linux-kernel - Re: [PATCH v6 05/14] usb: typec: tcpci: Add set

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Date:   Wed, 16 Sep 2020 02:07:11 -0700
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc:     Guenter Roeck <linux@...ck-us.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        USB <linux-usb@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 05/14] usb: typec: tcpci: Add set_vbus tcpci callback

On Tue, Sep 15, 2020 at 5:22 AM Heikki Krogerus
<heikki.krogerus@...ux.intel.com> wrote:
>
> On Mon, Aug 31, 2020 at 07:59:18PM -0700, Badhri Jagan Sridharan wrote:
> > set_vbus callback allows TCPC which are TCPCI based, however,
> > does not support turning on sink and source mode through
> > Command.SinkVbus and Command.SourceVbusDefaultVoltage.
> >
> > Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> > ---
> > Changes since v1:
> > - Changing patch version to v6 to fix version number confusion.
> > ---
> >  drivers/usb/typec/tcpm/tcpci.c | 7 +++++++
> >  drivers/usb/typec/tcpm/tcpci.h | 1 +
> >  2 files changed, 8 insertions(+)
> >
> > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > index b960fe5a0f28..d6a6fac82d48 100644
> > --- a/drivers/usb/typec/tcpm/tcpci.c
> > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > @@ -328,6 +328,13 @@ static int tcpci_set_vbus(struct tcpc_dev *tcpc, bool source, bool sink)
> >       struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> >       int ret;
> >
> > +     if (tcpci->data->set_vbus) {
> > +             ret = tcpci->data->set_vbus(tcpci, tcpci->data, source, sink);
> > +             /* Bypass when ret > 0 */
> > +             if (ret != 0)
> > +                     return ret < 0 ? ret : 0;
>
> Can it return positive value? What does positive value mean?

When a positive value is returned, tcpci->data->set_vbus is indicating
the tcpci.c code to bypass
other commands here. i.e. tcpci->data->set_vbus completely handles
sinking/sourcing vbus and
does not want tcpc.c to execute any other TCPC_CMD_* command.
Open to suggestions if you are not happy with this. All I want is to
make tcpci code pass on the call
from TCPM to chip level TCPC driver (i.e.  tcpci_maxim.c in this case)
and not do anything else.

>
> > +     }
> > +
> >       /* Disable both source and sink first before enabling anything */
> >
> >       if (!source) {
> > diff --git a/drivers/usb/typec/tcpm/tcpci.h b/drivers/usb/typec/tcpm/tcpci.h
> > index 04c49a0b0368..4d441bdf24d5 100644
> > --- a/drivers/usb/typec/tcpm/tcpci.h
> > +++ b/drivers/usb/typec/tcpm/tcpci.h
> > @@ -144,6 +144,7 @@ struct tcpci_data {
> >                        bool enable);
> >       int (*start_drp_toggling)(struct tcpci *tcpci, struct tcpci_data *data,
> >                                 enum typec_cc_status cc);
> > +     int (*set_vbus)(struct tcpci *tcpci, struct tcpci_data *data, bool source, bool sink);
> >  };
> >
> >  struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data);
> > --
> > 2.28.0.402.g5ffc5be6b7-goog
>
> --
> heikki