Re: [PATCH v1] usb: typec: tcpm: Return ENOTSUPP for power supply prop writes

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Aug 15, 2022 at 08:33:55PM -0700, Badhri Jagan Sridharan wrote:
> When the port does not support USB PD, prevent transition to PD
> only states when power supply property is written. In this case,
> TCPM transitions to SNK_NEGOTIATE_CAPABILITIES
> which should not be the case given that the port is not pd_capable.
> 
> [   84.308251] state change SNK_READY -> SNK_NEGOTIATE_CAPABILITIES [rev3 NONE_AMS]
> [   84.308335] Setting usb_comm capable false
> [   84.323367] set_auto_vbus_discharge_threshold mode:3 pps_active:n vbus:5000 ret:0
> [   84.323376] state change SNK_NEGOTIATE_CAPABILITIES -> SNK_WAIT_CAPABILITIES [rev3 NONE_AMS]
> 
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

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

> ---
>  drivers/usb/typec/tcpm/tcpm.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index ea5a917c51b1..904c7b4ce2f0 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -6320,6 +6320,13 @@ static int tcpm_psy_set_prop(struct power_supply *psy,
>  	struct tcpm_port *port = power_supply_get_drvdata(psy);
>  	int ret;
>  
> +	/*
> +	 * All the properties below are related to USB PD. The check needs to be
> +	 * property specific when a non-pd related property is added.
> +	 */
> +	if (!port->pd_supported)
> +		return -EOPNOTSUPP;
> +
>  	switch (psp) {
>  	case POWER_SUPPLY_PROP_ONLINE:
>  		ret = tcpm_psy_set_online(port, val);
> -- 
> 2.37.1.595.g718a3a8f04-goog
>