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,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 33AC7C433E0 for ; Thu, 14 Jan 2021 09:51:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2D53239EB for ; Thu, 14 Jan 2021 09:51:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726901AbhANJun (ORCPT ); Thu, 14 Jan 2021 04:50:43 -0500 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:54303 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726822AbhANJum (ORCPT ); Thu, 14 Jan 2021 04:50:42 -0500 X-Originating-IP: 86.202.109.140 Received: from localhost (lfbn-lyo-1-13-140.w86-202.abo.wanadoo.fr [86.202.109.140]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id DD4F4E0013; Thu, 14 Jan 2021 09:50:08 +0000 (UTC) Date: Thu, 14 Jan 2021 10:50:08 +0100 From: Alexandre Belloni To: Philipp Rosenberger Cc: dan.carpenter@oracle.com, u.kleine-koenig@pengutronix.de, biwen.li@nxp.com, lvb@xiphos.com, bruno.thomsen@gmail.com, l.sanfilippo@kunbus.com, Alessandro Zummo , linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] rtc: pcf2127: Run a OTP refresh if not done before Message-ID: <20210114095008.GV3654@piout.net> References: <20210113112742.7354-1-p.rosenberger@kunbus.com> <20210113112742.7354-3-p.rosenberger@kunbus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210113112742.7354-3-p.rosenberger@kunbus.com> Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org On 13/01/2021 12:27:42+0100, Philipp Rosenberger wrote: > The datasheet of the PCF2127 states,it is recommended to process an OTP > refresh once the power is up and the oscillator is operating stable. The > OTP refresh takes less than 100 ms to complete. > > Signed-off-by: Philipp Rosenberger > --- > drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > index 378b1ce812d6..ca56dba64e79 100644 > --- a/drivers/rtc/rtc-pcf2127.c > +++ b/drivers/rtc/rtc-pcf2127.c > @@ -58,6 +58,9 @@ > #define PCF2127_REG_ALARM_DM 0x0D > #define PCF2127_REG_ALARM_DW 0x0E > #define PCF2127_BIT_ALARM_AE BIT(7) > +/* CLKOUT control register */ > +#define PCF2127_REG_CLKOUT 0x0f > +#define PCF2127_BIT_CLKOUT_OTPR BIT(5) > /* Watchdog registers */ > #define PCF2127_REG_WD_CTL 0x10 > #define PCF2127_BIT_WD_CTL_TF0 BIT(0) > @@ -630,6 +633,19 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap, > dev_warn(dev, "Watchdog and alarm functions might not work properly\n"); > } > > + /* > + * Set the OTP refresh bit unconditionally. If an OTP refresh was > + * already done the bit is already set and will not rerun the refresh > + * operation. > + */ > + ret = regmap_set_bits(pcf2127->regmap, PCF2127_REG_CLKOUT, > + PCF2127_BIT_CLKOUT_OTPR); > + if (ret < 0) { > + dev_err(dev, "%s: OTP refresh (clkout_ctrl) failed.\n", __func__); Please drop this error message. > + return ret; > + } > + msleep(100); Maybe this should be done just before setting the time. Or if you want to keep it in probe, then you could optimise by not waiting but ensuring the time between pcf2127_probe and the first pcf2127_rtc_set_time is more than 100ms. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com