From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: Handling of modular boards Date: Fri, 4 May 2012 21:07:00 +0100 Message-ID: <20120504200659.GQ14230@opensource.wolfsonmicro.com> References: <20120504185850.GO14230@opensource.wolfsonmicro.com> <201205041934.08830.arnd@arndb.de> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <201205041934.08830.arnd@arndb.de> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arnd Bergmann Cc: linux-arm-kernel@lists.infradead.org, Lee Jones , Samuel Ortiz , Arnd Bergmann , Olof Johansson , Stephen Warren , Igor Grinberg , linux-embedded@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Walleij On Fri, May 04, 2012 at 07:34:08PM +0000, Arnd Bergmann 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. I think anything that relies on bootloaders (or DT for that matter) is a bit of a non-starter for my personal use cases. Even where we're using DT relying on a sane bootloader seems a bit scary - my personal use cases would rely on updating this stuff in the field for non-technical users who would have trouble recovering from issues. > An intermediate solution that I really like is the ability to > stuff device tree fragments on extension board themselves, but that > can only work for new designs and causes problems when that information > is not actually correct. I can see the theory, but I can also see some practical concerns. And with the boards I'm working with we currently have 8 bits of data so...