From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: Maxime Ripard , From: Michael Turquette In-Reply-To: <20150820151510.GD30520@lukather> Cc: linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, sboyd@codeaurora.org, lee.jones@linaro.org, s.hauer@pengutronix.de, geert@linux-m68k.org References: <1438974570-20812-1-git-send-email-mturquette@baylibre.com> <20150818154552.GI2547@lukather> <20150818164356.31346.80341@quantum> <20150820151510.GD30520@lukather> Message-ID: <20150825215051.31346.56261@quantum> Subject: Re: [PATCH RFC RFT 0/3] clk: detect per-user enable imbalances and implement hand-off Date: Tue, 25 Aug 2015 14:50:51 -0700 List-ID: Quoting Maxime Ripard (2015-08-20 08:15:10) > On Tue, Aug 18, 2015 at 09:43:56AM -0700, Michael Turquette wrote: > > Quoting Maxime Ripard (2015-08-18 08:45:52) > > > Hi Mike, > > > = > > > On Fri, Aug 07, 2015 at 12:09:27PM -0700, Michael Turquette wrote: > > > > All of the other kitchen sink stuff (DT binding, passing the flag b= ack > > > > to the framework when the clock consumer driver calls clk_put) was = left > > > > out because I do not see a real use case for it. If one can demonst= rate > > > > a real use case (and not a hypothetical one) then this patch series= can > > > > be expanded further. > > > = > > > I think there is a very trivial use case for passing back the > > > reference to the framework, if during the probed, we have something > > > like: > > > = > > > clk =3D clk_get() > > > clk_prepare_enable(clk) > > > foo_framework_register() > > > = > > > if foo_framework_register fails, the sensible thing to do would be to > > > call clk_disable_unprepare. If the clock was a critical clock, you > > > just gated it. > > = > > Hmm, a good point. Creating the "pass the reference back" call is not > > hard technically. But how to keep from abusing it? E.g. I do not want > > that call to become an alternative to correct use of clk_enable. > > = > > Maybe I'll need a Coccinelle script or just some regular sed to > > occasionally search for new users of this api and audit them? > > = > > I was hoping to not add any new consumer api at all :-/ > = > I don't think there's any abuse that can be done with the current API, > nor do I think you need to have new functions either. > = > If the clock is critical, when the customer calls > clk_unprepare_disable on it, simply take back the reference you gave > in the framework, and you're done. Or am I missing something? Maybe I am the one missing something? My goal was to allow the consumer driver to gate the critical clock. So we need clk_disable_unused to actually disable the clock for that to work. I think you are suggesting that clk_disable_unused should *not* disable the clock if it is critical. Can you confirm that? Thanks, Mike > = > Maxime > = > -- = > Maxime Ripard, Free Electrons > Embedded Linux, Kernel and Android engineering > http://free-electrons.com