From mboxrd@z Thu Jan 1 00:00:00 1970 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 1BC56C7EE2F for ; Thu, 25 May 2023 11:05:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234403AbjEYLFn (ORCPT ); Thu, 25 May 2023 07:05:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231605AbjEYLFn (ORCPT ); Thu, 25 May 2023 07:05:43 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 218A7C5; Thu, 25 May 2023 04:05:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1685012742; x=1716548742; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=TDUuNhwXDmmjarx2uF6dpg1kUSW8MpUrO3mxIEI6THU=; b=ZZNY7X2kqd9ybfkJhQBa3jppU1Chu6yeRtGyiyDN+ByEzDEm+kYZKbD5 MU5CD+yhMnLsPdyg7Jumek907paq+bb0syI1B30Ly3PFz3Gbfne52Xl1L QrugO5BAIAc+3E1stOuOombeMqjcz4sTjOfPZ2Scsl3XBTJZGsTvRfVfh YTwJW60wfHohfTHOliPVNo4GRMOfIAyg7kjMo+tRk0/RHsvoSGhn9k0mX 3kvU/CZUyelK9szvXB92prjvSht0j2lG/pvA0mNnZvhjjVd+sx6mTPpOv SPey7YlrrxTCdMTLl1OUv/sAPwJ4Ce4P1s/K3nYAvP7FIrRQlA4Yju6ea w==; X-IronPort-AV: E=McAfee;i="6600,9927,10720"; a="357084326" X-IronPort-AV: E=Sophos;i="6.00,191,1681196400"; d="scan'208";a="357084326" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2023 04:05:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10720"; a="1034935055" X-IronPort-AV: E=Sophos;i="6.00,191,1681196400"; d="scan'208";a="1034935055" Received: from aghiriba-mobl.ger.corp.intel.com ([10.249.40.17]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2023 04:05:37 -0700 Date: Thu, 25 May 2023 14:05:35 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: Hugo Villeneuve cc: Greg Kroah-Hartman , robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, Jiri Slaby , jringle@gridpoint.com, tomasz.mon@camlingroup.com, l.perczak@camlintechnologies.com, linux-serial , devicetree@vger.kernel.org, LKML , linux-gpio@vger.kernel.org, Hugo Villeneuve Subject: Re: [PATCH v3 04/11] serial: sc16is7xx: add post reset delay In-Reply-To: <20230525040324.3773741-5-hugo@hugovil.com> Message-ID: <1ae6fb11-6aa8-66e-86a-a9b5a6403f5e@linux.intel.com> References: <20230525040324.3773741-1-hugo@hugovil.com> <20230525040324.3773741-5-hugo@hugovil.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Thu, 25 May 2023, Hugo Villeneuve wrote: > 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 */ Does this fix a problem? You don't have a Fixes tag nor did you describe a problem that arises if the is not there in the changelog. -- i.