On Mon, Aug 03, 2015 at 10:37:51AM +0200, Timo Sigurdsson wrote: > Hi Julian, > > Julian Calaby schrieb am 03.08.2015 01:35: > >> sun7i-a20.dtsi contains an cpufreq operating point at 0.9 volts. Most A20 > >> boards > >> (or all?), however, do not allow the voltage to go below 1.0V. Thus, raise the > >> voltage for the lowest operating point to 1.0V so all boards can actually use > >> it. > > > > Surely it wouldn't be added here if some could supply 0.9v. > > Maybe. I just know some boards don't (e.g. Cubieboard 2, Cubietruck, BananaPi) > and don't know of any that does. But that's not my point. I think that a common > minimum operating point, defined on the SOC level, should be defined in a way > that works on all boards. All of them can supply it. The DCDC2 regulator they use for the CPU can go as low as 0.7V. The question is whether the CPU itself can work at such a low voltage. And the operating limits for the CPU is documented to be 1V - 1.4V. Anything else is either over or underclocking, which might or might not work on individual SoCs. So it's not something that we're going to support. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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