On Mon, Jul 03, 2017 at 11:45:52AM +0530, Viresh Kumar wrote: > On 30-06-17, 13:10, Mark Brown wrote: > > On Fri, Jun 30, 2017 at 02:13:30PM +0530, Viresh Kumar wrote: > > > On 30-06-17, 14:36, Chen-Yu Tsai wrote:
> > > And so the DT node shall have this: > > > regulator-min-microvolt = <1800000>; > > > regulator-max-microvolt = <3000000>; > > > Isn't it ? > > If the DMA can't tolerate more than 2.5V then why would the constraints > > allow the voltage to float that far? Similarly on the low end? > The above regulator-min/max-microvolt values I mentioned were for the > regulator > device and not what the consumers would request. Yes, DMA will request > something If you're putting the maximum possible range that the physical regulator can supply into machine constraints then you really haven't understood what machine constraints are at all. > > Please remember that devices shouldn't be managing their voltages unless > > they are actively changing them at runtime, simply setting them at > > startup is the job of the constraints. I would be very surprised to see > > a DMA controller doing anything like DVFS. > Sure, DMA would most likely set a constraint from probe. Maybe I could have > used No, it really shouldn't. Please read what I wrote. > MMC in the above example, which may actually do DVFS at runtime. Yes, MMC does vary voltage.
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