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

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Date:   Thu, 18 Mar 2021 15:26:27 +0000
From:   Adam Thomson <Adam.Thomson.Opensource@...semi.com>
To:     Badhri Jagan Sridharan <badhri@...gle.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH v2] usb: typec: tcpm: Invoke power_supply_changed for
 tcpm-source-psy-

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.

> @@ -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?

>  	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