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    SubjectRe: [linux-sunxi] [PATCH v2 14/14] ARM: dts: sun8i: Enable DVFS on Orange Pi One
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    On 30.6.2016 17:16, Michal Suchanek wrote:
    > On 30 June 2016 at 16:19, Ondřej Jirman <megous@megous.com> wrote:
    >> Hello,
    >>
    >> On 30.6.2016 13:13, Michal Suchanek wrote:
    >>> Hello,
    >>>
    >>> On 25 June 2016 at 05:45, <megous@megous.com> wrote:
    >>>> From: Ondrej Jirman <megous@megous.com>
    >>>>
    >>>> Use Xulong Orange Pi One GPIO based regulator for
    >>>> passive cooling and thermal management.
    >>>>
    >>>> Signed-off-by: Ondrej Jirman <megous@megous.com>
    >>>> ---
    >>>> 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@1.1V 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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