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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 44EC0C47254 for ; Tue, 5 May 2020 22:09:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2EAD8206B8 for ; Tue, 5 May 2020 22:09:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729218AbgEEWJP (ORCPT ); Tue, 5 May 2020 18:09:15 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:56265 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727089AbgEEWJO (ORCPT ); Tue, 5 May 2020 18:09:14 -0400 X-Originating-IP: 86.202.105.35 Received: from localhost (lfbn-lyo-1-9-35.w86-202.abo.wanadoo.fr [86.202.105.35]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id 2C875C0003; Tue, 5 May 2020 22:09:12 +0000 (UTC) Date: Wed, 6 May 2020 00:09:11 +0200 From: Alexandre Belloni To: Rasmus Villemoes Cc: linux-rtc@vger.kernel.org, Per =?iso-8859-1?Q?N=F8rgaard?= Christensen , linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] rtc: pcf2127: report battery switch over Message-ID: <20200505220911.GW34497@piout.net> References: <20200505201310.255145-1-alexandre.belloni@bootlin.com> <20200505201310.255145-5-alexandre.belloni@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/05/2020 23:30:18+0200, Rasmus Villemoes wrote: > On 05/05/2020 22.13, Alexandre Belloni wrote: > > Add support for the RTC_VL_BACKUP_SWITCH flag to report battery switch over > > events. > > > > Signed-off-by: Alexandre Belloni > > --- > > drivers/rtc/rtc-pcf2127.c | 16 ++++++++++++---- > > 1 file changed, 12 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c > > index 039078029bd4..967de68e1b03 100644 > > --- a/drivers/rtc/rtc-pcf2127.c > > +++ b/drivers/rtc/rtc-pcf2127.c > > @@ -188,18 +188,27 @@ static int pcf2127_rtc_ioctl(struct device *dev, > > unsigned int cmd, unsigned long arg) > > { > > struct pcf2127 *pcf2127 = dev_get_drvdata(dev); > > - int touser; > > + int val, touser = 0; > > int ret; > > > > switch (cmd) { > > case RTC_VL_READ: > > - ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &touser); > > + ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL3, &val); > > if (ret) > > return ret; > > > > - touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0; > > + if (val & PCF2127_BIT_CTRL3_BLF) > > + touser = RTC_VL_BACKUP_LOW; > > + > > + if (val & PCF2127_BIT_CTRL3_BF) > > + touser |= RTC_VL_BACKUP_SWITCH; > > I think it's a bit easier to read if you use |= in both cases. > > Re patch 3, one saves a little .text by eliding the ioctl function when, > as you say, it cannot be called anyway. No strong opinion either way, I > don't think anybody actually builds without CONFIG_RTC_INTF_DEV, but > those that do are probably the ones that care about having a tiny vmlinux. > Honestly, I don't think it is worth doing that. On armv7, this only removes 248 bytes. Also, compiling without CONFIG_RTC_INTF_DEV simply makes the RTC unusable. There are no tools actually using the sysfs interface instead of the char device interface. I prefer keeping CONFIG_RTC_INTF_DEV private to the core. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com