Re: [PATCH] arm64: dts: qcom: sc8280xp-x13s: Use the correct DP PHY compatible

From: Johan Hovold
Date: Mon Oct 16 2023 - 05:02:18 EST


On Mon, Oct 16, 2023 at 11:51:33AM +0300, Dmitry Baryshkov wrote:
> On Fri, 29 Sept 2023 at 19:03, Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> wrote:
> >
> > The DP PHY needs different settings when an eDP display is used.
> > Make sure these apply on the X13s.
>
> Could you please clarify, is it the same PHY type, just being
> repurposed for eDP or is it a different PHY type?

Same PHY, just different settings AFAIK.

> If the former is the case (and the same PHY can be used for both DP
> and eDP), it should carry the same compatible string and use software
> mechanisms (e.g. phy_set_mode_ext()) to be programmed for the correct
> operation mode.

Possibly, but that's not how the current binding and implementation
works:

6993c079cd58 ("dt-bindings: phy: qcom-edp: Add SC8280XP PHY compatibles")
2300d1cb24b3 ("phy: qcom: edp: Introduce support for DisplayPort")
3b7267dec445 ("phy: qcom: edp: Add SC8280XP eDP and DP PHYs")

https://lore.kernel.org/lkml/20220810040745.3582985-1-bjorn.andersson@xxxxxxxxxx/

And you'd still need to infer the mode from DT somehow.

Johan