/*********************************************************************************
 *      Copyright:  (C) 2018 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  sht20.c
 *    Description:  This file is temperature and relative humidity sensor SHT20 code
 *
 *        Version:  1.0.0(2018/10/14)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2018/10/14 12:13:26"
 *
 ********************************************************************************/

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

#include "sht20.h"
#include "logger.h"
#include "util_proc.h"

static int s_sht2x_fd = -1;

void sht2x_term(void)
{
    close(s_sht2x_fd);
    s_sht2x_fd = -1;
    log_warn("Terminate SHT2X\n");
}

static inline void dump_buf(const char *prompt, uint8_t *buf, int size)
{
    int          i;

    if( !buf )
    {
        return ;
    }

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

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

    return ;
}

#ifdef I2C_API_RDWR  /* Use I2C userspace driver read/write API */

int sht2x_softreset(int fd)
{
    uint8_t           buf[4];

    if( fd<0 )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    /* software reset SHT2x */
    memset(buf, 0, sizeof(buf));

    buf[0] = SOFTRESET;
    write(fd, buf, 1);

    msleep(50);

    return 0;
}

int sht2x_init(void)
{

    if( (s_sht2x_fd=open("/dev/i2c-1", O_RDWR)) < 0)
    {
        log_error("i2c device open failed: %s\n", strerror(errno));
        return -1;
    }

    /* set I2C mode and SHT2x slave address */
    ioctl(s_sht2x_fd, I2C_TENBIT, 0);    /* Not 10-bit but 7-bit mode */
    ioctl(s_sht2x_fd, I2C_SLAVE, 0x40); /* set SHT2x slava address 0x40*/

    if( sht2x_softreset(s_sht2x_fd) < 0 )
    {
        log_error("SHT2x softreset failure\n");
        sht2x_term();
        return -2;
    }

    log_debug("SHT2X initialise ok, s_sht2x_fd=%d\n", s_sht2x_fd);
    return s_sht2x_fd;
}

int sht2x_get_temp_humidity(float *temp, float *rh)
{
    uint8_t           buf[4];

    if( !temp || !rh )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    if( s_sht2x_fd < 0 )
    {
        if( sht2x_init() < 0)
        {
            log_error("SHT2x initialise failure\n");
            return -2;
        }
    }

    /* send trigger temperature measure command and read the data */
    memset(buf, 0, sizeof(buf));
    buf[0]=TRIGGER_TEMPERATURE_NO_HOLD;
    write(s_sht2x_fd, buf, 1);

    msleep(85); /* datasheet: typ=66, max=85 */

    memset(buf, 0, sizeof(buf));
    read(s_sht2x_fd, buf, 3);
    //dump_buf("Temperature sample data: ", buf, 3);
    *temp = 175.72 * (((((int) buf[0]) << 8) + buf[1]) / 65536.0) - 46.85;

    /* send trigger humidity measure command and read the data */
    memset(buf, 0, sizeof(buf));
    buf[0] = TRIGGER_HUMIDITY_NO_HOLD;
    write(s_sht2x_fd, buf, 1);

    msleep(29); /* datasheet: typ=22, max=29 */
    memset(buf, 0, sizeof(buf));

    read(s_sht2x_fd, buf, 3);
    //dump_buf("Relative humidity sample data: ", buf, 3);
    *rh = 125 * (((((int) buf[0]) << 8) + buf[1]) / 65536.0) - 6;

    return 0;
}

int sht2x_get_serialnumber(uint8_t *serialnumber, int size)
{
    uint8_t           buf[4];

    if( !serialnumber || size!=8 )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    if( s_sht2x_fd < 0 )
    {
        if( sht2x_init() < 0)
        {
            log_error("SHT2x initialise failure\n");
            return -2;
        }
    }

    /* Read SerialNumber from Location 1 */
    memset(buf, 0, sizeof(buf));
    buf[0] = 0xfa;  /* command for readout on-chip memory */
    buf[1] = 0x0f;  /* on-chip memory address */
    write(s_sht2x_fd, buf, 2);

    memset(buf, 0, sizeof(buf));
    read(s_sht2x_fd, buf, 4);

    serialnumber[5]=buf[0]; /* Read SNB_3 */
    serialnumber[4]=buf[1]; /* Read SNB_2 */
    serialnumber[3]=buf[2]; /* Read SNB_1 */
    serialnumber[2]=buf[3]; /* Read SNB_0 */

    /* Read SerialNumber from Location 2 */
    memset(buf, 0, sizeof(buf) );
    buf[0]=0xfc;  /* command for readout on-chip memory */
    buf[1]=0xc9;  /* on-chip memory address */
    write(s_sht2x_fd, buf, 2);

    memset(buf, 0, sizeof(buf) );
    read(s_sht2x_fd, buf, 4);

    serialnumber[1]=buf[0]; /* Read SNC_1 */
    serialnumber[0]=buf[1]; /* Read SNC_0 */
    serialnumber[7]=buf[2]; /* Read SNA_1 */
    serialnumber[6]=buf[3]; /* Read SNA_0 */

    //dump_buf("SHT2x Serial number: ", serialnumber, 8);

    return 0;
}

#elif (defined I2C_API_IOCTL)  /* Use I2C userspace driver read/write API */

int sht2x_softreset(int fd)
{
    struct i2c_msg               msg;
    struct i2c_rdwr_ioctl_data   sht2x_data;
    uint8_t                      buf[2];

    if( fd<0 )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    msg.addr= 0x40;
    msg.flags=0; //write
    msg.len= 1;
    msg.buf= buf;
    msg.buf[0]=SOFTRESET;

    sht2x_data.nmsgs= 1;
    sht2x_data.msgs= &msg;

    if( ioctl(fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    msleep(50);

    return 0;
}


int sht2x_init(void)
{
    if( (s_sht2x_fd=open("/dev/i2c-1", O_RDWR)) < 0)
    {
        log_error("i2c device open failed: %s\n", strerror(errno));
        return -1;
    }

    if( sht2x_softreset(s_sht2x_fd) < 0 )
    {
        log_error("SHT2x softreset failure\n");
        sht2x_term();
        return -2;
    }

    log_debug("SHT2X initialise ok, s_sht2x_fd=%d\n", s_sht2x_fd);
    return 0;
}

int sht2x_get_serialnumber(uint8_t *serialnumber, int size)
{
    struct i2c_msg               msgs[2];
    struct i2c_rdwr_ioctl_data   sht2x_data;
    uint8_t                      sbuf[2];
    uint8_t                      rbuf[4];

    if( !serialnumber || size!=8 )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    if( s_sht2x_fd < 0 )
    {
        if( sht2x_init() < 0)
        {
            log_error("SHT2x initialise failure\n");
            return -2;
        }
    }

    /*+------------------------------------------+
     *|     Read SerialNumber from Location 1    |
     *+------------------------------------------+*/

    msgs[0].addr= 0x40;
    msgs[0].flags=0; //write
    msgs[0].len= 2;
    msgs[0].buf= sbuf;
    msgs[0].buf[0]=0xfa;  /* command for readout on-chip memory */
    msgs[0].buf[1]=0x0f;  /* on-chip memory address */

    msgs[1].addr=0x40;
    msgs[1].flags=I2C_M_RD; //write
    msgs[1].len= 4;
    msgs[1].buf= rbuf;

    sht2x_data.nmsgs= 2;
    sht2x_data.msgs= msgs;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    serialnumber[5]=rbuf[0]; /* Read SNB_3 */
    serialnumber[4]=rbuf[1]; /* Read SNB_2 */
    serialnumber[3]=rbuf[2]; /* Read SNB_1 */
    serialnumber[2]=rbuf[3]; /* Read SNB_0 */


    /*+------------------------------------------+
     *|     Read SerialNumber from Location 2    |
     *+------------------------------------------+*/

    msgs[0].addr= 0x40;
    msgs[0].flags=0; //write
    msgs[0].len= 2;
    msgs[0].buf= sbuf;
    msgs[0].buf[0]=0xfc;  /* command for readout on-chip memory */
    msgs[0].buf[1]=0xc9;  /* on-chip memory address */

    msgs[1].addr=0x40;
    msgs[1].flags=I2C_M_RD; //write
    msgs[1].len= 4;
    msgs[1].buf= rbuf;

    sht2x_data.nmsgs= 2;
    sht2x_data.msgs= msgs;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    serialnumber[1]=rbuf[0]; /* Read SNC_1 */
    serialnumber[0]=rbuf[1]; /* Read SNC_0 */
    serialnumber[7]=rbuf[2]; /* Read SNA_1 */
    serialnumber[6]=rbuf[3]; /* Read SNA_0 */

    //dump_buf("SHT2x Serial number: ", serialnumber, 8);

    return 0;
}


int sht2x_get_temp_humidity(float *temp, float *rh)
{
    struct i2c_msg               msg;
    struct i2c_rdwr_ioctl_data   sht2x_data;
    uint8_t                      buf[4];

    if( !temp || !rh )
    {
        log_error("Invalid input arguments\n");
        return -1;
    }

    if( s_sht2x_fd < 0 )
    {
        if( sht2x_init() < 0)
        {
            log_error("SHT2x initialise failure\n");
            return -2;
        }
    }

    /*+------------------------------------------+
     *|       measure and get temperature        |
     *+------------------------------------------+*/

    msg.addr= 0x40;
    msg.flags=0; //write
    msg.len= 1;
    msg.buf= buf;
    msg.buf[0]=TRIGGER_TEMPERATURE_NO_HOLD;  /* trigger temperature without hold I2C bus */

    sht2x_data.nmsgs= 1;
    sht2x_data.msgs= &msg;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    msleep(85);

    memset(buf, 0, sizeof(buf));
    msg.addr=0x40;
    msg.flags=I2C_M_RD; //write
    msg.len= 3;
    msg.buf= buf;

    sht2x_data.nmsgs= 1;
    sht2x_data.msgs= &msg;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    //dump_buf("Temperature sample data: ", buf, 3);
    *temp = 175.72 * (((((int) buf[0]) << 8) + buf[1]) / 65536.0) - 46.85;


    /*+------------------------------------------+
     *|    measure and get relative humidity     |
     *+------------------------------------------+*/

    msg.addr= 0x40;
    msg.flags=0; //write
    msg.len= 1;
    msg.buf= buf;
    msg.buf[0]=TRIGGER_HUMIDITY_NO_HOLD;  /* trigger humidity without hold I2C bus */

    sht2x_data.nmsgs= 1;
    sht2x_data.msgs= &msg;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    msleep(29);

    memset(buf, 0, sizeof(buf));
    msg.addr=0x40;
    msg.flags=I2C_M_RD; //write
    msg.len= 3;
    msg.buf= buf;

    sht2x_data.nmsgs= 1;
    sht2x_data.msgs= &msg;

    if( ioctl(s_sht2x_fd, I2C_RDWR, &sht2x_data) < 0 )
    {
        log_error("sht2x I2C_RDWR ioctl failure: %s\n", strerror(errno));
        sht2x_term();
        return -2;
    }

    //dump_buf("Relative humidity sample data: ", buf, 3);
    *rh = 125 * (((((int) buf[0]) << 8) + buf[1]) / 65536.0) - 6;

    return 0;
}

#endif