Re: [PATCH 1/3] arm64: dts: qcom: sdm630: fix UART1 pin bias

From: Doug Anderson
Date: Mon Oct 03 2022 - 11:30:19 EST


On Sat, Oct 1, 2022 at 2:58 AM Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxx> wrote:
> > I would also note that convention on Qualcomm SoCs that I've worked on
> > was that bias shouldn't be specified in the SoC dtsi file and should
> > be left to board files. This is talked a bit about in a previous email
> > thread [1].
> Uh, that makes a lot of sense. It is almost always a property of a board.

Right, though it can make sense to have a "default" in the SoC
sometimes. For instance, for i2c you almost always want external
pullups so you can tune them to the speed/trace lengths. Thus having a
default in the SoC file to disable i2c pullups would make a lot of
sense. The problem is the ugly / non-obvious "delete-property" we need
to put in the board.dts file if we ever need to override the SoC's
pull. :(

I actually remember this not being a problem in Rockchip SoCs. I guess
it's because they end up having an extra level of indirection. I guess
there's no great way to do that for Qualcomm without changing the

> > That being said, it does look like this was the intention of the
> > original commit, so thus:
> >
> > Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> Thanks.
> I can also drop the property entirely to match existing behavior (not
> the intention).

Hopefully someone who cares about this board can test and let you know
either way.

> > [1]