From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Subject: Re: Handling of modular boards Date: Fri, 04 May 2012 22:54:41 +0200 Message-ID: <20120504205441.D293120645E@gemini.denx.de> References: <20120504185850.GO14230@opensource.wolfsonmicro.com> <201205041934.08830.arnd@arndb.de> <20120504203357.6B79B206451@gemini.denx.de> <201205042039.25794.arnd@arndb.de> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-reply-to: <201205042039.25794.arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Lee Jones , Mark Brown , Samuel Ortiz , Olof Johansson , Stephen Warren , Igor Grinberg , linux-embedded@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij Dear Arnd, In message <201205042039.25794.arnd@arndb.de> you wrote: > > > On the other hand, some of the issues we're trying to solve here > > for the kernel are also present in the boot loader, so this needs to > > do this anyway - whether by inserting new or modifying (enabling or > > disabling) existing properties in the DT is not really relevant here. > > I haven't seen a case where the add-on board is actually required > for booting. What examples are you thinking of? There are systems (and I bet it will be a growing number) where U-Boot itself uses the DT for configuration. Also, there are functions that are needed both by the boot loader and the kernel - for example to dislay a splash screen the boot loader needs to initialize the display, so it must be able to detect which type of LCD is attached (resolution, color-depth, orientation) - the device tree comes in very handy here. Why should Linux re-do all such things? Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de I must follow the people. Am I not their leader? - Benjamin Disraeli