From: poeschel@lemonage.de
To: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>,
linux-kernel@vger.kernel.org (open list)
Cc: Lars Poeschel <poeschel@lemonage.de>
Subject: [PATCH v6 19/25] auxdisplay: hd44780_common: Reduce clear_display timeout
Date: Tue, 3 Nov 2020 10:58:22 +0100 [thread overview]
Message-ID: <20201103095828.515831-20-poeschel@lemonage.de> (raw)
In-Reply-To: <20201103095828.515831-1-poeschel@lemonage.de>
From: Lars Poeschel <poeschel@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.GG16421@1wt.eu/
Link: https://www.crystalfontz.com/controllers/Hitachi/HD44780/433/
Signed-off-by: Lars Poeschel <poeschel@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 c528fb8e8808..bd93a4d3367e 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
next prev parent reply other threads:[~2020-11-03 9:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-03 9:58 [PATCH v6 00/25] Make charlcd device independent poeschel
2020-11-03 9:58 ` [PATCH v6 01/25] auxdisplay: Use an enum for charlcd backlight on/off ops poeschel
2020-11-03 9:58 ` [PATCH v6 02/25] auxdisplay: Introduce hd44780_common.[ch] poeschel
2020-11-03 9:58 ` [PATCH v6 03/25] auxdisplay: Move hwidth and bwidth to struct hd44780_common poeschel
2020-11-03 9:58 ` [PATCH v6 04/25] auxdisplay: Move ifwidth " poeschel
2020-11-03 9:58 ` [PATCH v6 05/25] auxdisplay: Move write_data pointer to hd44780_common poeschel
2020-11-03 9:58 ` [PATCH v6 06/25] auxdisplay: Move write_cmd pointers to hd44780 drivers poeschel
2020-11-03 9:58 ` [PATCH v6 07/25] auxdisplay: Move addr out of charlcd_priv poeschel
2020-11-03 9:58 ` [PATCH v6 08/25] auxdisplay: hd44780_common_print poeschel
2020-11-03 9:58 ` [PATCH v6 09/25] auxdisplay: provide hd44780_common_gotoxy poeschel
2020-11-03 9:58 ` [PATCH v6 10/25] auxdisplay: add home to charlcd_ops poeschel
2020-11-03 9:58 ` [PATCH v6 11/25] auxdisplay: Move clear_display to hd44780_common poeschel
2020-11-03 9:58 ` [PATCH v6 12/25] auxdisplay: make charlcd_backlight visible " poeschel
2020-11-03 9:58 ` [PATCH v6 13/25] auxdisplay: Make use of enum for backlight on / off poeschel
2020-11-03 9:58 ` [PATCH v6 14/25] auxdisplay: Move init_display to hd44780_common poeschel
2020-11-03 9:58 ` [PATCH v6 15/25] auxdisplay: implement various hd44780_common_ functions poeschel
2020-11-03 9:58 ` [PATCH v6 16/25] auxdisplay: cleanup unnecessary hd44780 code in charlcd poeschel
2020-11-03 9:58 ` [PATCH v6 17/25] auxdisplay: Move char redefine code to hd44780_common poeschel
2020-11-03 9:58 ` [PATCH v6 18/25] auxdisplay: Call charlcd_backlight in place poeschel
2020-11-03 9:58 ` poeschel [this message]
2020-11-03 9:58 ` [PATCH v6 20/25] auxdisplay: hd44780: Remove clear_fast poeschel
2020-11-03 9:58 ` [PATCH v6 21/25] auxdisplay: charlcd: replace last device specific stuff poeschel
2020-11-03 9:58 ` [PATCH v6 22/25] auxdisplay: Change gotoxy calling interface poeschel
2020-11-03 9:58 ` [PATCH v6 23/25] auxdisplay: charlcd: Do not print chars at end of line poeschel
2020-11-03 9:58 ` [PATCH v6 24/25] auxdisplay: lcd2s DT binding doc poeschel
2020-11-03 9:58 ` [PATCH v6 25/25] auxdisplay: add a driver for lcd2s character display poeschel
2020-11-04 13:30 ` [PATCH v6 00/25] Make charlcd device independent Miguel Ojeda
2020-11-06 10:11 ` Lars Poeschel
2020-11-06 12:17 ` Miguel Ojeda
2020-11-06 16:35 ` Randy Dunlap
2020-11-09 9:31 ` [PATCH] auxdisplay: hd44780_common: Fix build error poeschel
2020-11-09 9:45 ` Miguel Ojeda
2020-11-09 17:30 ` Randy Dunlap
2020-11-09 9:53 ` [PATCH v6 00/25] Make charlcd device independent Miguel Ojeda
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