From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gold.webfusion.co.uk (gold.webfusion.co.uk [212.67.202.159]) (using TLSv1 with cipher EDH-RSA-DES-CBC3-SHA (168/168 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id B984667A6D for ; Sat, 12 Mar 2005 07:39:56 +1100 (EST) From: Yuli Barcohen MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <16946.530.358572.465485@astp0002.localdomain> Date: Fri, 11 Mar 2005 22:39:46 +0200 To: "Vijay Padiyar" In-Reply-To: References: Cc: linuxppc-embedded@ozlabs.org Subject: Re: query regarding I2C controller on MPC8260 List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , >>>>> Vijay Padiyar writes: Vijay> Hi there I am using an MPC8260-based target board. My target Vijay> is running U-Boot 1.1.2 as the bootloader and Linux-2.6.10 as Vijay> the kernel with BusyBox-1.0. I wish to use the I2C controller Vijay> on the MPC8260 to access an external EEPROM connected to Vijay> it. I need to do this from *user space*. Vijay> From what I understand, we can open the I2C device with the Vijay> open command from our application as follows: Vijay> ret = open ("/dev/i2c-0", O_RDWR); Vijay> After this, the device should be accessible using either Vijay> standard I2C functions or SMBus functions. Vijay> I read that if the I2C controller supports SMBus, it will be Vijay> preferable to access the device via the SMBus read/write Vijay> functions, as they seem to be more "efficient." What I want Vijay> to know is, does the PowerPC I2C controller support the SMBus Vijay> protocol? I don't think it does, judging from the MPC8260 Vijay> manual, but just want to be sure. It does not support SMBus but since it's a full-featured I2C controller, it's not a problem. SMBus emulation mode can be used on any I2C controller. Vijay> Also, do we need to create the /dev/i2c-0 device file Vijay> manually or will it be created on the fly? It depends on the /dev filesystem which you use. If it's devfs (or you use udev), the file will be created on the fly, otherwise you have to create it manually. -- ======================================================================== Yuli Barcohen | Phone +972-9-765-1788 | Software Project Leader yuli@arabellasw.com | Fax +972-9-765-7494 | Arabella Software, Israel ========================================================================