Messages in this thread | | | From | Chen-Yu Tsai <> | Date | Mon, 3 Aug 2015 10:37:35 +0800 | Subject | Re: [linux-sunxi] [PATCH] ARM: dts: sunxi: Raise minimum CPU voltage for sun7i-a20 to a level all boards can supply |
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Hi,
On Mon, Aug 3, 2015 at 7:35 AM, Julian Calaby <julian.calaby@gmail.com> wrote: > Hi Timo, > > On Mon, Aug 3, 2015 at 5:23 AM, Timo Sigurdsson > <public_timo.s@silentcreek.de> wrote: >> 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.
On the side, the original OPPs in the FEX files are actually frequency/voltage ranges, and not just points. Mainlines OPPv2 will support these, along with turbo frequencies.
Furthermore, the FEX files also have fields that limit the minimum and maximum frequencies.
> Is the code that uses this smart enough to sensibly switch between two > operating points with the same frequency and different voltages? If > so, maybe just add a 144MHz @ 1.0v operating point?
You could try. Though I really don't see much to gain here.
> (Alternatively, would it make sense to modify the code that uses this > to use frequencies with voltages specified that are lower than can be > supplied with the lowest voltage it can?)
I think that's a bit harder to get accepted.
ChenYu
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