usb: typec: tcpci: add attempt_vconn_swap_discovery callback

Add attempt_vconn_swap_discovery callback to determine whether the TCPM
should perform a Vconn swap following Discover Identity on SOP. The tcpci
will return false unless chip level drivers implement the callback.

Maxim based TCPCs will return true unless the last connection resulted in
a Vconn Over Current Fault, which may be the result of the Vconn swap. In
addition to the port resetting, the TCPCI will veto the next Vconn swap
from occurring.

Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20240108191620.987785-21-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 28 insertions, 1 deletions

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index 8ea4ed159a13..40c7b6224c74 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -594,6 +594,16 @@ static bool tcpci_cable_comm_capable(struct tcpc_dev *tcpc)
 	return tcpci->data->cable_comm_capable;
 }
 
+static bool tcpci_attempt_vconn_swap_discovery(struct tcpc_dev *tcpc)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
+
+	if (tcpci->data->attempt_vconn_swap_discovery)
+		return tcpci->data->attempt_vconn_swap_discovery(tcpci, tcpci->data);
+
+	return false;
+}
+
 static int tcpci_init(struct tcpc_dev *tcpc)
 {
 	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
@@ -804,6 +814,7 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
 	tcpci->tcpc.frs_sourcing_vbus = tcpci_frs_sourcing_vbus;
 	tcpci->tcpc.set_partner_usb_comm_capable = tcpci_set_partner_usb_comm_capable;
 	tcpci->tcpc.cable_comm_capable = tcpci_cable_comm_capable;
+	tcpci->tcpc.attempt_vconn_swap_discovery = tcpci_attempt_vconn_swap_discovery;
 
 	if (tcpci->data->check_contaminant)
 		tcpci->tcpc.check_contaminant = tcpci_check_contaminant;
diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.h b/drivers/usb/typec/tcpm/tcpci_maxim.h
index 2c1c4d161b0d..78ff3b73ee7e 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim.h
+++ b/drivers/usb/typec/tcpm/tcpci_maxim.h
@@ -62,6 +62,7 @@ struct max_tcpci_chip {
 	struct i2c_client *client;
 	struct tcpm_port *port;
 	enum contamiant_state contaminant_state;
+	bool veto_vconn_swap;
 };
 
 static inline int max_tcpci_read16(struct max_tcpci_chip *chip, unsigned int reg, u16 *val)
diff --git a/drivers/usb/typec/tcpm/tcpci_maxim_core.c b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
index f9f838df43f7..eec3bcec119c 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim_core.c
+++ b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
@@ -323,8 +323,10 @@ static irqreturn_t _max_tcpci_irq(struct max_tcpci_chip *chip, u16 status)
 		if (ret < 0)
 			return ret;
 
-		if (reg_status & TCPC_FAULT_STATUS_VCONN_OC)
+		if (reg_status & TCPC_FAULT_STATUS_VCONN_OC) {
+			chip->veto_vconn_swap = true;
 			tcpm_port_error_recovery(chip->port);
+		}
 	}
 
 	if (status & TCPC_ALERT_EXTND) {
@@ -458,6 +460,18 @@ static void max_tcpci_check_contaminant(struct tcpci *tcpci, struct tcpci_data *
 		tcpm_port_clean(chip->port);
 }
 
+static bool max_tcpci_attempt_vconn_swap_discovery(struct tcpci *tcpci, struct tcpci_data *tdata)
+{
+	struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
+
+	if (chip->veto_vconn_swap) {
+		chip->veto_vconn_swap = false;
+		return false;
+	}
+
+	return true;
+}
+
 static int max_tcpci_probe(struct i2c_client *client)
 {
 	int ret;
@@ -493,6 +507,7 @@ static int max_tcpci_probe(struct i2c_client *client)
 	chip->data.set_partner_usb_comm_capable = max_tcpci_set_partner_usb_comm_capable;
 	chip->data.check_contaminant = max_tcpci_check_contaminant;
 	chip->data.cable_comm_capable = true;
+	chip->data.attempt_vconn_swap_discovery = max_tcpci_attempt_vconn_swap_discovery;
 
 	max_tcpci_init_regs(chip);
 	chip->tcpci = tcpci_register_port(chip->dev, &chip->data);