From patchwork Mon May 29 14:07:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hugo Villeneuve X-Patchwork-Id: 686768 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 28A58C7EE45 for ; Mon, 29 May 2023 14:07:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229529AbjE2OHf (ORCPT ); Mon, 29 May 2023 10:07:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230273AbjE2OHe (ORCPT ); Mon, 29 May 2023 10:07:34 -0400 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23C20A8; Mon, 29 May 2023 07:07:31 -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=j06j0xxAnTBWbm+RR07Ahwjb4COk2ZLwxArCeTG3Zrw=; b=FK/zyz5jag1Oy1osJK5trnHLQv 131njOxu9Pw+MPoeXBq0qYCpBW3PXRcd9e3Z7NCv0VsWNC9MrLGzudi2cHD7qRONDOyFDp2Lgahi+ rP0ZOWekuepnjJtBIoqi+RyJczMdAHsE+EFprDPI1j0coDhQuM3JjfusJ/6WK/kzo8vI=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:50024 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1q3dWq-0004Ht-Gu; Mon, 29 May 2023 10:07:21 -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, l.perczak@camlintechnologies.com, tomasz.mon@camlingroup.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: Mon, 29 May 2023 10:07:04 -0400 Message-Id: <20230529140711.896830-3-hugo@hugovil.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230529140711.896830-1-hugo@hugovil.com> References: <20230529140711.896830-1-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 v4 2/9] 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-gpio@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 fbaadec557d8..24c9336f6ab2 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(5, 10); + for (i = 0; i < devtype->nr_uart; ++i) { s->p[i].line = i; /* Initialize port data */