From mboxrd@z Thu Jan 1 00:00:00 1970 From: viresh.kumar@linaro.org (Viresh Kumar) Date: Thu, 21 May 2015 10:03:10 +0530 Subject: [PATCH V4 1/3] OPP: Redefine bindings to overcome shortcomings In-Reply-To: <555CE2E6.80304@codeaurora.org> References: <555BDA7C.7020506@codeaurora.org> <20150520020715.GA6465@linux> <555CE2E6.80304@codeaurora.org> Message-ID: <20150521043310.GD22904@linux> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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? @Stephen: Can you please provide your feedback on the updated version please. Thanks. -- viresh