Add hardware monitoring and regulator support for LT3074. The LT3074 is an
ultrafast, ultralow noise 3A, 5.5V dropout linear regulator. The PMBus
serial interface allows telemetry for input/output voltage, bias voltage,
output current, and die temperature.
Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@xxxxxxxxxx>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/lt3074.rst | 72 ++++++++++++++++++++++++
drivers/hwmon/pmbus/Kconfig | 18 ++++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/lt3074.c | 122 +++++++++++++++++++++++++++++++++++++++++
5 files changed, 214 insertions(+)
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index b1ea445479b0..5be511506d50 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -122,6 +122,7 @@ Hardware Monitoring Kernel Drivers
lm95234
lm95245
lochnagar
+ lt3074
lt7182s
ltc2992
ltc2945
diff --git a/Documentation/hwmon/lt3074.rst b/Documentation/hwmon/lt3074.rst
new file mode 100644
index 000000000000..234f369153cf
--- /dev/null
+++ b/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@xxxxxxxxxx>
+
+
+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
+======================= =======================================================
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 419469f40ba0..32564a64e225 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -209,6 +209,24 @@ 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
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index c7eb7739b7f8..5ef388c10581 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/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
diff --git a/drivers/hwmon/pmbus/lt3074.c b/drivers/hwmon/pmbus/lt3074.c
new file mode 100644
index 000000000000..430e3a0c0a5f
--- /dev/null
+++ b/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_ONE("vout"),
+};
+
+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, <3074_info);
+}
+
+static const struct i2c_device_id lt3074_id[] = {
+ { "lt3074", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, lt3074_id);
+
+static const struct of_device_id 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@xxxxxxxxxx>");
+MODULE_DESCRIPTION("PMBus driver for Analog Devices LT3074");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");
--
2.39.5
