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=-5.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 15A36C4361B for ; Sun, 6 Dec 2020 14:21:07 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BEB0E2312F for ; Sun, 6 Dec 2020 14:21:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BEB0E2312F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mess.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=IBybOw2uwjC25HjL8zs1d1fcEH0Bz48ZiXQSNg1+KEA=; b=sQXQsc9BY50gNapesTmGSIDXE F6AQm8lphrp+plqvaDsvSxFcNZT8FmXqqyyeF8GSGEMrxpaCw3V3IImb7g3TJ1MD/fdycNTGAZG0q tnleGodMSJtuouRt+Jp9B5ShTArsh1Se9/zwGOaj4bInxU6/QKZPZoSZHJd9nzeM8bqw/+6HqM0BH x7viLiXEuNLfS0YboctOodnxW9ZicNsVAJYa051nsQdAx53OHq0R+Bt4cnk9AsbrHQ5KHuwYXG27g kZrOFLTf+g3sDJ5EoaUgIAHwK63WLf8wIH19P5WkVYoYfqUi4BG9ALis+ZWwrRV+OtVUPX8ExuKVG ckkUZ7LLg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1klutB-0007Ae-Sw; Sun, 06 Dec 2020 14:19:49 +0000 Received: from gofer.mess.org ([2a02:8011:d000:212::1]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1klut9-0007A4-G2; Sun, 06 Dec 2020 14:19:48 +0000 Received: by gofer.mess.org (Postfix, from userid 1000) id 4F998C63D6; Sun, 6 Dec 2020 14:19:41 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mess.org; s=2020; t=1607264381; bh=b+lxpFhX380M587pcy0Ld+WRWVJiMOZQGdYfRe41wBs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t8uuCqeoDREUaHCJN3yn3zDTKf/wo6N1A+IrTAKE6hbJLJOzZ3DEo9p75zG8ETNeI 4YVLKwSK2Hjqpt/5faOEo27UhLxgiuRC8eRtPpzOO9660HPqc+vDt9H82WFGdhbDsx 3zUyV6uOpWty/QYKtdwdF0lXsococi/+bkEv5ahUjBVrQmdvYmD9eTcpBrir4RRU5r k9ZeATD6ZWJ2r1F2eMSlOxn/JssRLcbhAiVhrrCpOza9vzeBfrslqcExrpHkauwcfg RHRXXxJjguTLg6oJ5Tdnu+C5zf+5URo0Hd5Z0kYBeRk7AdlVyW4iEE0R8loE1Wonam 18h1BZGYAoI1g== Date: Sun, 6 Dec 2020 14:19:41 +0000 From: Sean Young To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [PATCH v2] pwm: bcm2835: Support apply function for atomic configuration Message-ID: <20201206141941.GA24807@gofer.mess.org> References: <202011281128.54eLfMWr-lkp@intel.com> <1606564926-19555-1-git-send-email-LinoSanfilippo@gmx.de> <20201129181050.p6rkif5vjoumvafm@pengutronix.de> <4683237c-7b40-11ab-b3c0-f94a5dd39b4d@gmx.de> <20201204084417.GA2154@gofer.mess.org> <20201204111326.qjux6k2472dmukot@pengutronix.de> <20201204113846.GA6547@gofer.mess.org> <20201204232834.xzsafkzfmfpw7pqz@pengutronix.de> <20201205173444.GA1265@gofer.mess.org> <20201205192510.o76pjs3yc524nwvm@pengutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201205192510.o76pjs3yc524nwvm@pengutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201206_091947_746592_9712B92B X-CRM114-Status: GOOD ( 13.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, linux-pwm@vger.kernel.org, f.fainelli@gmail.com, sbranden@broadcom.com, rjui@broadcom.com, linux-kernel@vger.kernel.org, Lino Sanfilippo , thierry.reding@gmail.com, linux-rpi-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, lee.jones@linaro.org, nsaenzjulienne@suse.de Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hello Uwe, On Sat, Dec 05, 2020 at 08:25:10PM +0100, Uwe Kleine-K=F6nig wrote: > On Sat, Dec 05, 2020 at 05:34:44PM +0000, Sean Young wrote: > > What real life uses-cases are there for round down? If you want to round > > down, is there any need for round up? > = > The scenario I have in mind is for driving a motor. I have to admit > however that usually the period doesn't matter much and it's the > duty_cycle that defines the motor's speed. So for this case the > conservative behaviour is round-down to not make the motor run faster > than expected. I am reading here that for driving motors, only the duty cycle matters, not the period. > For other usecases (fan, backlight, LED) exactness typically doesn't > matter that much. So, the use-cases you have are driving motor, fan, backlight, and led. And in all these cases the exact Hz does not matter. The only uses case where the exact Hz does matter is pwm-ir-tx. = So, I gather there are no use-cases for round-down. Yes, should round-down be needed, then this is more difficult to implement if the driver always does a round-closest. But, since there is no reason to have round-down, this is all academic. Your policy of forcing new pwm drivers to use round-down is breaking pwm-ir-tx. Thanks, Sean _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel