hwmon: (pmbus/lt3074) add support for lt3074

Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml

@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/pmbus/adi,lt3074.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LT3074 voltage regulator
+
+maintainers:
+  - Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
+
+description: |
+  The LT3074 is a low voltage, ultra-low noise and ultra-fast transient
+  response linear regulator. It allows telemetry for input/output voltage,
+  output current and temperature through the PMBus serial interface.
+
+  Datasheet:
+    https://www.analog.com/en/products/lt3074.html
+
+allOf:
+  - $ref: /schemas/regulator/regulator.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,lt3074
+
+  reg:
+    maxItems: 1
+
+  regulators:
+    type: object
+    description: |
+      list of regulators provided by this controller.
+
+    properties:
+      vout:
+        $ref: /schemas/regulator/regulator.yaml#
+        type: object
+
+        unevaluatedProperties: false
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        regulator@6d {
+            compatible = "adi,lt3074";
+            reg = <0x6d>;
+
+            regulators {
+                vout0 {
+                    regulator-name = "vout";
+                    regulator-max-microvolt = <1250000>;
+                    regulator-min-microvolt = <1150000>;
+                };
+            };
+        };
+    };

Documentation/hwmon/index.rst

@@ -115,6 +115,7 @@ Hardware Monitoring Kernel Drivers
    lm95234
    lm95245
    lochnagar
+   lt3074
    lt7182s
    ltc2992
    ltc2945

Documentation/hwmon/lt3074.rst

@@ -0,0 +1,72 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver lt3074
+====================
+
+Supported chips:
+
+  * Analog Devices LT3074
+
+    Prefix: 'lt3074'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/en/products/lt3074.html
+
+Authors: Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices LT3074 Linear
+Regulator with PMBus interface.
+
+The LT3074 is a low voltage, ultra-low noise and ultra-fast transient
+response linear regulator with PMBus serial interface. PMBus telemetry
+feature provides information regarding the output voltage and current,
+input voltage, bias voltage and die temperature.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate
+the devices explicitly. Please see Documentation/i2c/instantiating-devices.rst
+for details.
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+Sysfs entries
+-------------
+
+======================= =======================================================
+in1_label		"vin"
+in1_input		Measured input voltage
+in1_max			Input overvoltage warning limit
+in1_max_alarm		Input overvoltage warning status
+in1_min			Input undervoltage warning limit
+in1_min_alarm		Input undervoltage warning status
+in2_label		"vmon"
+in2_input		Measured bias voltage
+in2_max			Bias overvoltage warning limit
+in2_min			Bias undervoltage warning limit
+in3_label		"vout1"
+in3_input		Measured output voltage
+in3_max			Output overvoltage warning limit
+in3_max_alarm		Output overvoltage warning status
+in3_min			Output undervoltage warning limit
+in3_min_alarm		Output undervoltage warning status
+curr1_label		"iout1"
+curr1_input		Measured output current.
+curr1_crit		Output overcurrent fault limit
+curr1_crit_alarm	Output overcurrent fault status
+temp1_input		Measured temperature
+temp1_max		Maximum temperature limit
+temp1_max_alarm		Overtemperature warning status
+======================= =======================================================

MAINTAINERS

@@ -12626,6 +12626,15 @@ L:	linux-scsi@vger.kernel.org
 S:	Maintained
 F:	drivers/scsi/sym53c8xx_2/
 
+LT3074 HARDWARE MONITOR DRIVER
+M:	Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Supported
+W:	https://ez.analog.com/linux-software-drivers
+F:	Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml
+F:	Documentation/hwmon/lt3074.rst
+F:	drivers/hwmon/pmbus/lt3074.c
+
 LTC1660 DAC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>
 L:	linux-iio@vger.kernel.org

drivers/hwmon/Kconfig.adi

@@ -26,6 +26,8 @@ config HWMON_ALL_ADI_DRIVERS
 	imply SENSORS_ADT7462
 	imply SENSORS_ADT7470
 	imply SENSORS_ADT7475
+	imply SENSORS_LT3074
+	imply SENSORS_LT3074_REGULATOR
 	imply SENSORS_LTC2945
 	imply SENSORS_LTC2947_I2C
 	imply SENSORS_LTC2947_SPI

drivers/hwmon/pmbus/Kconfig

@@ -200,6 +200,24 @@ config SENSORS_LM25066_REGULATOR
 	  If you say yes here you get regulator support for National
 	  Semiconductor LM25066, LM5064, and LM5066.
 
+config SENSORS_LT3074
+	tristate "Analog Devices LT3074"
+	help
+	  If you say yes here you get hardware monitoring support for Analog
+	  Devices LT3074.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called lt3074.
+
+config SENSORS_LT3074_REGULATOR
+	tristate "Regulator support for LT3074"
+	depends on SENSORS_LT3074 && REGULATOR
+	help
+	  If you say yes here you get regulator support for Analog Devices
+	  LT3074. The LT3074 is a low voltage, ultralow noise, high PSRR,
+	  dropout linear regulator. The device supplies up to 3A with a
+	  typical dropout voltage of 45mV.
+
 config SENSORS_LT7182S
 	tristate "Analog Devices LT7182S"
 	help

drivers/hwmon/pmbus/Makefile

@@ -22,6 +22,7 @@ obj-$(CONFIG_SENSORS_IR38064)	+= ir38064.o
 obj-$(CONFIG_SENSORS_IRPS5401)	+= irps5401.o
 obj-$(CONFIG_SENSORS_ISL68137)	+= isl68137.o
 obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
+obj-$(CONFIG_SENSORS_LT3074)	+= lt3074.o
 obj-$(CONFIG_SENSORS_LT7182S)	+= lt7182s.o
 obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o

drivers/hwmon/pmbus/lt3074.c

@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hardware monitoring driver for Analog Devices LT3074
+ *
+ * Copyright (C) 2025 Analog Devices, Inc.
+ */
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+
+#include "pmbus.h"
+
+#define LT3074_MFR_READ_VBIAS			0xc6
+#define LT3074_MFR_BIAS_OV_WARN_LIMIT		0xc7
+#define LT3074_MFR_BIAS_UV_WARN_LIMIT		0xc8
+#define LT3074_MFR_SPECIAL_ID			0xe7
+
+#define LT3074_SPECIAL_ID_VALUE			0x1c1d
+
+static const struct regulator_desc __maybe_unused lt3074_reg_desc[] = {
+	PMBUS_REGULATOR("vout", 0),
+};
+
+static int lt3074_read_word_data(struct i2c_client *client, int page,
+				 int phase, int reg)
+{
+	switch (reg) {
+	case PMBUS_VIRT_READ_VMON:
+		return pmbus_read_word_data(client, page, phase,
+					   LT3074_MFR_READ_VBIAS);
+	case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
+		return pmbus_read_word_data(client, page, phase,
+					   LT3074_MFR_BIAS_UV_WARN_LIMIT);
+	case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
+		return pmbus_read_word_data(client, page, phase,
+					   LT3074_MFR_BIAS_OV_WARN_LIMIT);
+	default:
+		return -ENODATA;
+	}
+}
+
+static int lt3074_write_word_data(struct i2c_client *client, int page,
+				  int reg, u16 word)
+{
+	switch (reg) {
+	case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
+		return pmbus_write_word_data(client, 0,
+					    LT3074_MFR_BIAS_UV_WARN_LIMIT,
+					    word);
+	case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
+		return pmbus_write_word_data(client, 0,
+					    LT3074_MFR_BIAS_OV_WARN_LIMIT,
+					    word);
+	default:
+		return -ENODATA;
+	}
+}
+
+static struct pmbus_driver_info lt3074_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+		   PMBUS_HAVE_TEMP | PMBUS_HAVE_VMON |
+		   PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
+		   PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP,
+	.read_word_data = lt3074_read_word_data,
+	.write_word_data = lt3074_write_word_data,
+#if IS_ENABLED(CONFIG_SENSORS_LT3074_REGULATOR)
+	.num_regulators = 1,
+	.reg_desc = lt3074_reg_desc,
+#endif
+};
+
+static int lt3074_probe(struct i2c_client *client)
+{
+	int ret;
+	struct device *dev = &client->dev;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -ENODEV;
+
+	ret = i2c_smbus_read_word_data(client, LT3074_MFR_SPECIAL_ID);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to read ID\n");
+
+	if (ret != LT3074_SPECIAL_ID_VALUE)
+		return dev_err_probe(dev, -ENODEV, "ID mismatch\n");
+
+	return pmbus_do_probe(client, &lt3074_info);
+}
+
+static const struct i2c_device_id lt3074_id[] = {
+	{ "lt3074", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, lt3074_id);
+
+static const struct of_device_id __maybe_unused lt3074_of_match[] = {
+	{ .compatible = "adi,lt3074" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, lt3074_of_match);
+
+static struct i2c_driver lt3074_driver = {
+	.driver = {
+		.name = "lt3074",
+		.of_match_table = of_match_ptr(lt3074_of_match),
+	},
+	.probe = lt3074_probe,
+	.id_table = lt3074_id,
+};
+module_i2c_driver(lt3074_driver);
+
+MODULE_AUTHOR("Cedric Encarnacion <cedricjustine.encarnacion@analog.com>");
+MODULE_DESCRIPTION("PMBus driver for Analog Devices LT3074");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");