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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 1549BC433E0 for ; Thu, 9 Jul 2020 14:50:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F1A272076C for ; Thu, 9 Jul 2020 14:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726910AbgGIOuR (ORCPT ); Thu, 9 Jul 2020 10:50:17 -0400 Received: from mga14.intel.com ([192.55.52.115]:5994 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726353AbgGIOuR (ORCPT ); Thu, 9 Jul 2020 10:50:17 -0400 IronPort-SDR: NtF7VqloOu4BEECHyCeT9rQGJGIiIpyOtcKX/qevTa2/O3I0RkjmbM6UPbBq4RcX6iKq2agPGO 2f2kWBO38tfQ== X-IronPort-AV: E=McAfee;i="6000,8403,9677"; a="147081022" X-IronPort-AV: E=Sophos;i="5.75,331,1589266800"; d="scan'208";a="147081022" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Jul 2020 07:50:16 -0700 IronPort-SDR: D/XUYMSp7pV3RqXOFUNrDLm8myVFN+vUXCjDbk4u4enIZwh5VeaP3rkTuAjMvg45USqZ04zgtD IrKqRKUSO7lA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,331,1589266800"; d="scan'208";a="389163251" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga001.fm.intel.com with ESMTP; 09 Jul 2020 07:50:13 -0700 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1jtXsL-000sMF-Dd; Thu, 09 Jul 2020 17:50:13 +0300 Date: Thu, 9 Jul 2020 17:50:13 +0300 From: Andy Shevchenko To: Hans de Goede Cc: Thierry Reding , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , "Rafael J . Wysocki" , Len Brown , linux-pwm@vger.kernel.org, intel-gfx , dri-devel@lists.freedesktop.org, Mika Westerberg , linux-acpi@vger.kernel.org Subject: Re: [PATCH v4 06/16] pwm: lpss: Correct get_state result for base_unit == 0 Message-ID: <20200709145013.GA3703480@smile.fi.intel.com> References: <20200708211432.28612-1-hdegoede@redhat.com> <20200708211432.28612-7-hdegoede@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200708211432.28612-7-hdegoede@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Wed, Jul 08, 2020 at 11:14:22PM +0200, Hans de Goede wrote: > The datasheet specifies that programming the base_unit part of the > ctrl register to 0 results in a contineous low signal. > > Adjust the get_state method to reflect this by setting pwm_state.period > to 1 and duty_cycle to 0. ... > + if (freq == 0) { > + /* In this case the PWM outputs a continous low signal */ > + state->period = 1; I guess this should be something like half of the range (so base unit calc will give 128). Because with period = 1 (too small) it will give too small base unit (if apply) and as a result we get high frequency pulses. > + state->duty_cycle = 0; > + } else { > state->period = NSEC_PER_SEC / (unsigned long)freq; > + on_time_div *= state->period; > + do_div(on_time_div, 255); > + state->duty_cycle = on_time_div; > + } -- With Best Regards, Andy Shevchenko