/********************************************************************\

  Name:         gpio.c
  Created by:   Stefan Ritt

  Contents:     Driver for MCP23S17 General Purpose IO Chip
  
  

\********************************************************************/
      
#include <stdio.h>
#include <string.h>
#include <intrins.h>
#include <stdlib.h>
#include "mscbemb.h"
#include "fe_cc.h"

// register addresses for non-banked layout (bank=0)
#define GPIO_IODIRA    0x00
#define GPIO_IODIRB    0x01
#define GPIO_IPOLA     0x02
#define GPIO_IPOLB     0x03
#define GPIO_GPINTENA  0x04
#define GPIO_GPINTENB  0x05
#define GPIO_DEFVALA   0x06
#define GPIO_DEFVALB   0x07
#define GPIO_INTCONA   0x08
#define GPIO_INTCONB   0x09
#define GPIO_IOCON     0x0A
#define GPIO_GPPUA     0x0C
#define GPIO_GPPUB     0x0D
#define GPIO_INTFA     0x0E
#define GPIO_INTFB     0x0F
#define GPIO_INTCAPA   0x10
#define GPIO_INTCAPB   0x11
#define GPIO_GPIOA     0x12
#define GPIO_GPIOB     0x13
#define GPIO_OLATA     0x14
#define GPIO_OLATB     0x15

static unsigned char gpio_mask[4][2] = { { 0xFF, 0xFF },
                                         { 0xFF, 0xFF },
                                         { 0xFF, 0xFF },
                                         { 0xFF, 0xFF } };

/*------------------------------------------------------------------*/

void gpio_init()
{
   unsigned char i;
   
   // program all four devices as outputs
   for (i=0 ; i< 4 ; i++) {
      gpio_write(i, GPIO_IOCON, 1<<3); // HAEN = 1
      gpio_write(i, GPIO_IODIRA, 0x00);
      gpio_write(i, GPIO_IODIRB, 0x00);
   }
   
   // set /select lines to default state (high)
   gpio_board_select(0xFF);

	 // set init lines to high (inactive)
   gpio_out(3, 1, 1);
   gpio_out(3, 2, 1);
   gpio_out(3, 3, 1);

	 // set BP mode
	 gpio_bp_mode_sel(0);
	 gpio_attention(0);
}

/*------------------------------------------------------------------*/

void gpio_write(unsigned char device, unsigned char adr, unsigned char d)
{
   spi_adr(SPI_ADR_SR, 0);
   // Device opcode 0x40 combined 3-bit hardware address, R/W = 0 (=write)
   spi_write_msb(0x40 | ((device & 0x07) << 1));
   spi_write_msb(adr);  
   spi_write_msb(d);  
   spi_adr(0, 1);
}

/*------------------------------------------------------------------*/

unsigned char gpio_read(unsigned char device, unsigned char adr)
{
   unsigned char d;
   
   spi_adr(SPI_ADR_SR, 0);
   // Device opcode 0x40 combined 3-bit hardware address, R/W = 1 (=read)
   spi_write_msb(0x40 | ((device & 0x07) << 1) | 0x01);
   spi_write_msb(adr);  
   d = spi_read_msb();  
   spi_adr(0, 1);
   return d;
}

/*------------------------------------------------------------------*/

void gpio_out(unsigned char device, unsigned char bit_no, unsigned char flag)
{
   unsigned char port;
   
   // write one bit to device

   if (bit_no < 8)
      port = 0;
   else {
      port = 1;
      bit_no -= 8;
   }
   
   if (flag) 
      gpio_mask[device][port] |= (1 << bit_no);
   else
      gpio_mask[device][port] &= ~(1 << bit_no);
   
   gpio_write(device, port == 0 ? GPIO_OLATA : GPIO_OLATB, gpio_mask[device][port]);
}

/*------------------------------------------------------------------*/

unsigned char gpio_in(unsigned char device, unsigned char port)
{
   // read port through GPIOA (port==0) or GPIOB (port==1)
   return gpio_read(device, port == 0 ? GPIO_GPIOA : GPIO_GPIOB);
}

/*------------------------------------------------------------------*/

void gpio_board_power(unsigned char p[16])
{
   unsigned char d;
   
   for (d=0 ; d<16 ; d++)
      gpio_out(2, d, !(p[d] & 0x01)); 
}

/*------------------------------------------------------------------*/

void gpio_board_select(unsigned char b)
{
   unsigned char d;

   for (d=0 ; d<16 ; d++)
      gpio_out(0, d, d != b); // inverse polarity
}

/*------------------------------------------------------------------*/

void gpio_max_config_select(unsigned char flag)
{
   gpio_out(3, 0, flag);
}

/*------------------------------------------------------------------*/

void gpio_reset_fpga()
{
   gpio_out(3, 1, 0); // inverse polarity
   gpio_out(3, 1, 1);
}

/*------------------------------------------------------------------*/

void gpio_reset_cpu()
{
   gpio_out(3, 2, 0); // inverse polarity
   gpio_out(3, 2, 1);
}

/*------------------------------------------------------------------*/

void gpio_reset_max()
{
   gpio_out(3, 3, 0); // inverse polarity
   gpio_out(3, 3, 1);
}

/*------------------------------------------------------------------*/

void gpio_bp_mode_sel(unsigned char mode)
{
   gpio_out(3, 4, (mode >> 0) & 1);
   gpio_out(3, 5, (mode >> 1) & 1);
}

/*------------------------------------------------------------------*/

void gpio_attention(unsigned char mode)
{
   gpio_out(3, 10, !((mode >> 0) & 1)); // inverse polarity
   gpio_out(3, 11, !((mode >> 1) & 1)); // inverse polarity
}