From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from de01egw02.freescale.net (de01egw02.freescale.net [192.88.165.103]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "de01egw02.freescale.net", Issuer "Thawte Premium Server CA" (verified OK)) by ozlabs.org (Postfix) with ESMTP id 54F31DDE37 for ; Tue, 12 Feb 2008 04:57:24 +1100 (EST) Message-ID: <47B08C76.3000009@freescale.com> Date: Mon, 11 Feb 2008 11:57:10 -0600 From: Timur Tabi MIME-Version: 1.0 To: Arnd Bergmann Subject: Re: Could the DTS experts look at this? References: <47ACE630.8090101@pikatech.com> <200802100647.56590.arnd@arndb.de> In-Reply-To: <200802100647.56590.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Arnd Bergmann wrote: > Maybe we can introduce a more generic way of having conditional > device nodes in the tree that get knocked out in the boot wrapper. I've been thinking about doing just this for quite some time now. I've had a few informal discussions without people about. One idea is to allow attaching simple conditional expressions (like X is <, =, or > than Y) to a node. It is the responsibility of the code that parses the device tree to assign values to X and Y. For instance, they could be the names of U-Boot environment variables. If the expression is false, then the node is removed (or ignored) from the device tree. If it's true, then it's kept in. -- Timur Tabi Linux kernel developer at Freescale