Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757356Ab3FKU22 (ORCPT ); Tue, 11 Jun 2013 16:28:28 -0400 Received: from mail-pa0-f47.google.com ([209.85.220.47]:55456 "EHLO mail-pa0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756432Ab3FKU2Z convert rfc822-to-8bit (ORCPT ); Tue, 11 Jun 2013 16:28:25 -0400 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT To: Arnd Bergmann , Linus Walleij From: Mike Turquette In-Reply-To: <201306042252.03340.arnd@arndb.de> Cc: Lee Jones , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Linus WALLEIJ , Srinidhi KASAGAR , Ulf Hansson , "devicetree-discuss@lists.ozlabs.org" References: <1370266965-7901-1-git-send-email-lee.jones@linaro.org> <1370266965-7901-22-git-send-email-lee.jones@linaro.org> <201306042252.03340.arnd@arndb.de> Message-ID: <20130611202821.8816.86653@quantum> User-Agent: alot/0.3.4 Subject: Re: [PATCH 21/21] clk: ux500: Supply provider look-up functionality to support Device Tree Date: Tue, 11 Jun 2013 13:28:21 -0700 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1931 Lines: 45 Quoting Arnd Bergmann (2013-06-04 13:52:03) > On Tuesday 04 June 2013, Linus Walleij wrote: > > The whole thing is very different from other DT clock things > > I've seen, usually you add a compatible node for each > > clock type, and a node for each physical gate. But there > > may be several ways to skin this cat... > > > > Based on the IRC discussion we had, I would think that the "prcc" clocks > would best be represented using multiple clock-cells since you can describe > them easily a tuple of register index, bit number some way to distinguish > the two types. > > The "prcmu" clocks are harder, and we probably need either a more verbose > representation using one node per clock there, or have a single node > for the entire prcmu and not bother to describe them in DT but hardcode > everything in the source. The current patch does the latter, which is > easier now but means we cannot simplify the code much in the future > when we remove ATAGS boot support. > > I hope Mike can give some better insight to what his preferences are. I'm still learning about DT so my inputs should be weighed, measured and then promptly thrown out. With that said I recently published an RFC to convert the OMAP4 PRCM clocks to DT and my approach was a single node per clock. The register mapping for those clocks is mostly orderly, but not so orderly that a neat and tidy tuple would suffice. Also the recent MMP clock series represents many of the clocks as single nodes. I am not opposed to this design choice and it removes more data from C files. Some concerns were brought up about impacts to boot time but no one has quantified that yet. Regards, Mike > > Arnd -- 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/