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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6AD0EC4451C for ; Tue, 21 Jul 2026 09:36:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LkbTUzJ7Xgd7EcsbWW/V1SykEOd0nQdvevXT30R5Sls=; b=tEeE9/Ewmt+UonxOYHzMRpfb1g 5r/Hn/c4opbvyegyjJRJajdI3O897tjszsViJLuEyKANXEy6HuFFgmJOmJYsr1gj1oTqUjAj+O7jB TQGAlQhk0vh76yntTxA61PR1ywbM48pKaR6Ldl6im/RSpdp7fMohzGfkDidCoUPNBuj5f0GE5E9Bd e4dBCgYg3Ps75WROxdqoS6GGnX/MZ+0Oxysz69WqXXJu/krD68SAd5WzlUKlybQa7CC4cwCtR3D61 X5B3fiZ0VadZVGfnoFoPJfidl8sutmweGmZEAkg+AK3GD/3kuNwp4wEWPEsj5yKxl8M0FDFRtBEMF GA/nWneQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wm6tY-0000000909I-2nsN; Tue, 21 Jul 2026 09:36:12 +0000 Received: from mail11.truemail.it ([217.194.8.81]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wm6tV-0000000908S-0rmw for linux-arm-kernel@lists.infradead.org; Tue, 21 Jul 2026 09:36:11 +0000 Received: from francesco-nb (xcpe-178-82-120-96.dyn.res.sunrise.net [178.82.120.96]) by mail11.truemail.it (Postfix) with ESMTPA id C96472061E; Tue, 21 Jul 2026 11:36:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dolcini.it; s=default; t=1784626562; bh=LkbTUzJ7Xgd7EcsbWW/V1SykEOd0nQdvevXT30R5Sls=; h=From:To:Subject; b=AI3np4m1E64keLXTufUzfthcPErhnjJFYusJRMeMCRhbwgxM3yQt9ljj2GHGr0Cuh c1QhN+XiWip8PQXJKyZzBbCTNGeAr3h7gp4sxwF9ZT8zL7yKLUcNOUcZGSxl8AHIlg h2+2od8AllziKPWeMiRmQd5xyDpTrWeX7Q4GvMs66w3CbyfUqIrJP+8hm5IdtX4xAB lcjMJpMaOA5X4dRLGkMLGNagLWc/Hq8HsEu2b8vGCNn+hgkKzBQkEnMG9tCFC2ztsV SWDvaSb6YGCctjBcN2PIlbUd1GRylT0Kny1N63wu0TVFPX6Db8Mq8CHgpndRxhMMp7 3WQlXLfCapMOw== Date: Tue, 21 Jul 2026 11:35:57 +0200 From: Francesco Dolcini To: Marco Felsch Cc: Francesco Dolcini , Marek Vasut , Stefan Agner , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , imx@lists.linux.dev, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Francesco Dolcini , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v1 2/4] drm: mxsfb: Allow optional LCDIF interface format override Message-ID: <20260721093557.GA61843@francesco-nb> References: <20260717121847.488148-1-francesco@dolcini.it> <20260717121847.488148-3-francesco@dolcini.it> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260721_023609_840107_96195DA3 X-CRM114-Status: GOOD ( 17.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hello Marco, On Tue, Jul 21, 2026 at 10:52:37AM +0200, Marco Felsch wrote: > On 26-07-17, Francesco Dolcini wrote: > > From: Francesco Dolcini > > > > LCDIF programs LCD_DATABUS_WIDTH from the selected media bus format. The > > format reported by the downstream panel or bridge describes the display > > input, but it does not describe how the LCDIF data pins are physically > > wired on the board. > > > > These can differ. For example, a 16-bit LCDIF bus can be connected to a > > 24-bit display by wiring the available color bits to the corresponding > > display inputs. In that case, using the display's 24-bit format to > > configure LCDIF selects the wrong data-bus mode and changes the assignment > > of color bits on the LCD_DATA pins. > > > > Read the optional interface-pix-fmt property from the LCDIF node and use > > it to select the media bus format used to configure LCDIF. This allows > > the LCDIF bus mode to describe the physical interface independently of > > the downstream display format. > > > > When the optional property is absent, continue using the format reported > > by the downstream display device, preserving the existing behavior. > > > > This follows the same approach already implemented in > > drivers/gpu/drm/imx/ipuv3/parallel-display.c. > > According the driver comment, this is a legacy property. If you just > want to limit the physical bus width you could use the common of-graph > endpoint bus-width property. Yes, I will change to that. Thanks for the feedback. Francesco