Messages in this thread | | | Date | Fri, 13 May 2022 16:23:20 +0800 | Subject | Re: [PATCH v3 2/2] ARM: dts: sun8i-r40: Add "cpu-supply" node for sun8i-r40 based board | From | qianfan <> |
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在 2022/5/13 16:15, Maxime Ripard 写道: > On Fri, May 13, 2022 at 03:48:50PM +0800, qianfan wrote: >> >> 在 2022/5/13 15:38, Maxime Ripard 写道: >>> Hi, >>> >>> On Thu, May 12, 2022 at 03:18:58PM +0800, qianfanguijin@163.com wrote: >>>> From: qianfan Zhao <qianfanguijin@163.com> >>>> >>>> sun8i-r40 actived cpufreq feature now, let's add "cpu-supply" node on >>>> board. >>>> >>>> Signed-off-by: qianfan Zhao <qianfanguijin@163.com> >>>> --- >>>> arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts | 4 ++++ >>>> arch/arm/boot/dts/sun8i-r40-feta40i.dtsi | 4 ++++ >>>> arch/arm/boot/dts/sun8i-t3-cqa3t-bv3.dts | 4 ++++ >>>> arch/arm/boot/dts/sun8i-v40-bananapi-m2-berry.dts | 4 ++++ >>>> 4 files changed, 16 insertions(+) >>>> >>>> diff --git a/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts b/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts >>>> index a6a1087a0c9b..4f30018ec4a2 100644 >>>> --- a/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts >>>> +++ b/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts >>>> @@ -113,6 +113,10 @@ &ahci { >>>> status = "okay"; >>>> }; >>>> +&cpu0 { >>>> + cpu-supply = <®_dcdc2>; >>>> +}; >>>> + >>> This will break bisection on those boards. Indeed, you added the OPPs on >>> the first patch, and if you only apply that patch, the boards in the >>> second patch will be missing their CPU regulator. The kernel will then >>> ramp up the frequency to the highest OPP, but will not change the >>> voltage, resulting in a crash. >> This is a good point and I will merge those two patch. > That's not what I meant to say. Those two patches are great separated. > You can invert them though. haha, invert them, so interesting. good idea. > >>> There's a similar issue for all the boards that don't have a regulator >>> in the first place. >>> >>> The way we worked around this for the other SoCs is to have a DTSI with >>> the OPPs with a frequency higher than what U-Boot boots with (1008MHz?), >>> and only include that DTSI on boards that have a CPU regulator hooked in. >> Is this really necessary? It seems like every board based on sun8i-r40 >> have a cpu regulator. > This probably won't be the case whenever someone starts a new design, > and then they'll face random crashes for no apparent reason, and waste a > lot of time in the process. > > Whereas the alternative is that you would be missing some OPPs, > something that is fairly easy to figure out. How about remove the OPPs which greate that 1.08G in sun8i-r40.dtsi, If some boards want to run at a higher frequency, can add them byself in the board's file. > > Maxime
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