lcd.c
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/*
* Driver for the LCD display on the Tensilica XTFPGA board family.
* http://www.mytechcorp.com/cfdata/productFile/File1/MOC-16216B-B-A0A04.pdf
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001, 2006 Tensilica Inc.
* Copyright (C) 2015 Cadence Design Systems Inc.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/io.h>
#include <platform/hardware.h>
#include <platform/lcd.h>
/* LCD instruction and data addresses. */
#define LCD_INSTR_ADDR ((char *)IOADDR(CONFIG_XTFPGA_LCD_BASE_ADDR))
#define LCD_DATA_ADDR (LCD_INSTR_ADDR + 4)
#define LCD_CLEAR 0x1
#define LCD_DISPLAY_ON 0xc
/* 8bit and 2 lines display */
#define LCD_DISPLAY_MODE8BIT 0x38
#define LCD_DISPLAY_MODE4BIT 0x28
#define LCD_DISPLAY_POS 0x80
#define LCD_SHIFT_LEFT 0x18
#define LCD_SHIFT_RIGHT 0x1c
static void lcd_put_byte(u8 *addr, u8 data)
{
#ifdef CONFIG_XTFPGA_LCD_8BIT_ACCESS
ACCESS_ONCE(*addr) = data;
#else
ACCESS_ONCE(*addr) = data & 0xf0;
ACCESS_ONCE(*addr) = (data << 4) & 0xf0;
#endif
}
static int __init lcd_init(void)
{
ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE8BIT;
mdelay(5);
ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE8BIT;
udelay(200);
ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE8BIT;
udelay(50);
#ifndef CONFIG_XTFPGA_LCD_8BIT_ACCESS
ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE4BIT;
udelay(50);
lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_MODE4BIT);
udelay(50);
#endif
lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_ON);
udelay(50);
lcd_put_byte(LCD_INSTR_ADDR, LCD_CLEAR);
mdelay(10);
lcd_disp_at_pos("XTENSA LINUX", 0);
return 0;
}
void lcd_disp_at_pos(char *str, unsigned char pos)
{
lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_POS | pos);
udelay(100);
while (*str != 0) {
lcd_put_byte(LCD_DATA_ADDR, *str);
udelay(200);
str++;
}
}
void lcd_shiftleft(void)
{
lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_LEFT);
udelay(50);
}
void lcd_shiftright(void)
{
lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_RIGHT);
udelay(50);
}
arch_initcall(lcd_init);