hwmon: driver for Texas Instruments amc6821 chip

Signed-off-by: <tomaz.mertelj@guest.arnes.si>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 1127 insertions, 0 deletions

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 46c3c56..07a0f03 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -792,6 +792,16 @@ config SENSORS_ADS7828
 	  This driver can also be built as a module.  If so, the module
 	  will be called ads7828.
 
+config SENSORS_AMC6821
+	tristate "Texas Instruments AMC6821"
+	depends on I2C  && EXPERIMENTAL
+	help
+	  If you say yes here you get support for the Texas Instruments
+	  AMC6821 hardware monitoring chips.
+
+	  This driver can also be build as a module.  If so, the module
+	  will be called amc6821.
+
 config SENSORS_THMC50
 	tristate "Texas Instruments THMC50 / Analog Devices ADM1022"
 	depends on I2C && EXPERIMENTAL
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 450c8e8..4bc215c 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_SENSORS_SIS5595)	+= sis5595.o
 obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
+obj-$(CONFIG_SENSORS_AMC6821)	+= amc6821.o
 obj-$(CONFIG_SENSORS_THMC50)	+= thmc50.o
 obj-$(CONFIG_SENSORS_TMP401)	+= tmp401.o
 obj-$(CONFIG_SENSORS_TMP421)	+= tmp421.o
diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
new file mode 100644
index 0000000..1c89d92
--- /dev/null
+++ b/drivers/hwmon/amc6821.c
@@ -0,0 +1,1116 @@
+/*
+	amc6821.c - Part of lm_sensors, Linux kernel modules for hardware
+	monitoring
+	Copyright (C) 2009 T. Mertelj <tomaz.mertelj@guest.arnes.si>
+
+	Based on max6650.c:
+	Copyright (C) 2007 Hans J. Koch <hjk@linutronix.de>
+
+	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.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to the Free Software
+	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+
+#include <linux/kernel.h>	/* Needed for KERN_INFO */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+
+/*
+ * Addresses to scan.
+ */
+
+static const unsigned short normal_i2c[] = {0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e,
+	0x4c, 0x4d, 0x4e, I2C_CLIENT_END};
+
+
+
+/*
+ * Insmod parameters
+ */
+
+static int pwminv = 0;	/*Inverted PWM output. */
+module_param(pwminv, int, S_IRUGO);
+
+static int init = 1; /*Power-on initialization.*/
+module_param(init, int, S_IRUGO);
+
+
+enum chips { amc6821 };
+
+#define AMC6821_REG_DEV_ID 0x3D
+#define AMC6821_REG_COMP_ID 0x3E
+#define AMC6821_REG_CONF1 0x00
+#define AMC6821_REG_CONF2 0x01
+#define AMC6821_REG_CONF3 0x3F
+#define AMC6821_REG_CONF4 0x04
+#define AMC6821_REG_STAT1 0x02
+#define AMC6821_REG_STAT2 0x03
+#define AMC6821_REG_TDATA_LOW 0x08
+#define AMC6821_REG_TDATA_HI 0x09
+#define AMC6821_REG_LTEMP_HI 0x0A
+#define AMC6821_REG_RTEMP_HI 0x0B
+#define AMC6821_REG_LTEMP_LIMIT_MIN 0x15
+#define AMC6821_REG_LTEMP_LIMIT_MAX 0x14
+#define AMC6821_REG_RTEMP_LIMIT_MIN 0x19
+#define AMC6821_REG_RTEMP_LIMIT_MAX 0x18
+#define AMC6821_REG_LTEMP_CRIT 0x1B
+#define AMC6821_REG_RTEMP_CRIT 0x1D
+#define AMC6821_REG_PSV_TEMP 0x1C
+#define AMC6821_REG_DCY 0x22
+#define AMC6821_REG_LTEMP_FAN_CTRL 0x24
+#define AMC6821_REG_RTEMP_FAN_CTRL 0x25
+#define AMC6821_REG_DCY_LOW_TEMP 0x21
+
+#define AMC6821_REG_TACH_LLIMITL 0x10
+#define AMC6821_REG_TACH_LLIMITH 0x11
+#define AMC6821_REG_TACH_HLIMITL 0x12
+#define AMC6821_REG_TACH_HLIMITH 0x13
+
+#define AMC6821_CONF1_START 0x01
+#define AMC6821_CONF1_FAN_INT_EN 0x02
+#define AMC6821_CONF1_FANIE 0x04
+#define AMC6821_CONF1_PWMINV 0x08
+#define AMC6821_CONF1_FAN_FAULT_EN 0x10
+#define AMC6821_CONF1_FDRC0 0x20
+#define AMC6821_CONF1_FDRC1 0x40
+#define AMC6821_CONF1_THERMOVIE 0x80
+
+#define AMC6821_CONF2_PWM_EN 0x01
+#define AMC6821_CONF2_TACH_MODE 0x02
+#define AMC6821_CONF2_TACH_EN 0x04
+#define AMC6821_CONF2_RTFIE 0x08
+#define AMC6821_CONF2_LTOIE 0x10
+#define AMC6821_CONF2_RTOIE 0x20
+#define AMC6821_CONF2_PSVIE 0x40
+#define AMC6821_CONF2_RST 0x80
+
+#define AMC6821_CONF3_THERM_FAN_EN 0x80
+#define AMC6821_CONF3_REV_MASK 0x0F
+
+#define AMC6821_CONF4_OVREN 0x10
+#define AMC6821_CONF4_TACH_FAST 0x20
+#define AMC6821_CONF4_PSPR 0x40
+#define AMC6821_CONF4_MODE 0x80
+
+#define AMC6821_STAT1_RPM_ALARM 0x01
+#define AMC6821_STAT1_FANS 0x02
+#define AMC6821_STAT1_RTH 0x04
+#define AMC6821_STAT1_RTL 0x08
+#define AMC6821_STAT1_R_THERM 0x10
+#define AMC6821_STAT1_RTF 0x20
+#define AMC6821_STAT1_LTH 0x40
+#define AMC6821_STAT1_LTL 0x80
+
+#define AMC6821_STAT2_RTC 0x08
+#define AMC6821_STAT2_LTC 0x10
+#define AMC6821_STAT2_LPSV 0x20
+#define AMC6821_STAT2_L_THERM 0x40
+#define AMC6821_STAT2_THERM_IN 0x80
+
+enum {IDX_TEMP1_INPUT = 0, IDX_TEMP1_MIN, IDX_TEMP1_MAX,
+	IDX_TEMP1_CRIT, IDX_TEMP2_INPUT, IDX_TEMP2_MIN,
+	IDX_TEMP2_MAX, IDX_TEMP2_CRIT,
+	TEMP_IDX_LEN, };
+
+static const u8 temp_reg[] = {AMC6821_REG_LTEMP_HI,
+			AMC6821_REG_LTEMP_LIMIT_MIN,
+			AMC6821_REG_LTEMP_LIMIT_MAX,
+			AMC6821_REG_LTEMP_CRIT,
+			AMC6821_REG_RTEMP_HI,
+			AMC6821_REG_RTEMP_LIMIT_MIN,
+			AMC6821_REG_RTEMP_LIMIT_MAX,
+			AMC6821_REG_RTEMP_CRIT, };
+
+enum {IDX_FAN1_INPUT = 0, IDX_FAN1_MIN, IDX_FAN1_MAX,
+	FAN1_IDX_LEN, };
+
+static const u8 fan_reg_low[] = {AMC6821_REG_TDATA_LOW,
+			AMC6821_REG_TACH_LLIMITL,
+			AMC6821_REG_TACH_HLIMITL, };
+
+
+static const u8 fan_reg_hi[] = {AMC6821_REG_TDATA_HI,
+			AMC6821_REG_TACH_LLIMITH,
+			AMC6821_REG_TACH_HLIMITH, };
+
+static int amc6821_probe(
+		struct i2c_client *client,
+		const struct i2c_device_id *id);
+static int amc6821_detect(
+		struct i2c_client *client,
+		struct i2c_board_info *info);
+static int amc6821_init_client(struct i2c_client *client);
+static int amc6821_remove(struct i2c_client *client);
+static struct amc6821_data *amc6821_update_device(struct device *dev);
+
+/*
+ * Driver data (common to all clients)
+ */
+
+static const struct i2c_device_id amc6821_id[] = {
+	{ "amc6821", amc6821 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, amc6821_id);
+
+static struct i2c_driver amc6821_driver = {
+	.class = I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "amc6821",
+	},
+	.probe = amc6821_probe,
+	.remove = amc6821_remove,
+	.id_table = amc6821_id,
+	.detect = amc6821_detect,
+	.address_list = normal_i2c,
+};
+
+
+/*
+ * Client data (each client gets its own)
+  */
+
+struct amc6821_data {
+	struct device *hwmon_dev;
+	struct mutex update_lock;
+	char valid; /* zero until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* register values */
+	int temp[TEMP_IDX_LEN];
+
+	u16 fan[FAN1_IDX_LEN];
+	u8 fan1_div;
+
+	u8 pwm1;
+	u8 temp1_auto_point_temp[3];
+	u8 temp2_auto_point_temp[3];
+	u8 pwm1_auto_point_pwm[3];
+	u8 pwm1_enable;
+	u8 pwm1_auto_channels_temp;
+
+	u8 stat1;
+	u8 stat2;
+};
+
+
+static ssize_t get_temp(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	int ix = to_sensor_dev_attr(devattr)->index;
+
+	return sprintf(buf, "%d\n", data->temp[ix] * 1000);
+}
+
+
+
+static ssize_t set_temp(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	int ix = to_sensor_dev_attr(attr)->index;
+	long val;
+
+	int ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+	val = SENSORS_LIMIT(val / 1000, -128, 127);
+
+	mutex_lock(&data->update_lock);
+	data->temp[ix] = val;
+	if (i2c_smbus_write_byte_data(client, temp_reg[ix], data->temp[ix])) {
+		dev_err(&client->dev, "Register write error, aborting.\n");
+		count = -EIO;
+	}
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+
+
+
+static ssize_t get_temp_alarm(
+	struct device *dev,
+	struct device_attribute *devattr,
+	char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	int ix = to_sensor_dev_attr(devattr)->index;
+	u8 flag;
+
+	switch (ix) {
+	case IDX_TEMP1_MIN:
+		flag = data->stat1 & AMC6821_STAT1_LTL;
+		break;
+	case IDX_TEMP1_MAX:
+		flag = data->stat1 & AMC6821_STAT1_LTH;
+		break;
+	case IDX_TEMP1_CRIT:
+		flag = data->stat2 & AMC6821_STAT2_LTC;
+		break;
+	case IDX_TEMP2_MIN:
+		flag = data->stat1 & AMC6821_STAT1_RTL;
+		break;
+	case IDX_TEMP2_MAX:
+		flag = data->stat1 & AMC6821_STAT1_RTH;
+		break;
+	case IDX_TEMP2_CRIT:
+		flag = data->stat2 & AMC6821_STAT2_RTC;
+		break;
+	default:
+		dev_dbg(dev, "Unknown attr->index (%d).\n", ix);
+		return -EINVAL;
+	}
+	if (flag)
+		return sprintf(buf, "1");
+	else
+		return sprintf(buf, "0");
+}
+
+
+
+
+static ssize_t get_temp2_fault(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	if (data->stat1 & AMC6821_STAT1_RTF)
+		return sprintf(buf, "1");
+	else
+		return sprintf(buf, "0");
+}
+
+static ssize_t get_pwm1(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	return sprintf(buf, "%d\n", data->pwm1);
+}
+
+static ssize_t set_pwm1(
+		struct device *dev,
+		struct device_attribute *devattr,
+		const char *buf,
+		size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	long val;
+	int ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->update_lock);
+	data->pwm1 = SENSORS_LIMIT(val , 0, 255);
+	i2c_smbus_write_byte_data(client, AMC6821_REG_DCY, data->pwm1);
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static ssize_t get_pwm1_enable(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	return sprintf(buf, "%d\n", data->pwm1_enable);
+}
+
+static ssize_t set_pwm1_enable(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	long val;
+	int config = strict_strtol(buf, 10, &val);
+	if (config)
+		return config;
+
+	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
+	if (config < 0) {
+			dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+			return -EIO;
+	}
+
+	switch (val) {
+	case 1:
+		config &= ~AMC6821_CONF1_FDRC0;
+		config &= ~AMC6821_CONF1_FDRC1;
+		break;
+	case 2:
+		config &= ~AMC6821_CONF1_FDRC0;
+		config |= AMC6821_CONF1_FDRC1;
+		break;
+	case 3:
+		config |= AMC6821_CONF1_FDRC0;
+		config |= AMC6821_CONF1_FDRC1;
+		break;
+	default:
+		return -EINVAL;
+	}
+	mutex_lock(&data->update_lock);
+	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF1, config)) {
+			dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+			count = -EIO;
+	}
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+
+static ssize_t get_pwm1_auto_channels_temp(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	return sprintf(buf, "%d\n", data->pwm1_auto_channels_temp);
+}
+
+
+static ssize_t get_temp_auto_point_temp(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	int ix = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+	struct amc6821_data *data = amc6821_update_device(dev);
+	switch (nr) {
+	case 1:
+		return sprintf(buf, "%d\n",
+			data->temp1_auto_point_temp[ix] * 1000);
+		break;
+	case 2:
+		return sprintf(buf, "%d\n",
+			data->temp2_auto_point_temp[ix] * 1000);
+		break;
+	default:
+		dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
+		return -EINVAL;
+	}
+}
+
+
+static ssize_t get_pwm1_auto_point_pwm(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	int ix = to_sensor_dev_attr(devattr)->index;
+	struct amc6821_data *data = amc6821_update_device(dev);
+	return sprintf(buf, "%d\n", data->pwm1_auto_point_pwm[ix]);
+}
+
+
+static inline ssize_t set_slope_register(struct i2c_client *client,
+		u8 reg,
+		u8 dpwm,
+		u8 *ptemp)
+{
+	int dt;
+	u8 tmp;
+
+	dt = ptemp[2]-ptemp[1];
+	for (tmp = 4; tmp > 0; tmp--) {
+		if (dt * (0x20 >> tmp) >= dpwm)
+			break;
+	}
+	tmp |= (ptemp[1] & 0x7C) << 1;
+	if (i2c_smbus_write_byte_data(client,
+			reg, tmp)) {
+		dev_err(&client->dev, "Register write error, aborting.\n");
+		return -EIO;
+	}
+	return 0;
+}
+
+
+
+static ssize_t set_temp_auto_point_temp(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = amc6821_update_device(dev);
+	int ix = to_sensor_dev_attr_2(attr)->index;
+	int nr = to_sensor_dev_attr_2(attr)->nr;
+	u8 *ptemp;
+	u8 reg;
+	int dpwm;
+	long val;
+	int ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	switch (nr) {
+	case 1:
+		ptemp = data->temp1_auto_point_temp;
+		reg = AMC6821_REG_LTEMP_FAN_CTRL;
+		break;
+	case 2:
+		ptemp = data->temp2_auto_point_temp;
+		reg = AMC6821_REG_RTEMP_FAN_CTRL;
+		break;
+	default:
+		dev_dbg(dev, "Unknown attr->nr (%d).\n", nr);
+		return -EINVAL;
+	}
+
+	data->valid = 0;
+	mutex_lock(&data->update_lock);
+	switch (ix) {
+	case 0:
+		ptemp[0] = SENSORS_LIMIT(val / 1000, 0,
+				data->temp1_auto_point_temp[1]);
+		ptemp[0] = SENSORS_LIMIT(ptemp[0], 0,
+				data->temp2_auto_point_temp[1]);
+		ptemp[0] = SENSORS_LIMIT(ptemp[0], 0, 63);
+		if (i2c_smbus_write_byte_data(
+					client,
+					AMC6821_REG_PSV_TEMP,
+					ptemp[0])) {
+				dev_err(&client->dev,
+					"Register write error, aborting.\n");
+				count = -EIO;
+		}
+		goto EXIT;
+		break;
+	case 1:
+		ptemp[1] = SENSORS_LIMIT(
+					val / 1000,
+					(ptemp[0] & 0x7C) + 4,
+					124);
+		ptemp[1] &= 0x7C;
+		ptemp[2] = SENSORS_LIMIT(
+					ptemp[2], ptemp[1] + 1,
+					255);
+		break;
+	case 2:
+		ptemp[2] = SENSORS_LIMIT(
+					val / 1000,
+					ptemp[1]+1,
+					255);
+		break;
+	default:
+		dev_dbg(dev, "Unknown attr->index (%d).\n", ix);
+		count = -EINVAL;
+		goto EXIT;
+	}
+	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
+	if (set_slope_register(client, reg, dpwm, ptemp))
+		count = -EIO;
+
+EXIT:
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+
+
+static ssize_t set_pwm1_auto_point_pwm(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	int dpwm;
+	long val;
+	int ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&data->update_lock);
+	data->pwm1_auto_point_pwm[1] = SENSORS_LIMIT(val, 0, 254);
+	if (i2c_smbus_write_byte_data(client, AMC6821_REG_DCY_LOW_TEMP,
+			data->pwm1_auto_point_pwm[1])) {
+		dev_err(&client->dev, "Register write error, aborting.\n");
+		count = -EIO;
+		goto EXIT;
+	}
+	dpwm = data->pwm1_auto_point_pwm[2] - data->pwm1_auto_point_pwm[1];
+	if (set_slope_register(client, AMC6821_REG_LTEMP_FAN_CTRL, dpwm,
+			data->temp1_auto_point_temp)) {
+		count = -EIO;
+		goto EXIT;
+	}
+	if (set_slope_register(client, AMC6821_REG_RTEMP_FAN_CTRL, dpwm,
+			data->temp2_auto_point_temp)) {
+		count = -EIO;
+		goto EXIT;
+	}
+
+EXIT:
+	data->valid = 0;
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+static ssize_t get_fan(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	int ix = to_sensor_dev_attr(devattr)->index;
+	if (0 == data->fan[ix])
+		return sprintf(buf, "0");
+	return sprintf(buf, "%d\n", (int)(6000000 / data->fan[ix]));
+}
+
+
+
+static ssize_t get_fan1_fault(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	if (data->stat1 & AMC6821_STAT1_FANS)
+		return sprintf(buf, "1");
+	else
+		return sprintf(buf, "0");
+}
+
+
+
+static ssize_t set_fan(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	long val;
+	int ix = to_sensor_dev_attr(attr)->index;
+	int ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+	val = 1 > val ? 0xFFFF : 6000000/val;
+
+	mutex_lock(&data->update_lock);
+	data->fan[ix] = (u16) SENSORS_LIMIT(val, 1, 0xFFFF);
+	if (i2c_smbus_write_byte_data(client, fan_reg_low[ix],
+			data->fan[ix] & 0xFF)) {
+		dev_err(&client->dev, "Register write error, aborting.\n");
+		count = -EIO;
+		goto EXIT;
+	}
+	if (i2c_smbus_write_byte_data(client,
+			fan_reg_hi[ix], data->fan[ix] >> 8)) {
+		dev_err(&client->dev, "Register write error, aborting.\n");
+		count = -EIO;
+	}
+EXIT:
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+
+
+static ssize_t get_fan1_div(
+		struct device *dev,
+		struct device_attribute *devattr,
+		char *buf)
+{
+	struct amc6821_data *data = amc6821_update_device(dev);
+	return sprintf(buf, "%d\n", data->fan1_div);
+}
+
+static ssize_t set_fan1_div(
+		struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	long val;
+	int config = strict_strtol(buf, 10, &val);
+	if (config)
+		return config;
+
+	config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
+	if (config < 0) {
+		dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+		return -EIO;
+	}
+	mutex_lock(&data->update_lock);
+	switch (val) {
+	case 2:
+		config &= ~AMC6821_CONF4_PSPR;
+		data->fan1_div = 2;
+		break;
+	case 4:
+		config |= AMC6821_CONF4_PSPR;
+		data->fan1_div = 4;
+		break;
+	default:
+		mutex_unlock(&data->update_lock);
+		count = -EINVAL;
+		goto EXIT;
+	}
+	if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4, config)) {
+		dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+		count = -EIO;
+	}
+EXIT:
+	mutex_unlock(&data->update_lock);
+	return count;
+}
+
+
+
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
+	get_temp, NULL, IDX_TEMP1_INPUT);
+static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP1_MIN);
+static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP1_MAX);
+static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP1_CRIT);
+static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP1_MIN);
+static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP1_MAX);
+static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP1_CRIT);
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO | S_IWUSR,
+	get_temp, NULL, IDX_TEMP2_INPUT);
+static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP2_MIN);
+static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP2_MAX);
+static SENSOR_DEVICE_ATTR(temp2_crit, S_IRUGO | S_IWUSR, get_temp,
+	set_temp, IDX_TEMP2_CRIT);
+static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO,
+	get_temp2_fault, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP2_MIN);
+static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP2_MAX);
+static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO,
+	get_temp_alarm, NULL, IDX_TEMP2_CRIT);
+static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, get_fan, NULL, IDX_FAN1_INPUT);
+static SENSOR_DEVICE_ATTR(fan1_min, S_IRUGO | S_IWUSR,
+	get_fan, set_fan, IDX_FAN1_MIN);
+static SENSOR_DEVICE_ATTR(fan1_max, S_IRUGO | S_IWUSR,
+	get_fan, set_fan, IDX_FAN1_MAX);
+static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, get_fan1_fault, NULL, 0);
+static SENSOR_DEVICE_ATTR(fan1_div, S_IRUGO | S_IWUSR,
+	get_fan1_div, set_fan1_div, 0);
+
+static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, get_pwm1, set_pwm1, 0);
+static SENSOR_DEVICE_ATTR(pwm1_enable, S_IWUSR | S_IRUGO,
+	get_pwm1_enable, set_pwm1_enable, 0);
+static SENSOR_DEVICE_ATTR(pwm1_auto_point1_pwm, S_IRUGO,
+	get_pwm1_auto_point_pwm, NULL, 0);
+static SENSOR_DEVICE_ATTR(pwm1_auto_point2_pwm, S_IWUSR | S_IRUGO,
+	get_pwm1_auto_point_pwm, set_pwm1_auto_point_pwm, 1);
+static SENSOR_DEVICE_ATTR(pwm1_auto_point3_pwm, S_IRUGO,
+	get_pwm1_auto_point_pwm, NULL, 2);
+static SENSOR_DEVICE_ATTR(pwm1_auto_channels_temp, S_IRUGO,
+	get_pwm1_auto_channels_temp, NULL, 0);
+static SENSOR_DEVICE_ATTR_2(temp1_auto_point1_temp, S_IRUGO,
+	get_temp_auto_point_temp, NULL, 1, 0);
+static SENSOR_DEVICE_ATTR_2(temp1_auto_point2_temp, S_IWUSR | S_IRUGO,
+	get_temp_auto_point_temp, set_temp_auto_point_temp, 1, 1);
+static SENSOR_DEVICE_ATTR_2(temp1_auto_point3_temp, S_IWUSR | S_IRUGO,
+	get_temp_auto_point_temp, set_temp_auto_point_temp, 1, 2);
+
+static SENSOR_DEVICE_ATTR_2(temp2_auto_point1_temp, S_IWUSR | S_IRUGO,
+	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 0);
+static SENSOR_DEVICE_ATTR_2(temp2_auto_point2_temp, S_IWUSR | S_IRUGO,
+	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 1);
+static SENSOR_DEVICE_ATTR_2(temp2_auto_point3_temp, S_IWUSR | S_IRUGO,
+	get_temp_auto_point_temp, set_temp_auto_point_temp, 2, 2);
+
+
+
+static struct attribute *amc6821_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_min.dev_attr.attr,
+	&sensor_dev_attr_temp2_max.dev_attr.attr,
+	&sensor_dev_attr_temp2_crit.dev_attr.attr,
+	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp2_fault.dev_attr.attr,
+	&sensor_dev_attr_fan1_input.dev_attr.attr,
+	&sensor_dev_attr_fan1_min.dev_attr.attr,
+	&sensor_dev_attr_fan1_max.dev_attr.attr,
+	&sensor_dev_attr_fan1_fault.dev_attr.attr,
+	&sensor_dev_attr_fan1_div.dev_attr.attr,
+	&sensor_dev_attr_pwm1.dev_attr.attr,
+	&sensor_dev_attr_pwm1_enable.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_channels_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
+	&sensor_dev_attr_temp1_auto_point1_temp.dev_attr.attr,
+	&sensor_dev_attr_temp1_auto_point2_temp.dev_attr.attr,
+	&sensor_dev_attr_temp1_auto_point3_temp.dev_attr.attr,
+	&sensor_dev_attr_temp2_auto_point1_temp.dev_attr.attr,
+	&sensor_dev_attr_temp2_auto_point2_temp.dev_attr.attr,
+	&sensor_dev_attr_temp2_auto_point3_temp.dev_attr.attr,
+	NULL
+};
+
+static struct attribute_group amc6821_attr_grp = {
+	.attrs = amc6821_attrs,
+};
+
+
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int amc6821_detect(
+		struct i2c_client *client,
+		struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	int address = client->addr;
+	int dev_id, comp_id;
+
+	dev_dbg(&adapter->dev, "amc6821_detect called.\n");
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_dbg(&adapter->dev,
+			"amc6821: I2C bus doesn't support byte mode, "
+			"skipping.\n");
+		return -ENODEV;
+	}
+
+	dev_id = i2c_smbus_read_byte_data(client, AMC6821_REG_DEV_ID);
+	comp_id = i2c_smbus_read_byte_data(client, AMC6821_REG_COMP_ID);
+	if (dev_id != 0x21 || comp_id != 0x49) {
+		dev_dbg(&adapter->dev,
+			"amc6821: detection failed at 0x%02x.\n",
+			address);
+		return -ENODEV;
+	}
+
+	/* Bit 7 of the address register is ignored, so we can check the
+	   ID registers again */
+	dev_id = i2c_smbus_read_byte_data(client, 0x80 | AMC6821_REG_DEV_ID);
+	comp_id = i2c_smbus_read_byte_data(client, 0x80 | AMC6821_REG_COMP_ID);
+	if (dev_id != 0x21 || comp_id != 0x49) {
+		dev_dbg(&adapter->dev,
+			"amc6821: detection failed at 0x%02x.\n",
+			address);
+		return -ENODEV;
+	}
+
+	dev_info(&adapter->dev, "amc6821: chip found at 0x%02x.\n", address);
+	strlcpy(info->type, "amc6821", I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int amc6821_probe(
+	struct i2c_client *client,
+	const struct i2c_device_id *id)
+{
+	struct amc6821_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct amc6821_data), GFP_KERNEL);
+	if (!data) {
+		dev_err(&client->dev, "out of memory.\n");
+		return -ENOMEM;
+	}
+
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/*
+	 * Initialize the amc6821 chip
+	 */
+	err = amc6821_init_client(client);
+	if (err)
+		goto err_free;
+
+	err = sysfs_create_group(&client->dev.kobj, &amc6821_attr_grp);
+	if (err)
+		goto err_free;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (!IS_ERR(data->hwmon_dev))
+		return 0;
+
+	err = PTR_ERR(data->hwmon_dev);
+	dev_err(&client->dev, "error registering hwmon device.\n");
+	sysfs_remove_group(&client->dev.kobj, &amc6821_attr_grp);
+err_free:
+	kfree(data);
+	return err;
+}
+
+static int amc6821_remove(struct i2c_client *client)
+{
+	struct amc6821_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &amc6821_attr_grp);
+
+	kfree(data);
+
+	return 0;
+}
+
+
+static int amc6821_init_client(struct i2c_client *client)
+{
+	int config;
+	int err = -EIO;
+
+	if (init) {
+		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF4);
+
+		if (config < 0) {
+				dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+				return err;
+		}
+
+		config |= AMC6821_CONF4_MODE;
+
+		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF4,
+				config)) {
+			dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+			return err;
+		}
+
+		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF3);
+
+		if (config < 0) {
+			dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+			return err;
+		}
+
+		dev_info(&client->dev, "Revision %d\n", config & 0x0f);
+
+		config &= ~AMC6821_CONF3_THERM_FAN_EN;
+
+		if (i2c_smbus_write_byte_data(client, AMC6821_REG_CONF3,
+				config)) {
+			dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+			return err;
+		}
+
+		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF2);
+
+		if (config < 0) {
+			dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+			return err;
+		}
+
+		config &= ~AMC6821_CONF2_RTFIE;
+		config &= ~AMC6821_CONF2_LTOIE;
+		config &= ~AMC6821_CONF2_RTOIE;
+		if (i2c_smbus_write_byte_data(client,
+				AMC6821_REG_CONF2, config)) {
+			dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+			return err;
+		}
+
+		config = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
+
+		if (config < 0) {
+			dev_err(&client->dev,
+			"Error reading configuration register, aborting.\n");
+			return err;
+		}
+
+		config &= ~AMC6821_CONF1_THERMOVIE;
+		config &= ~AMC6821_CONF1_FANIE;
+		config |= AMC6821_CONF1_START;
+		if (pwminv)
+			config |= AMC6821_CONF1_PWMINV;
+		else
+			config &= ~AMC6821_CONF1_PWMINV;
+
+		if (i2c_smbus_write_byte_data(
+				client, AMC6821_REG_CONF1, config)) {
+			dev_err(&client->dev,
+			"Configuration register write error, aborting.\n");
+			return err;
+		}
+	}
+	return 0;
+}
+
+
+static struct amc6821_data *amc6821_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct amc6821_data *data = i2c_get_clientdata(client);
+	int timeout = HZ;
+	u8 reg;
+	int i;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + timeout) ||
+			!data->valid) {
+
+		for (i = 0; i < TEMP_IDX_LEN; i++)
+			data->temp[i] = i2c_smbus_read_byte_data(client,
+				temp_reg[i]);
+
+		data->stat1 = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_STAT1);
+		data->stat2 = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_STAT2);
+
+		data->pwm1 = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_DCY);
+		for (i = 0; i < FAN1_IDX_LEN; i++) {
+			data->fan[i] = i2c_smbus_read_byte_data(
+					client,
+					fan_reg_low[i]);
+			data->fan[i] += i2c_smbus_read_byte_data(
+					client,
+					fan_reg_hi[i]) << 8;
+		}
+		data->fan1_div = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_CONF4);
+		data->fan1_div = data->fan1_div & AMC6821_CONF4_PSPR ? 4 : 2;
+
+		data->pwm1_auto_point_pwm[0] = 0;
+		data->pwm1_auto_point_pwm[2] = 255;
+		data->pwm1_auto_point_pwm[1] = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_DCY_LOW_TEMP);
+
+		data->temp1_auto_point_temp[0] =
+			i2c_smbus_read_byte_data(client,
+					AMC6821_REG_PSV_TEMP);
+		data->temp2_auto_point_temp[0] =
+				data->temp1_auto_point_temp[0];
+		reg = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_LTEMP_FAN_CTRL);
+		data->temp1_auto_point_temp[1] = (reg & 0xF8) >> 1;
+		reg &= 0x07;
+		reg = 0x20 >> reg;
+		if (reg > 0)
+			data->temp1_auto_point_temp[2] =
+				data->temp1_auto_point_temp[1] +
+				(data->pwm1_auto_point_pwm[2] -
+				data->pwm1_auto_point_pwm[1]) / reg;
+		else
+			data->temp1_auto_point_temp[2] = 255;
+
+		reg = i2c_smbus_read_byte_data(client,
+			AMC6821_REG_RTEMP_FAN_CTRL);
+		data->temp2_auto_point_temp[1] = (reg & 0xF8) >> 1;
+		reg &= 0x07;
+		reg = 0x20 >> reg;
+		if (reg > 0)
+			data->temp2_auto_point_temp[2] =
+				data->temp2_auto_point_temp[1] +
+				(data->pwm1_auto_point_pwm[2] -
+				data->pwm1_auto_point_pwm[1]) / reg;
+		else
+			data->temp2_auto_point_temp[2] = 255;
+
+		reg = i2c_smbus_read_byte_data(client, AMC6821_REG_CONF1);
+		reg = (reg >> 5) & 0x3;
+		switch (reg) {
+		case 0: /*open loop: software sets pwm1*/
+			data->pwm1_auto_channels_temp = 0;
+			data->pwm1_enable = 1;
+			break;
+		case 2: /*closed loop: remote T (temp2)*/
+			data->pwm1_auto_channels_temp = 2;
+			data->pwm1_enable = 2;
+			break;
+		case 3: /*closed loop: local and remote T (temp2)*/
+			data->pwm1_auto_channels_temp = 3;
+			data->pwm1_enable = 3;
+			break;
+		case 1: /*semi-open loop: software sets rpm, chip controls pwm1,
+			  *currently not implemented
+			  */
+			data->pwm1_auto_channels_temp = 0;
+			data->pwm1_enable = 0;
+			break;
+		}
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+	mutex_unlock(&data->update_lock);
+	return data;
+}
+
+
+static int __init amc6821_init(void)
+{
+	return i2c_add_driver(&amc6821_driver);
+}
+
+static void __exit amc6821_exit(void)
+{
+	i2c_del_driver(&amc6821_driver);
+}
+
+module_init(amc6821_init);
+module_exit(amc6821_exit);
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("T. Mertelj <tomaz.mertelj@guest.arnes.si>");
+MODULE_DESCRIPTION("Texas Instruments amc6821 hwmon driver");