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 X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4645EC5519F for ; Sun, 22 Nov 2020 23:11:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 16FB720773 for ; Sun, 22 Nov 2020 23:11:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726849AbgKVXLB (ORCPT ); Sun, 22 Nov 2020 18:11:01 -0500 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:60791 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726781AbgKVXLA (ORCPT ); Sun, 22 Nov 2020 18:11:00 -0500 X-Originating-IP: 86.194.74.19 Received: from localhost (lfbn-lyo-1-997-19.w86-194.abo.wanadoo.fr [86.194.74.19]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id 7F3591BF206; Sun, 22 Nov 2020 23:10:54 +0000 (UTC) Date: Mon, 23 Nov 2020 00:10:54 +0100 From: Alexandre Belloni To: Jonathan =?iso-8859-1?Q?Neusch=E4fer?= Cc: linux-kernel@vger.kernel.org, Lee Jones , Rob Herring , Thierry Reding , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Alessandro Zummo , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Sam Ravnborg , Linus Walleij , Heiko Stuebner , Stephan Gerhold , Lubomir Rintel , Mark Brown , allen , Mauro Carvalho Chehab , "David S. Miller" , devicetree@vger.kernel.org, linux-pwm@vger.kernel.org, linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Heiko Stuebner , Josua Mayer , Andreas Kemnade , Arnd Bergmann , Daniel Palmer , Andy Shevchenko Subject: Re: [PATCH v4 5/7] rtc: New driver for RTC in Netronix embedded controller Message-ID: <20201122231054.GH348979@piout.net> References: <20201122222739.1455132-1-j.neuschaefer@gmx.net> <20201122222739.1455132-6-j.neuschaefer@gmx.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201122222739.1455132-6-j.neuschaefer@gmx.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 22/11/2020 23:27:37+0100, Jonathan Neuschäfer wrote: > With this driver, mainline Linux can keep its time and date in sync with > the vendor kernel. > > Advanced functionality like alarm and automatic power-on is not yet > supported. > > Signed-off-by: Jonathan Neuschäfer Acked-by: Alexandre Belloni However, two comments below: > +static int ntxec_set_time(struct device *dev, struct rtc_time *tm) > +{ > + struct ntxec_rtc *rtc = dev_get_drvdata(dev); > + int res = 0; > + > + /* > + * To avoid time overflows while we're writing the full date/time, > + * set the seconds field to zero before doing anything else. For the > + * next 59 seconds (plus however long it takes until the RTC's next > + * update of the second field), the seconds field will not overflow > + * into the other fields. > + */ > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_SECOND, ntxec_reg8(0)); > + if (res) > + return res; > + > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_YEAR, ntxec_reg8(tm->tm_year - 100)); > + if (res) > + return res; > + > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_MONTH, ntxec_reg8(tm->tm_mon + 1)); > + if (res) > + return res; > + > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_DAY, ntxec_reg8(tm->tm_mday)); > + if (res) > + return res; > + > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_HOUR, ntxec_reg8(tm->tm_hour)); > + if (res) > + return res; > + > + res = regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_MINUTE, ntxec_reg8(tm->tm_min)); > + if (res) > + return res; > + > + return regmap_write(rtc->ec->regmap, NTXEC_REG_WRITE_SECOND, ntxec_reg8(tm->tm_sec)); Couldn't you do a regmap_block_write or a regmap_multi_reg_write which would be more efficient as they would be locking the regmap only once. > +} > + > +static const struct rtc_class_ops ntxec_rtc_ops = { > + .read_time = ntxec_read_time, > + .set_time = ntxec_set_time, > +}; > + > +static int ntxec_rtc_probe(struct platform_device *pdev) > +{ > + struct rtc_device *dev; > + struct ntxec_rtc *rtc; > + > + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); > + if (!rtc) > + return -ENOMEM; > + > + rtc->dev = &pdev->dev; > + rtc->ec = dev_get_drvdata(pdev->dev.parent); > + platform_set_drvdata(pdev, rtc); > + > + dev = devm_rtc_allocate_device(&pdev->dev); > + if (IS_ERR(dev)) > + return PTR_ERR(dev); > + > + dev->ops = &ntxec_rtc_ops; > + dev->range_min = RTC_TIMESTAMP_BEGIN_2000; > + dev->range_max = 9025257599LL; /* 2255-12-31 23:59:59 */ > + > + return rtc_register_device(dev); Note that this won't compile after https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git/commit/?id=fdcfd854333be5b30377dc5daa9cd0fa1643a979 We can solve that with immutable branches though. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com