Re: [PATCH v2 6/7] platform/chrome: cros_ec_typec: Thunderbolt support

Abhishek Pandit-Subedi
2024-10-31T22:23:40Z

On Thu, Oct 31, 2024 at 11:51 AM Dmitry Baryshkov
<dmitry.baryshkov@linaro.org> wrote:
>
> On Wed, Oct 30, 2024 at 02:28:37PM -0700, Abhishek Pandit-Subedi wrote:
> > Add support for entering and exiting Thunderbolt alt-mode using AP
> > driven alt-mode.
> >
> > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
> > ---
> >
> > Changes in v2:
> > - Refactored thunderbolt support into cros_typec_altmode.c
> >
> > drivers/platform/chrome/cros_ec_typec.c | 29 ++++---
> > drivers/platform/chrome/cros_typec_altmode.c | 85 ++++++++++++++++++++
> > drivers/platform/chrome/cros_typec_altmode.h | 14 ++++
> > 3 files changed, 116 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> > index 7997e7136c4c..3e043b1c1cc8 100644
> > --- a/drivers/platform/chrome/cros_ec_typec.c
> > +++ b/drivers/platform/chrome/cros_ec_typec.c
> > @@ -304,21 +304,26 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
> > typec_altmode_set_drvdata(amode, port);
> > amode->ops = &port_amode_ops;
> > #endif
> > -
> > /*
> > * Register TBT compatibility alt mode. The EC will not enter the mode
> > - * if it doesn't support it, so it's safe to register it unconditionally
> > - * here for now.
> > + * if it doesn't support it and it will not enter automatically by
> > + * design so we can use the |ap_driven_altmode| feature to check if we
> > + * should register it.
> > */
> > - memset(&desc, 0, sizeof(desc));
> > - desc.svid = USB_TYPEC_TBT_SID;
> > - desc.mode = TYPEC_ANY_MODE;
> > - amode = typec_port_register_altmode(port->port, &desc);
> > - if (IS_ERR(amode))
> > - return PTR_ERR(amode);
> > - port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> > - typec_altmode_set_drvdata(amode, port);
> > - amode->ops = &port_amode_ops;
> > + if (typec->ap_driven_altmode) {
> > + memset(&desc, 0, sizeof(desc));
> > + desc.svid = USB_TYPEC_TBT_SID;
> > + desc.mode = TYPEC_ANY_MODE;
> > + amode = cros_typec_register_thunderbolt(port, &desc);
> > + if (IS_ERR(amode))
> > + return PTR_ERR(amode);
> > + port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> > +
> > +#if !IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> > + typec_altmode_set_drvdata(amode, port);
> > + amode->ops = &port_amode_ops;
> > +#endif
>
> Why? Usually having the code block under an #if is a frowned upon
> practice.

There are some CrosEC implementations that provide full VDM access for
mode entry and this code was previously added to support that. I'm
looking into whether this was fully deployed -- if not, I will remove
this #if block entirely in my next patch series.

Will do the same for displayport above.

>
> > + }
> >
> > port->state.alt = NULL;
> > port->state.mode = TYPEC_STATE_USB;
>
> [...]
>
> > diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
> > index c6f8fb02c99c..c71568314e3f 100644
> > --- a/drivers/platform/chrome/cros_typec_altmode.h
> > +++ b/drivers/platform/chrome/cros_typec_altmode.h
> > @@ -31,4 +31,18 @@ static inline int cros_typec_displayport_status_update(struct typec_altmode *alt
> > return 0;
> > }
> > #endif
> > +
> > +#if IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> > +struct typec_altmode *
> > +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> > + struct typec_altmode_desc *desc);
> > +#else
> > +struct typec_altmode *
>
> static inline struct ...
> LGTM otherwise

I ran allmodconfig and x86_64_defconfig but forgot to run allmodconfig
- these features :( -- argh... I'll add this to my testing steps.

>
> > +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> > + struct typec_altmode_desc *desc)
> > +{
> > + return typec_port_register_altmode(port->port, desc);
> > +}
> > +#endif
> > +
> > #endif /* __CROS_TYPEC_ALTMODE_H__ */
> > --
> > 2.47.0.163.g1226f6d8fa-goog
> >
>
> --
> With best wishes
> Dmitry