From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Chou Subject: Re: [PATCH v6] i2c-gpio: add devicetree support Date: Fri, 25 Feb 2011 10:04:59 +0800 Message-ID: <4D670E4B.6000407@wytron.com.tw> References: <20110223011232.GC15795@trinity.fluff.org> <1298520013-3630-1-git-send-email-thomas@wytron.com.tw> <20110224162210.GC17735@angua.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110224162210.GC17735-MrY2KI0G/OVr83L8+7iqerDks+cytr/Z@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: Ben Dooks , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, nios2-dev-1eJk0qcHJCcaeqlQEoCUNoJY59XmG8rH@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Albert Herranz List-Id: devicetree@vger.kernel.org Hi Grant, On 02/25/2011 12:22 AM, Grant Likely wrote: >> +Required properties: >> +- compatible : should be "i2c-gpio". >> +- gpios : should specify GPIOs used for SDA and SCL lines, in that order. >> +Optional properties: >> +- sda-is-open-drain : present if SDA gpio is open-drain. >> +- scl-is-open-drain : present if SCL gpio is open-drain. >> +- scl-is-output-only : present if the output driver for SCL cannot be >> + turned off. this will prevent clock stretching from working. >> +- speed-hz : SCL frequency. > > Hi Thomas, > > One nitpick; I just looked, and other i2c controllers are already > using 'clock-frequency' instead of 'speed-hz' for the speed of the > bus. I'd like to see this patch use the same terminology. I studied 'clock-frequency' usage of existing i2c drivers before working on this patch. i2c-ibm_iic.c, i2c-mpc.c, i2c-ocores.c : use as bus clock frequency input to the core. i2c-cpm.c : use as i2c SCL output frequency. Most other non-i2c drivers use clock-frequency as bus clock frequency input, too. I think the SCL freq usage in i2c-cpm.c is confusing. So I would suggest we borrow 'speed-hz' from spi subsystem, which means the clock freq output on the peripheral bus. Best regards, Thomas