linux-kernel - Re: [PATCH v1 1/6] usb: typec: tcpm: Address incorrect values of tcpm psy for fixed supply

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Message-ID: <9ca3dbe9-af32-62cf-fa27-7da4e6967b85@roeck-us.net>
Date:   Mon, 5 Apr 2021 18:56:17 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Badhri Jagan Sridharan <badhri@...gle.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Adam Thomson <Adam.Thomson.Opensource@...semi.com>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Kyle Tso <kyletso@...gle.com>
Subject: Re: [PATCH v1 1/6] usb: typec: tcpm: Address incorrect values of tcpm
 psy for fixed supply

On 4/5/21 6:36 PM, Badhri Jagan Sridharan wrote:
> tcpm_pd_build_request overwrites current_limit and supply_voltage
> even before port partner accepts the requests. This leaves stale
> values in current_limit and supply_voltage that get exported by
> "tcpm-source-psy-". Solving this problem by caching the request
> values of current limit/supply voltage in req_current_limit
> and req_supply_voltage. current_limit/supply_voltage gets updated
> once the port partner accepts the request.
> 
> Fixes: f2a8aa053c176 ("typec: tcpm: Represent source supply through power_supply")
> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index ca1fc77697fc..03eca5061132 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -389,7 +389,10 @@ struct tcpm_port {
>  	unsigned int operating_snk_mw;
>  	bool update_sink_caps;
>  
> -	/* Requested current / voltage */
> +	/* Requested current / voltage to the port partner */
> +	u32 req_current_limit;
> +	u32 req_supply_voltage;
> +	/* Acutal current / voltage limit of the local port */

Actual

Otherwise makes sense.

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

>  	u32 current_limit;
>  	u32 supply_voltage;
>  
> @@ -2435,8 +2438,8 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
>  		case SNK_TRANSITION_SINK:
>  			if (port->vbus_present) {
>  				tcpm_set_current_limit(port,
> -						       port->current_limit,
> -						       port->supply_voltage);
> +						       port->req_current_limit,
> +						       port->req_supply_voltage);
>  				port->explicit_contract = true;
>  				tcpm_set_auto_vbus_discharge_threshold(port,
>  								       TYPEC_PWR_MODE_PD,
> @@ -2545,8 +2548,8 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
>  			break;
>  		case SNK_NEGOTIATE_PPS_CAPABILITIES:
>  			port->pps_data.active = true;
> -			port->supply_voltage = port->pps_data.out_volt;
> -			port->current_limit = port->pps_data.op_curr;
> +			port->req_supply_voltage = port->pps_data.out_volt;
> +			port->req_current_limit = port->pps_data.op_curr;
>  			tcpm_set_state(port, SNK_TRANSITION_SINK, 0);
>  			break;
>  		case SOFT_RESET_SEND:
> @@ -3195,8 +3198,8 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
>  			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
>  	}
>  
> -	port->current_limit = ma;
> -	port->supply_voltage = mv;
> +	port->req_current_limit = ma;
> +	port->req_supply_voltage = mv;
>  
>  	return 0;
>  }
>