arch/xtensa/platforms/xtfpga/lcd.c

   1 /*
   2  * Driver for the LCD display on the Tensilica LX60 Board.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2001, 2006 Tensilica Inc.
   9  */
  10
  11 /*
  12  *
  13  * FIXME: this code is from the examples from the LX60 user guide.
  14  *
  15  * The lcd_pause function does busy waiting, which is probably not
  16  * great. Maybe the code could be changed to use kernel timers, or
  17  * change the hardware to not need to wait.
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/io.h>
  22
  23 #include <platform/hardware.h>
  24 #include <platform/lcd.h>
  25 #include <linux/delay.h>
  26
  27 #define LCD_PAUSE_ITERATIONS    4000
  28 #define LCD_CLEAR               0x1
  29 #define LCD_DISPLAY_ON          0xc
  30
  31 /* 8bit and 2 lines display */
  32 #define LCD_DISPLAY_MODE8BIT    0x38
  33 #define LCD_DISPLAY_POS         0x80
  34 #define LCD_SHIFT_LEFT          0x18
  35 #define LCD_SHIFT_RIGHT         0x1c
  36
  37 static int __init lcd_init(void)
  38 {
  39         *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
  40         mdelay(5);
  41         *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
  42         udelay(200);
  43         *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
  44         udelay(50);
  45         *LCD_INSTR_ADDR = LCD_DISPLAY_ON;
  46         udelay(50);
  47         *LCD_INSTR_ADDR = LCD_CLEAR;
  48         mdelay(10);
  49         lcd_disp_at_pos("XTENSA LINUX", 0);
  50         return 0;
  51 }
  52
  53 void lcd_disp_at_pos(char *str, unsigned char pos)
  54 {
  55         *LCD_INSTR_ADDR = LCD_DISPLAY_POS | pos;
  56         udelay(100);
  57         while (*str != 0) {
  58                 *LCD_DATA_ADDR = *str;
  59                 udelay(200);
  60                 str++;
  61         }
  62 }
  63
  64 void lcd_shiftleft(void)
  65 {
  66         *LCD_INSTR_ADDR = LCD_SHIFT_LEFT;
  67         udelay(50);
  68 }
  69
  70 void lcd_shiftright(void)
  71 {
  72         *LCD_INSTR_ADDR = LCD_SHIFT_RIGHT;
  73         udelay(50);
  74 }
  75
  76 arch_initcall(lcd_init);