linux-kernel - [PATCH v1 2/2] usb: typec: tcpci: add vconn over current fault handling to maxim

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Message-ID: <20231121203845.170234-6-rdbabiera@google.com>
Date:   Tue, 21 Nov 2023 20:38:48 +0000
From:   RD Babiera <rdbabiera@...gle.com>
To:     linux@...ck-us.net, heikki.krogerus@...ux.intel.com,
        gregkh@...uxfoundation.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        badhri@...gle.com, RD Babiera <rdbabiera@...gle.com>
Subject: [PATCH v1 2/2] usb: typec: tcpci: add vconn over current fault
 handling to maxim_core

Add TCPC_FAULT_STATUS_VCONN_OC constant and corresponding mask definition.
Maxim TCPC is capable of detecting VConn over current faults, so add
fault to alert mask. When a Vconn over current fault is triggered, put the
port in an error recovery state via tcpm_port_error_recovery.

Signed-off-by: RD Babiera <rdbabiera@...gle.com>
---
 drivers/usb/typec/tcpm/tcpci_maxim_core.c | 20 +++++++++++++++++++-
 include/linux/usb/tcpci.h                 |  5 ++++-
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpci_maxim_core.c b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
index 9454b12a073c..7fb966fd639b 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim_core.c
+++ b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
@@ -92,11 +92,16 @@ static void max_tcpci_init_regs(struct max_tcpci_chip *chip)
 		return;
 	}
 
+	/* Vconn Over Current Protection */
+	ret = max_tcpci_write8(chip, TCPC_FAULT_STATUS_MASK, TCPC_FAULT_STATUS_MASK_VCONN_OC);
+	if (ret < 0)
+		return;
+
 	alert_mask = TCPC_ALERT_TX_SUCCESS | TCPC_ALERT_TX_DISCARDED | TCPC_ALERT_TX_FAILED |
 		TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_RX_STATUS | TCPC_ALERT_CC_STATUS |
 		TCPC_ALERT_VBUS_DISCNCT | TCPC_ALERT_RX_BUF_OVF | TCPC_ALERT_POWER_STATUS |
 		/* Enable Extended alert for detecting Fast Role Swap Signal */
-		TCPC_ALERT_EXTND | TCPC_ALERT_EXTENDED_STATUS;
+		TCPC_ALERT_EXTND | TCPC_ALERT_EXTENDED_STATUS | TCPC_ALERT_FAULT;
 
 	ret = max_tcpci_write16(chip, TCPC_ALERT_MASK, alert_mask);
 	if (ret < 0) {
@@ -295,6 +300,19 @@ static irqreturn_t _max_tcpci_irq(struct max_tcpci_chip *chip, u16 status)
 		}
 	}
 
+	if (status & TCPC_ALERT_FAULT) {
+		ret = max_tcpci_read8(chip, TCPC_FAULT_STATUS, &reg_status);
+		if (ret < 0)
+			return ret;
+
+		ret = max_tcpci_write8(chip, TCPC_FAULT_STATUS, reg_status);
+		if (ret < 0)
+			return ret;
+
+		if (reg_status & TCPC_FAULT_STATUS_VCONN_OC)
+			tcpm_port_error_recovery(chip->port);
+	}
+
 	if (status & TCPC_ALERT_EXTND) {
 		ret = max_tcpci_read8(chip, TCPC_ALERT_EXTENDED, &reg_status);
 		if (ret < 0)
diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
index 83376473ac76..467e8045e9f8 100644
--- a/include/linux/usb/tcpci.h
+++ b/include/linux/usb/tcpci.h
@@ -36,7 +36,9 @@
 
 #define TCPC_ALERT_MASK			0x12
 #define TCPC_POWER_STATUS_MASK		0x14
-#define TCPC_FAULT_STATUS_MASK		0x15
+
+#define TCPC_FAULT_STATUS_MASK			0x15
+#define TCPC_FAULT_STATUS_MASK_VCONN_OC		BIT(1)
 
 #define TCPC_EXTENDED_STATUS_MASK		0x16
 #define TCPC_EXTENDED_STATUS_MASK_VSAFE0V	BIT(0)
@@ -104,6 +106,7 @@
 
 #define TCPC_FAULT_STATUS		0x1f
 #define TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT BIT(7)
+#define TCPC_FAULT_STATUS_VCONN_OC	BIT(1)
 
 #define TCPC_ALERT_EXTENDED		0x21
 
-- 
2.43.0.rc1.413.gea7ed67945-goog