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/*
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 * mcp23016.c:
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 *        Extend wiringPi with the MCP 23016 I2C GPIO expander chip
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 *        Copyright (c) 2013 Gordon Henderson
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 ***********************************************************************
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 * This file is part of wiringPi:
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 *        https://projects.drogon.net/raspberry-pi/wiringpi/
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 *
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 *    wiringPi is free software: you can redistribute it and/or modify
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 *    it under the terms of the GNU Lesser General Public License as
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 *    published by the Free Software Foundation, either version 3 of the
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 *    License, or (at your option) any later version.
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 *
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 *    wiringPi is distributed in the hope that it will be useful,
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 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *    GNU Lesser General Public License for more details.
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 *
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 *    You should have received a copy of the GNU Lesser General Public
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 *    License along with wiringPi.
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 *    If not, see <http://www.gnu.org/licenses/>.
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 ***********************************************************************
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 */
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#include <stdio.h>
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#include <pthread.h>
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#include "wiringPi.h"
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#include "wiringPiI2C.h"
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#include "mcp23016.h"
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#include "mcp23016reg.h"
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/*
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 * myPinMode:
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 *********************************************************************************
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 */
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static void myPinMode (struct wiringPiNodeStruct *node, int pin, int mode)
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{
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  int mask, old, reg ;
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  pin -= node->pinBase ;
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  if (pin < 8)                // Bank A
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    reg  = MCP23016_IODIR0 ;
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  else
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  {
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    reg  = MCP23016_IODIR1 ;
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    pin &= 0x07 ;
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  }
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  mask = 1 << pin ;
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  old  = wiringPiI2CReadReg8 (node->fd, reg) ;
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  if (mode == OUTPUT)
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    old &= (~mask) ;
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  else
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    old |=   mask ;
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  wiringPiI2CWriteReg8 (node->fd, reg, old) ;
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}
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/*
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 * myDigitalWrite:
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 *********************************************************************************
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 */
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static void myDigitalWrite (struct wiringPiNodeStruct *node, int pin, int value)
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{
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  int bit, old ;
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  pin -= node->pinBase ;        // Pin now 0-15
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  bit = 1 << (pin & 7) ;
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  if (pin < 8)                        // Bank A
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  {
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    old = node->data2 ;
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    if (value == LOW)
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      old &= (~bit) ;
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    else
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      old |=   bit ;
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    wiringPiI2CWriteReg8 (node->fd, MCP23016_GP0, old) ;
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    node->data2 = old ;
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  }
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  else                                // Bank B
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  {
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    old = node->data3 ;
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    if (value == LOW)
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      old &= (~bit) ;
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    else
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      old |=   bit ;
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    wiringPiI2CWriteReg8 (node->fd, MCP23016_GP1, old) ;
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    node->data3 = old ;
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  }
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}
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/*
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 * myDigitalRead:
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 *********************************************************************************
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 */
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static int myDigitalRead (struct wiringPiNodeStruct *node, int pin)
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{
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  int mask, value, gpio ;
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  pin -= node->pinBase ;
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  if (pin < 8)                // Bank A
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    gpio  = MCP23016_GP0 ;
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  else
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  {
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    gpio  = MCP23016_GP1 ;
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    pin  &= 0x07 ;
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  }
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  mask  = 1 << pin ;
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  value = wiringPiI2CReadReg8 (node->fd, gpio) ;
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  if ((value & mask) == 0)
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    return LOW ;
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  else 
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    return HIGH ;
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}
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/*
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 * mcp23016Setup:
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 *        Create a new instance of an MCP23016 I2C GPIO interface. We know it
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 *        has 16 pins, so all we need to know here is the I2C address and the
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 *        user-defined pin base.
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 *********************************************************************************
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 */
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int mcp23016Setup (const int pinBase, const int i2cAddress)
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{
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  int fd ;
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  struct wiringPiNodeStruct *node ;
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  if ((fd = wiringPiI2CSetup (i2cAddress)) < 0)
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    return FALSE ;
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  wiringPiI2CWriteReg8 (fd, MCP23016_IOCON0, IOCON_INIT) ;
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  wiringPiI2CWriteReg8 (fd, MCP23016_IOCON1, IOCON_INIT) ;
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  node = wiringPiNewNode (pinBase, 16) ;
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  node->fd              = fd ;
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  node->pinMode         = myPinMode ;
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  node->digitalRead     = myDigitalRead ;
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  node->digitalWrite    = myDigitalWrite ;
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  node->data2           = wiringPiI2CReadReg8 (fd, MCP23016_OLAT0) ;
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  node->data3           = wiringPiI2CReadReg8 (fd, MCP23016_OLAT1) ;
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  return TRUE ;
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}