From b3991e27b26930ef46206dad17715d8ac2f38a4e Mon Sep 17 00:00:00 2001
From: Timothy Pearson <tpearson@raptorengineering.com>
Date: Tue, 11 Oct 2016 09:35:51 -0500
Subject: [PATCH] hwmon: Add support for MAX31785 intelligent fan controller

Add a basic driver for the MAX31785, focusing on the fan control
features but ignoring the temperature and voltage monitoring
features of the device.

This driver supports all fan control modes and tachometer / PWM
readback where applicable.

Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
 Documentation/hwmon/max31785 |  36 +++
 drivers/hwmon/Kconfig        |  10 +
 drivers/hwmon/Makefile       |   1 +
 drivers/hwmon/max31785.c     | 714 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 761 insertions(+)
 create mode 100644 Documentation/hwmon/max31785
 create mode 100644 drivers/hwmon/max31785.c

diff --git a/Documentation/hwmon/max31785 b/Documentation/hwmon/max31785
new file mode 100644
index 0000000..0911d20
--- /dev/null
+++ b/Documentation/hwmon/max31785
@@ -0,0 +1,36 @@
+Kernel driver max31785
+======================
+
+Supported chips:
+  * Maxim MAX31785
+    Prefix: 'max31785'
+    Addresses scanned: 0x52 0x53 0x54 0x55
+    Datasheet: http://pdfserv.maximintegrated.com/en/ds/MAX31785.pdf
+
+Author: Timothy Pearson <tpearson@raptorengineering.com>
+
+
+Description
+-----------
+
+This driver implements support for the Maxim MAX31785 chip.
+
+The MAX31785 controls the speeds of up to six fans using six independent
+PWM outputs. The desired fan speeds (or PWM duty cycles) are written
+through the I2C interface. The outputs drive "4-wire" fans directly,
+or can be used to modulate the fan's power terminals using an external
+pass transistor.
+
+Tachometer inputs monitor fan tachometer logic outputs for precise (+/-1%)
+monitoring and control of fan RPM as well as detection of fan failure.
+
+
+Sysfs entries
+-------------
+
+fan[1-6]_input           RO  fan tachometer speed in RPM
+fan[1-6]_fault           RO  fan experienced fault
+fan[1-6]_pulses          RW  tachometer pulses per fan revolution
+fan[1-6]_target          RW  desired fan speed in RPM
+pwm[1-6]_enable          RW  pwm mode, 0=disabled, 1=pwm, 2=rpm, 3=automatic
+pwm[1-6]                 RW  fan target duty cycle (0-255)
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 190d270..136605d 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -886,6 +886,16 @@ config SENSORS_MAX6697
 	  This driver can also be built as a module.  If so, the module
 	  will be called max6697.
 
+config SENSORS_MAX31785
+	tristate "Maxim MAX31785 sensor chip"
+	depends on I2C
+	help
+	  If you say yes here you get support for 6-Channel PWM-Output
+	  Fan RPM Controller.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called max31785.
+
 config SENSORS_MAX31790
 	tristate "Maxim MAX31790 sensor chip"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index d2cb7e8..e8ba5c6 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_SENSORS_MAX6639)	+= max6639.o
 obj-$(CONFIG_SENSORS_MAX6642)	+= max6642.o
 obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o
 obj-$(CONFIG_SENSORS_MAX6697)	+= max6697.o
+obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
 obj-$(CONFIG_SENSORS_MAX31790)	+= max31790.o
 obj-$(CONFIG_SENSORS_MC13783_ADC)+= mc13783-adc.o
 obj-$(CONFIG_SENSORS_MCP3021)	+= mcp3021.o
diff --git a/drivers/hwmon/max31785.c b/drivers/hwmon/max31785.c
new file mode 100644
index 0000000..fb7b3f0
--- /dev/null
+++ b/drivers/hwmon/max31785.c
@@ -0,0 +1,714 @@
+/*
+ * max31785.c - Part of lm_sensors, Linux kernel modules for hardware
+ *             monitoring.
+ *
+ * (C) 2016 Raptor Engineering, LLC
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+/* MAX31785 device IDs */
+#define MAX31785_MFR_ID				0x4d
+#define MAX31785_MFR_MODEL			0x53
+
+/* MAX31785 registers */
+#define MAX31785_REG_PAGE			0x00
+#define MAX31785_PAGE_FAN_CONFIG(ch)		(0x00 + (ch))
+#define MAX31785_REG_FAN_CONFIG_1_2		0x3a
+#define MAX31785_REG_FAN_COMMAND_1		0x3b
+#define MAX31785_REG_STATUS_FANS_1_2		0x81
+#define MAX31785_REG_FAN_SPEED_1		0x90
+#define MAX31785_REG_MFR_ID			0x99
+#define MAX31785_REG_MFR_MODEL			0x9a
+#define MAX31785_REG_MFR_FAN_CONFIG		0xf1
+#define MAX31785_REG_READ_FAN_PWM		0xf3
+
+/* Fan Config register bits */
+#define MAX31785_FAN_CFG_PWM_ENABLE		0x80
+#define MAX31785_FAN_CFG_CONTROL_MODE_RPM	0x40
+#define MAX31785_FAN_CFG_PULSE_MASK		0x30
+#define MAX31785_FAN_CFG_PULSE_SHIFT		4
+#define MAX31785_FAN_CFG_PULSE_OFFSET		1
+
+/* Fan Status register bits */
+#define MAX31785_FAN_STATUS_FAULT_MASK		0x80
+
+/* Fan Command constants */
+#define MAX31785_FAN_COMMAND_PWM_RATIO		40
+
+#define NR_CHANNEL				6
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x52, 0x53, 0x54, 0x55,
+							I2C_CLIENT_END };
+
+/*
+ * Client data (each client gets its own)
+ */
+struct max31785_data {
+	struct i2c_client *client;
+	struct mutex device_lock;
+	bool valid; /* zero until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* register values */
+	u8 fan_config[NR_CHANNEL];
+	u16 fan_command[NR_CHANNEL];
+	u8 mfr_fan_config[NR_CHANNEL];
+	u8 fault_status[NR_CHANNEL];
+	u16 tach_rpm[NR_CHANNEL];
+	u16 pwm[NR_CHANNEL];
+};
+
+static int max31785_set_page(struct i2c_client *client,
+				u8 page)
+{
+	return i2c_smbus_write_byte_data(client,
+			MAX31785_REG_PAGE,
+			page);
+}
+
+static int max31785_read_fan_data(struct i2c_client *client,
+				u8 fan, u8 reg, u8 byte_mode)
+{
+	int rv;
+
+	rv = max31785_set_page(client, MAX31785_PAGE_FAN_CONFIG(fan));
+	if (rv < 0)
+		return rv;
+
+	if (byte_mode)
+		rv = i2c_smbus_read_byte_data(client, reg);
+	else
+		rv = i2c_smbus_read_word_data(client, reg);
+
+	return rv;
+}
+
+static int max31785_write_fan_data(struct i2c_client *client,
+				u8 fan, u8 reg, u16 data,
+				u8 byte_mode)
+{
+	int err;
+
+	err = max31785_set_page(client, MAX31785_PAGE_FAN_CONFIG(fan));
+	if (err < 0)
+		return err;
+
+	if (byte_mode)
+		err = i2c_smbus_write_byte_data(client, reg, data);
+	else
+		err = i2c_smbus_write_word_data(client, reg, data);
+
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static bool is_automatic_control_mode(struct max31785_data *data,
+			int index)
+{
+	if (data->fan_command[index] > 0x7fff)
+		return true;
+	else
+		return false;
+}
+
+static struct max31785_data *max31785_update_device(struct device *dev)
+{
+	struct max31785_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	struct max31785_data *ret = data;
+	int i;
+	int rv;
+
+	mutex_lock(&data->device_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		for (i = 0; i < NR_CHANNEL; i++) {
+			rv = max31785_read_fan_data(client, i,
+					MAX31785_REG_STATUS_FANS_1_2, 1);
+			if (rv < 0)
+				goto abort;
+			data->fault_status[i] = rv;
+
+			rv = max31785_read_fan_data(client, i,
+					MAX31785_REG_FAN_SPEED_1, 0);
+			if (rv < 0)
+				goto abort;
+			data->tach_rpm[i] = rv;
+
+			if ((data->fan_config[i]
+				& MAX31785_FAN_CFG_CONTROL_MODE_RPM)
+				|| is_automatic_control_mode(data, i)) {
+				rv = max31785_read_fan_data(client, i,
+						MAX31785_REG_READ_FAN_PWM, 0);
+				if (rv < 0)
+					goto abort;
+				data->pwm[i] = rv;
+			}
+
+			if (!is_automatic_control_mode(data, i)) {
+				/* Poke watchdog for manual fan control */
+				rv = max31785_write_fan_data(client,
+					i, MAX31785_REG_FAN_COMMAND_1,
+					data->fan_command[i], 0);
+				if (rv < 0)
+					goto abort;
+			}
+		}
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+	goto done;
+
+abort:
+	data->valid = false;
+	ret = ERR_PTR(rv);
+
+done:
+	mutex_unlock(&data->device_lock);
+
+	return ret;
+}
+
+static ssize_t get_fan(struct device *dev,
+		       struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return sprintf(buf, "%d\n", data->tach_rpm[attr->index]);
+}
+
+static ssize_t get_fan_target(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+	int rpm;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (data->fan_config[attr->index]
+		& MAX31785_FAN_CFG_CONTROL_MODE_RPM)
+		rpm = data->fan_command[attr->index];
+	else
+		rpm = data->fan_command[attr->index]
+					/ MAX31785_FAN_COMMAND_PWM_RATIO;
+
+	return sprintf(buf, "%d\n", rpm);
+}
+
+static ssize_t set_fan_target(struct device *dev,
+			      struct device_attribute *devattr,
+			      const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long rpm;
+	int err;
+
+	err = kstrtoul(buf, 10, &rpm);
+	if (err)
+		return err;
+
+	if (rpm > 0x7fff)
+		return -EINVAL;
+
+	mutex_lock(&data->device_lock);
+
+	/* Write new RPM value */
+	data->fan_command[attr->index] = rpm;
+	err = max31785_write_fan_data(client, attr->index,
+				MAX31785_REG_FAN_COMMAND_1,
+				data->fan_command[attr->index], 0);
+
+	mutex_unlock(&data->device_lock);
+
+	if (err < 0)
+		return err;
+
+	return count;
+}
+
+static ssize_t get_fan_pulses(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+	int pulses;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	pulses = ((data->fan_config[attr->index] & MAX31785_FAN_CFG_PULSE_MASK)
+			>> MAX31785_FAN_CFG_PULSE_SHIFT)
+			+ MAX31785_FAN_CFG_PULSE_OFFSET;
+
+	return sprintf(buf, "%d\n", pulses);
+}
+
+static ssize_t set_fan_pulses(struct device *dev,
+			      struct device_attribute *devattr,
+			      const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long pulses;
+	int err;
+
+	err = kstrtoul(buf, 10, &pulses);
+	if (err)
+		return err;
+
+	if (pulses > 4)
+		return -EINVAL;
+
+	data->fan_config[attr->index] &= MAX31785_FAN_CFG_PULSE_MASK;
+	data->fan_config[attr->index] |=
+				((pulses - MAX31785_FAN_CFG_PULSE_OFFSET)
+				<< MAX31785_FAN_CFG_PULSE_SHIFT);
+
+	mutex_lock(&data->device_lock);
+
+	/* Write new pulse value */
+	data->fan_command[attr->index] = pulses;
+	err = max31785_write_fan_data(client, attr->index,
+				MAX31785_REG_FAN_CONFIG_1_2,
+				data->fan_config[attr->index], 1);
+
+	mutex_unlock(&data->device_lock);
+
+	if (err < 0)
+		return err;
+
+	return count;
+}
+
+static ssize_t get_pwm(struct device *dev,
+		       struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+	int pwm;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if ((data->fan_config[attr->index]
+		& MAX31785_FAN_CFG_CONTROL_MODE_RPM)
+		|| is_automatic_control_mode(data, attr->index))
+		pwm = data->pwm[attr->index] / 100;
+	else
+		pwm = data->fan_command[attr->index]
+					/ MAX31785_FAN_COMMAND_PWM_RATIO;
+
+	return sprintf(buf, "%d\n", pwm);
+}
+
+static ssize_t set_pwm(struct device *dev,
+		       struct device_attribute *devattr,
+		       const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long pwm;
+	int err;
+
+	err = kstrtoul(buf, 10, &pwm);
+	if (err)
+		return err;
+
+	if (pwm > 255)
+		return -EINVAL;
+
+	mutex_lock(&data->device_lock);
+
+	/* Write new PWM value */
+	data->fan_command[attr->index] = pwm * MAX31785_FAN_COMMAND_PWM_RATIO;
+	err = max31785_write_fan_data(client, attr->index,
+				MAX31785_REG_FAN_COMMAND_1,
+				data->fan_command[attr->index], 0);
+
+	mutex_unlock(&data->device_lock);
+
+	if (err < 0)
+		return err;
+
+	return count;
+}
+
+static ssize_t get_pwm_enable(struct device *dev,
+			      struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+	int mode;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	if (!(data->fan_config[attr->index] & MAX31785_FAN_CFG_PWM_ENABLE))
+		mode = 0;
+	else if (is_automatic_control_mode(data, attr->index))
+		mode = 3;
+	else if (data->fan_config[attr->index]
+		& MAX31785_FAN_CFG_CONTROL_MODE_RPM)
+		mode = 2;
+	else
+		mode = 1;
+
+	return sprintf(buf, "%d\n", mode);
+}
+
+static ssize_t set_pwm_enable(struct device *dev,
+			      struct device_attribute *devattr,
+			      const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long mode;
+	int err;
+
+	err = kstrtoul(buf, 10, &mode);
+	if (err)
+		return err;
+
+	switch (mode) {
+	case 0:
+		data->fan_config[attr->index] =
+			data->fan_config[attr->index]
+			& ~MAX31785_FAN_CFG_PWM_ENABLE;
+		break;
+	case 1:
+	case 2:
+	case 3:
+		data->fan_config[attr->index] =
+			data->fan_config[attr->index]
+			 | MAX31785_FAN_CFG_PWM_ENABLE;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (mode) {
+	case 0:
+		break;
+	case 1:
+		data->fan_config[attr->index] =
+			data->fan_config[attr->index]
+			& ~MAX31785_FAN_CFG_CONTROL_MODE_RPM;
+		break;
+	case 2:
+		data->fan_config[attr->index] =
+			data->fan_config[attr->index]
+			| MAX31785_FAN_CFG_CONTROL_MODE_RPM;
+		break;
+	case 3:
+		data->fan_command[attr->index] = 0xffff;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	mutex_lock(&data->device_lock);
+
+	err = max31785_write_fan_data(client, attr->index,
+				MAX31785_REG_FAN_CONFIG_1_2,
+				data->fan_config[attr->index], 1);
+
+	if (err < 0)
+		goto abort;
+
+	err = max31785_write_fan_data(client, attr->index,
+				MAX31785_REG_FAN_COMMAND_1,
+				data->fan_command[attr->index], 0);
+
+abort:
+	mutex_unlock(&data->device_lock);
+
+	if (err < 0)
+		return err;
+
+	return count;
+}
+
+static ssize_t get_fan_fault(struct device *dev,
+			     struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct max31785_data *data = max31785_update_device(dev);
+	int fault;
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	fault = !!(data->fault_status[attr->index]
+			& MAX31785_FAN_STATUS_FAULT_MASK);
+
+	return sprintf(buf, "%d\n", fault);
+}
+
+static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, get_fan, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan3_input, S_IRUGO, get_fan, NULL, 2);
+static SENSOR_DEVICE_ATTR(fan4_input, S_IRUGO, get_fan, NULL, 3);
+static SENSOR_DEVICE_ATTR(fan5_input, S_IRUGO, get_fan, NULL, 4);
+static SENSOR_DEVICE_ATTR(fan6_input, S_IRUGO, get_fan, NULL, 5);
+
+static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_fan_fault, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan2_fault, S_IRUGO, get_fan_fault, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan3_fault, S_IRUGO, get_fan_fault, NULL, 2);
+static SENSOR_DEVICE_ATTR(fan4_fault, S_IRUGO, get_fan_fault, NULL, 3);
+static SENSOR_DEVICE_ATTR(fan5_fault, S_IRUGO, get_fan_fault, NULL, 4);
+static SENSOR_DEVICE_ATTR(fan6_fault, S_IRUGO, get_fan_fault, NULL, 5);
+
+static SENSOR_DEVICE_ATTR(fan1_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 0);
+static SENSOR_DEVICE_ATTR(fan2_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 1);
+static SENSOR_DEVICE_ATTR(fan3_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 2);
+static SENSOR_DEVICE_ATTR(fan4_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 3);
+static SENSOR_DEVICE_ATTR(fan5_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 4);
+static SENSOR_DEVICE_ATTR(fan6_target, S_IWUSR | S_IRUGO,
+		get_fan_target, set_fan_target, 5);
+
+static SENSOR_DEVICE_ATTR(fan1_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 0);
+static SENSOR_DEVICE_ATTR(fan2_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 1);
+static SENSOR_DEVICE_ATTR(fan3_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 2);
+static SENSOR_DEVICE_ATTR(fan4_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 3);
+static SENSOR_DEVICE_ATTR(fan5_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 4);
+static SENSOR_DEVICE_ATTR(fan6_pulses, S_IWUSR | S_IRUGO,
+		get_fan_pulses, set_fan_pulses, 5);
+
+static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 0);
+static SENSOR_DEVICE_ATTR(pwm2, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 1);
+static SENSOR_DEVICE_ATTR(pwm3, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 2);
+static SENSOR_DEVICE_ATTR(pwm4, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 3);
+static SENSOR_DEVICE_ATTR(pwm5, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 4);
+static SENSOR_DEVICE_ATTR(pwm6, S_IWUSR | S_IRUGO, get_pwm, set_pwm, 5);
+
+static SENSOR_DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 0);
+static SENSOR_DEVICE_ATTR(pwm2_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 1);
+static SENSOR_DEVICE_ATTR(pwm3_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 2);
+static SENSOR_DEVICE_ATTR(pwm4_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 3);
+static SENSOR_DEVICE_ATTR(pwm5_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 4);
+static SENSOR_DEVICE_ATTR(pwm6_enable, S_IWUSR | S_IRUGO,
+		get_pwm_enable, set_pwm_enable, 5);
+
+static struct attribute *max31785_attrs[] = {
+	&sensor_dev_attr_fan1_input.dev_attr.attr,
+	&sensor_dev_attr_fan2_input.dev_attr.attr,
+	&sensor_dev_attr_fan3_input.dev_attr.attr,
+	&sensor_dev_attr_fan4_input.dev_attr.attr,
+	&sensor_dev_attr_fan5_input.dev_attr.attr,
+	&sensor_dev_attr_fan6_input.dev_attr.attr,
+
+	&sensor_dev_attr_fan1_fault.dev_attr.attr,
+	&sensor_dev_attr_fan2_fault.dev_attr.attr,
+	&sensor_dev_attr_fan3_fault.dev_attr.attr,
+	&sensor_dev_attr_fan4_fault.dev_attr.attr,
+	&sensor_dev_attr_fan5_fault.dev_attr.attr,
+	&sensor_dev_attr_fan6_fault.dev_attr.attr,
+
+	&sensor_dev_attr_fan1_target.dev_attr.attr,
+	&sensor_dev_attr_fan2_target.dev_attr.attr,
+	&sensor_dev_attr_fan3_target.dev_attr.attr,
+	&sensor_dev_attr_fan4_target.dev_attr.attr,
+	&sensor_dev_attr_fan5_target.dev_attr.attr,
+	&sensor_dev_attr_fan6_target.dev_attr.attr,
+
+	&sensor_dev_attr_fan1_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan2_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan3_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan4_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan5_pulses.dev_attr.attr,
+	&sensor_dev_attr_fan6_pulses.dev_attr.attr,
+
+	&sensor_dev_attr_pwm1.dev_attr.attr,
+	&sensor_dev_attr_pwm2.dev_attr.attr,
+	&sensor_dev_attr_pwm3.dev_attr.attr,
+	&sensor_dev_attr_pwm4.dev_attr.attr,
+	&sensor_dev_attr_pwm5.dev_attr.attr,
+	&sensor_dev_attr_pwm6.dev_attr.attr,
+
+	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm2_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm3_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm4_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm5_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm6_enable.dev_attr.attr,
+	NULL
+};
+
+static umode_t max31785_attrs_visible(struct kobject *kobj,
+				     struct attribute *a, int n)
+{
+	return a->mode;
+}
+
+static const struct attribute_group max31785_group = {
+	.attrs = max31785_attrs,
+	.is_visible = max31785_attrs_visible,
+};
+__ATTRIBUTE_GROUPS(max31785);
+
+static int max31785_init_client(struct i2c_client *client,
+				struct max31785_data *data)
+{
+	int i, rv;
+
+	for (i = 0; i < NR_CHANNEL; i++) {
+		rv = max31785_read_fan_data(client, i,
+				MAX31785_REG_FAN_CONFIG_1_2, 1);
+		if (rv < 0)
+			return rv;
+		data->fan_config[i] = rv;
+
+		rv = max31785_read_fan_data(client, i,
+				MAX31785_REG_FAN_COMMAND_1, 0);
+		if (rv < 0)
+			return rv;
+		data->fan_command[i] = rv;
+
+		rv = max31785_read_fan_data(client, i,
+				MAX31785_REG_MFR_FAN_CONFIG, 1);
+		if (rv < 0)
+			return rv;
+		data->mfr_fan_config[i] = rv;
+
+		if (!((data->fan_config[i]
+			& MAX31785_FAN_CFG_CONTROL_MODE_RPM)
+			|| is_automatic_control_mode(data, i))) {
+			data->pwm[i] = 0;
+		}
+	}
+
+	return rv;
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int max31785_detect(struct i2c_client *client,
+			  struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	int rv;
+
+	if (!i2c_check_functionality(adapter,
+			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	/* Probe manufacturer / model registers */
+	rv = i2c_smbus_read_byte_data(client, MAX31785_REG_MFR_ID);
+	if (rv < 0)
+		return -ENODEV;
+	if (rv != MAX31785_MFR_ID)
+		return -ENODEV;
+
+	rv = i2c_smbus_read_byte_data(client, MAX31785_REG_MFR_MODEL);
+	if (rv < 0)
+		return -ENODEV;
+	if (rv != MAX31785_MFR_MODEL)
+		return -ENODEV;
+
+	strlcpy(info->type, "max31785", I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int max31785_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct device *dev = &client->dev;
+	struct max31785_data *data;
+	struct device *hwmon_dev;
+	int err;
+
+	if (!i2c_check_functionality(adapter,
+			I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(dev, sizeof(struct max31785_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->device_lock);
+
+	/*
+	 * Initialize the max31785 chip
+	 */
+	err = max31785_init_client(client, data);
+	if (err)
+		return err;
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
+			client->name, data, max31785_groups);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id max31785_id[] = {
+	{ "max31785", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max31785_id);
+
+static struct i2c_driver max31785_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.probe		= max31785_probe,
+	.driver = {
+		.name	= "max31785",
+	},
+	.id_table	= max31785_id,
+	.detect		= max31785_detect,
+	.address_list	= normal_i2c,
+};
+
+module_i2c_driver(max31785_driver);
+
+MODULE_AUTHOR("Timothy Pearson <tpearson@raptorengineering.com>");
+MODULE_DESCRIPTION("MAX31785 sensor driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.1