/*
 * Author: Benedikt Sauter
 * Author: Peter Huewe, Hubert Hogel
 * All rights reserved.
 *
 * Short descripton of file:
 *
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright 
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above 
 *     copyright notice, this list of conditions and the following 
 *     disclaimer in the documentation and/or other materials provided 
 *     with the distribution.
 *   * Neither the name of the FH Augsburg nor the names of its 
 *     contributors may be used to endorse or promote products derived 
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "common.h"
#include "protocol.h"
#include "i2c.h"
#define I2C_WAIT_FOR_COMPLETE() while (!(TWCR & (1<<TWINT)));

void i2c_parser(char *buf)
{
  answer[0] = buf[0];

  switch(buf[0]){
    case CMD_I2C_INIT:
      i2c_init_usb();
      break;
    case CMD_I2C_DEINIT:         
      i2c_deinit_usb();
      break;
    case CMD_I2C_SET_BITRATE:  
      i2c_set_bitrate_usb((char)buf[2]);
      break;

    case CMD_I2C_SEND:
      i2c_send_usb((int)buf[2], &buf[3]);
      break;
    case CMD_I2C_RECV:
      i2c_recv_usb((int)buf[2],(int)buf[3]);
      break;

    case CMD_I2C_SEND_START:
      i2c_send_start_usb();
      break;
    case CMD_I2C_SEND_STOP:
      i2c_send_stop_usb();
      break;

    default:
      answer[1] = RSP_UNKOWN_CMD;
      answer[2] = 0;
      CommandAnswer(3);
  }
}



void i2c_init_usb(void)
{
  answer[1]=(unsigned char)i2c_init();
  answer[2]=0;
  CommandAnswer(3);
}

int i2c_init(void)
{
  TWCR |= (1<<TWEN);
  octopus.ports[12] = PIN_SCL;
  octopus.ports[13] = PIN_SDA;
  
  return RSP_OK;
}


void i2c_deinit_usb(void)
{
  answer[1]=(unsigned char)i2c_deinit();
  answer[2]=0;
  CommandAnswer(3);
}

int i2c_deinit(void)
{
  TWCR &= ~(1<<TWEN); // deinit
  octopus.ports[12]=PIN_NONE;
  octopus.ports[13]=PIN_NONE;

  return RSP_OK;
}


void i2c_set_bitrate_usb(char bitrate) {
  answer[1] = (unsigned char)i2c_set_bitrate(bitrate);
  answer[2] =  0;
  CommandAnswer(3);
}

int i2c_set_bitrate(char bitrate) {
  TWBR = bitrate;

  TWSR &= ~((1<<TWPS1) | (1<<TWPS0));
  TWSR |= (0<<TWPS0);

  return RSP_OK;
}


void i2c_send_start_usb(void)
{
  answer[1] = (unsigned char)i2c_send_start();
  answer[2] = 0;
  CommandAnswer(3);
}

unsigned char i2c_get_twsr(void)
{
  return (TWSR & 0xF8);
}

int i2c_send_start(void)
{
  i2c_get_twsr();
  TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
  I2C_WAIT_FOR_COMPLETE();
  return RSP_OK;
}




void i2c_send_stop_usb(void)
{
  answer[1]=(unsigned char)i2c_send_stop();
  answer[2]=0;
  CommandAnswer(3);
}

int i2c_send_stop(void)
{
  TWCR = (1<<TWINT)|(1<<TWEN)|(1<<TWSTO);
  while(TWCR & (1<<TWSTO));
  return RSP_OK;
}


void i2c_send_usb(int length, char *data)
{
  i2c_send(data, length);

  answer[1] = RSP_OK;
  answer[2] = 0;
  CommandAnswer(3);
}

void i2c_send(char *data, int length)
{
  int i;

  for(i = 0; i < length; i++) {
    TWDR = data[i];
    TWCR = (1<<TWINT) | (1<<TWEN);
    I2C_WAIT_FOR_COMPLETE();
  }
}


void i2c_recv_usb(int address, int length)
{
  int i;

  answer[0]=CMD_I2C_RECV;
  answer[1]=RSP_OK;

  for(i = 0; i < length; i++)
    answer[2+i] = i2c_recv_byte();

  answer[length+2] = 0;

  CommandAnswer(3+length);
}


unsigned char i2c_recv_byte(void)
{
  TWCR = (1<<TWINT) | (1<<TWEN);
  I2C_WAIT_FOR_COMPLETE();
  return TWDR;
}