Re: [PATCH v4 0/7] typec: tcpm: Add sink side support for PPS

[Guenter Roeck]

On 01/30/2018 05:25 AM, Heikki Krogerus wrote:
> On Tue, Jan 02, 2018 at 03:50:48PM +0000, Adam Thomson wrote:
> > This patch set adds sink side support for the PPS feature introduced in the
> > USB PD 3.0 specification.
> >
> > The source PPS supply is represented using the Power Supply framework to provide
> > access and control APIs for dealing with it's operating voltage and current,
> > and switching between a standard PDO and PPS APDO operation. During standard PDO
> > operation the voltage and current is read-only, but for APDO PPS these are
> > writable as well to allow for control.
> >
> > It should be noted that the keepalive for PPS is not handled within TCPM. The
> > expectation is that the external user will be required to ensure re-requests
> > occur regularly to ensure PPS remains and the source does not hard reset.
>
> Sorry for the late reply. I don't have any major problems with these
> other than with 6/7. The documentation should be for the psy class,
> not tcpm. I'm also not comfortable with the "select POWER_SUPPLY", but
> if Guenter does not think it's a problem, I'm fine with it. I guess we

"select POWER_SUPPLY" seems to be quite widely used, so I don't have problems
with it as long as it is ok for PS maintainers.

> can always, for example, introduce stubs for the power_supply*
> functions, and drop the dependency later.
That doesn't sound like a good idea unless generic stubs are already available.

> But as usual with tcpm.c, Guenter needs to give his ACK.
I'll try to get to it this week.

Guenter

> Oh yes, and Sebastian needs to ACK the power_supply changes or course.
>
>
> Thanks,