From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756487AbbJHTU2 (ORCPT ); Thu, 8 Oct 2015 15:20:28 -0400 Received: from smtp03.smtpout.orange.fr ([80.12.242.125]:19447 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756430AbbJHTUX (ORCPT ); Thu, 8 Oct 2015 15:20:23 -0400 X-ME-Helo: belgarion X-ME-Auth: amFyem1pay5yb2JlcnRAb3JhbmdlLmZy X-ME-Date: Thu, 08 Oct 2015 21:20:21 +0200 X-ME-IP: 90.38.170.78 From: Robert Jarzmik To: Rob Herring , Philipp Zabel Cc: Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , "devicetree\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , "linux-fbdev\@vger.kernel.org" Subject: Re: [PATCH v2] video: fbdev: add Marvell PXA framebuffer binding References: <1443954683-13126-1-git-send-email-robert.jarzmik@free.fr> <87y4ffaj3m.fsf@belgarion.home> X-URL: http://belgarath.falguerolles.org/ Date: Thu, 08 Oct 2015 21:15:00 +0200 In-Reply-To: (Rob Herring's message of "Thu, 8 Oct 2015 08:30:36 -0500") Message-ID: <87lhbd9npn.fsf@belgarion.home> User-Agent: Gnus/5.130008 (Ma Gnus v0.8) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rob Herring writes: >> The pxafb driver acts today on the subset of registers which are the same across >> all pxaXXX variants. This is what made me think only one compatible property was >> required. >> >> If I'm wrong, I could add "marvell,pxa3xx-lcdc", is that what you think I should >> do ? > > I would prefer specific compatibles (e.g. marvell,pxa270-lcdc) in > addition to a generic one. You never know when a specific chip will > have some quirk even though "the IP is the same". Okay. >> And then, when a board maintainer will create a devicetree description, he will >> write something like : >> compatible = "toshiba,ltm0305a776"; >> compatible = "marvell,pxa2xx-panel"; > > Drop this compatible. > >> lcd-type = "color-tft"; >> ... >> >> If that's the case, I wonder how to "enforce" that a panel used with >> marvell,pxa2xx-lcdc (through the of_graph 'port' node) be compatible with >> marvell,pxa2xx-panel ? > > I'm not sure what you mean. Putting the panel into the dts ensures > that. The FB driver may check for toshiba,ltm0305a776 or a list of > panels. However, a DRM driver would probably not check that. > > Rob What I mean is that the LDLC controller _must_ be programmmed with the correct panel type, ie. one register of the LDLC should be set according to this type. The type is a hardware property of the panel, and yet it is absolutely mandatory to have it set in the panel. What I mean is : what is the good way to enforce that this property is set somewhere in the devicetree description ? Philipp adviced for it to be transfered to the ldlc description (ie. marvell,pxa2xx-ldlc), while I was thinking of having it in a panel description. Cheers. -- Robert