staging: typec: tcpm: Check for Rp for tPDDebounce

According the spec, the following is the conditions for exiting Try.SNK
state:
"The port shall wait for tDRPTry and only then begin monitoring the CC1 and
CC2 pins for the SNK.Rp state. The port shall then transition to
Attached.SNK when the SNK.Rp state is detected on exactly one of the CC1
or CC2 pins for at least tPDDebounce and V BUS is detected. Alternatively,
the port shall transition to TryWait.SRC if SNK.Rp state is not detected
for tPDDebounce."
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/typec/tcpm.c

@@ -105,6 +105,8 @@
 						\
 	S(SNK_TRY),				\
 	S(SNK_TRY_WAIT),			\
+	S(SNK_TRY_WAIT_DEBOUNCE),               \
+	S(SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS),    \
 	S(SRC_TRYWAIT),				\
 	S(SRC_TRYWAIT_DEBOUNCE),		\
 	S(SRC_TRYWAIT_UNATTACHED),		\
@@ -2207,18 +2209,24 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, SNK_TRY_WAIT, PD_T_DRP_TRY);
 		break;
 	case SNK_TRY_WAIT:
+		if (tcpm_port_is_sink(port)) {
+			tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE, 0);
+		} else {
+			tcpm_set_state(port, SRC_TRYWAIT, 0);
+			port->max_wait = 0;
+		}
+		break;
+	case SNK_TRY_WAIT_DEBOUNCE:
+		tcpm_set_state(port, SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS,
+			       PD_T_PD_DEBOUNCE);
+		break;
+	case SNK_TRY_WAIT_DEBOUNCE_CHECK_VBUS:
 		if (port->vbus_present && tcpm_port_is_sink(port)) {
 			tcpm_set_state(port, SNK_ATTACHED, 0);
-			break;
-		}
-		if (!tcpm_port_is_sink(port)) {
-			tcpm_set_state(port, SRC_TRYWAIT,
-				       PD_T_PD_DEBOUNCE);
+		} else {
+			tcpm_set_state(port, SRC_TRYWAIT, 0);
 			port->max_wait = 0;
-			break;
 		}
-		/* No vbus, cc state is sink or open */
-		tcpm_set_state(port, SRC_TRYWAIT_UNATTACHED, PD_T_DRP_TRYWAIT);
 		break;
 	case SRC_TRYWAIT:
 		tcpm_set_cc(port, tcpm_rp_cc(port));
@@ -2926,20 +2934,12 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
 		if (port->vbus_present || !tcpm_port_is_source(port))
 			tcpm_set_state(port, SRC_TRYWAIT, 0);
 		break;
-	case SNK_TRY_WAIT:
-		if (port->vbus_present && tcpm_port_is_sink(port)) {
-			tcpm_set_state(port, SNK_ATTACHED, 0);
-			break;
+	case SNK_TRY_WAIT_DEBOUNCE:
+		if (!tcpm_port_is_sink(port)) {
+			port->max_wait = 0;
+			tcpm_set_state(port, SRC_TRYWAIT, 0);
 		}
-		if (!tcpm_port_is_sink(port))
-			new_state = SRC_TRYWAIT;
-		else
-			new_state = SRC_TRYWAIT_UNATTACHED;
-
-		if (new_state != port->delayed_state)
-			tcpm_set_state(port, SNK_TRY_WAIT, 0);
 		break;
-
 	case SRC_TRY:
 		if (tcpm_port_is_source(port))
 			tcpm_set_state(port, SRC_TRY_DEBOUNCE, 0);
@@ -2979,8 +2979,6 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
 
 static void _tcpm_pd_vbus_on(struct tcpm_port *port)
 {
-	enum tcpm_state new_state;
-
 	tcpm_log_force(port, "VBUS on");
 	port->vbus_present = true;
 	switch (port->state) {
@@ -3016,18 +3014,8 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
 	case SRC_TRYWAIT_DEBOUNCE:
 		tcpm_set_state(port, SRC_TRYWAIT, 0);
 		break;
-	case SNK_TRY_WAIT:
-		if (tcpm_port_is_sink(port)) {
-			tcpm_set_state(port, SNK_ATTACHED, 0);
-			break;
-		}
-		if (!tcpm_port_is_sink(port))
-			new_state = SRC_TRYWAIT;
-		else
-			new_state = SRC_TRYWAIT_UNATTACHED;
-
-		if (new_state != port->delayed_state)
-			tcpm_set_state(port, SNK_TRY_WAIT, 0);
+	case SNK_TRY_WAIT_DEBOUNCE:
+		/* Do nothing, waiting for PD_DEBOUNCE to do be done */
 		break;
 	case SNK_TRYWAIT:
 		tcpm_set_state(port, SNK_TRYWAIT_VBUS, 0);
@@ -3040,8 +3028,6 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
 
 static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 {
-	enum tcpm_state new_state;
-
 	tcpm_log_force(port, "VBUS off");
 	port->vbus_present = false;
 	port->vbus_never_low = false;
@@ -3063,14 +3049,8 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 		if (tcpm_port_is_source(port))
 			tcpm_set_state(port, SRC_TRYWAIT_DEBOUNCE, 0);
 		break;
-	case SNK_TRY_WAIT:
-		if (!tcpm_port_is_sink(port))
-			new_state = SRC_TRYWAIT;
-		else
-			new_state = SRC_TRYWAIT_UNATTACHED;
-
-		if (new_state != port->delayed_state)
-			tcpm_set_state(port, SNK_TRY_WAIT, 0);
+	case SNK_TRY_WAIT_DEBOUNCE:
+		/* Do nothing, waiting for PD_DEBOUNCE to do be done */
 		break;
 	case SNK_TRYWAIT_VBUS:
 		tcpm_set_state(port, SNK_TRYWAIT, 0);