From patchwork Thu May 25 04:03:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hugo Villeneuve X-Patchwork-Id: 686358 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D24DC7EE31 for ; Thu, 25 May 2023 04:06:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238649AbjEYEF7 (ORCPT ); Thu, 25 May 2023 00:05:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237734AbjEYEE3 (ORCPT ); Thu, 25 May 2023 00:04:29 -0400 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FAA91A6; Wed, 24 May 2023 21:04:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-Id:Date:Cc:To:From:Sender:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=JzQwwWHfLn5GqJ+sUpssIPjhRdBj01gT2s8uoqlHWI4=; b=YJgReEa/vE2riAdBxkk5ViBMZs F8EVEKjd/h5NYSZ8FL+TWOdz/aaDrUNBHbuZ4qbjQ9HOx52QgkIeruEDteW69XE7Ji+nHcNL6TAJN RN2DHwkXn3+zgfWCLpQCBsLfxl+VX1cQLNtCDtL9DFAHcva5Vpdc6vAu9vRNQgtoXhWE=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:52970 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1q22D2-0001dB-Ii; Thu, 25 May 2023 00:04:17 -0400 From: Hugo Villeneuve To: gregkh@linuxfoundation.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, jirislaby@kernel.org, jringle@gridpoint.com, tomasz.mon@camlingroup.com, l.perczak@camlintechnologies.com Cc: linux-serial@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, hugo@hugovil.com, linux-gpio@vger.kernel.org, Hugo Villeneuve Date: Thu, 25 May 2023 00:03:17 -0400 Message-Id: <20230525040324.3773741-5-hugo@hugovil.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230525040324.3773741-1-hugo@hugovil.com> References: <20230525040324.3773741-1-hugo@hugovil.com> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com Subject: [PATCH v3 04/11] serial: sc16is7xx: add post reset delay X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Hugo Villeneuve Make sure we wait at least 3us before initiating communication with the device after reset. Signed-off-by: Hugo Villeneuve --- drivers/tty/serial/sc16is7xx.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index a7c4da3cfd2b..af7e66db54b4 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1428,6 +1428,12 @@ static int sc16is7xx_probe(struct device *dev, regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT, SC16IS7XX_IOCONTROL_SRESET_BIT); + /* + * After reset, the host must wait at least 3us before initializing a + * communication with the device. + */ + usleep_range(3, 5); + for (i = 0; i < devtype->nr_uart; ++i) { s->p[i].line = i; /* Initialize port data */