From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752198AbaHTJg2 (ORCPT ); Wed, 20 Aug 2014 05:36:28 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:43669 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750866AbaHTJg1 (ORCPT ); Wed, 20 Aug 2014 05:36:27 -0400 Date: Wed, 20 Aug 2014 10:36:21 +0100 From: Mark Rutland To: "atull@opensource.altera.com" Cc: "wsa@the-dreams.de" , "baruch@tkos.co.il" , "mika.westerberg@linux.intel.com" , "grant.likely@linaro.org" , "robh+dt@kernel.org" , "skuribay@pobox.com" , "Romain.Baeriswyl@abilis.com" , "rafael.j.wysocki@intel.com" , "alan@linux.intel.com" , "linux-i2c@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "delicious.quinoa@gmail.com" , "dinguyen@opensource.altera.com" , "yvanderv@opensource.altera.com" Subject: Re: [PATCH 1/2] i2c: designware: device tree bindings for i2c speed mode Message-ID: <20140820093621.GC21174@leverpostej> References: <1408473276-10847-1-git-send-email-atull@opensource.altera.com> <20140820093459.GB21174@leverpostej> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140820093459.GB21174@leverpostej> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 20, 2014 at 10:34:59AM +0100, Mark Rutland wrote: > On Tue, Aug 19, 2014 at 07:34:35PM +0100, atull@opensource.altera.com wrote: > > From: Alan Tull > > > > Add "speed-mode" Device Tree property to select between > > standard and fast i2c mode. Previously, driver was hardwired > > as fast mode. Default to fast mode if property is not > > present. > > > > Signed-off-by: Alan Tull > > --- > > .../devicetree/bindings/i2c/i2c-designware.txt | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > > index 5199b0c..0e4cd21 100644 > > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt > > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > > @@ -9,6 +9,8 @@ Required properties : > > Recommended properties : > > > > - clock-frequency : desired I2C bus clock frequency in Hz. > > + - speed-mode : 0 = standard (0 - 100Kb/s) > > + : 1 = fast (<= 400Kb/s) <== default > > This is a bit opaque. > > Is this a limit on the max bit-rate the device should operate at? > > Why not just have an optional boolean property to limit to standard > speed? I see there's a new patch doing this based on clock-frequency, so feel free to ignore this. Mark.