From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756660Ab2CQUaO (ORCPT ); Sat, 17 Mar 2012 16:30:14 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:50467 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755432Ab2CQUaG (ORCPT ); Sat, 17 Mar 2012 16:30:06 -0400 Date: Sat, 17 Mar 2012 21:29:31 +0100 From: Sascha Hauer To: "Turquette, Mike" Cc: Arnd Bergmann , Paul Walmsley , linux-arm-kernel@lists.infradead.org, Amit Kucheria , Nicolas Pitre , linaro-dev@lists.linaro.org, Linus Walleij , Grant Likely , Saravana Kannan , Jeremy Kerr , Magnus Damm , Deepak Saxena , patches@linaro.org, Rob Herring , Russell King , Thomas Gleixner , Richard Zhao , Shawn Guo , Linus Walleij , Mark Brown , Stephen Boyd , linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 1/3] Documentation: common clk API Message-ID: <20120317202931.GN3852@pengutronix.de> References: <1331878280-2758-1-git-send-email-mturquette@linaro.org> <201203170905.33191.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 21:25:07 up 126 days, 4:12, 26 users, load average: 0.00, 0.01, 0.05 User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:21e:67ff:fe11:9c5c X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 17, 2012 at 11:02:11AM -0700, Turquette, Mike wrote: > On Sat, Mar 17, 2012 at 2:05 AM, Arnd Bergmann wrote: > > On Friday 16 March 2012, Turquette, Mike wrote: > >> On Fri, Mar 16, 2012 at 3:21 PM, Paul Walmsley wrote: > >> > From: Paul Walmsley > >> > Date: Fri, 16 Mar 2012 16:06:30 -0600 > >> > Subject: [PATCH] clk: mark the common clk code as EXPERIMENTAL for now > >> > > >> > Mark the common clk code as depending on CONFIG_EXPERIMENTAL.  The API > >> > is not well-defined and both it and the underlying mechanics are likely > >> > to need significant changes to support non-trivial uses of the rate > >> > changing code, such as DVFS with external I/O devices.  So any platforms > >> > that switch their implementation over to this may need to revise much > >> > of their driver code and revalidate their implementations until the > >> > behavior of the code is better-defined. > >> > > >> > A good time for removing this EXPERIMENTAL designation would be after at > >> > least two platforms that do DVFS on groups of external I/O devices have > >> > ported their clock implementations over to the common clk code. > >> > > >> > Signed-off-by: Paul Walmsley > >> > Cc: Mike Turquette > >> > >> ACK.  This will set some reasonable expectations while things are in flux. > >> > >> Arnd are you willing to take this in? > > > > I think it's rather pointless, because the option is not going to > > be user selectable but will get selected by the platform unless I'm > > mistaken. The platform maintainers that care already know the state > > of the framework. Also, there are no user space interfaces that we > > have to warn users about not being stable, because the framework > > is internal to the kernel. > > The consensus seems to be to not set experimental. > > > However, I wonder whether we need the patch below to prevent > > users from accidentally enabling COMMON_CLK on platforms that > > already provide their own implementation. > > > >        Arnd > > > > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig > > index 2eaf17e..a0a83de 100644 > > --- a/drivers/clk/Kconfig > > +++ b/drivers/clk/Kconfig > > @@ -12,7 +12,7 @@ config HAVE_MACH_CLKDEV > > > >  menuconfig COMMON_CLK > > -       bool "Common Clock Framework" > > +       bool > >        select HAVE_CLK_PREPARE > >        ---help--- > >          The common clock framework is a single definition of struct > >          clk, useful across many platforms, as well as an > > Much like experimental I'm not sure how needed this change is. The > help section does say to leave it disabled by default, if unsure. If > you merge it I won't object but this might be fixing an imaginary > problem. Architectures without common clock support won't build with this option enabled (multiple definition of clk_enable etc), so I think this should not be user visible. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |