Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755727Ab2EVNwN (ORCPT ); Tue, 22 May 2012 09:52:13 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:34910 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750896Ab2EVNwM (ORCPT ); Tue, 22 May 2012 09:52:12 -0400 Message-ID: <4FBB9A08.2050803@gmail.com> Date: Tue, 22 May 2012 08:52:08 -0500 From: Rob Herring User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Stephen Boyd CC: Shawn Guo , Mike Turquette , "linux-kernel@vger.kernel.org" , Grant Likely , "arm@kernel.org" , Shawn Guo , "linux-arm-kernel@lists.infradead.org" , Saravana Kannan Subject: Re: [GIT PULL] DT clk binding support References: <4FB80F32.5090309@gmail.com> <20120520030653.GB5810@S2100-06.ap.freescale.net> <4FB9A5E7.2070000@gmail.com> <20120521064901.GE8140@S2101-09.ap.freescale.net> <4FBA89E3.7010106@gmail.com> <20120521232616.GF8140@S2101-09.ap.freescale.net> <4FBAD545.7060803@gmail.com> <20120522021535.GG8140@S2101-09.ap.freescale.net> <4FBB134D.6050409@codeaurora.org> In-Reply-To: <4FBB134D.6050409@codeaurora.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2560 Lines: 54 On 05/21/2012 11:17 PM, Stephen Boyd wrote: > On 05/21/12 19:15, Shawn Guo wrote: >> On Mon, May 21, 2012 at 06:52:37PM -0500, Rob Herring wrote: >>> As Grant states: "This proposed binding is only about one thing: >>> attaching clock providers to clock consumers." This means you have to >>> have at least a single provider and a single consumer defined in the DT. >>> >> I just read through Grant's comments over again. I agree with the >> statement which implicitly requires the clk provider defined in DT. >> However, for some case, this provider in DT is just a skeleton which >> is backed by clock driver where the provider is actually defined. >> >> Looking at Grant's comment below, the second option is also to match >> the clock in driver just using name. The only difference to my >> proposal is the name here is given by the argument of phandle pointing >> to that skeleton provider node. >> >> I'm fine with that. So go ahead with your bindings. >> > > Can we do what the regulator framework has done and have a common > binding of -clk = <&phandle>? Something like: > > core-clk = <&uart3_clk> > > and then have clk_get() use the of node of the device passed in to find > a property named %s-clk and find the clock with the matching phandle. Sigh... That is what we had in previous versions from over a year ago and we moved away from that approach. The current binding has been reviewed multiple times in the last 6 months... The current approach is aligned with how interrupts are handled (with the addition of a phandle). I think not having per clock property names is easier to parse and easier to document. > This looks like it's trying to cover both the end consumers (uart uses > uart3_clk) and the internal clock tree consumers (a crystal oscillator > connects to a PLL or a mux has multiple parents). We can certainly use > these bindings for muxes and internal parent-child relationships but I > would prefer we use different bindings for consumer bindings that match > what regulators do today. The binding supports either defining every last internal clock or just the leaf clocks. I took the former route on highbank since I don't have a lot of clocks. If I was doing imx or omap for example, I'd probably just define all the clock controller outputs. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/