From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Subject: Re: Handling of modular boards Date: Fri, 04 May 2012 22:33:57 +0200 Message-ID: <20120504203357.6B79B206451@gemini.denx.de> References: <20120504185850.GO14230@opensource.wolfsonmicro.com> <201205041934.08830.arnd@arndb.de> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-reply-to: <201205041934.08830.arnd@arndb.de> Sender: linux-embedded-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 , Arnd Bergmann , Olof Johansson , Stephen Warren , Igor Grinberg , linux-embedded@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij Dear Arnd, In message <201205041934.08830.arnd@arndb.de> you wrote: > > One idea that I've heard before is to put device tree fragments into the > kernel and dynamically add them to the device tree that was passed by the > boot loader whenever we detect the presence of a specific device. > This obviously means it works only for boards using DT for booting, but > it allows us to use some infrastructure that we already have. > > Another idea was to put all the possible extensions into the device tree > for a given board and disable them by default, putting it into the > responsibility of the boot loader to enable the one that is actually > being used. This has serious scalibility problems when there are many > possible extensions and also relies more on the boot loader than I would > like. 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. 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 Our business is run on trust. We trust you will pay in advance.