Re: [PATCH 1/3] arm64: dts: rockchip: adjust dcin regulator on ROCK 4D

["Diederik de Haas" <didi.debian@cknow.org>]

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Hi,

On Tue Jul 1, 2025 at 1:10 AM CEST, Sebastian Reichel wrote:
> On Mon, Jun 30, 2025 at 08:12:27PM +0200, Diederik de Haas wrote:
>> On Mon Jun 30, 2025 at 5:36 PM CEST, Nicolas Frattaroli wrote:
>> > The ROCK 4D's actual DC input is 5V, and the schematic names it as being
>> > 5V as well.
>> >
>> > Rename the regulator, and change the voltage it claims to be at.
>> 
>> Shouldn't it have a fixes tag then? Providing 12V where 5V is expected
>> sounds problematic ;-)
>
> This is basically "just" documentation, as the DT just describes
> a fixed regulator (i.e. nothing software controllable). This just
> changes a number in sysfs :)
>
> Note, that the 5V DCIN is a USB-C port, which does not do any PD
> negotiation, but has the 5K1 resistors on the CC lines to "request"
> 5V. If for whatever reason a higher voltage is applied (which does
> not happen as long as the power is provided by anything remotely
> following the USB specifications) there also is an over-voltage
> protection chip. So it's not problematic :)

I was worried about and wondered why I/we did NOT receive reports about
boards being fried. Good to know, thanks!

> OTOH adding a Fixes tag does not hurt ;)

Cheers,
  Diederik

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