Message-Id: <20260107144507.46491-1-Ashish.Yadav@infineon.com>
Date: Wed,  7 Jan 2026 20:15:06 +0530
From: ASHISH YADAV <ashishyadav78@...il.com>
To: Guenter Roeck <linux@...ck-us.net>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Cc: linux-hwmon@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	ASHISH YADAV <Ashish.Yadav@...ineon.com>
Subject: [PATCH v2 1/2] hwmon:(pmbus/tda38740a) TDA38740A Voltage Regulator Driver

Add the pmbus driver for the Infineon TDA38740A/TDA38725A
DC-DC voltage regulator.

Signed-off-by: ASHISH YADAV <Ashish.Yadav@...ineon.com>
---
Changes in v2:
 - Review comments address.
 - Another Patch for Devicetree binding submitted for Driver
   Documentation.
---
 drivers/hwmon/pmbus/Kconfig     |  16 +++
 drivers/hwmon/pmbus/Makefile    |   1 +
 drivers/hwmon/pmbus/tda38740a.c | 203 ++++++++++++++++++++++++++++++++
 3 files changed, 220 insertions(+)
 create mode 100644 drivers/hwmon/pmbus/tda38740a.c

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index f3fb94cebf1a..e7d7ff1b57df 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -602,6 +602,22 @@ config SENSORS_TDA38640_REGULATOR
 	  If you say yes here you get regulator support for Infineon
 	  TDA38640 as regulator.
 
+config SENSORS_TDA38740A
+	tristate "Infineon TDA38740A"
+	help
+	  If you say yes here you get hardware monitoring support for Infineon
+	  TDA38740A/25A.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called tda38740a.
+
+config SENSORS_TDA38740A_REGULATOR
+	bool "Regulator support for TDA38740A and compatibles"
+	depends on SENSORS_TDA38740A && REGULATOR
+	help
+	  If you say yes here you get regulator support for Infineon
+	  TDA38740A/25A as regulator.
+
 config SENSORS_TPS25990
 	tristate "TI TPS25990"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 349a89b6d92e..f422c80cf3d8 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_SENSORS_PXE1610)	+= pxe1610.o
 obj-$(CONFIG_SENSORS_Q54SJ108A2)	+= q54sj108a2.o
 obj-$(CONFIG_SENSORS_STPDDC60)	+= stpddc60.o
 obj-$(CONFIG_SENSORS_TDA38640)	+= tda38640.o
+obj-$(CONFIG_SENSORS_TDA38740A)  += tda38740a.o
 obj-$(CONFIG_SENSORS_TPS25990)	+= tps25990.o
 obj-$(CONFIG_SENSORS_TPS40422)	+= tps40422.o
 obj-$(CONFIG_SENSORS_TPS53679)	+= tps53679.o
diff --git a/drivers/hwmon/pmbus/tda38740a.c b/drivers/hwmon/pmbus/tda38740a.c
new file mode 100644
index 000000000000..b31e1b5c6916
--- /dev/null
+++ b/drivers/hwmon/pmbus/tda38740a.c
@@ -0,0 +1,203 @@
+// SPDX-License-Identifier: GPL-2.0+
+/**
+ * Hardware monitoring driver for Infineon Integrated-pol-voltage-regulators
+ * Driver for TDA38725A and TDA38740A
+ *
+ * Copyright (c) 2025 Infineon Technologies
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/driver.h>
+#include "pmbus.h"
+
+#define TDA38725A_IC_DEVICE_ID "\xA9"
+#define TDA38740A_IC_DEVICE_ID "\xA8"
+
+static const struct i2c_device_id tda38740a_id[];
+
+enum chips { tda38725a, tda38740a };
+
+struct tda38740a_data {
+	enum chips id;
+	struct pmbus_driver_info info;
+	u32 vout_voltage_multiplier[2];
+};
+
+#define to_tda38740a_data(x) container_of(x, struct tda38740a_data, info)
+
+static const struct regulator_desc __maybe_unused tda38740a_reg_desc[] = {
+	PMBUS_REGULATOR("vout", 0),
+};
+
+static int tda38740a_read_word_data(struct i2c_client *client, int page,
+				    int phase, int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	const struct tda38740a_data *data = to_tda38740a_data(info);
+	int ret;
+
+	/* Virtual PMBUS Command not supported */
+	if (reg >= PMBUS_VIRT_BASE)
+		return -ENXIO;
+
+	switch (reg) {
+	case PMBUS_READ_VOUT:
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		if (ret < 0)
+			return ret;
+		ret = ((ret * data->vout_voltage_multiplier[0]) /
+		       data->vout_voltage_multiplier[1]);
+		break;
+	case PMBUS_VOUT_COMMAND:
+	case PMBUS_VOUT_MAX:
+	case PMBUS_VOUT_MARGIN_HIGH:
+	case PMBUS_VOUT_MARGIN_LOW:
+	case PMBUS_VOUT_TRANSITION_RATE:
+	case PMBUS_VOUT_DROOP:
+	case PMBUS_VOUT_SCALE_LOOP:
+	case PMBUS_VOUT_OV_FAULT_LIMIT:
+	case PMBUS_VOUT_UV_FAULT_LIMIT:
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+	case PMBUS_OT_FAULT_LIMIT:
+	case PMBUS_OT_WARN_LIMIT:
+	case PMBUS_VIN_OV_FAULT_LIMIT:
+	case PMBUS_STATUS_WORD:
+	case PMBUS_READ_VIN:
+	case PMBUS_READ_IIN:
+	case PMBUS_READ_IOUT:
+	case PMBUS_READ_TEMPERATURE_1:
+	case PMBUS_READ_POUT:
+	case PMBUS_READ_PIN:
+		ret = pmbus_read_word_data(client, page, phase, reg);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+	return ret;
+}
+
+static struct pmbus_driver_info tda38740a_info[] = {
+	[tda38740a] = {
+		.pages = 1,
+		.read_word_data = tda38740a_read_word_data,
+		.format[PSC_VOLTAGE_IN] = linear,
+		.format[PSC_VOLTAGE_OUT] = linear,
+		.format[PSC_CURRENT_OUT] = linear,
+		.format[PSC_CURRENT_IN] = linear,
+		.format[PSC_POWER] = linear,
+		.format[PSC_TEMPERATURE] = linear,
+
+		.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+			| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
+			| PMBUS_HAVE_IIN
+			| PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+			| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+			| PMBUS_HAVE_POUT | PMBUS_HAVE_PIN,
+#if IS_ENABLED(CONFIG_SENSORS_TDA38740A_REGULATOR)
+		.num_regulators = 1,
+		.reg_desc = tda38740a_reg_desc,
+#endif
+	},
+};
+
+static int tda38740a_get_device_id(struct i2c_client *client)
+{
+	u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
+	enum chips id;
+	int status;
+
+	status = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID,
+					   device_id);
+	if (status < 0 || status > 1) {
+		dev_err(&client->dev,
+			"Failed to read Device ID or unexpected/unsupported Device\n");
+		return -ENODEV;
+	}
+
+	if (!memcmp(TDA38725A_IC_DEVICE_ID, device_id, 1)) {
+		id = tda38725a;
+	} else if (!memcmp(TDA38740A_IC_DEVICE_ID, device_id, 1)) {
+		id = tda38740a;
+	} else {
+		dev_err(&client->dev, "Unsupported device with ID:%s\n",
+			device_id);
+		return -ENODEV;
+	}
+
+	return id;
+}
+
+static int tda38740a_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct tda38740a_data *data;
+	int chip_id;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE |
+					     I2C_FUNC_SMBUS_BYTE_DATA |
+					     I2C_FUNC_SMBUS_WORD_DATA |
+					     I2C_FUNC_SMBUS_BLOCK_DATA))
+		return -ENODEV;
+
+	chip_id = tda38740a_get_device_id(client);
+	if (chip_id < 0)
+		return chip_id;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->id = chip_id;
+	memcpy(&data->info, &tda38740a_info[chip_id], sizeof(data->info));
+
+	if (!of_property_read_u32_array(client->dev.of_node, "infineon,vout-voltage-multiplier",
+					data->vout_voltage_multiplier,
+		    ARRAY_SIZE(data->vout_voltage_multiplier))) {
+		dev_info(&client->dev,
+			 "vout-voltage-multiplier from Device Tree:%d %d\n",
+			 data->vout_voltage_multiplier[0],
+			 data->vout_voltage_multiplier[1]);
+	} else {
+		dev_info(&client->dev,
+			 "vout-voltage-multiplier not available from Device Tree,using default values");
+		data->vout_voltage_multiplier[0] = 0x01;
+		data->vout_voltage_multiplier[1] = 0x01;
+	}
+
+	return pmbus_do_probe(client, &data->info);
+}
+
+static const struct i2c_device_id tda38740a_id[] = { { "tda38725a", tda38725a },
+						     { "tda38740a", tda38740a },
+						     {} };
+
+MODULE_DEVICE_TABLE(i2c, tda38740a_id);
+
+static const struct of_device_id __maybe_unused tda38740a_of_match[] = {
+	{ .compatible = "infineon,tda38725a", .data = (void *)tda38725a },
+	{ .compatible = "infineon,tda38740a", .data = (void *)tda38740a },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, tda38740a_of_match);
+
+static struct i2c_driver tda38740a_driver = {
+	.driver = {
+		.name = "tda38740a",
+		.of_match_table = of_match_ptr(tda38740a_of_match),
+	},
+	.probe = tda38740a_probe,
+	.id_table = tda38740a_id,
+};
+
+module_i2c_driver(tda38740a_driver);
+
+MODULE_AUTHOR("Ashish Yadav <Ashish.Yadav@...ineon.com>");
+MODULE_DESCRIPTION("PMBus driver for Infineon TDA38725A/40A IPOL");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
-- 
2.39.5

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