Am 30. März 2016 09:55:54 MESZ, schrieb Hans de Goede <>:
>On 30-03-16 06:57, Michael Haas wrote:
>> On 03/28/2016 03:01 PM, Hans de Goede wrote:
>>>> but unless there's a real need
>>>> for me to verify this,
>>>> I'll simply revert the u-boot patch and enjoy working GPIO.
>>> Given the entire discussion in this thread, I agree that fixing this
>>> in u-boot
>>> is best. But I do not see reverting the u-boot patch disabling
>>> by default
>>> as the solution. ldo3/4 are unused on most boards, so disabling them
>>> by default
>>> clearly is the right thing todo IMHO.
>> I just checked the Banana Pi, which exposes ports from bank E on its
>> CON1. Admittedly,
>> that's the "Camera Serial Interface", but that connector is
>> also labelled
>> as supporting various GPIO pins:
>That connector is not usable unless you've got a really special cable,
>also ldo3/4 are disabled in the kernel dts, so it does not matter what
>> On the Cubietruck, there's also CN9, exposing some GPIO ports from
>bank G:
>The Cubietruck also has ldo3/4 disabled in the kernel dts.
>> Given that there tend to be crashes on re-enabling LDO3+LDO4 and many
>> boards expose affected pins (not only for CSI!): wouldn't be it be
>> best to keep them enabled?
>s/Many boards/Lime 2/ and we still do not fully understand what is
>on there, we just know that not enabling ldo3/4 at the u-boot level
>causes issues, we do not know / understand why though.
>U-boot supports 52 boards with an axp209 pmic, yet you only name a
>few which need ldo3/4 according to you, and for 2 of your examples the
>kernel dts says differently.
>I'm not going to enable ldo3/4 by default on all boards just because
>are needed on the Lime 2.

Hi Hans,

You are making an excellent point. I will submit patches for the lime* boards 
as proposed in your earlier mail.

Just to ask for some clarification: you are saying the regulators are disabled 
in the kernel dts files.
I looked at the cubietruck dts files and the regulators are not mentioned in 
there. If they are not mentioned, are they turned off or do they remain in 
their default state, e.g the way that u-boot left them?

Stepping back from kernel/u-boot issues, would it make sense to also turn on 
the regulators for the cubietruck? Perhaps in u-boot and the kernel?


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