/*********************************************************************************
 *      Copyright:  (C) 2023 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  sht20.c
 *    Description:  This file is the Lux sensor TSL2561 code
 *
 *        Version:  1.0.0(10/08/23)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "10/08/23 17:52:00"
 *
 * Pin connection:
 *               STH20 Module            Raspberry Pi Board
 *                   VCC      <----->      #Pin1(3.3V)
 *                   SDA      <----->      #Pin27(SDA, BCM GPIO0)
 *                   SCL      <----->      #Pin28(SCL, BCM GPIO1)
 *                   GND      <----->      GND
 *
 * /boot/config.txt:
 *                  dtoverlay=i2c0,pins_0_1
 *
 ********************************************************************************/


#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <errno.h>
#include <libgen.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <sys/types.h>
#include <sys/stat.h>

#define TSL2561_I2C_ADDR                0x39

#define CONTROL_REG                     0x80
#define REG_COUNT                       4

#define POWER_UP                        0x03
#define POWER_DOWN                      0x00

#define OFF                             0
#define ON                              1

/* Register Address  */
enum
{
    /* Channel_0 = DATA0HIGH<<8 + DATA0LOW */
    DATA0LOW = 0x8C,
    DATA0HIGH,

    /* Channel_1 = DATA1HIGH<<8 + DATA1LOW */
    DATA1LOW,
    DATA1HIGH,
};

static const int  regs_addr[REG_COUNT]={DATA0LOW, DATA0HIGH, DATA1LOW, DATA1HIGH};

float tsl2561_get_lux(int fd);
static inline void print_datime(void);

static inline void banner(const char *progname)
{
    printf("%s program Version v1.0.0\n", progname);
    printf("Copyright (C) 2023 LingYun IoT System Studio.\n");
}

static void program_usage(const char *progname)
{

    printf("Usage: %s [OPTION]...\n", progname);
    printf(" %s is TSL2561 Lux sensor program.\n", progname);

    printf(" -d[device  ]  Specify I2C device, such as /dev/i2c-0\n");
    printf(" -h[help    ]  Display this help information\n");
    printf(" -v[version ]  Display the program version\n");

    printf("\n");
    banner(progname);
    return;
}

int main(int argc, char **argv)
{
    int             fd, rv;
    float           lux;
    char           *dev = "/dev/i2c-0";
    char           *progname=NULL;

    struct option long_options[] = {
        {"device", required_argument, NULL, 'd'},
        {"version", no_argument, NULL, 'v'},
        {"help", no_argument, NULL, 'h'},
        {NULL, 0, NULL, 0}
    };

    progname = basename(argv[0]);

    /* Parser the command line parameters */
    while ((rv = getopt_long(argc, argv, "d:vh", long_options, NULL)) != -1)
    {
        switch (rv)
        {
            case 'd': /*  Set I2C device path: /dev/i2c-1 */
                dev = optarg;
                break;

            case 'v':  /*  Get software version */
                banner(progname);
                return EXIT_SUCCESS;

            case 'h':  /*  Get help information */
                program_usage(progname);
                return 0;

            default:
                break;
        }
    }

    /*+--------------------------------+
     *|     open /dev/i2c-x device     |
     *+--------------------------------+*/
    if( (fd=open(dev, O_RDWR)) < 0)
    {
        printf("i2c device '%s' open failed: %s\n", dev, strerror(errno));
        return -1;
    }

    while(1)
    {
        lux = tsl2561_get_lux(fd);

        print_datime();
        printf("TSLl2561 get lux: %.3f\n", lux);

        sleep(1);
    }

    close(fd);
    return 0;
}

static inline void print_datime(void)
{
    time_t         tmp;
    struct tm     *p;

    time(&tmp);

    p=localtime(&tmp);


    printf("%d-%02d-%02d %02d:%02d:%02d\t", (p->tm_year+1900),(p->tm_mon+1),
            p->tm_mday, p->tm_hour, p->tm_min, p->tm_sec);

}

static inline void msleep(unsigned long ms)
{
    struct timespec cSleep;
    unsigned long ulTmp;

    cSleep.tv_sec = ms / 1000;
    if (cSleep.tv_sec == 0)
    {
        ulTmp = ms * 10000;
        cSleep.tv_nsec = ulTmp * 100;
    }
    else
    {
        cSleep.tv_nsec = 0;
    }

    nanosleep(&cSleep, 0);
    return ;
}

void tsl2561_power(int fd, int cmd)
{
    struct i2c_msg               msg;
    struct i2c_rdwr_ioctl_data   data;
    unsigned char                buf[2];

    msg.addr= TSL2561_I2C_ADDR;
    msg.flags=0;  /* write */
    msg.len= 1;
    msg.buf= buf;

    data.nmsgs= 1;
    data.msgs= &msg;

    msg.buf[0]=CONTROL_REG;
    if( ioctl(fd, I2C_RDWR, &data) < 0 )
    {
        printf("%s() ioctl failure: %s\n", __func__, strerror(errno));
        return ;
    }


    if( cmd )
        msg.buf[0]=POWER_UP;
    else
        msg.buf[0]=POWER_DOWN;

    if( ioctl(fd, I2C_RDWR, &data) < 0 )
    {
        printf("%s() ioctl failure: %s\n", __func__, strerror(errno));
        return ;
    }

    return ;
}

int tsl2561_readreg(int fd, unsigned char regaddr, unsigned char *regval)
{
    struct i2c_msg               msg;
    struct i2c_rdwr_ioctl_data   data;
    unsigned char                buf[2];

    msg.addr= TSL2561_I2C_ADDR;
    msg.flags=0;  /* write */
    msg.len= 1;
    msg.buf= buf;
    msg.buf[0] = regaddr;

    data.nmsgs= 1;
    data.msgs= &msg;

    if( ioctl(fd, I2C_RDWR, &data) < 0 )
    {
        printf("%s() ioctl failure: %s\n", __func__, strerror(errno));
        return -1;
    }

    memset(buf, 0, sizeof(buf));

    msg.addr= TSL2561_I2C_ADDR;
    msg.flags=I2C_M_RD;  /* read */
    msg.len= 1;
    msg.buf= buf;

    data.nmsgs= 1;
    data.msgs= &msg;

    if( ioctl(fd, I2C_RDWR, &data) < 0 )
    {
        printf("%s() ioctl failure: %s\n", __func__, strerror(errno));
        return -1;
    }

    *regval = msg.buf[0];
    return 0;
}

float tsl2561_get_lux(int fd)
{
    int                 i;
    unsigned char       reg_data[REG_COUNT];
    unsigned char       buf;

    int                 chn0_data = 0;
    int                 chn1_data = 0;

    float               div = 0.0;
    float               lux = 0.0;

    tsl2561_power(fd, ON);

    msleep(410);  /* t(CONV) MAX 400ms */

    /* Read register Channel0 and channel1 data from register */
    for(i=0; i<REG_COUNT; i++)
    {
        tsl2561_readreg(fd, regs_addr[i], &reg_data[i]);
    }

    chn0_data = reg_data[1]*256 + reg_data[0]; /* Channel0 = DATA0HIGH<<8 + DATA0LOW  */
    chn1_data = reg_data[3]*256 + reg_data[2]; /* channel1 = DATA1HIGH<<8 +  DATA1LOW */

    if( chn0_data<=0 || chn1_data<0 )
    {
        lux = 0.0;
        goto OUT;
    }

    div = (float)chn1_data / (float)chn0_data;

    if( div>0 && div<=0.5 )
        lux = 0.304*chn0_data-0.062*chn0_data*pow(div,1.4);

    else if( div>0.5 && div<=0.61 )
        lux = 0.0224*chn0_data-0.031*chn1_data;

    else if( div>0.61 && div<=0.8 )
        lux = 0.0128*chn0_data-0.0153*chn1_data;

    else if( div>0.8 && div<=1.3 )
        lux = 0.00146*chn0_data-0.00112*chn1_data;

    else if( div>1.3 )
        lux = 0.0;

OUT:
    tsl2561_power(fd, OFF);
    return lux;
}

static inline void dump_buf(const char *prompt, char *buf, int size)
{
    int          i;

    if( !buf )
    {
        return ;
    }

    if( prompt )
    {
        printf("%-32s ", prompt);
    }

    for(i=0; i<size; i++)
    {
        printf("%02x ", buf[i]);
    }
    printf("\n");

    return ;
}