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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 EA77AC2BB1D for ; Thu, 12 Mar 2020 14:21:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1C2420650 for ; Thu, 12 Mar 2020 14:21:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="elAvbo1K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727621AbgCLOVa (ORCPT ); Thu, 12 Mar 2020 10:21:30 -0400 Received: from mail-pj1-f67.google.com ([209.85.216.67]:39706 "EHLO mail-pj1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727340AbgCLOVa (ORCPT ); Thu, 12 Mar 2020 10:21:30 -0400 Received: by mail-pj1-f67.google.com with SMTP id d8so2721711pje.4; Thu, 12 Mar 2020 07:21:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=xA6hYZYQHhZOK5w4gl5vlgvd5UjngUj1HWav2zK4YIE=; b=elAvbo1K35UXfjiU7s7C6Fr9ny3r+zuq45aGb0obKM6MUmebz83Om5sR5EldQ2SDgz Og0VcNpXOI9i+t4VR3d7CMdNkJus2nXmDWCBFyVCIl4V8DrooAAFnWMis1sxuv53Y0B+ ku1ZKLsP0J8dg8z3MBUH+p1Q1SxXHFZXQ6PdsRVVhAAMSF0Uf9EnvNeh0bYSu4Rrom8i UhZMG8hOG8pEczd9Ogd+3+Q8DE0JK3rn8ERKhEgv03HyVQ7oaawEy0Afd2Chbmdhb53W QeJQh4lX+sN6H2dX6bUnRWq8OJmv+OV+m3ZmAdSqDwq0awnF2/tMa9LC60qbWSBqG+EG 5kwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=xA6hYZYQHhZOK5w4gl5vlgvd5UjngUj1HWav2zK4YIE=; b=Co1KgQkYuoQZkghdr6t2Wc0ivrIWtxAM3QaxC527cfPov27oj1/jjsFyQjP2EbIDLj 94Or81YhHE62q57LJhdsj5TqRQcQK2td+JaFpew6DIjfXDHtsZQ0ZxLkEazU52ZBFLi6 b5ZEWHNsdUgsrUDHNR5Dr0gtPGa+NLUMnjDZZxczq9dWjw1+F4OY6aSrGssznQgWNEYJ +Gb0NirMg6LnFVKu+8rJDm6HpQsly31qlleG+Dr0GKWxWk+ggLncyslKGONWtsE1X14n Wn+37tnrr85W3nIgMANc0QPW6HGEguO7e58ZfYx6WAta4/BoYfkEmvufPdtAu6Nfg4Mf qzVw== X-Gm-Message-State: ANhLgQ0uhAZX19MuB85vJNyEqt4GWRAm6XQumrAz8k7NbxRRNY75bvhc SbBsQkFkIGAqd6Q0erMF0HoNQ5wI X-Google-Smtp-Source: ADFU+vsTQyN4Pfu6NQPzwD6SbwLEp4VXwcjudj3agC6kETt85Aq0K0JBWrXCGhcDemgNyIORo3UffQ== X-Received: by 2002:a17:902:bcc5:: with SMTP id o5mr8187811pls.174.1584022889113; Thu, 12 Mar 2020 07:21:29 -0700 (PDT) Received: from localhost (c-73-241-114-122.hsd1.ca.comcast.net. [73.241.114.122]) by smtp.gmail.com with ESMTPSA id 15sm49441428pfp.125.2020.03.12.07.21.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2020 07:21:28 -0700 (PDT) Date: Thu, 12 Mar 2020 07:21:26 -0700 From: Richard Cochran To: Lokesh Vutla Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Thierry Reding , Tony Lindgren , Linux OMAP Mailing List , linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, Sekhar Nori , Vignesh R , kernel@pengutronix.de Subject: Re: [PATCH v3 4/5] pwm: omap-dmtimer: Do not disable pwm before changing period/duty_cycle Message-ID: <20200312142126.GB2466@localhost> References: <20200312042210.17344-1-lokeshvutla@ti.com> <20200312042210.17344-5-lokeshvutla@ti.com> <20200312064042.p7himm3odxjyzroi@pengutronix.de> <20200312084739.isixgdo3txr6rjzg@pengutronix.de> <2a5a06cd-7aca-c450-b048-33329d058eca@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2a5a06cd-7aca-c450-b048-33329d058eca@ti.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 12, 2020 at 04:14:34PM +0530, Lokesh Vutla wrote: > But the problem here is that inactive breaks between two periods is not desired. > Because the pwm is used to generate a 1PPS signal and is continuously > synchronized with PTP clock. The 1-PPS case is the "easy" one. If the PWM is adjustable on the fly, then people will use it with higher frequency signals. > I am up if this can be solved generically. But updating period is very specific > to hardware implementation. Not sure what generic solution can be brought out of > this. Please correct me if I am wrong. What happens today when the PWM frequency or duty cycle are changed while the signal is enabled? Do different PWM devices/drivers behave the same way? Does this series change the behavior of the am335x and friends? Thanks, Richard