Merge tag 'auxdisplay-6.6' of https://github.com/ojeda/linux

5ea0cf77 · Linus Torvalds <[email protected]> · 2023-08-29 08:32:28 -07:00

Pull auxdisplay update from Miguel Ojeda:

 - hd44780: move cursor home after clear display command

   The change allows to support displays like the NewHaven
   NHD-0220DZW-AG5 which has a non-standard controller.

* tag 'auxdisplay-6.6' of https://github.com/ojeda/linux:
  auxdisplay: hd44780: move cursor home after clear display command

Commit: 5ea0cf77583ec768c8e2403ecb2a930fa948b444
Parents: a031fe8d · 35b464e3

Merge commit. Changes below are compared with the first parent: a031fe8d.

Changes

1 files changed · +9 −1

File	Status	Add	Del	Content
drivers/auxdisplay/hd44780_common.c	modified	+9	−1	View file

drivers/auxdisplay/hd44780_common.c

View file

diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c
index 3934c2e..7cbf375 100644
--- a/drivers/auxdisplay/hd44780_common.c
+++ b/drivers/auxdisplay/hd44780_common.c
@@ -82,7 +82,15 @@ int hd44780_common_clear_display(struct charlcd *lcd)
 	hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR);
 	/* datasheet says to wait 1,64 milliseconds */
 	long_sleep(2);
-	return 0;
+
+	/*
+	 * The Hitachi HD44780 controller (and compatible ones) reset the DDRAM
+	 * address when executing the DISPLAY_CLEAR command, thus the
+	 * following call is not required. However, other controllers do not
+	 * (e.g. NewHaven NHD-0220DZW-AG5), thus move the cursor to home
+	 * unconditionally to support both.
+	 */
+	return hd44780_common_home(lcd);
 }
 EXPORT_SYMBOL_GPL(hd44780_common_clear_display);
 