[PATCH] hwmon: Driver for Sensylink CTF2304

[Il Han <corone.il.han@gmail.com>]

From: Il Han <corone.il.han@gmail.com>

The driver supports the Sensylink CTF2304.

Signed-off-by: Il Han <corone.il.han@gmail.com>
---
 Documentation/hwmon/ctf2304.rst |  41 +++
 drivers/hwmon/Kconfig           |  10 +
 drivers/hwmon/Makefile          |   1 +
 drivers/hwmon/ctf2304.c         | 554 ++++++++++++++++++++++++++++++++
 4 files changed, 606 insertions(+)
 create mode 100644 Documentation/hwmon/ctf2304.rst
 create mode 100644 drivers/hwmon/ctf2304.c

diff --git a/Documentation/hwmon/ctf2304.rst b/Documentation/hwmon/ctf2304.rst
new file mode 100644
index 000000000000..d0e9ef9ea52e
--- /dev/null
+++ b/Documentation/hwmon/ctf2304.rst
@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver ctf2304
+=====================
+
+Supported chips:
+
+  * Sensylink CTF2304
+
+    Prefix: 'ctf2304'
+
+    Addresses scanned: -
+
+    Datasheet:
+
+Author: Il Han <corone.il.han@gmail.com>
+
+
+Description
+-----------
+
+This driver implements support for the Sensylink CTF2304 chip.
+
+The CTF2304 controls the speeds of up to four fans using four independent
+PWM outputs with local and remote temperature and remote voltage sensing.
+
+
+Sysfs entries
+-------------
+
+================== === =======================================================
+fan[1-4]_input     RO  fan tachometer speed in RPM
+fan[1-4]_target    RW  desired fan speed in RPM
+fan[1-4]_div       RW  sets the RPM range of the fan.
+pwm[1-4]_enable    RW  regulator mode,
+                       0=auto temperature mode, 1=manual mode, 2=rpm mode
+pwm[1-4]           RW  read: current pwm duty cycle,
+                       write: target pwm duty cycle (0-255)
+in[1-8]_input      RO  measured output voltage
+temp[1-9]_input    RO  measured temperature
+================== === =======================================================
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 5b3b76477b0e..da9fbb0f8af3 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -474,6 +474,16 @@ config SENSORS_CORSAIR_PSU
 	  This driver can also be built as a module. If so, the module
 	  will be called corsair-psu.
 
+config SENSORS_CTF2304
+	tristate "Sensylink CTF2304 sensor chip"
+	depends on I2C
+	help
+	  If you say yes here you get support for PWM and Fan Controller
+	  with temperature and voltage sensing.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called ctf2304.
+
 config SENSORS_DRIVETEMP
 	tristate "Hard disk drives with temperature sensors"
 	depends on SCSI && ATA
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 88712b5031c8..3742b52f032d 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -60,6 +60,7 @@ obj-$(CONFIG_SENSORS_BT1_PVT)	+= bt1-pvt.o
 obj-$(CONFIG_SENSORS_CORETEMP)	+= coretemp.o
 obj-$(CONFIG_SENSORS_CORSAIR_CPRO) += corsair-cpro.o
 obj-$(CONFIG_SENSORS_CORSAIR_PSU) += corsair-psu.o
+obj-$(CONFIG_SENSORS_CTF2304)	+= ctf2304.o
 obj-$(CONFIG_SENSORS_DA9052_ADC)+= da9052-hwmon.o
 obj-$(CONFIG_SENSORS_DA9055)+= da9055-hwmon.o
 obj-$(CONFIG_SENSORS_DELL_SMM)	+= dell-smm-hwmon.o
diff --git a/drivers/hwmon/ctf2304.c b/drivers/hwmon/ctf2304.c
new file mode 100644
index 000000000000..5788740a57e5
--- /dev/null
+++ b/drivers/hwmon/ctf2304.c
@@ -0,0 +1,554 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ctf2304.c - Part of lm_sensors, Linux kernel modules for hardware
+ *             monitoring.
+ *
+ * (C) 2023 by Il Han <corone.il.han@gmail.com>
+ */
+
+#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>
+
+/* CTF2304 registers */
+#define CTF2304_REG_LOCAL_TEMP		0x00
+#define CTF2304_REG_REMOTE_CHANNEL(ch)	(0x01 + (ch))
+#define CTF2304_REG_TACH_COUNT(ch)	(0x09 + (ch))
+#define CTF2304_REG_FAN_CONFIG1		0x10
+#define CTF2304_REG_FAN_CONFIG2		0x11
+#define CTF2304_REG_FAN_RPM_CTRL	0x18
+#define CTF2304_REG_PWMOUT(ch)		(0x40 + (ch))
+#define CTF2304_REG_TARGET_COUNT(ch)	(0x44 + (ch))
+
+/* Fan Configure1 register bits */
+#define CTF2304_FAN_CFG1_TRANGE		0x0400
+#define CTF2304_FAN_CFG1_MODE_MASK	(0x7)
+#define CTF2304_FAN_CFG1_MODE_SHIFT	7
+
+/* Fan Configure2 register bits */
+#define CTF2304_FAN_CFG2_MODE_MASK(ch)	(0x6 << (ch) * 4)
+#define CTF2304_FAN_CFG2_MODE_SHIFT(ch)	(1 + (ch) * 4)
+#define CTF2304_FAN_CFG2_DCY_MODE	0
+#define CTF2304_FAN_CFG2_RPM_MODE	1
+#define CTF2304_FAN_CFG2_TEMP_MODE	2
+#define CTF2304_FAN_CFG2_MAX_MODE	3
+
+/* Fan RPM CTRL register bits */
+#define CTF2304_FAN_DIV_MASK(ch)	(0x6 << (ch) * 4)
+#define CTF2304_FAN_DIV_SHIFT(ch)	(1 + (ch) * 4)
+
+#define CTF2304_VCC			3300
+
+#define FAN_RPM_MIN			480
+#define FAN_RPM_MAX			1966080
+
+#define FAN_COUNT_REG_MAX		0xFFF
+
+#define TEMP_FROM_REG(reg)		(((reg) * 1000) >> 8)
+#define VOLT_FROM_REG(reg, fs)		((((reg) >> 4) * (fs)) >> 12)
+#define DIV_FROM_REG(reg)		(1 << (reg))
+#define DIV_TO_REG(div)			((div == 8) ? 0x3 : \
+					 (div == 4) ? 0x2 : \
+					 (div == 1) ? 0x0 : 0x1)
+#define RPM_FROM_REG(reg)		(((reg) >> 4) ? \
+					 ((32768 * 60) / ((reg) >> 4)) : \
+					 FAN_RPM_MAX)
+#define RPM_TO_REG(rpm)			((rpm) ? \
+					 ((32768 * 60) / (rpm)) : \
+					 FAN_COUNT_REG_MAX)
+
+#define NR_CHANNEL			8
+#define NR_FAN_CHANNEL			4
+
+/*
+ * Client data (each client gets its own)
+ */
+struct ctf2304_data {
+	struct i2c_client *client;
+	struct mutex update_lock;
+	char valid; /* zero until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* register values */
+	u16 local_temp;
+	u16 remote_channel[NR_CHANNEL];
+	u16 tach[NR_FAN_CHANNEL];
+	u16 fan_config1;
+	u16 fan_config2;
+	u16 fan_rpm_ctrl;
+	u16 pwm[NR_FAN_CHANNEL];
+	u16 target_count[NR_FAN_CHANNEL];
+};
+
+static struct ctf2304_data *ctf2304_update_device(struct device *dev)
+{
+	struct ctf2304_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	int i;
+	int rv;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		rv = i2c_smbus_read_word_swapped(client,
+				CTF2304_REG_LOCAL_TEMP);
+		if (rv >= 0)
+			data->local_temp = rv;
+
+		for (i = 0; i < NR_CHANNEL; i++) {
+			rv = i2c_smbus_read_word_swapped(client,
+					CTF2304_REG_REMOTE_CHANNEL(i));
+			if (rv >= 0)
+				data->remote_channel[i] = rv;
+		}
+
+		rv = i2c_smbus_read_word_swapped(client,
+				CTF2304_REG_FAN_CONFIG1);
+		if (rv >= 0)
+			data->fan_config1 = rv;
+		rv = i2c_smbus_read_word_swapped(client,
+				CTF2304_REG_FAN_CONFIG2);
+		if (rv >= 0)
+			data->fan_config2 = rv;
+		rv = i2c_smbus_read_word_swapped(client,
+				CTF2304_REG_FAN_RPM_CTRL);
+		if (rv >= 0)
+			data->fan_rpm_ctrl = rv;
+
+		for (i = 0; i < NR_FAN_CHANNEL; i++) {
+			rv = i2c_smbus_read_word_swapped(client,
+					CTF2304_REG_TACH_COUNT(i));
+			if (rv >= 0)
+				data->tach[i] = rv;
+			rv = i2c_smbus_read_word_swapped(client,
+					CTF2304_REG_PWMOUT(i));
+			if (rv >= 0)
+				data->pwm[i] = rv;
+			rv = i2c_smbus_read_word_swapped(client,
+					CTF2304_REG_TARGET_COUNT(i));
+			if (rv >= 0)
+				data->target_count[i] = rv;
+		}
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+static int register_to_temp(u16 reg, u16 config)
+{
+	if (config & CTF2304_FAN_CFG1_TRANGE)
+		return TEMP_FROM_REG(reg & 0x7FF0) + ((reg >> 15) ? -64000:0);
+	else
+		return TEMP_FROM_REG(reg);
+}
+
+static ssize_t show_temp(struct device *dev,
+			 struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct ctf2304_data *data = ctf2304_update_device(dev);
+	u16 reg;
+
+	if (attr->index == 0)
+		reg = data->local_temp;
+	else
+		reg = data->remote_channel[attr->index-1];
+
+	return sprintf(buf, "%d\n", register_to_temp(reg, data->fan_config1));
+}
+
+static int get_full_scale(u16 config)
+{
+	int full_scale;
+	u8 bits;
+
+	bits = (config >> CTF2304_FAN_CFG1_MODE_SHIFT)
+	       & CTF2304_FAN_CFG1_MODE_MASK;
+
+	if (bits == 0x0)
+		full_scale = 2560;
+	else if (bits == 0x1)
+		full_scale = CTF2304_VCC;
+	else if (bits == 0x2)
+		full_scale = 4096;
+	else if (bits == 0x3)
+		full_scale = 2048;
+	else if (bits == 0x4)
+		full_scale = 1024;
+	else if (bits == 0x5)
+		full_scale = 512;
+	else
+		full_scale = 256;
+
+	return full_scale;
+}
+
+static int register_to_volt(u16 reg, u16 config)
+{
+	int full_scale;
+
+	full_scale = get_full_scale(config);
+
+	return VOLT_FROM_REG(reg, full_scale);
+}
+
+static ssize_t show_voltage(struct device *dev,
+			    struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct ctf2304_data *data = ctf2304_update_device(dev);
+	int voltage;
+
+	voltage = register_to_volt(data->remote_channel[attr->index],
+			data->fan_config1);
+
+	return sprintf(buf, "%d\n", voltage);
+}
+
+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 ctf2304_data *data = ctf2304_update_device(dev);
+	int rpm;
+
+	rpm = RPM_FROM_REG(data->tach[attr->index]);
+
+	return sprintf(buf, "%d\n", rpm);
+}
+
+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 ctf2304_data *data = ctf2304_update_device(dev);
+	int rpm;
+
+	rpm = RPM_FROM_REG(data->target_count[attr->index]);
+
+	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 ctf2304_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long rpm;
+	int target_count;
+	int err;
+
+	err = kstrtoul(buf, 10, &rpm);
+	if (err)
+		return err;
+
+	rpm = clamp_val(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
+	target_count = RPM_TO_REG(rpm);
+	target_count = clamp_val(target_count, 0x1, 0xFFF);
+
+	mutex_lock(&data->update_lock);
+
+	data->target_count[attr->index] = target_count << 4;
+	i2c_smbus_write_word_swapped(client,
+			CTF2304_REG_TARGET_COUNT(attr->index),
+			data->target_count[attr->index]);
+
+	mutex_unlock(&data->update_lock);
+
+	return count;
+}
+
+static ssize_t show_fan_div(struct device *dev,
+			    struct device_attribute *devattr, char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct ctf2304_data *data = ctf2304_update_device(dev);
+	u8 bits;
+
+	bits = (data->fan_rpm_ctrl & CTF2304_FAN_DIV_MASK(attr->index))
+	       >> CTF2304_FAN_DIV_SHIFT(attr->index);
+
+	return sprintf(buf, "%d\n", DIV_FROM_REG(bits));
+}
+
+static ssize_t set_fan_div(struct device *dev,
+			   struct device_attribute *devattr,
+			   const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct ctf2304_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	unsigned long div;
+	int err;
+
+	err = kstrtoul(buf, 10, &div);
+	if (err)
+		return err;
+
+	mutex_lock(&data->update_lock);
+
+	data->fan_rpm_ctrl = (data->fan_rpm_ctrl
+			      & ~CTF2304_FAN_DIV_MASK(attr->index))
+			     | (DIV_TO_REG(div)
+				<< CTF2304_FAN_DIV_SHIFT(attr->index));
+
+	i2c_smbus_write_word_swapped(client,
+			CTF2304_REG_FAN_RPM_CTRL, data->fan_rpm_ctrl);
+
+	mutex_unlock(&data->update_lock);
+
+	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 ctf2304_data *data = ctf2304_update_device(dev);
+	int pwm;
+
+	pwm = data->pwm[attr->index] >> 8;
+
+	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 ctf2304_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;
+
+	pwm = clamp_val(pwm, 0, 255);
+
+	mutex_lock(&data->update_lock);
+
+	data->pwm[attr->index] = (data->pwm[attr->index] & 0xFF) | (pwm << 8);
+	i2c_smbus_write_word_swapped(client,
+			CTF2304_REG_PWMOUT(attr->index),
+			data->pwm[attr->index]);
+
+	mutex_unlock(&data->update_lock);
+
+	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 ctf2304_data *data = ctf2304_update_device(dev);
+	int config;
+	int mode;
+
+	config = (data->fan_config2 & CTF2304_FAN_CFG2_MODE_MASK(attr->index))
+		 >> CTF2304_FAN_CFG2_MODE_SHIFT(attr->index);
+	if (config == CTF2304_FAN_CFG2_RPM_MODE)
+		mode = 2;
+	else if (config == CTF2304_FAN_CFG2_DCY_MODE)
+		mode = 1;
+	else
+		mode = 0;
+
+	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 ctf2304_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;
+
+	mutex_lock(&data->update_lock);
+
+	switch (mode) {
+	case 0:
+		data->fan_config2 =
+			(data->fan_config2
+			 & ~CTF2304_FAN_CFG2_MODE_MASK(attr->index))
+			| (CTF2304_FAN_CFG2_TEMP_MODE
+			   << CTF2304_FAN_CFG2_MODE_SHIFT(attr->index));
+		break;
+	case 1:
+		data->fan_config2 =
+			(data->fan_config2
+			 & ~CTF2304_FAN_CFG2_MODE_MASK(attr->index))
+			| (CTF2304_FAN_CFG2_DCY_MODE
+			   << CTF2304_FAN_CFG2_MODE_SHIFT(attr->index));
+		break;
+	case 2:
+		data->fan_config2 =
+			(data->fan_config2
+			 & ~CTF2304_FAN_CFG2_MODE_MASK(attr->index))
+			| (CTF2304_FAN_CFG2_RPM_MODE
+			   << CTF2304_FAN_CFG2_MODE_SHIFT(attr->index));
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	i2c_smbus_write_word_swapped(client,
+			CTF2304_REG_FAN_CONFIG2, data->fan_config2);
+
+	mutex_unlock(&data->update_lock);
+
+	return count;
+}
+
+static SENSOR_DEVICE_ATTR(temp1_input, 0444, show_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp2_input, 0444, show_temp, NULL, 1);
+static SENSOR_DEVICE_ATTR(temp3_input, 0444, show_temp, NULL, 2);
+static SENSOR_DEVICE_ATTR(temp4_input, 0444, show_temp, NULL, 3);
+static SENSOR_DEVICE_ATTR(temp5_input, 0444, show_temp, NULL, 4);
+static SENSOR_DEVICE_ATTR(temp6_input, 0444, show_temp, NULL, 5);
+static SENSOR_DEVICE_ATTR(temp7_input, 0444, show_temp, NULL, 6);
+static SENSOR_DEVICE_ATTR(temp8_input, 0444, show_temp, NULL, 7);
+static SENSOR_DEVICE_ATTR(temp9_input, 0444, show_temp, NULL, 8);
+static SENSOR_DEVICE_ATTR(in1_input, 0444, show_voltage, NULL, 0);
+static SENSOR_DEVICE_ATTR(in2_input, 0444, show_voltage, NULL, 1);
+static SENSOR_DEVICE_ATTR(in3_input, 0444, show_voltage, NULL, 2);
+static SENSOR_DEVICE_ATTR(in4_input, 0444, show_voltage, NULL, 3);
+static SENSOR_DEVICE_ATTR(in5_input, 0444, show_voltage, NULL, 4);
+static SENSOR_DEVICE_ATTR(in6_input, 0444, show_voltage, NULL, 5);
+static SENSOR_DEVICE_ATTR(in7_input, 0444, show_voltage, NULL, 6);
+static SENSOR_DEVICE_ATTR(in8_input, 0444, show_voltage, NULL, 7);
+static SENSOR_DEVICE_ATTR(fan1_input, 0444, get_fan, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan2_input, 0444, get_fan, NULL, 1);
+static SENSOR_DEVICE_ATTR(fan3_input, 0444, get_fan, NULL, 2);
+static SENSOR_DEVICE_ATTR(fan4_input, 0444, get_fan, NULL, 3);
+static SENSOR_DEVICE_ATTR(fan1_target, 0644,
+		get_fan_target, set_fan_target, 0);
+static SENSOR_DEVICE_ATTR(fan2_target, 0644,
+		get_fan_target, set_fan_target, 1);
+static SENSOR_DEVICE_ATTR(fan3_target, 0644,
+		get_fan_target, set_fan_target, 2);
+static SENSOR_DEVICE_ATTR(fan4_target, 0644,
+		get_fan_target, set_fan_target, 3);
+static SENSOR_DEVICE_ATTR(fan1_div, 0644, show_fan_div, set_fan_div, 0);
+static SENSOR_DEVICE_ATTR(fan2_div, 0644, show_fan_div, set_fan_div, 1);
+static SENSOR_DEVICE_ATTR(fan3_div, 0644, show_fan_div, set_fan_div, 2);
+static SENSOR_DEVICE_ATTR(fan4_div, 0644, show_fan_div, set_fan_div, 3);
+static SENSOR_DEVICE_ATTR(pwm1, 0644, get_pwm, set_pwm, 0);
+static SENSOR_DEVICE_ATTR(pwm2, 0644, get_pwm, set_pwm, 1);
+static SENSOR_DEVICE_ATTR(pwm3, 0644, get_pwm, set_pwm, 2);
+static SENSOR_DEVICE_ATTR(pwm4, 0644, get_pwm, set_pwm, 3);
+static SENSOR_DEVICE_ATTR(pwm1_enable, 0644,
+		get_pwm_enable, set_pwm_enable, 0);
+static SENSOR_DEVICE_ATTR(pwm2_enable, 0644,
+		get_pwm_enable, set_pwm_enable, 1);
+static SENSOR_DEVICE_ATTR(pwm3_enable, 0644,
+		get_pwm_enable, set_pwm_enable, 2);
+static SENSOR_DEVICE_ATTR(pwm4_enable, 0644,
+		get_pwm_enable, set_pwm_enable, 3);
+
+static struct attribute *ctf2304_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	&sensor_dev_attr_temp4_input.dev_attr.attr,
+	&sensor_dev_attr_temp5_input.dev_attr.attr,
+	&sensor_dev_attr_temp6_input.dev_attr.attr,
+	&sensor_dev_attr_temp7_input.dev_attr.attr,
+	&sensor_dev_attr_temp8_input.dev_attr.attr,
+	&sensor_dev_attr_temp9_input.dev_attr.attr,
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+	&sensor_dev_attr_in7_input.dev_attr.attr,
+	&sensor_dev_attr_in8_input.dev_attr.attr,
+	&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_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_fan1_div.dev_attr.attr,
+	&sensor_dev_attr_fan2_div.dev_attr.attr,
+	&sensor_dev_attr_fan3_div.dev_attr.attr,
+	&sensor_dev_attr_fan4_div.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_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,
+	NULL
+};
+
+ATTRIBUTE_GROUPS(ctf2304);
+
+static int ctf2304_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ctf2304_data *data;
+	struct device *hwmon_dev;
+
+	data = devm_kzalloc(dev, sizeof(struct ctf2304_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->update_lock);
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
+							   data,
+							   ctf2304_groups);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ctf2304_id[] = {
+	{ "ctf2304", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ctf2304_id);
+
+static struct i2c_driver ctf2304_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.probe		= ctf2304_probe,
+	.driver = {
+		.name	= "ctf2304",
+	},
+	.id_table	= ctf2304_id,
+};
+
+module_i2c_driver(ctf2304_driver);
+
+MODULE_AUTHOR("Il Han <corone.il.han@gmail.com>");
+MODULE_DESCRIPTION("CTF2304 sensor driver");
+MODULE_LICENSE("GPL");
-- 
2.26.2