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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C12AC05027 for ; Fri, 20 Jan 2023 15:04:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229661AbjATPEy (ORCPT ); Fri, 20 Jan 2023 10:04:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231305AbjATPEv (ORCPT ); Fri, 20 Jan 2023 10:04:51 -0500 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 998ADDA129 for ; Fri, 20 Jan 2023 07:04:43 -0800 (PST) Received: by mail-wr1-x42d.google.com with SMTP id h16so5086746wrz.12 for ; Fri, 20 Jan 2023 07:04:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=uM/AZbTE0N3wZ9K7Id9185G9SFTYGVUQ4zyUZJh9c2w=; b=CMZNxqXQ9bGvQVB4/W/6bW3PRwNIRC70HtD6CJVTdSa9HMXFonB3kv/2HjpA3yAJYZ 2Eej0Hg0oKuHk7A7GvhK911K0PUvz6QcPBrxWwUzAmK1zU7vF8JS0A4dTmjdTVo0WLxz bMao64u/Dkp3wTuQpMD898RVrGzo2AYyEll6Yg1fjU1Sm6o2M6W7181K66UiYEufB089 I3SjVlGJ+o3k1ujThb7R7A+ZvC7uYm3vOdHlq+Y68eAhAkRjQpnzCpU5sfCZZw5P84OY yxBmT1RS1Kv5Ywa4oW1Hg9Y95w9I2ZogmB+44X6Gf6eVa/FkQW+I3vOT+PNh6u8GpUMe hLNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=uM/AZbTE0N3wZ9K7Id9185G9SFTYGVUQ4zyUZJh9c2w=; b=pPcalN8aU6mPjq7jkuZbn8zrC2na3quE66TH8CndskSVWIKtg3Ndgx5RxaIMgSoqJy lQD2ghCM9jkiIkf+t30pSHwUpuGl5PFH2EF2rxO0KMynD112vIyXx5F4oXHE5z1G7swG 803aS5hcjCMtppq1y7N4qi7YZ9LxGCPyJW0Gjf13zEWy5vZ6KA1vjTHenjrX9kyArayK gRbJzUw6xBMBC5o4XrYCxLLs5JuynZmV9Gc+wRm3Wf+0fMPf6oJXIxkyiR69ee4dHf3O /J/IU3V1EIAr3zxMzpkA1ymOV0MKwd1O55Bkgdd6e8U7dCdEKqYnUdRALcjtxNKDHgcC XFVQ== X-Gm-Message-State: AFqh2kpjfGhZIMv3Mp+jKGqwo2rTLsDjpQNnZER37kh7p7am3UvBcKZZ ScrjgmgnUUOvk19rD0gpHsIktg== X-Google-Smtp-Source: AMrXdXsPQxYA6ZUOJLdOPKyWDyB3wvLu9sSjvk0brOwg0HIxvtJpTyjbgqStno4YTK6idzKQeiT5Sw== X-Received: by 2002:a5d:5190:0:b0:2bd:fde4:885c with SMTP id k16-20020a5d5190000000b002bdfde4885cmr12005062wrv.63.1674227081607; Fri, 20 Jan 2023 07:04:41 -0800 (PST) Received: from aspen.lan (cpc141216-aztw34-2-0-cust174.18-1.cable.virginm.net. [80.7.220.175]) by smtp.gmail.com with ESMTPSA id j15-20020adfd20f000000b002be2a4b521fsm8858850wrh.45.2023.01.20.07.04.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Jan 2023 07:04:40 -0800 (PST) Date: Fri, 20 Jan 2023 15:04:38 +0000 From: Daniel Thompson To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Cc: Lee Jones , Jingoo Han , Liam Girdwood , Mark Brown , Thierry Reding , Helge Deller , linux-pwm@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, kernel@pengutronix.de Subject: Re: [PATCH v2 2/2] backlight: pwm_bl: Don't rely on a disabled PWM emiting inactive state Message-ID: References: <20230120120018.161103-1-u.kleine-koenig@pengutronix.de> <20230120120018.161103-3-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230120120018.161103-3-u.kleine-koenig@pengutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Fri, Jan 20, 2023 at 01:00:18PM +0100, Uwe Kleine-König wrote: > Most but not all PWMs drive the PWM pin to its inactive state when > disabled. However if there is no enable_gpio and no regulator the PWM > must drive the inactive state to actually disable the backlight. > > So keep the PWM on in this case. > > Note that to determine if there is a regulator some effort is required > because it might happen that there isn't actually one but the regulator > core gave us a dummy. (A nice side effect is that this makes the > regulator actually optional even on fully constrained systems.) > > This fixes backlight disabling e.g. on i.MX6 when an inverted PWM is > used. > > Hint for the future: If this change results in a regression, the bug is > in the lowlevel PWM driver. :-) > Signed-off-by: Uwe Kleine-König Thanks for the changes. Looks good: Reviewed-by: Daniel Thompson Daniel.