linux-kernel - [PATCH 6/6] usb: typec: tcpm/tcpci_maxim: deprecate WAR for setting charger mode

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Message-Id: <20251123-max77759-charger-v1-6-6b2e4b8f7f54@google.com>
Date: Sun, 23 Nov 2025 08:35:53 +0000
From: Amit Sunil Dhamne via B4 Relay <devnull+amitsd.google.com@...nel.org>
To: Sebastian Reichel <sre@...nel.org>, Rob Herring <robh@...nel.org>, 
 Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, 
 André Draszik <andre.draszik@...aro.org>, 
 Lee Jones <lee@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Badhri Jagan Sridharan <badhri@...gle.com>, 
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Peter Griffin <peter.griffin@...aro.org>, 
 Tudor Ambarus <tudor.ambarus@...aro.org>, 
 Alim Akhtar <alim.akhtar@...sung.com>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
 devicetree@...r.kernel.org, linux-usb@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org, 
 RD Babiera <rdbabiera@...gle.com>, Kyle Tso <kyletso@...gle.com>, 
 Amit Sunil Dhamne <amitsd@...gle.com>
Subject: [PATCH 6/6] usb: typec: tcpm/tcpci_maxim: deprecate WAR for
 setting charger mode

From: Amit Sunil Dhamne <amitsd@...gle.com>

TCPCI maxim driver directly writes to the charger's register space to
set charger mode depending on the power role. As MAX77759 chg driver
exists, this WAR is not required.

Instead, use a regulator interface to set OTG Boost mode.

Signed-off-by: Amit Sunil Dhamne <amitsd@...gle.com>
---
 drivers/usb/typec/tcpm/tcpci_maxim.h      |  1 +
 drivers/usb/typec/tcpm/tcpci_maxim_core.c | 48 +++++++++++++++++++++----------
 2 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpci_maxim.h b/drivers/usb/typec/tcpm/tcpci_maxim.h
index b33540a42a95..6c82a61efe46 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim.h
+++ b/drivers/usb/typec/tcpm/tcpci_maxim.h
@@ -60,6 +60,7 @@ struct max_tcpci_chip {
 	struct tcpm_port *port;
 	enum contamiant_state contaminant_state;
 	bool veto_vconn_swap;
+	struct regulator *otg_reg;
 };
 
 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 19f638650796..6d819a762fa1 100644
--- a/drivers/usb/typec/tcpm/tcpci_maxim_core.c
+++ b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/usb/pd.h>
 #include <linux/usb/tcpci.h>
 #include <linux/usb/tcpm.h>
@@ -202,32 +203,49 @@ static void process_rx(struct max_tcpci_chip *chip, u16 status)
 	tcpm_pd_receive(chip->port, &msg, rx_type);
 }
 
+static int get_otg_regulator_handle(struct max_tcpci_chip *chip)
+{
+	if (IS_ERR_OR_NULL(chip->otg_reg)) {
+		chip->otg_reg = devm_regulator_get_exclusive(chip->dev,
+							     "otg-vbus");
+		if (IS_ERR_OR_NULL(chip->otg_reg)) {
+			dev_err(chip->dev,
+				"Failed to get otg regulator handle");
+			return -ENODEV;
+		}
+	}
+
+	return 0;
+}
+
 static int max_tcpci_set_vbus(struct tcpci *tcpci, struct tcpci_data *tdata, bool source, bool sink)
 {
 	struct max_tcpci_chip *chip = tdata_to_max_tcpci(tdata);
-	u8 buffer_source[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_SOURCE};
-	u8 buffer_sink[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_SINK};
-	u8 buffer_none[2] = {MAX_BUCK_BOOST_OP, MAX_BUCK_BOOST_OFF};
-	struct i2c_client *i2c = chip->client;
 	int ret;
 
-	struct i2c_msg msgs[] = {
-		{
-			.addr = MAX_BUCK_BOOST_SID,
-			.flags = i2c->flags & I2C_M_TEN,
-			.len = 2,
-			.buf = source ? buffer_source : sink ? buffer_sink : buffer_none,
-		},
-	};
-
 	if (source && sink) {
 		dev_err(chip->dev, "Both source and sink set\n");
 		return -EINVAL;
 	}
 
-	ret = i2c_transfer(i2c->adapter, msgs, 1);
+	ret = get_otg_regulator_handle(chip);
+	if (ret) {
+		/*
+		 * Regulator is not necessary for sink only applications. Return
+		 * success in cases where sink mode is being modified.
+		 */
+		return source ? ret : 1;
+	}
+
+	if (source) {
+		if (!regulator_is_enabled(chip->otg_reg))
+			ret = regulator_enable(chip->otg_reg);
+	} else {
+		if (regulator_is_enabled(chip->otg_reg))
+			ret = regulator_disable(chip->otg_reg);
+	}
 
-	return  ret < 0 ? ret : 1;
+	return ret < 0 ? ret : 1;
 }
 
 static void process_power_status(struct max_tcpci_chip *chip)

-- 
2.52.0.rc2.455.g230fcf2819-goog