Re: [PATCH v3] drm/bridge: analogix_dp: use devm_phy_optional_get() for the DP PHY

[Jun Yan <jerrysteve1101@gmail.com>]

Hi Luca,

> Hello,
> 
> On Fri Nov 13, 2026 at 2:12 PM CET, Jun Yan wrote:
> > Hi Damon,
> >
> >> You are right, this is really a valid concern.
> >>
> >> If CONFIG_GENERIC_PHY is disabled, the old code could still proceed and
> >> keep the driver probing, while the new version would return an error
> >> directly.
> >
> > -ENOSYS can only come from the !CONFIG_GENERIC_PHY stubs in
> > include/linux/phy/phy.h; the real implementation in drivers/phy/phy-core.=
> c
> > never returns it. And the stub for the optional variant returns NULL, not
> > -ENOSYS:
> >
> >     static inline struct phy *devm_phy_optional_get(struct device *dev,
> >                                                     const char *string)
> >     {
> >             return NULL;
> >     }
> >
> > So with CONFIG_GENERIC_PHY disabled the PHY is still treated as absent
> > (NULL), exactly as the old -ENOSYS branch did. With CONFIG_GENERIC_PHY
> > enabled, -ENOSYS cannot occur, devm_phy_optional_get() turns -ENODEV into
> > NULL, and any other error is still propagated - same as the open-coded
> > check.
> >
> >> It should be better to keep the -ENOSYS handling to preserve the
> >> original behavior.
> >
> > Overall the behaviour is unchanged in both configurations, so no separate
> > handling is needed.
> 
> Thanks for the analysis! Cna you send a v4 with that explained in the
> commit message, possibly in a more concise way, maybe with bullets for the
> various CONFIG_GENERIC_PHY on/off cases or so, for readability?
> 

Yes, I'll send a v4.

> Reading it now, this v3 commit message kind of said the same things. but it
> misled both me and Damon, so it's worth a clear explanation.
> 
> Thanks!
> 
> Luca

Thanks,
Jun