From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757389Ab2ARPdI (ORCPT ); Wed, 18 Jan 2012 10:33:08 -0500 Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:49735 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752228Ab2ARPdH (ORCPT ); Wed, 18 Jan 2012 10:33:07 -0500 X-Mail-Handler: MailHop Outbound by DynDNS X-Originating-IP: 98.234.237.12 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX195OzaAk2XX+vE3ixyu6S99 Date: Wed, 18 Jan 2012 07:32:56 -0800 From: Tony Lindgren To: Shawn Guo Cc: Grant Likely , "linus.walleij@stericsson.com" , "devicetree-discuss@lists.ozlabs.org" , "s.hauer@pengutronix.de" , "linux-kernel@vger.kernel.org" , "rob.herring@calxeda.com" , "kernel@pengutronix.de" , "cjb@laptop.org" , "linux-arm-kernel@lists.infradead.org" , Dong Aisheng Subject: Re: Pinmux bindings proposal Message-ID: <20120118153256.GB22818@atomide.com> References: <74CDBE0F657A3D45AFBB94109FB122FF17801D202F@HQMAIL01.nvidia.com> <20120116182808.GG4223@ponder.secretlab.ca> <20120118141329.GA22818@atomide.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Shawn Guo [120118 05:57]: > On 18 January 2012 22:13, Tony Lindgren wrote: > > Hi, > > > > * Grant Likely [120116 09:55]: > >> On Fri, Jan 13, 2012 at 12:39:42PM -0800, Stephen Warren wrote: > >> >                 pinmux = > >> >                         <"default" &pmx_sdhci_active> > >> >                         <"suspend" &pmx_sdhci_suspend>; > >> > > >> >                 /* 1:n example: */ > >> >                 pinmux = > >> >                         <"default" &pmx_sdhci_mux_a> > >> >                         <"default" &pmx_sdhci_pincfg_a> > >> >                         <"suspend" &pmx_sdhci_mux_a> > >> >                         <"suspend" &pmx_sdhci_pincfg_a_suspend>; > >> > >> > >> Yeah, don't do this.  Mixing phandle, string and cell values in a > >> property gets messy and could become troublesome to parse.  I've > >> backed away from it in the clk binding. > > > > Yup, that's because the string is embedded directly into the mixed > > mode array and will likely make the following data unaligned. That > > means it's extremely flakey to parse, and will lead into horrible > > errors if you have typos in the .dts file.. Tried that and gave up > > on it. > > > > I think I've found a way to avoid using names at all, assuming we set > > each pin as a phandle for the drivers to use :) > > > The problem with doing that is we will have to represent each pin as a > node in device tree. For imx6q case, we have 197 pins. Doing so will > bloat the device tree. Sure there's some overhead. I've got it working with 220 pins, it's not too bad as threre's not much string parsing involved. I don't have all the devices mapping the pins though. The .dtb for omap4 is about 25k now. If we wanted to avoid adding phandles for each pin, then we could do: serial@0x48020000 { compatible = "ti,8250"; reg = <0x48020000 0x100>; reg-shift = <2>; interrupts = <106>; /* controller, offset, value */ pins = <&mux1 0xabcd 0x10 &mux1 0xabcf 0x0>; }; But then the .dts file becomes an unreadable matrix unless we have a preprocessor.. Regards, Tony