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 EBE15C4332F for ; Tue, 1 Feb 2022 09:47:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236181AbiBAJrT (ORCPT ); Tue, 1 Feb 2022 04:47:19 -0500 Received: from mga01.intel.com ([192.55.52.88]:62549 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233633AbiBAJrR (ORCPT ); Tue, 1 Feb 2022 04:47:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1643708837; x=1675244837; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=nbH4qI7u9cfJLtzUmRrSg0eYBDFxCuv9yYJvWGip0I0=; b=hPb80OuuOJemaRXn4R6w2IajJ6RHdtvyREXJisLUbxEfgU2LGv2DPgMK l99nFRAJo8kC/8ecYmQCao/5H1TRY6DUaespO0JcDlCeivywEdY0kZGBd 9OdDlE1CfUpquQmz4i1wIsF0eHfuSEHFq1bEfrra8u8CrcwVZKHhqY+Dr eLqCxWyDrhA1vUQxJvyNVrN3bgSD/bn1KTXw9fBeZhJEwzvVTMKae+aMw 1fxdBtWETD2togre9ubByWihhMR2l4ijZgjg6JBu2IGfhTOn0CtRIsTyj aPVZCc+g89YuTBeIukG6QNfZ+wj74z7wR8Ceg+roz0y9zns+iNMrHCs87 A==; X-IronPort-AV: E=McAfee;i="6200,9189,10244"; a="272133068" X-IronPort-AV: E=Sophos;i="5.88,333,1635231600"; d="scan'208";a="272133068" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 01:47:16 -0800 X-IronPort-AV: E=Sophos;i="5.88,333,1635231600"; d="scan'208";a="599179155" Received: from smile.fi.intel.com ([10.237.72.61]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2022 01:47:14 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1nEphh-00HFWy-0q; Tue, 01 Feb 2022 11:44:01 +0200 Date: Tue, 1 Feb 2022 11:44:00 +0200 From: Andy Shevchenko To: Javier Martinez Canillas Cc: Sam Ravnborg , linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, Daniel Vetter , dri-devel@lists.freedesktop.org, Noralf =?iso-8859-1?Q?Tr=F8nnes?= , Geert Uytterhoeven , Maxime Ripard Subject: Re: [PATCH 3/4] drm/tiny: Add driver for Solomon SSD1307 OLED displays Message-ID: References: <20220131202916.2374502-1-javierm@redhat.com> <3aac291a-b30e-2775-336f-66dd08d634e2@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3aac291a-b30e-2775-336f-66dd08d634e2@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 01, 2022 at 01:14:22AM +0100, Javier Martinez Canillas wrote: > On 1/31/22 22:30, Sam Ravnborg wrote: > > On Mon, Jan 31, 2022 at 09:29:16PM +0100, Javier Martinez Canillas wrote: ... > > The driver uses the pwms property for the backlight. > > It would have been much better to bite the bullet and require the > > backlight to be specified using a backlight node in the DT. > > This is the standard way to do it and then the driver could use the > > existing backlight driver rather than embedding a backlight driver here. > > > > I did consider that. Because that would allow me to use a struct drm_panel > and as you said make the core to manage the backlight. But then decied to > just keep the backward compatibility with the existing binding to make it > easier for users to migrate to the DRM driver. > > I wonder if we could make the driver to support both ? That is, to query > if there's a backlight with drm_panel_of_backlight() and if not found then > registering it's own backlight like the driver is currently doing. If we keep 100% backward compatibility, just drop the old driver. After all module name is not so important as compatibility strings. The problem with no backward compatibility means that removal of old driver makes users unhappy since DT is kinda ABI and we do not break it. -- With Best Regards, Andy Shevchenko