#include <stdio.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/ioctl.h>

#include <fcntl.h>

#include <linux/i2c-dev.h>

#include <epicsExport.h>

#include <dbAccess.h>

#include <devSup.h>

#include <recGbl.h>

#include <aiRecord.h>

// ADCPi definitions

#define ADC_1 		0x68

#define ADC_2 		0x69

#define ADC_CHANNEL1	0x98

#define ADC_CHANNEL2	0xB8

#define ADC_CHANNEL3 	0xD8

#define ADC_CHANNEL4	0xF8

static long init_record(aiRecord *pai);

static long read_ai(aiRecord *pai);

struct adcPiChannel {

  unsigned int channel;

};

int getadc (int chn){

  unsigned int fh,dummy, adc, adc_channel;

//  double val;

  __u8  res[4];

printf(" Read channel Nr: %d\n", chn);

  switch (chn){

    case 1: { adc=ADC_1; adc_channel=ADC_CHANNEL1; }; break;

    case 2: { adc=ADC_1; adc_channel=ADC_CHANNEL2; }; break;

    case 3: { adc=ADC_1; adc_channel=ADC_CHANNEL3; }; break;

    case 4: { adc=ADC_1; adc_channel=ADC_CHANNEL4; }; break;

    case 5: { adc=ADC_2; adc_channel=ADC_CHANNEL1; }; break;

    case 6: { adc=ADC_2; adc_channel=ADC_CHANNEL2; }; break;

    case 7: { adc=ADC_2; adc_channel=ADC_CHANNEL3; }; break;

    case 8: { adc=ADC_2; adc_channel=ADC_CHANNEL4; }; break;

    default: { adc=ADC_1; adc_channel=ADC_CHANNEL1; }; break;

  }

  fh = open("/dev/i2c-1", O_RDWR);

  ioctl(fh,I2C_SLAVE,adc);

  i2c_smbus_write_byte (fh, adc_channel);

  usleep (50000);

  i2c_smbus_read_i2c_block_data(fh,adc_channel,4,res);

  usleep(50000);

  close (fh);

  dummy = (res[0]<<8|res[1]);

  if (dummy>=32768) dummy=65536-dummy;

  //val = dummy * 0.000154;

// printf(" dummy = %d, val = %lf\n", dummy, val);

  //return val;

  return dummy;

}

static long init_record(aiRecord *pai)

{

  struct adcPiChannel* priv;

  unsigned long channel;

  priv=malloc(sizeof(struct adcPiChannel));

  if(!priv){

    recGblRecordError(S_db_noMemory, (void*)pai,

      "devAoTimebase failed to allocate private struct");

    return S_db_noMemory;

  }

  recGblInitConstantLink(&pai->inp,DBF_ULONG,&channel);

  priv->channel=channel;

  pai->dpvt=priv;

  return 0;

}

static long read_ai(aiRecord *pai)

{

  struct adcPiChannel* priv=pai->dpvt;

  pai->rval = getadc(priv->channel);

  return 0;

}

struct {

  long num;

  DEVSUPFUN  report;

  DEVSUPFUN  init;

  DEVSUPFUN  init_record;

  DEVSUPFUN  get_ioint_info;

  DEVSUPFUN  read_ai;

  DEVSUPFUN  special_linconv;

} devAiAdcPi = {

  6, /* space for 6 functions */

  NULL,

  NULL,

  init_record,

  NULL,

  read_ai,

  NULL

};

epicsExportAddress(dset,devAiAdcPi);