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Date: Sat, 17 Mar 2012 21:29:31 +0100 From: Sascha Hauer <s.hauer@...gutronix.de> To: "Turquette, Mike" <mturquette@...com> Cc: Arnd Bergmann <arnd@...db.de>, Paul Walmsley <paul@...an.com>, linux-arm-kernel@...ts.infradead.org, Amit Kucheria <amit.kucheria@...aro.org>, Nicolas Pitre <nicolas.pitre@...aro.org>, linaro-dev@...ts.linaro.org, Linus Walleij <linus.walleij@...aro.org>, Grant Likely <grant.likely@...retlab.ca>, Saravana Kannan <skannan@...eaurora.org>, Jeremy Kerr <jeremy.kerr@...onical.com>, Magnus Damm <magnus.damm@...il.com>, Deepak Saxena <dsaxena@...aro.org>, patches@...aro.org, Rob Herring <rob.herring@...xeda.com>, Russell King <linux@....linux.org.uk>, Thomas Gleixner <tglx@...utronix.de>, Richard Zhao <richard.zhao@...aro.org>, Shawn Guo <shawn.guo@...escale.com>, Linus Walleij <linus.walleij@...ricsson.com>, Mark Brown <broonie@...nsource.wolfsonmicro.com>, Stephen Boyd <sboyd@...eaurora.org>, linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v7 1/3] Documentation: common clk API On Sat, Mar 17, 2012 at 11:02:11AM -0700, Turquette, Mike wrote: > On Sat, Mar 17, 2012 at 2:05 AM, Arnd Bergmann <arnd@...db.de> wrote: > > On Friday 16 March 2012, Turquette, Mike wrote: > >> On Fri, Mar 16, 2012 at 3:21 PM, Paul Walmsley <paul@...an.com> wrote: > >> > From: Paul Walmsley <paul@...an.com> > >> > 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 <paul@...an.com> > >> > Cc: Mike Turquette <mturquette@...com> > >> > >> 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 | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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