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

[Xu Yang <xu.yang_2@nxp.com>]

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>

---
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