x21
#define MLX90614_PWMCTRL 0x22
#define MLX90614_TARANGE 0x23
#define MLX90614_EMISS 0x24
#define MLX90614_CONFIG 0x25
#define MLX90614_ADDR 0x2E
#define MLX90614_ID1 0x1C
#define MLX90614_ID2 0x1D
#define MLX90614_ID3 0x1E
#define MLX90614_ID4 0x1F

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <linux/i2c-dev.h>
#include <errno.h>
#include "mlx_addrs.h"

// buffer for data reading or writing
typedef union i2c_smbus_data i2c_data;


static int DEBUG_MODE = 0;

extern const char* __progname;
///

int get_device(const int bus_num, const unsigned char i2c_addr)
{
        char dev_path[11] = { 0 };

        // construct path to i2c device
        snprintf(dev_path, 11, "/dev/i2c-%i", bus_num);

        if (DEBUG_MODE) {
                fprintf(stderr, "Opening i2c interface %s\n", dev_path);
        }

        int fdev = open(dev_path, O_RDWR);

        if (fdev < 0) {
                fprintf(stderr, "Failed to open I2C interface %s Error: %s\n", dev_path, strerror(errno));
                return -1;
        }

        if (DEBUG_MODE) {
                fprintf(stderr, "Setting up slave address 0x%02X\n", i2c_addr);
        }

        // set addr of the slave i2c device
        if (ioctl(fdev, I2C_SLAVE, i2c_addr) < 0) {
                fprintf(stderr, "Failed to select I2C slave device! Error: %s\n", strerror(errno));
                return -1;
        }





        // enable checksums
        if (ioctl(fdev, I2C_PEC, 1) < 0) {
                fprintf(stderr, "Failed to enable SMBus packet error checking, error: %s\n", strerror(errno));
                return -1;
        }

        return fdev;
}

int talk_to_device(const int fdev, const int read, const char command, i2c_data* data)
{
        // initialize i2c_smus structure for combined write/read request to device
        struct i2c_smbus_ioctl_data sdat = {
                .read_write = (read ? I2C_SMBUS_READ : I2C_SMBUS_WRITE), // set operation type: read or write
                .command = command,             // set command, i.e. register number
                .size = I2C_SMBUS_WORD_DATA,   // set data size, note: mlx supports only WORD
                .data = data    // pointer to data
        };

        if (DEBUG_MODE) {
                fprintf(stderr, "Perfoming %s request to device, command = 0x%02X\n"
                                                , (read ? "I2C_SMBUS_READ" : "I2C_SMBUS_WRITE"), command);
        }

        // perfom combined request to device
        if (ioctl(fdev, I2C_SMBUS, &sdat) < 0) {
                fprintf(stderr, "Failed to perfom I2C_SMBUS transaction, error: %s\n", strerror(errno));
                return -1;
        }

        if (DEBUG_MODE) {
                fprintf(stderr, "Ok, got answer from device\n");
        }

        return 0;
}

int check_args(const int bus_num, const unsigned char i2c_addr)
{
        if (bus_num > 1 || bus_num < 0) {
                fprintf(stderr, "Invalid bus number %i, please select 0 or 1\n", bus_num);
                return -1;
        }

        if (i2c_addr == 0) {
                fprintf(stderr, "Invalid i2c device address, please set proper address of the MLX\n");
                return -1;
        }

        return 0;
}

int read_data_from_sensor(const int fdev, const char command)
{
        i2c_data data;

        if (talk_to_device(fdev, 1, command, &data) < 0) {
                return  -1;
        }

        double temp = 0;

        switch (command) {
                case MLX90614_TA:
                case MLX90614_TOBJ1:
                case MLX90614_TOBJ2:
                        temp = (double) data.word;
                        temp = (temp * 0.02)-0.01;
                        temp = temp - 273.15;
                        printf("%s = %04.2f\n", (command == MLX90614_TA ? "Tamb" : "Tobj"), temp);

                        break;

                case MLX90614_EMISS:
                        printf("Emissivity correction coefficient = %i\n", data.word);
                        break;

                case MLX90614_PWMCTRL:
                        if (!(data.word & (1 << 1))) {
                                printf("PWM mode - disabled\n");
                        } else {
                                printf("PWM mode - enabled\n");
                                printf("In order to disable pwm mode - pull down SCL for >=1.2 ms and change EEPROM setting.\n");
                        }

                        break;
        }

        return 0;
}

int write_data_to_sensor(const int fdev, const char command, const unsigned short write_arg)
{
        i2c_data msg;

    // get current value of the register
        if (talk_to_device(fdev, 1, command, &msg) < 0) {
                return  -1;
        }

        unsigned short current_val = msg.word;

    if (DEBUG_MODE) {
        fprintf(stderr, "EEPROM cell = 0x%02X current value = 0x%04X\n", command, current_val);
    }

        msg.word = 0x0;

        if (DEBUG_MODE) {
                fprintf(stderr, "Erasing EEPROM cell = 0x%02X\n", command);
        }

    // provide some time for device
        usleep(1000);

        if (talk_to_device(fdev, 0, command, &msg) < 0) {
                fprintf(stderr, "Unable to erase EEPROM cell\n");
                return -1;
        }

        // delay between eeprom erasing and writing new value
    // without this delay writing to device may fail
        usleep(5000);

        if (command == MLX90614_ADDR) {
                msg.word = 0xFFFF;
                msg.word = msg.word << 8 | write_arg;  // MLX devices uses LSByte only for address, other bits are ignored
    } else if(command == MLX90614_PWMCTRL) {
                if (write_arg) {   // enable PWM bit
                        current_val |= (1 << 1);
                } else {     //disable PWM bit
                        current_val &= ~(1 << 1);
                }

                msg.word = current_val;
        } else {
                msg.word = write_arg;
        }

        if (DEBUG_MODE) {
                fprintf(stderr, "Trying to store value = 0x%04X to the EEPROM cell = 0x%02X\n", msg.word, command);
        }

        if (talk_to_device(fdev, 0, command, &msg) < 0) {
                fprintf(stderr, "Unable to write to EEPROM\n");
                return -1;
        }

        usleep(5000);

        if (command == MLX90614_ADDR) {
                printf("MLX device address succesfully changed to 0x%X\n", msg.word);
                printf("Please, power off and power on again the device to apply changes\n");
        } else if (command == MLX90614_EMISS) {
                printf("Warning! Emissivity correction coefficient was changed to %i\n", msg.word);
        } else if (command == MLX90614_PWMCTRL) {
                printf("PWM mode is now %s\n", (write_arg ? "enabled" : "disabled"));
        }

        return 0;
}

void show_usage()
{
        printf("Usage\n");
        printf("\t%s --bus [0-1] --i2c_addr [0x00-0x7F] command|command=values wflag\n", __progname);
        printf("\n");
        printf("\t\t-b, --bus\t\t- set i2c bus number (0 for Raspbery PI model A, 1 for Raspberry PI model B, default is 0)\n");
        printf("\t\t-c, --i2c_addr\t\t- set slave device address (default = 0x5A)\n");
        printf("\t\t-r, --new_addr=ADDR\t- set new i2c ADDR for the device\n");
        printf("\t\t-w, --write\t\t- perfom writing to the device (wflag)\n");
        printf("\t\t-i, --get_ir_temp\t- get temperature in C from the infrared sensor\n");
        printf("\t\t-a, --get_ambient_temp\t- get temperature in C from the PTAT element\n");
        printf("\t\t-e, --emissivity_coefficient\t- get value of the emissivity coefficient\n");
        printf("\t\t--emissivity_coefficient=VALUE\t- set new VALUE for emissivity coefficient, use with --write argument\n");
        printf("\t\t-p, --pwm_mode\t\t- check current state of the PWM\n");
        printf("\t\t--pwm_mode=1|0\t\t- disable (0) or enable (1) PWM mode, use with --write argument\n");
}

int main(int argc, char **argv)
{
        int bus_num = 0;
        unsigned char i2c_addr = MLX90614_I2CADDR;

        int op_read = 1;
        int write_arg_set = 0;

        unsigned char command = 0x00;
        unsigned short write_arg = 0x00;

        static struct option long_options[] = {
                { "help", no_argument, NULL, 'h' },
                { "bus", required_argument, NULL, 'b' },
                { "i2c_addr", required_argument, NULL, 'c' },
                { "new_addr", required_argument, NULL, 'r'},
                { "write", no_argument, NULL, 'w' },
                { "get_ir_temp", no_argument, NULL, 'i' },
                { "get_ambient_temp", no_argument, NULL, 'a' },
                { "emissivity_coefficient", optional_argument, NULL, 'e'},
                { "pwm_mode", optional_argument, NULL,'p'},
                { "debug", no_argument, NULL, 'd' }
        };

        int option_index = 0;
        int opt = getopt_long(argc, argv, "hbc:r:wiae:p:d", long_options, &option_index);

        while (opt != -1) {
                switch (opt) {
                        case 'h':
                                show_usage();
                                return 0;

                        case 'b':
                                bus_num = atoi(optarg);
                                break;

                        case 'c':
                                i2c_addr = strtol(optarg, NULL, 16);
                                break;

                        case 'r':
                                write_arg = strtol(optarg, NULL, 16);;
                                write_arg_set = 1;
                                command = MLX90614_ADDR;
                                break;

                        case 'w':
                                op_read = 0;
                                break;

                        case 'i':
                                command = MLX90614_TOBJ1;
                                break;

                        case 'a':
                                command = MLX90614_TA;
                                break;

                        case 'e':
                                command = MLX90614_EMISS;

                                if (optarg) {
                                        write_arg = atoi(optarg);
                                        printf("%i\n", write_arg);
                                        write_arg_set = 1;
                                }

                                break;

                        case 'p':
                                command = MLX90614_PWMCTRL;

                                if (optarg) {
                                        write_arg = atoi(optarg);
                                        write_arg_set = 1;
                                }

                                break;

                        case 'd':
                                DEBUG_MODE = 1;
                                break;

                        default:
                                show_usage();
                                abort();
                }

                opt = getopt_long(argc, argv, "bc:wiaep", long_options, &option_index);
        }

        if (check_args(bus_num, i2c_addr) < 0) {
                return -1;
        }

        if (!op_read && (command == MLX90614_TOBJ1 || command == MLX90614_TA)) {
                fprintf(stderr, "Read only data!\n");
                return -1;
        }

        if (!op_read && !write_arg_set) {
                fprintf(stderr, "Plese set parameter value for writing\n");
                return -1;
        }

        int fdev = get_device(bus_num, i2c_addr);

        if (fdev < 0) {
                return -1;
        }

        int res;

        if (op_read) {
                res = read_data_from_sensor(fdev, command);
        } else {
                res = write_data_to_sensor(fdev, command, write_arg);
        }

        close(fdev);

        return res;
}

CC := gcc
PROGRAM = read_mlx90614
SRC := mlx90614.c
CFLAGS := -Wall -std=gnu99
TARGET_DIR := /opt/allsky/bin

all: $(PROGRAM)

$(PROGRAM): $(OBJECTS)

$(CC) $(CFLAGS) $(SRC) $(LDFLAG) -o $(PROGRAM)

install:
    mkdir -p $(TARGET_DIR)
    cp $(PROGRAM) $(TARGET_DIR)
    cp dht_to_db.sh $(TARGET_DIR)

clean:
    rm -fr $(PROGRAM) $(PROGRAM).o