Received: by 2002:a05:6a10:16a7:0:0:0:0 with SMTP id gp39csp382389pxb; Tue, 3 Nov 2020 02:01:44 -0800 (PST) X-Google-Smtp-Source: ABdhPJyk2jh4JW2GLDNmOqdZcBJV0q6HOpQZ8uU916S/Xnh2xzaYbSIgTdrNzZ/dtCMWpwFuwovk X-Received: by 2002:a17:906:f943:: with SMTP id ld3mr19768623ejb.96.1604397703912; Tue, 03 Nov 2020 02:01:43 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1604397703; cv=none; d=google.com; s=arc-20160816; b=TriPcqw4FqokcwbfQ/NOnHirZnu/NMxnqz1TPRMnkkxlhYt8RH8CdR4aGQhg7joQpA urESvUy4Zbez7pOqgL9KEtzWKhgaWLd2VkhzFfbka1UtgosqgGLjvFHy6qTZtG80KmkW mtxMcfS6jArKZbnu7BbSgOAkUHMtnVbR/dVA4mPzcxxdEe9cjtRzaQgpSkFEp7VbHwnn PStBsU+eURZnkPPYIyHh3sPk7LSWJqjerK/X+6qIRKVyVxajuaC1asWv4+B1HoSObW1W MyB8OqJCTCXQ+v3Lb8WXWd/FjMNNWNKrmKEze9yE8Tl3Jm2ec5yVjFtd98oIdFcmYnc4 zWww== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=GFqK8xxEJhXl100BSOo6BDKHRlb/pVcr/OsXqE8qHyw=; b=ABCPDpjWS+/ZyGTNihOfWxCiJxZbe9iaaMvIoKtbr70cnSB4l1rh6c9ofvhDk5xuhs tcFlueGL2j4MEh57d2oOfhlrnXG6TN1RoFNj0aV07vQskQ5LBFGbN3TGGj0WZ26iMOy2 BRySMcg7Sozh06UdSlY/jbs3uZ5K15cow9ex2yMqSmbPceMrWvjMaVjgJQMKhZ/2f4vk iynA6b/OY+iHMaVsTRpkbJmZh+qWHRV6d5RQxunb2szs51p3jurmCmoPNINj8nSUIr6u tlfPsDsjuIBFfFqJseukAgy/b1JBPk92eoA9pGmUj1NzmMuLgGxNEPFNawk28bzGcf8c L1hA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id bk9si498397ejb.42.2020.11.03.02.01.21; Tue, 03 Nov 2020 02:01:43 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728243AbgKCJ7b (ORCPT + 99 others); Tue, 3 Nov 2020 04:59:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728144AbgKCJ7B (ORCPT ); Tue, 3 Nov 2020 04:59:01 -0500 Received: from smtp3-1.goneo.de (smtp3.goneo.de [IPv6:2001:1640:5::8:37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75D31C0613D1 for ; Tue, 3 Nov 2020 01:58:59 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by smtp3.goneo.de (Postfix) with ESMTP id 5E3CB23FF75; Tue, 3 Nov 2020 10:58:58 +0100 (CET) X-Virus-Scanned: by goneo X-Spam-Flag: NO X-Spam-Score: -2.942 X-Spam-Level: X-Spam-Status: No, score=-2.942 tagged_above=-999 tests=[ALL_TRUSTED=-1, AWL=-0.042, BAYES_00=-1.9] autolearn=ham Received: from smtp3.goneo.de ([127.0.0.1]) by localhost (smtp3.goneo.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kjBn6dXjJN3H; Tue, 3 Nov 2020 10:58:56 +0100 (CET) Received: from lem-wkst-02.lemonage.de. (hq.lemonage.de [87.138.178.34]) by smtp3.goneo.de (Postfix) with ESMTPA id 873AC23FEE3; Tue, 3 Nov 2020 10:58:56 +0100 (CET) From: poeschel@lemonage.de To: Miguel Ojeda Sandonis , linux-kernel@vger.kernel.org (open list) Cc: Lars Poeschel Subject: [PATCH v6 19/25] auxdisplay: hd44780_common: Reduce clear_display timeout Date: Tue, 3 Nov 2020 10:58:22 +0100 Message-Id: <20201103095828.515831-20-poeschel@lemonage.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201103095828.515831-1-poeschel@lemonage.de> References: <20201103095828.515831-1-poeschel@lemonage.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lars Poeschel 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 --- 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