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Diffstat (limited to 'arch/xtensa/platforms/xtfpga/lcd.c')
-rw-r--r--arch/xtensa/platforms/xtfpga/lcd.c55
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);
}