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

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

[Xu Yang]

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>
---
 drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 829d75ebab42..4f7e4c50e847 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4301,7 +4301,12 @@ 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);
+
+			if (pdo_max_current(port->snk_pdo[0]))
+				tcpm_set_charge(port, true);
+			else
+				tcpm_log(port, "Not require power from Source");
+
 			if (!port->pd_supported)
 				tcpm_set_state(port, SNK_READY, 0);
 			else
@@ -4582,7 +4587,10 @@ 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);
+			if (pdo_max_current(port->snk_pdo[0]))
+				tcpm_set_charge(port, true);
+			else
+				tcpm_log(port, "Not require power from Source");
 		}
 		if (port->ams == HARD_RESET)
 			tcpm_ams_finish(port);
-- 
2.34.1

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

[Xu Yang]

> -----Original Message-----
> From: Xu Yang
> Sent: Friday, June 30, 2023 6:53 PM
> To: linux@roeck-us.net; heikki.krogerus@linux.intel.com
> Cc: gregkh@linuxfoundation.org; dl-linux-imx <linux-imx@nxp.com>; linux-usb@vger.kernel.org; Jun Li <jun.li@nxp.com>;
> Xu Yang <xu.yang_2@nxp.com>
> Subject: [PATCH] usb: typec: tcpm: not sink vbus if operational current is 0mA
> 
> 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>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 829d75ebab42..4f7e4c50e847 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4301,7 +4301,12 @@ 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);
> +
> +			if (pdo_max_current(port->snk_pdo[0]))
> +				tcpm_set_charge(port, true);
> +			else
> +				tcpm_log(port, "Not require power from Source");
> +
>  			if (!port->pd_supported)
>  				tcpm_set_state(port, SNK_READY, 0);
>  			else
> @@ -4582,7 +4587,10 @@ 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);
> +			if (pdo_max_current(port->snk_pdo[0]))
> +				tcpm_set_charge(port, true);
> +			else
> +				tcpm_log(port, "Not require power from Source");
>  		}
>  		if (port->ams == HARD_RESET)
>  			tcpm_ams_finish(port);
> --
> 2.34.1

A gentle ping.

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

[Heikki Krogerus]

Hi,

I'm sorry to keep you waiting.

On Fri, Jun 30, 2023 at 06:56:56PM +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>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 829d75ebab42..4f7e4c50e847 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4301,7 +4301,12 @@ 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);
> +
> +			if (pdo_max_current(port->snk_pdo[0]))
> +				tcpm_set_charge(port, true);
> +			else
> +				tcpm_log(port, "Not require power from Source");
> +
>  			if (!port->pd_supported)
>  				tcpm_set_state(port, SNK_READY, 0);
>  			else
> @@ -4582,7 +4587,10 @@ 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);
> +			if (pdo_max_current(port->snk_pdo[0]))
> +				tcpm_set_charge(port, true);
> +			else
> +				tcpm_log(port, "Not require power from Source");

Shouldn't you still always call tcpm_set_charge()?

        tcpm_set_charge(port, pdo_max_current(port->snk_pdo[0]));

I think we need to wait for comments from Guenter. I don't know this
driver well enough.

thanks,

-- 
heikki

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

[Guenter Roeck]

On 7/31/23 06:33, Heikki Krogerus wrote:
> Hi,
> 
> I'm sorry to keep you waiting.
> 
> On Fri, Jun 30, 2023 at 06:56:56PM +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>
>> ---
>>   drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++--
>>   1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
>> index 829d75ebab42..4f7e4c50e847 100644
>> --- a/drivers/usb/typec/tcpm/tcpm.c
>> +++ b/drivers/usb/typec/tcpm/tcpm.c
>> @@ -4301,7 +4301,12 @@ 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);
>> +
>> +			if (pdo_max_current(port->snk_pdo[0]))
>> +				tcpm_set_charge(port, true);
>> +			else
>> +				tcpm_log(port, "Not require power from Source");
>> +
>>   			if (!port->pd_supported)
>>   				tcpm_set_state(port, SNK_READY, 0);
>>   			else
>> @@ -4582,7 +4587,10 @@ 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);
>> +			if (pdo_max_current(port->snk_pdo[0]))
>> +				tcpm_set_charge(port, true);
>> +			else
>> +				tcpm_log(port, "Not require power from Source");
> 
> Shouldn't you still always call tcpm_set_charge()?
> 
>          tcpm_set_charge(port, pdo_max_current(port->snk_pdo[0]));
> 

I think so, something like
	tcpm_set_charge(port, !!pdo_max_current(port->snk_pdo[0]));

Guenter

> I think we need to wait for comments from Guenter. I don't know this
> driver well enough.
> 
> thanks,
> 

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

[Xu Yang]

Hi Heikki and Guenter,

> On 7/31/23 06:33, Heikki Krogerus wrote:
> > Hi,
> >
> > I'm sorry to keep you waiting.
> >
> > On Fri, Jun 30, 2023 at 06:56:56PM +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>
> >> ---
> >>   drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++--
> >>   1 file changed, 10 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> >> index 829d75ebab42..4f7e4c50e847 100644
> >> --- a/drivers/usb/typec/tcpm/tcpm.c
> >> +++ b/drivers/usb/typec/tcpm/tcpm.c
> >> @@ -4301,7 +4301,12 @@ 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);
> >> +
> >> +                    if (pdo_max_current(port->snk_pdo[0]))
> >> +                            tcpm_set_charge(port, true);
> >> +                    else
> >> +                            tcpm_log(port, "Not require power from Source");
> >> +
> >>                      if (!port->pd_supported)
> >>                              tcpm_set_state(port, SNK_READY, 0);
> >>                      else
> >> @@ -4582,7 +4587,10 @@ 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);
> >> +                    if (pdo_max_current(port->snk_pdo[0]))
> >> +                            tcpm_set_charge(port, true);
> >> +                    else
> >> +                            tcpm_log(port, "Not require power from Source");
> >
> > Shouldn't you still always call tcpm_set_charge()?
> >
> >          tcpm_set_charge(port, pdo_max_current(port->snk_pdo[0]));
> >
> 
> I think so, something like
>         tcpm_set_charge(port, !!pdo_max_current(port->snk_pdo[0]));

I assume the sink path is already closed before tcpm_set_charge(). But
this way of handling is also okay for me. Will send out v2 later.

Thanks,
Xu Yang

> 
> Guenter
> 
> > I think we need to wait for comments from Guenter. I don't know this
> > driver well enough.
> >
> > thanks,
> >