From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [PATCH V4 1/3] OPP: Redefine bindings to overcome shortcomings Date: Mon, 25 May 2015 17:29:13 +0530 Message-ID: <20150525115913.GC23464@linux> References: <555BDA7C.7020506@codeaurora.org> <20150520020715.GA6465@linux> <555CE2E6.80304@codeaurora.org> <20150521043310.GD22904@linux> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20150521043310.GD22904@linux> Sender: linux-pm-owner@vger.kernel.org To: rob.herring@linaro.org, Stephen Boyd Cc: Rafael Wysocki , arnd.bergmann@linaro.org, nm@ti.com, broonie@kernel.org, mike.turquette@linaro.org, linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, grant.likely@linaro.org, olof@lixom.net, Sudeep.Holla@arm.com, devicetree@vger.kernel.org, viswanath.puttagunta@linaro.org, l.stach@pengutronix.de, thomas.petazzoni@free-electrons.com, linux-arm-kernel@lists.infradead.org, ta.omasab@gmail.com, kesavan.abhilash@gmail.com, khilman@linaro.org, santosh.shilimkar@oracle.com List-Id: devicetree@vger.kernel.org On 21-05-15, 10:03, Viresh Kumar wrote: > On 20-05-15, 12:39, Stephen Boyd wrote: > > On 05/19/15 19:07, Viresh Kumar wrote: > > > On 19-05-15, 17:51, Stephen Boyd wrote: > > > > > >> Also I wonder if all properties should be optional? I don't have this > > >> scenario today, but perhaps the frequencies could be encoded in fuses, > > >> but the voltages wouldn't be and so we might want to read out the > > >> frequencies for a fixed set of voltages. Of course, if there's nothing > > >> in the OPP node at all, it's not very useful, so perhaps some statement > > >> that at least one of the frequency/voltage/amperage properties should be > > >> present. > > > I am not sure. What we are trying to do (fill partially in DT and > > > partially in platform), is a trick and not the right use of bindings. > > > > > > Ideally whatever is passed in DT should be complete by itself and > > > doesn't require platform to tweak it (which it can't). For example, > > > the cpufreq-dt driver will try to initialize OPPs from the DT directly > > > and wouldn't know about the platform tweaks. That can work eventually > > > as platform will add OPPs for the same bindings before cpufreq driver > > > will try to do, but that's a trick. > > > > > > And then its all about frequency in the first place, and so marking > > > that optional looks wrong. Probably not the right use of these > > > bindings. > > > > Ok then I won't be using these bindings on any of the new platforms I > > have where half the data is in one place, and half in another. But for > > some of Krait based platforms I have they should be useable. > > You are not the only one, I have seen other requests (even for the > existing bindings) to fill stuff partially in DT as they want freq to > come from bootloader. > > @Rob: What do you suggest for such platforms? Let them keep (ab)using > old or new OPP DT bindings or create another binding to just pass on > freq table? Rob: Can you please comment on this one as well ? Thanks. -- viresh