Re: [linux-sunxi] [PATCH v2 14/14] ARM: dts: sun8i: Enable DVFS on Orange Pi One

[OndÅej Jirman]

On 30.6.2016 17:16, Michal Suchanek wrote:
> On 30 June 2016 at 16:19, OndÅej Jirman <megous@xxxxxxxxxx> wrote:
>> Hello,
>>
>> On 30.6.2016 13:13, Michal Suchanek wrote:
>>> Hello,
>>>
>>> On 25 June 2016 at 05:45,  <megous@xxxxxxxxxx> wrote:
>>>> From: Ondrej Jirman <megous@xxxxxxxxxx>
>>>>
>>>> Use Xulong Orange Pi One GPIO based regulator for
>>>> passive cooling and thermal management.
>>>>
>>>> Signed-off-by: Ondrej Jirman <megous@xxxxxxxxxx>
>>>> ---
>>>>  arch/arm/boot/dts/sun8i-h3-orangepi-one.dts | 39 +++++++++++++++++++++++++++++
>>>>  1 file changed, 39 insertions(+)
>>>>
>>>> diff --git a/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts b/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts
>>>> index b1bd6b0..a38d871 100644
>>>> --- a/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts
>>>> +++ b/arch/arm/boot/dts/sun8i-h3-orangepi-one.dts
>>>> @@ -109,6 +109,45 @@
>>>>         };
>>>>  };
>>>>
>>>> +&cpu0 {
>>>> +       operating-points = <
>>>> +               /* kHz    uV */
>>>> +               1296000 1300000
>>>> +               1200000 1300000
>>>
>>> First problem is that the board boots at 1008000 which is not listed
>>> and the kernel complains.
>>>
>>> Second problem is that the board locks up during boot with this enabled.
>>>
>>> Do you have some suggestion for alternate configuration to test?
>>
>> Just to verify, did you test with the entire series applied? (especially
>> the PLL1 clk application changes)
> 
> Yes, I applied the whole series.
> 
>>
>> You may try dropping the highest operating point, it's probably overly
>> optimistic for Orange Pi One.
>>
>> Is the power supply/cable you're using hard enough?
> 
> I use a 7 port hub to power the board. It worked with some other small
> devboards.
> 
> The cable is some random Chinese USB to power jack adaptor with an
> extra adaptor to fit the Pi socket. It looks ok but I did not test
> this particular combination thoroughly.
> 
>>
>> Where during the boot process does it lock up?
> 
> Usually sometime around enabling cpufreq  before getty starts.
> Different runs and settings give slightly different results. In
> particular adding the 1008000 point seems to make it go further.
> 
> Removing all traces of the regulator, cpufreq and thermal I can boot
> pretty much 100% to login prompt.
> 
> I don't think the difference between 1GHz and 1.3GHz frequency on the
> core would put much additional stress on the supply but I can try with
> 35W PSU and some alternative cabling to be sure.
> 
> I did some more tests and it seems 1008000@xxxx is fine but switching
> to 1.3V crashes the board. Even with only the first 1.3V state. Maybe
> there is need for some delay somewhere for the regulator to get
> stable?

Please try adding:

  regulator-ramp-delay = <10>

to the gpio regulator.

which will allow 100ms per 1V change, which should b enough for
determining, if this is the cause.

regards,
  Ondrej

> Thanks
> 
> Michal
>

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