Re: [PATCH v2] usb: typec: tcpm: not sink vbus if operational current is 0mA

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Tue, Aug 01, 2023 at 03:01:10PM +0800, Xu Yang wrote:
> PD3.0 Spec 6.4.1.3.1 said:
> For a Sink requiring no power from the Source, the Voltage (B19-10)
> shall be set to 5V and the Operational Current Shall be set to 0mA.
> 
> Therefore, we can keep sink path closed if the operational current of
> the first fixed PDO is 0mA.
> 
> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> Changes in v2:
>   - also call tcpm_set_charge() when charge is false as suggested from
>     Heikki and Guenter.
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 829d75ebab42..d999e6984fea 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4301,7 +4301,9 @@ static void run_state_machine(struct tcpm_port *port)
>  			if (port->slow_charger_loop && (current_lim > PD_P_SNK_STDBY_MW / 5))
>  				current_lim = PD_P_SNK_STDBY_MW / 5;
>  			tcpm_set_current_limit(port, current_lim, 5000);
> -			tcpm_set_charge(port, true);
> +			/* Not sink vbus if operational current is 0mA */
> +			tcpm_set_charge(port, !!pdo_max_current(port->snk_pdo[0]));
> +
>  			if (!port->pd_supported)
>  				tcpm_set_state(port, SNK_READY, 0);
>  			else
> @@ -4582,7 +4584,8 @@ static void run_state_machine(struct tcpm_port *port)
>  			tcpm_set_current_limit(port,
>  					       tcpm_get_current_limit(port),
>  					       5000);
> -			tcpm_set_charge(port, true);
> +			/* Not sink vbus if operational current is 0mA */
> +			tcpm_set_charge(port, !!pdo_max_current(port->snk_pdo[0]));
>  		}
>  		if (port->ams == HARD_RESET)
>  			tcpm_ams_finish(port);
> -- 
> 2.34.1

-- 
heikki