1 files changed, 52 insertions, 11 deletions

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 1c64b831bbb5..cedc6cf82d61 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -258,7 +258,19 @@ struct tcpm_port {
 	bool attached;
 	bool connected;
 	enum typec_port_type port_type;
+
+	/*
+	 * Set to true when vbus is greater than VSAFE5V min.
+	 * Set to false when vbus falls below vSinkDisconnect max threshold.
+	 */
 	bool vbus_present;
+
+	/*
+	 * Set to true when vbus is less than VSAFE0V max.
+	 * Set to false when vbus is greater than VSAFE0V max.
+	 */
+	bool vbus_vsafe0v;
+
 	bool vbus_never_low;
 	bool vbus_source;
 	bool vbus_charge;
@@ -3093,7 +3105,7 @@ static void run_state_machine(struct tcpm_port *port)
 		else if (tcpm_port_is_audio(port))
 			tcpm_set_state(port, AUDIO_ACC_ATTACHED,
 				       PD_T_CC_DEBOUNCE);
-		else if (tcpm_port_is_source(port))
+		else if (tcpm_port_is_source(port) && port->vbus_vsafe0v)
 			tcpm_set_state(port,
 				       tcpm_try_snk(port) ? SNK_TRY
 							  : SRC_ATTACHED,
@@ -4096,6 +4108,12 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
 {
 	tcpm_log_force(port, "VBUS on");
 	port->vbus_present = true;
+	/*
+	 * When vbus_present is true i.e. Voltage at VBUS is greater than VSAFE5V implicitly
+	 * states that vbus is not at VSAFE0V, hence clear the vbus_vsafe0v flag here.
+	 */
+	port->vbus_vsafe0v = false;
+
 	switch (port->state) {
 	case SNK_TRANSITION_SINK_VBUS:
 		port->explicit_contract = true;
@@ -4185,16 +4203,8 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 	case SNK_HARD_RESET_SINK_OFF:
 		tcpm_set_state(port, SNK_HARD_RESET_WAIT_VBUS, 0);
 		break;
-	case SRC_HARD_RESET_VBUS_OFF:
-		/*
-		 * After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait
-		 * tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V.
-		 */
-		tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER);
-		break;
 	case HARD_RESET_SEND:
 		break;
-
 	case SNK_TRY:
 		/* Do nothing, waiting for timeout */
 		break;
@@ -4265,6 +4275,28 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 	}
 }
 
+static void _tcpm_pd_vbus_vsafe0v(struct tcpm_port *port)
+{
+	tcpm_log_force(port, "VBUS VSAFE0V");
+	port->vbus_vsafe0v = true;
+	switch (port->state) {
+	case SRC_HARD_RESET_VBUS_OFF:
+		/*
+		 * After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait
+		 * tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V.
+		 */
+		tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER);
+		break;
+	case SRC_ATTACH_WAIT:
+		if (tcpm_port_is_source(port))
+			tcpm_set_state(port, tcpm_try_snk(port) ? SNK_TRY : SRC_ATTACHED,
+				       PD_T_CC_DEBOUNCE);
+		break;
+	default:
+		break;
+	}
+}
+
 static void _tcpm_pd_hard_reset(struct tcpm_port *port)
 {
 	tcpm_log_force(port, "Received hard reset");
@@ -4300,10 +4332,19 @@ static void tcpm_pd_event_handler(struct kthread_work *work)
 			bool vbus;
 
 			vbus = port->tcpc->get_vbus(port->tcpc);
-			if (vbus)
+			if (vbus) {
 				_tcpm_pd_vbus_on(port);
-			else
+			} else {
 				_tcpm_pd_vbus_off(port);
+				/*
+				 * When TCPC does not support detecting vsafe0v voltage level,
+				 * treat vbus absent as vsafe0v. Else invoke is_vbus_vsafe0v
+				 * to see if vbus has discharge to VSAFE0V.
+				 */
+				if (!port->tcpc->is_vbus_vsafe0v ||
+				    port->tcpc->is_vbus_vsafe0v(port->tcpc))
+					_tcpm_pd_vbus_vsafe0v(port);
+			}
 		}
 		if (events & TCPM_CC_EVENT) {
 			enum typec_cc_status cc1, cc2;