diff --git a/Documentation/hwmon/max31785 b/Documentation/hwmon/max31785
new file mode 100644
index 0000000000000..45fb6093dec20
--- /dev/null
+++ b/Documentation/hwmon/max31785
@@ -0,0 +1,51 @@
+Kernel driver max31785
+======================
+
+Supported chips:
+ * Maxim MAX31785, MAX31785A
+ Prefix: 'max31785' or 'max31785a'
+ Addresses scanned: -
+ Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
+
+Author: Andrew Jeffery <andrew@aj.id.au>
+
+Description
+-----------
+
+The Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
+management with temperature and remote voltage sensing. Various fan control
+features are provided, including PWM frequency control, temperature hysteresis,
+dual tachometer measurements, and fan health monitoring.
+
+For dual rotor fan configuration, the MAX31785 exposes the slowest rotor of the
+two in the fan[1-4]_input attributes.
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Sysfs attributes
+----------------
+
+fan[1-4]_alarm Fan alarm.
+fan[1-4]_fault Fan fault.
+fan[1-4]_input Fan RPM.
+
+in[1-6]_crit Critical maximum output voltage
+in[1-6]_crit_alarm Output voltage critical high alarm
+in[1-6]_input Measured output voltage
+in[1-6]_label "vout[18-23]"
+in[1-6]_lcrit Critical minimum output voltage
+in[1-6]_lcrit_alarm Output voltage critical low alarm
+in[1-6]_max Maximum output voltage
+in[1-6]_max_alarm Output voltage high alarm
+in[1-6]_min Minimum output voltage
+in[1-6]_min_alarm Output voltage low alarm
+
+temp[1-11]_crit Critical high temperature
+temp[1-11]_crit_alarm Chip temperature critical high alarm
+temp[1-11]_input Measured temperature
+temp[1-11]_max Maximum temperature
+temp[1-11]_max_alarm Chip temperature high alarm
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 40019325b517f..08479006c7f9e 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -114,6 +114,16 @@ config SENSORS_MAX20751
This driver can also be built as a module. If so, the module will
be called max20751.
+config SENSORS_MAX31785
+ tristate "Maxim MAX31785 and compatibles"
+ default n
+ help
+ If you say yes here you get hardware monitoring support for Maxim
+ MAX31785.
+
+ This driver can also be built as a module. If so, the module will
+ be called max31785.
+
config SENSORS_MAX34440
tristate "Maxim MAX34440 and compatibles"
default n
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 459a6be3390e8..a8bf0e490db9a 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SENSORS_LTC2978) += ltc2978.o
obj-$(CONFIG_SENSORS_LTC3815) += ltc3815.o
obj-$(CONFIG_SENSORS_MAX16064) += max16064.o
obj-$(CONFIG_SENSORS_MAX20751) += max20751.o
+obj-$(CONFIG_SENSORS_MAX31785) += max31785.o
obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
obj-$(CONFIG_SENSORS_TPS40422) += tps40422.o
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
new file mode 100644
index 0000000000000..9313849d51600
--- /dev/null
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2017 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+enum max31785_regs {
+ MFR_REVISION = 0x9b,
+};
+
+#define MAX31785_NR_PAGES 23
+
+#define MAX31785_FAN_FUNCS \
+ (PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12)
+
+#define MAX31785_TEMP_FUNCS \
+ (PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP)
+
+#define MAX31785_VOUT_FUNCS \
+ (PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT)
+
+static const struct pmbus_driver_info max31785_info = {
+ .pages = MAX31785_NR_PAGES,
+
+ /* RPM */
+ .format[PSC_FAN] = direct,
+ .m[PSC_FAN] = 1,
+ .b[PSC_FAN] = 0,
+ .R[PSC_FAN] = 0,
+ .func[0] = MAX31785_FAN_FUNCS,
+ .func[1] = MAX31785_FAN_FUNCS,
+ .func[2] = MAX31785_FAN_FUNCS,
+ .func[3] = MAX31785_FAN_FUNCS,
+ .func[4] = MAX31785_FAN_FUNCS,
+ .func[5] = MAX31785_FAN_FUNCS,
+
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_TEMPERATURE] = 1,
+ .b[PSC_TEMPERATURE] = 0,
+ .R[PSC_TEMPERATURE] = 2,
+ .func[6] = MAX31785_TEMP_FUNCS,
+ .func[7] = MAX31785_TEMP_FUNCS,
+ .func[8] = MAX31785_TEMP_FUNCS,
+ .func[9] = MAX31785_TEMP_FUNCS,
+ .func[10] = MAX31785_TEMP_FUNCS,
+ .func[11] = MAX31785_TEMP_FUNCS,
+ .func[12] = MAX31785_TEMP_FUNCS,
+ .func[13] = MAX31785_TEMP_FUNCS,
+ .func[14] = MAX31785_TEMP_FUNCS,
+ .func[15] = MAX31785_TEMP_FUNCS,
+ .func[16] = MAX31785_TEMP_FUNCS,
+
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .m[PSC_VOLTAGE_OUT] = 1,
+ .b[PSC_VOLTAGE_OUT] = 0,
+ .R[PSC_VOLTAGE_OUT] = 0,
+ .func[17] = MAX31785_VOUT_FUNCS,
+ .func[18] = MAX31785_VOUT_FUNCS,
+ .func[19] = MAX31785_VOUT_FUNCS,
+ .func[20] = MAX31785_VOUT_FUNCS,
+ .func[21] = MAX31785_VOUT_FUNCS,
+ .func[22] = MAX31785_VOUT_FUNCS,
+};
+
+static int max31785_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct pmbus_driver_info *info;
+ s64 ret;
+
+ info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ *info = max31785_info;
+
+ ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 255);
+ if (ret < 0)
+ return ret;
+
+ return pmbus_do_probe(client, id, info);
+}
+
+static const struct i2c_device_id max31785_id[] = {
+ { "max31785", 0 },
+ { "max31785a", 0 },
+ { },
+};
+
+MODULE_DEVICE_TABLE(i2c, max31785_id);
+
+static struct i2c_driver max31785_driver = {
+ .driver = {
+ .name = "max31785",
+ },
+ .probe = max31785_probe,
+ .remove = pmbus_do_remove,
+ .id_table = max31785_id,
+};
+
+module_i2c_driver(max31785_driver);
+
+MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
+MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785");
+MODULE_LICENSE("GPL");