From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp106.mail.ukl.yahoo.com (smtp106.mail.ukl.yahoo.com [77.238.184.38]) by ozlabs.org (Postfix) with SMTP id 55A0BB7B3E for ; Tue, 24 Nov 2009 08:55:58 +1100 (EST) Message-ID: <4B0B04ED.9080307@yahoo.es> Date: Mon, 23 Nov 2009 22:55:57 +0100 From: Albert Herranz MIME-Version: 1.0 To: Grant Likely Subject: Re: [RFC PATCH 04/19] powerpc: wii: device tree References: <1258927311-4340-1-git-send-email-albert_herranz@yahoo.es> <1258927311-4340-2-git-send-email-albert_herranz@yahoo.es> <1258927311-4340-3-git-send-email-albert_herranz@yahoo.es> <1258927311-4340-4-git-send-email-albert_herranz@yahoo.es> <1258927311-4340-5-git-send-email-albert_herranz@yahoo.es> <4B0AE865.4030502@yahoo.es> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Grant Likely wrote: > This looks pretty good to me. The documentation format isn't strict, > just follow the pattern seen in other bindings. Make sure you post > new bindings to devicetree-discuss@lists.ozlabs.org for review. A > couple of comments below. > Ok. I know it now for the next time :) >> Documentation/powerpc/dts-bindings/gpio/i2c.txt >> >> GPIO-based I2C >> >> Required properties: >> - compatible : should be "virtual,i2c-gpio". >> - gpios : should specify GPIOs used for SDA and SCL lines, in that order. >> - sda-is-open-drain : should be non-zero if SDA gpio is open-drain. >> - sda-enforce-dir : should be non-zero if SDA gpio must be configured for >> input before reading and for output before writing. >> - scl-is-open-drain : should be non-zero if SCL gpio is open-drain. >> - scl-is-output-only : should be non-zero if SCL is an output gpio only. > > Instead of looking for a value in these properties, just make them > empty properties and change behaviour based on whether or not the > property is present. > It seems reasonable. Thanks. > Why is the scl-is-output-only property needed? > It is needed to specify that the I2C master can't honour clock stretching done by I2C slave devices, as it cannot read back SCL. >> - udelay : signal toggle delay. SCL frequency is (500 / udelay) kHz > > You should follow the lead of > Documentation/powerpc/dts-bindings/fsl/i2c.txt here and specify a > clock-frequency property. > Ok. >> - timeout : clock stretching timeout in milliseconds. > > I don't understand what this property means. > It is the maximum time that the I2C master should wait for SCL to go high when a I2C slave is "clock-stretching". Cheers, Albert