/*
 * 8-bit driver module for Hitachi HD44780 based LCD displays.
 * The LCD is operated in it's 8 bit-mode to be connected to a single
 * PC parallel port.
 *
 * Copyright (c)  1999, 1995 Benjamin Tse <blt@Comports.com>
 *                2001 Joris Robijn <joris@robijn.net>
 *
 * The connections are:
 * printer port   LCD
 * D0 (2)	  D0 (7)
 * D1 (3)	  D1 (8)
 * D2 (4)	  D2 (9)
 * D3 (5)	  D3 (10)
 * D4 (6)	  D4 (11)
 * D5 (7)	  D5 (12)
 * D6 (8)	  D6 (13)
 * D7 (9)	  D7 (14)
 * nSEL  (17)     -
 * nSTRB (1)      RS (4)
 * nLF   (14)     RW (5) (LCD2 - 6) (optional - pull all LCD RW low)
 * INIT  (16)     EN (6)
 *
 * Keypad connection (optional):
 * Some diodes and resistors are needed, see further documentation.
 * printer port   keypad
 * D0 (2)	  Y0
 * D1 (3)	  Y1
 * D2 (4)	  Y2
 * D3 (5)	  Y3
 * D4 (6)	  Y4
 * D5 (7)	  Y5
 * D6 (7)	  Y6
 * D7 (7)	  Y7
 * nSTRB  (1)     Y8
 * nSEL   (17)    Y9
 * nACK   (10)    X0
 * BUSY   (11)    X1
 * PAPEREND (12)  X2
 * SELIN  (13)    X3
 * nFAULT (15)    X4
 *
 * Created modular driver Dec 1999, Benjamin Tse <blt@Comports.com>
 *
 * Based on the code in the lcdtime package which uses the LCD
 * controller in its 8-bit mode.
 *
 * This file is released under the GNU General Public License. Refer to the
 * COPYING file distributed with this package.
 */

#include "hd44780-ext8bit.h"
#include "hd44780.h"

#include "port.h"
#include "lcd_sem.h"
#include <stdio.h>
#include <string.h>
#include <errno.h>

// Generally, any function that accesses the LCD control lines needs to be
// implemented separately for each HW design. This is typically (but not
// restricted to):
// HD44780_senddata
// HD44780_readkeypad

void lcdtime_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch);
unsigned char lcdtime_HD44780_readkeypad (unsigned int YData);

#define nRS     nSTRB
#define nRW     nLF
#define EN1     INIT
#define METER_OFF nSEL

#define SETUPLCD (METER_OFF | nRS)
#define CTRL    (nRW | METER_OFF | nRS)
#define CHAR    (nRW | METER_OFF)

static int extIF = 0;		   // non-zero if extended interface
static unsigned int lptPort;
static char stuckinputs = 0;	    // if an input line is stuck, it will be ignored

static int semid;

// initialise the driver
int
hd_init_ext8bit (HD44780_functions * hd44780_functions, lcd_logical_driver * driver, char *args, unsigned int port)
{
	semid = sem_get ();

	// Reserve the port registers
	lptPort = port;
	port_access(lptPort);
	port_access(lptPort+1);
	port_access(lptPort+2);

	hd44780_functions->senddata = lcdtime_HD44780_senddata;
	hd44780_functions->readkeypad = lcdtime_HD44780_readkeypad;

	// setup the lcd in 8 bit mode
	hd44780_functions->senddata (0, RS_INSTR, FUNCSET | IF_8BIT);
	hd44780_functions->uPause (4100);
	hd44780_functions->senddata (0, RS_INSTR, FUNCSET | IF_8BIT);
	hd44780_functions->uPause (100);
	hd44780_functions->senddata (0, RS_INSTR, FUNCSET | IF_8BIT | TWOLINE | SMALLCHAR);
	hd44780_functions->uPause (40);

	common_init ();
	return 0;
}

// lcdtime_HD44780_senddata
void
lcdtime_HD44780_senddata (unsigned char displayID, unsigned char flags, unsigned char ch)
{
	unsigned char dispID = 0, portControl;

	if (displayID == 1)
		dispID |= EN1;
	else							      //if (displayID == 0)
		dispID |= EN1;

	if (flags == RS_DATA)
		portControl = CHAR;
	else
		portControl = CTRL;

	sem_wait (semid);
	port_out (lptPort + 2, SETUPLCD);
	port_out (lptPort, ch);
	port_out (lptPort + 2, dispID | portControl);
	hd44780_functions->uPause (1);
	port_out (lptPort + 2, portControl);
	sem_signal (semid);
}

unsigned char lcdtime_HD44780_readkeypad (unsigned int YData)
{
	unsigned char readval;

	// 10 bits output
	// Convert the positive logic to the negative logic on the LPT port
	port_out (lptPort, ~YData & 0x00FF );
	if (!extIF) {
		port_out (lptPort + 2, ( ((~YData & 0x0100) >> 8) | ((~YData & 0x0200) >> 6)) ^ OUTMASK);
	}

	// And convert it back.
	readval = ~ port_in (lptPort + 1) ^ INMASK;
	return ( (readval >> 4 & 0x03) | (readval >> 5 & 0x04) | (readval >> 3 & 0x08) | (readval << 1 & 0x10) ) & ~stuckinputs;
}