From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 5383EDDE3A for ; Thu, 5 Apr 2007 17:32:29 +1000 (EST) Subject: Re: SPI devices and OF From: Benjamin Herrenschmidt To: Kumar Gala In-Reply-To: <5199678E-7A42-4B91-BBB8-81DF33E92F2A@kernel.crashing.org> References: <20070404110916.GA9910@localhost.localdomain> <4850DC60-A560-4A38-8416-ADA776B69509@kernel.crashing.org> <200704041903.46629.arnd@arndb.de> <5199678E-7A42-4B91-BBB8-81DF33E92F2A@kernel.crashing.org> Content-Type: text/plain Date: Thu, 05 Apr 2007 17:32:18 +1000 Message-Id: <1175758338.30879.123.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org, Arnd Bergmann List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > From explicitly board code like we do today. I mean the mechanism > can very so greatly that trying to decided and come up with all > possible cases and somehow encoding that in the device tree isn't > worth the effort. Additionally you'll still need code to handle the > actual chip select and I don't see how you make that generic at all. > > A board designer could use I2C, GPIO, or something off an FPGA. I > just dont see trying to 'encode' this in the device tree as providing > any real value. Or board designers can use board specific device-tree bits and board specific code to udnerstand them :-) That works too and can be handy if you have for example several versions of a board with small differences that you want to expose that way in the device-tree. That is, the devive-tree -can- be used to put proprietary stuff, though if you do so, you should try to use prefixes on your properties, like mycompany,xxxx Ben.