arch/xtensa/platforms/xtfpga/lcd.c

   1 /*
   2  * Driver for the LCD display on the Tensilica XTFPGA board family.
   3  * http://www.mytechcorp.com/cfdata/productFile/File1/MOC-16216B-B-A0A04.pdf
   4  *
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  *
   9  * Copyright (C) 2001, 2006 Tensilica Inc.
  10  * Copyright (C) 2015 Cadence Design Systems Inc.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/init.h>
  15 #include <linux/io.h>
  16
  17 #include <platform/hardware.h>
  18 #include <platform/lcd.h>
  19
  20 /* LCD instruction and data addresses. */
  21 #define LCD_INSTR_ADDR          ((char *)IOADDR(CONFIG_XTFPGA_LCD_BASE_ADDR))
  22 #define LCD_DATA_ADDR           (LCD_INSTR_ADDR + 4)
  23
  24 #define LCD_CLEAR               0x1
  25 #define LCD_DISPLAY_ON          0xc
  26
  27 /* 8bit and 2 lines display */
  28 #define LCD_DISPLAY_MODE8BIT    0x38
  29 #define LCD_DISPLAY_MODE4BIT    0x28
  30 #define LCD_DISPLAY_POS         0x80
  31 #define LCD_SHIFT_LEFT          0x18
  32 #define LCD_SHIFT_RIGHT         0x1c
  33
  34 static void lcd_put_byte(u8 *addr, u8 data)
  35 {
  36 #ifdef CONFIG_XTFPGA_LCD_8BIT_ACCESS
  37         WRITE_ONCE(*addr, data);
  38 #else
  39         WRITE_ONCE(*addr, data & 0xf0);
  40         WRITE_ONCE(*addr, (data << 4) & 0xf0);
  41 #endif
  42 }
  43
  44 static int __init lcd_init(void)
  45 {
  46         WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);
  47         mdelay(5);
  48         WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);
  49         udelay(200);
  50         WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE8BIT);
  51         udelay(50);
  52 #ifndef CONFIG_XTFPGA_LCD_8BIT_ACCESS
  53         WRITE_ONCE(*LCD_INSTR_ADDR, LCD_DISPLAY_MODE4BIT);
  54         udelay(50);
  55         lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_MODE4BIT);
  56         udelay(50);
  57 #endif
  58         lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_ON);
  59         udelay(50);
  60         lcd_put_byte(LCD_INSTR_ADDR, LCD_CLEAR);
  61         mdelay(10);
  62         lcd_disp_at_pos("XTENSA LINUX", 0);
  63         return 0;
  64 }
  65
  66 void lcd_disp_at_pos(char *str, unsigned char pos)
  67 {
  68         lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_POS | pos);
  69         udelay(100);
  70         while (*str != 0) {
  71                 lcd_put_byte(LCD_DATA_ADDR, *str);
  72                 udelay(200);
  73                 str++;
  74         }
  75 }
  76
  77 void lcd_shiftleft(void)
  78 {
  79         lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_LEFT);
  80         udelay(50);
  81 }
  82
  83 void lcd_shiftright(void)
  84 {
  85         lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_RIGHT);
  86         udelay(50);
  87 }
  88
  89 arch_initcall(lcd_init);