#include < stdio.h>
#include < unistd.h>
#include < stdlib.h>
#include < fcntl.h>
#include < sys/mman.h>

#define DEV_NAME  "/dev/mem"  //MEMORY DEVICE
#define ADDROFLCD    0x10700000  //PHYSICAL ADDRESS OF CHARACTER LCD
#define BYTE_LEN    2        //SIZE OF BYTE for MEMORY

static int txtlcd_fd;    //device description

static unsigned int *lcd;  //pointer for LCD ADDRESS

void set_command (unsigned short cmd)
{

    cmd=cmd&0x00ff;

    *lcd=cmd|0x0000;
    *lcd=cmd|0x0400;
    //*lcd=cmd&0xFDFF;
    *lcd=cmd&0x0000;
    usleep(50);
  
}

void write_byte (char ch)
{
    unsigned char data;
    data = ch &0x00ff;
    *lcd=data|0x100;
    *lcd=data|0x500;
    *lcd=data|0x100; 
    usleep(50);
}

void set_func()
{
  unsigned short cmd = 0x30; //00110000 data length : 8-bit    
  cmd |= 0x08; //set rows : 2-line    
  set_command (cmd);
}

void ctrl_display ()
{
  unsigned short cmd = 0x08; 
  cmd |= 0x04;  //display enable
  set_command(cmd);
}

void shift_cursor (int set_scr , int set_rshift)
{
  unsigned short cmd = 0x10;
  cmd = set_scr ? cmd | 0x08 : cmd;
  cmd = set_rshift ? cmd | 0x04 : cmd;
  set_command ( cmd );
}

void set_entrymode ()
{
  unsigned short cmd = 0x04;
  cmd |= 0x2;   //increment , do not shift
  set_command ( cmd );
}

void ret_home ()
{
  unsigned short cmd = 0x02;
  set_command (cmd);
  //usleep(2000);
}

void clr_display()
{
  unsigned short cmd = 0x01;
  set_command (cmd);
  usleep(2000);
}

void set_ddr_addr(unsigned char pos)
{
  unsigned short cmd = 0x80; //set D7
  cmd |= (pos & 127); // 7-bit
  set_command ( cmd );
}

void init_lcd(unsigned char *addr)
{
  txtlcd_fd = open(DEV_NAME , O_RDWR | O_SYNC);
  
  if (!txtlcd_fd)
  {
    printf ("device open failed\n");
    exit(-1);
  }
  
  addr = mmap(NULL,BYTE_LEN , PROT_WRITE , MAP_SHARED , txtlcd_fd , ADDROFLCD);
  
  if (addr == NULL)
  {
    close(txtlcd_fd);
    printf ("memory map error\n");
    exit(-1);
  }
  
  lcd = (unsigned int*)addr; //pointer fowarding
  
  set_func();
  ctrl_display();
  clr_display ();
  ret_home();
  set_entrymode();  //fix : increment /do not shift
  //usleep(2000);
}

void close_lcd(unsigned char *addr)
{
  lcd = NULL;
  munmap(addr , BYTE_LEN);
  close(txtlcd_fd);  
}

#include < stdio.h>
#include < stdlib.h>

int main( void )
{
  unsigned char *p_lcd;
  char buf1[100] = "Hello Embeded World";
  char buf2[100] = "RTA LAB with Ohyung";
  int i;
  int len1,len2;
  len1 = strlen(buf1);
  len2 = strlen(buf2);

  init_lcd(p_lcd);
  if(p_lcd == NULL)
  {
    printf("lcd init error!\n");
    exit(-1);
  }

  for(i=0;i < len1;i++)
    write_byte (buf1[i]);
  set_ddr_addr(0x40);
  for(i=0;i < len2;i++)
    write_byte (buf2[i]);

  /**
   * Insert your own code
   */

  close_lcd(p_lcd);
}