1 files changed, 34 insertions, 21 deletions

diff --git a/arch/xtensa/platforms/xtfpga/lcd.c b/arch/xtensa/platforms/xtfpga/lcd.c
index 2872301598df..4dc0c1b43f4b 100644
--- a/arch/xtensa/platforms/xtfpga/lcd.c
+++ b/arch/xtensa/platforms/xtfpga/lcd.c
@@ -1,50 +1,63 @@
 /*
- * Driver for the LCD display on the Tensilica LX60 Board.
+ * 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.
  */
 
-/*
- *
- * FIXME: this code is from the examples from the LX60 user guide.
- *
- * The lcd_pause function does busy waiting, which is probably not
- * great. Maybe the code could be changed to use kernel timers, or
- * change the hardware to not need to wait.
- */
-
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 
 #include <platform/hardware.h>
 #include <platform/lcd.h>
-#include <linux/delay.h>
 
-#define LCD_PAUSE_ITERATIONS    4000
+/* 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)
 {
-        *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
+        ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE8BIT;
         mdelay(5);
-        *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
+        ACCESS_ONCE(*LCD_INSTR_ADDR) = LCD_DISPLAY_MODE8BIT;
         udelay(200);
-        *LCD_INSTR_ADDR = LCD_DISPLAY_MODE8BIT;
+        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);
-        *LCD_INSTR_ADDR = LCD_DISPLAY_ON;
+#endif
+        lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_ON);
         udelay(50);
-        *LCD_INSTR_ADDR = LCD_CLEAR;
+        lcd_put_byte(LCD_INSTR_ADDR, LCD_CLEAR);
         mdelay(10);
         lcd_disp_at_pos("XTENSA LINUX", 0);
         return 0;
@@ -52,10 +65,10 @@ static int __init lcd_init(void)
 
 void lcd_disp_at_pos(char *str, unsigned char pos)
 {
-        *LCD_INSTR_ADDR = LCD_DISPLAY_POS | pos;
+        lcd_put_byte(LCD_INSTR_ADDR, LCD_DISPLAY_POS | pos);
         udelay(100);
         while (*str != 0) {
-                *LCD_DATA_ADDR = *str;
+                lcd_put_byte(LCD_DATA_ADDR, *str);
                 udelay(200);
                 str++;
         }
@@ -63,13 +76,13 @@ void lcd_disp_at_pos(char *str, unsigned char pos)
 
 void lcd_shiftleft(void)
 {
-        *LCD_INSTR_ADDR = LCD_SHIFT_LEFT;
+        lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_LEFT);
         udelay(50);
 }
 
 void lcd_shiftright(void)
 {
-        *LCD_INSTR_ADDR = LCD_SHIFT_RIGHT;
+        lcd_put_byte(LCD_INSTR_ADDR, LCD_SHIFT_RIGHT);
         udelay(50);
 }