Staging: panel: Add support for TI CLCD interface

On TI DA850/OMAP-L138 EVM, HD44780 (24x2) LCD panel is being
used[1], but it is interfaced through the SoC specific LCD
interface and not through parallel port. A parallel port
driver has been developed which interfaces to the panel driver
through the SoC specific LCD interface.

Basically, both the serial and parallel interfaces supported
by the panel driver do not suit the specific interface SoC is
supporting so, a new interface type has been introduced.

Ideally the panel driver should be de-coupled from parallel
and serial port related items but this patch is something
that can be merged in the meantime.

[1]Specification of the character LCD interface on TI DA850/OMAP-L138:
http://www.ti.com/litv/pdf/sprufm0a.
Signed-off-by: Sudhakar Rajashekhara <sudhakar.raj@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/panel/panel.c

@@ -243,6 +243,7 @@ static unsigned char lcd_bits[LCD_PORTS][LCD_BITS][BIT_STATES];
  */
 #define LCD_PROTO_PARALLEL      0
 #define LCD_PROTO_SERIAL        1
+#define LCD_PROTO_TI_DA8XX_LCD	2
 
 /*
  * LCD character sets
@@ -440,7 +441,8 @@ MODULE_PARM_DESC(lcd_type,
 
 static int lcd_proto = -1;
 module_param(lcd_proto, int, 0000);
-MODULE_PARM_DESC(lcd_proto, "LCD communication: 0=parallel (//), 1=serial");
+MODULE_PARM_DESC(lcd_proto, "LCD communication: 0=parallel (//), 1=serial,"
+		"2=TI LCD Interface");
 
 static int lcd_charset = -1;
 module_param(lcd_charset, int, 0000);
@@ -797,6 +799,26 @@ static void lcd_write_data_p8(int data)
 	spin_unlock(&pprt_lock);
 }
 
+/* send a command to the TI LCD panel */
+static void lcd_write_cmd_tilcd(int cmd)
+{
+	spin_lock(&pprt_lock);
+	/* present the data to the control port */
+	w_ctr(pprt, cmd);
+	udelay(60);
+	spin_unlock(&pprt_lock);
+}
+
+/* send data to the TI LCD panel */
+static void lcd_write_data_tilcd(int data)
+{
+	spin_lock(&pprt_lock);
+	/* present the data to the data port */
+	w_dtr(pprt, data);
+	udelay(60);
+	spin_unlock(&pprt_lock);
+}
+
 static void lcd_gotoxy(void)
 {
 	lcd_write_cmd(0x80	/* set DDRAM address */
@@ -870,6 +892,26 @@ static void lcd_clear_fast_p8(void)
 	lcd_gotoxy();
 }
 
+/* fills the display with spaces and resets X/Y */
+static void lcd_clear_fast_tilcd(void)
+{
+	int pos;
+	lcd_addr_x = lcd_addr_y = 0;
+	lcd_gotoxy();
+
+	spin_lock(&pprt_lock);
+	for (pos = 0; pos < lcd_height * lcd_hwidth; pos++) {
+		/* present the data to the data port */
+		w_dtr(pprt, ' ');
+		udelay(60);
+	}
+
+	spin_unlock(&pprt_lock);
+
+	lcd_addr_x = lcd_addr_y = 0;
+	lcd_gotoxy();
+}
+
 /* clears the display and resets X/Y */
 static void lcd_clear_display(void)
 {
@@ -1396,7 +1438,7 @@ void lcd_init(void)
 		if (lcd_da_pin == PIN_NOT_SET)
 			lcd_da_pin = DEFAULT_LCD_PIN_SDA;
 
-	} else {		/* PARALLEL */
+	} else if (lcd_proto == LCD_PROTO_PARALLEL) {	/* PARALLEL */
 		lcd_write_cmd = lcd_write_cmd_p8;
 		lcd_write_data = lcd_write_data_p8;
 		lcd_clear_fast = lcd_clear_fast_p8;
@@ -1407,6 +1449,10 @@ void lcd_init(void)
 			lcd_rs_pin = DEFAULT_LCD_PIN_RS;
 		if (lcd_rw_pin == PIN_NOT_SET)
 			lcd_rw_pin = DEFAULT_LCD_PIN_RW;
+	} else {
+		lcd_write_cmd = lcd_write_cmd_tilcd;
+		lcd_write_data = lcd_write_data_tilcd;
+		lcd_clear_fast = lcd_clear_fast_tilcd;
 	}
 
 	if (lcd_bl_pin == PIN_NOT_SET)