auxdisplay: add home to charlcd_ops

This adds a home function to the charlcd_ops struct and offer an
implementation for hd44780_common. This implementation is used by our
two hd44780 drivers. This is to make charlcd device independent.
Reviewed-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

drivers/auxdisplay/charlcd.c

@@ -144,7 +144,7 @@ static void charlcd_home(struct charlcd *lcd)
 {
 	lcd->addr.x = 0;
 	lcd->addr.y = 0;
-	lcd->ops->gotoxy(lcd);
+	lcd->ops->home(lcd);
 }
 
 static void charlcd_print(struct charlcd *lcd, char c)

drivers/auxdisplay/charlcd.h

@@ -41,12 +41,15 @@ struct charlcd {
  * wrap to the next line at the end of a line.
  * @gotoxy: Set cursor to x, y. The x and y values to set the cursor to are
  * previously set in addr.x and addr.y by charlcd.
+ * @home: Set cursor to 0, 0. The values in addr.x and addr.y are set to 0, 0 by
+ * charlcd prior to calling this function.
  */
 struct charlcd_ops {
 	void (*clear_fast)(struct charlcd *lcd);
 	void (*backlight)(struct charlcd *lcd, enum charlcd_onoff on);
 	int (*print)(struct charlcd *lcd, int c);
 	int (*gotoxy)(struct charlcd *lcd);
+	int (*home)(struct charlcd *lcd);
 };
 
 struct charlcd *charlcd_alloc(void);

drivers/auxdisplay/hd44780.c

@@ -128,6 +128,7 @@ static const struct charlcd_ops hd44780_ops_gpio8 = {
 	.backlight	= hd44780_backlight,
 	.print		= hd44780_common_print,
 	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
 };
 
 /* Send a command to the LCD panel in 4 bit GPIO mode */
@@ -173,6 +174,7 @@ static const struct charlcd_ops hd44780_ops_gpio4 = {
 	.backlight	= hd44780_backlight,
 	.print		= hd44780_common_print,
 	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
 };
 
 static int hd44780_probe(struct platform_device *pdev)

drivers/auxdisplay/hd44780_common.c

@@ -41,6 +41,14 @@ int hd44780_common_gotoxy(struct charlcd *lcd)
 }
 EXPORT_SYMBOL_GPL(hd44780_common_gotoxy);
 
+int hd44780_common_home(struct charlcd *lcd)
+{
+	lcd->addr.x = 0;
+	lcd->addr.y = 0;
+	return hd44780_common_gotoxy(lcd);
+}
+EXPORT_SYMBOL_GPL(hd44780_common_home);
+
 struct hd44780_common *hd44780_common_alloc(void)
 {
 	struct hd44780_common *hd;

drivers/auxdisplay/hd44780_common.h

@@ -16,4 +16,5 @@ struct hd44780_common {
 
 int hd44780_common_print(struct charlcd *lcd, int c);
 int hd44780_common_gotoxy(struct charlcd *lcd);
+int hd44780_common_home(struct charlcd *lcd);
 struct hd44780_common *hd44780_common_alloc(void);

drivers/auxdisplay/panel.c

@@ -876,18 +876,21 @@ static const struct charlcd_ops charlcd_serial_ops = {
 	.clear_fast	= lcd_clear_fast_s,
 	.backlight	= lcd_backlight,
 	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
 };
 
 static const struct charlcd_ops charlcd_parallel_ops = {
 	.clear_fast	= lcd_clear_fast_p8,
 	.backlight	= lcd_backlight,
 	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
 };
 
 static const struct charlcd_ops charlcd_tilcd_ops = {
 	.clear_fast	= lcd_clear_fast_tilcd,
 	.backlight	= lcd_backlight,
 	.gotoxy		= hd44780_common_gotoxy,
+	.home		= hd44780_common_home,
 };
 
 /* initialize the LCD driver */