linux-kernel - Re: [PATCH v2] usb: typec: tcpm: Invoke power_supply

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Date:   Thu, 18 Mar 2021 13:40:05 -0700
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     Adam Thomson <Adam.Thomson.Opensource@...semi.com>
Cc:     Guenter Roeck <linux@...ck-us.net>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: Re: [PATCH v2] usb: typec: tcpm: Invoke power_supply_changed for tcpm-source-psy-

On Thu, Mar 18, 2021 at 8:26 AM Adam Thomson
<Adam.Thomson.Opensource@...semi.com> wrote:
>
> On 17 March 2021 18:13, Badhri Jagan Sridharan wrote:
>
> > tcpm-source-psy- does not invoke power_supply_changed API when
> > one of the published power supply properties is changed.
> > power_supply_changed needs to be called to notify
> > userspace clients(uevents) and kernel clients.
> >
> > Fixes: f2a8aa053c176("typec: tcpm: Represent source supply through
> > power_supply")
> > Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> > Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> > Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> > ---
> > Changes since V1:
> > - Fixed commit message as per Guenter's suggestion
> > - Added Reviewed-by tags
> > - cc'ed stable
> > ---
> >  drivers/usb/typec/tcpm/tcpm.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> > index 11d0c40bc47d..e8936ea17f80 100644
> > --- a/drivers/usb/typec/tcpm/tcpm.c
> > +++ b/drivers/usb/typec/tcpm/tcpm.c
> > @@ -945,6 +945,7 @@ static int tcpm_set_current_limit(struct tcpm_port *port,
> > u32 max_ma, u32 mv)
> >
> >       port->supply_voltage = mv;
> >       port->current_limit = max_ma;
> > +     power_supply_changed(port->psy);
> >
> >       if (port->tcpc->set_current_limit)
> >               ret = port->tcpc->set_current_limit(port->tcpc, max_ma, mv);
> > @@ -2931,6 +2932,7 @@ static int tcpm_pd_select_pdo(struct tcpm_port *port,
> > int *sink_pdo,
> >
> >       port->pps_data.supported = false;
> >       port->usb_type = POWER_SUPPLY_USB_TYPE_PD;
> > +     power_supply_changed(port->psy);
> >
> >       /*
> >        * Select the source PDO providing the most power which has a
> > @@ -2955,6 +2957,7 @@ static int tcpm_pd_select_pdo(struct tcpm_port *port,
> > int *sink_pdo,
> >                               port->pps_data.supported = true;
> >                               port->usb_type =
> >                                       POWER_SUPPLY_USB_TYPE_PD_PPS;
> > +                             power_supply_changed(port->psy);
> >                       }
> >                       continue;
> >               default:
> > @@ -3112,6 +3115,7 @@ static unsigned int tcpm_pd_select_pps_apdo(struct
> > tcpm_port *port)
> >                                                 port->pps_data.out_volt));
> >               port->pps_data.op_curr = min(port->pps_data.max_curr,
> >                                            port->pps_data.op_curr);
> > +             power_supply_changed(port->psy);
> >       }
> >
> >       return src_pdo;
>
> Regarding selecting PDOs or PPS APDOs, surely we should only notify of a change
> when we reach SNK_READY which means a new contract has been established? Until
> that point it's possible any requested change could be rejected so why inform
> clients before we know the settings have taken effect? I could be missing
> something here as it's been a little while since I delved into this, but this
> doesn't seem to make sense to me.

I was trying to keep the power_supply_changed call close to the
variables which are used to infer the power supply property values.
Since port->pps_data.max_curr is already updated here and that's used
to infer the CURRENT_MAX a client could still read this before the
request goes through right ?
>
> > @@ -3347,6 +3351,7 @@ static int tcpm_set_charge(struct tcpm_port *port, bool
> > charge)
> >                       return ret;
> >       }
> >       port->vbus_charge = charge;
> > +     power_supply_changed(port->psy);
> >       return 0;
> >  }
> >
> > @@ -3530,6 +3535,7 @@ static void tcpm_reset_port(struct tcpm_port *port)
> >       port->try_src_count = 0;
> >       port->try_snk_count = 0;
> >       port->usb_type = POWER_SUPPLY_USB_TYPE_C;
> > +     power_supply_changed(port->psy);
>
> This is already taken care of at the end of this function, isn't it?
I thought I deleted that. Looks like I didn't. Will send in a patch to
remove that.
Will wait for what we decide for the PPS case so that I can send in
both in the same patch.

Thanks,
Badhri

>
> >       port->nr_sink_caps = 0;
> >       port->sink_cap_done = false;
> >       if (port->tcpc->enable_frs)
> > @@ -5957,7 +5963,7 @@ static int tcpm_psy_set_prop(struct power_supply
> > *psy,
> >               ret = -EINVAL;
> >               break;
> >       }
> > -
> > +     power_supply_changed(port->psy);
> >       return ret;
> >  }
> >
> > @@ -6110,6 +6116,7 @@ struct tcpm_port *tcpm_register_port(struct device
> > *dev, struct tcpc_dev *tcpc)
> >       err = devm_tcpm_psy_register(port);
> >       if (err)
> >               goto out_role_sw_put;
> > +     power_supply_changed(port->psy);
> >
> >       port->typec_port = typec_register_port(port->dev, &port->typec_caps);
> >       if (IS_ERR(port->typec_port)) {
> > --
> > 2.31.0.rc2.261.g7f71774620-goog
>