On Sun, Jul 17, 2016 at 04:39:27PM +0200, Ondřej Jirman wrote: > > > On 25.6.2016 09:02, Maxime Ripard wrote: > > On Sat, Jun 25, 2016 at 09:02:48AM +0800, Chen-Yu Tsai wrote: > >> On Sat, Jun 25, 2016 at 6:51 AM, Ondřej Jirman <megous@xxxxxxxxxx> wrote: > >>> Hello, > >>> > >>> comments below. > >>> > >>> On 24.6.2016 05:48, Chen-Yu Tsai wrote: > >>>> On Fri, Jun 24, 2016 at 3:20 AM, <megous@xxxxxxxxxx> wrote: > >>>>> From: Ondrej Jirman <megous@xxxxxxxxxx> > >>>>> > >>>>> Add label to the first cpu so that it can be referenced > >>>>> from derived dts files. > >>>>> > >>>>> Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx> > >>>>> --- > >>>>> arch/arm/boot/dts/sun8i-h3.dtsi | 2 +- > >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/arch/arm/boot/dts/sun8i-h3.dtsi b/arch/arm/boot/dts/sun8i-h3.dtsi > >>>>> index 9938972..82faefc 100644 > >>>>> --- a/arch/arm/boot/dts/sun8i-h3.dtsi > >>>>> +++ b/arch/arm/boot/dts/sun8i-h3.dtsi > >>>>> @@ -52,7 +52,7 @@ > >>>>> #address-cells = <1>; > >>>>> #size-cells = <0>; > >>>>> > >>>>> - cpu@0 { > >>>>> + cpu0: cpu@0 { > >>>>> compatible = "arm,cortex-a7"; > >>>>> device_type = "cpu"; > >>>>> reg = <0>; > >>>> > >>>> Can you also set the cpu clock here? It is part of the SoC > >>>> and does not belong in the board DTS files. > >>> > >>> Do you mean operating-points, or something else? Different SBCs will > >>> probably require different combinations of operating points just for > >>> safety's sake, because they have different regulators and [some have > >>> botched] thermal designs, so it might make sense to customize it for > >>> differnt boards, and I don't feel adventurous enough setting it for all > >>> H3 boards out there. > >> > >> I meant clocks = <...> and clock-latency = <...>. > >> > >> These 2 are part of the SoC. > >> > >> The OPP can stay in the board files. It's a pity there's no standard > >> OPP table for H3 though. :( > > > > This has never been the case, and we always had some deviation in the > > FEX files for all the SoCs. > > > > If we could come up with standard OPPs that work for every one, > > there's no reason it can't happen here. > > > > I don't really see why the thermal design should change anything. If a > > boards heats faster, it will throttle down to a lower OPP faster, but > > those OPPs are not going to change. > > So I tried, and found out that it will not be so easy. Different boards > have different regulators, and linux doesn't deal well with voltages > that are not supported by the regulator. > > So even if the board can run at certain frequency if you round the > voltage to the next higher voltage supported by the regulator, opp > implementation doesn't do the rounding and just drops the operating > points that have no support in the voltage regulator. > > We have boards that have 1.1/1.3V switching, only 1.3V, fine tuned > voltage regulation and every such board will need it's own set of > operating points. > > I'd leave the OPP definitions in the board files for now. Works for me. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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