From: Lars Poeschel <poesc...@lemonage.de> Digging in the hd44780 datasheet revealed that the timeout needed after clearing the whole display is only 1,64ms not 15ms. So we can reduce that timeout.
Link: https://lore.kernel.org/lkml/20200922092121.gg16...@1wt.eu/ Link: https://www.crystalfontz.com/controllers/Hitachi/HD44780/433/ Signed-off-by: Lars Poeschel <poesc...@lemonage.de> --- Changes in v3: - This patch is new in v3 --- drivers/auxdisplay/hd44780_common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/auxdisplay/hd44780_common.c b/drivers/auxdisplay/hd44780_common.c index 82afae78f46e..fbce8835a650 100644 --- a/drivers/auxdisplay/hd44780_common.c +++ b/drivers/auxdisplay/hd44780_common.c @@ -83,8 +83,8 @@ int hd44780_common_clear_display(struct charlcd *lcd) struct hd44780_common *hdc = lcd->drvdata; hdc->write_cmd(hdc, LCD_CMD_DISPLAY_CLEAR); - /* we must wait a few milliseconds (15) */ - long_sleep(15); + /* datasheet says to wait 1,64 milliseconds */ + long_sleep(2); return 0; } EXPORT_SYMBOL_GPL(hd44780_common_clear_display); -- 2.28.0
