Linux 3.12.39

[linux/fpc-iii.git] / drivers / hwmon / lm80.c

/*
 * lm80.c - From lm_sensors, Linux kernel modules for hardware
 *          monitoring
 * Copyright (C) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
 *                           and Philip Edelbrock <phil@netroedge.com>
 *
 * Ported to Linux 2.6 by Tiago Sousa <mirage@kaotik.org>
 *
 * 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/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[] = { 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d,
                                                0x2e, 0x2f, I2C_CLIENT_END };

/* Many LM80 constants specified below */

/* The LM80 registers */
#define LM80_REG_IN_MAX(nr)             (0x2a + (nr) * 2)
#define LM80_REG_IN_MIN(nr)             (0x2b + (nr) * 2)
#define LM80_REG_IN(nr)                 (0x20 + (nr))

#define LM80_REG_FAN1                   0x28
#define LM80_REG_FAN2                   0x29
#define LM80_REG_FAN_MIN(nr)            (0x3b + (nr))

#define LM80_REG_TEMP                   0x27
#define LM80_REG_TEMP_HOT_MAX           0x38
#define LM80_REG_TEMP_HOT_HYST          0x39
#define LM80_REG_TEMP_OS_MAX            0x3a
#define LM80_REG_TEMP_OS_HYST           0x3b

#define LM80_REG_CONFIG                 0x00
#define LM80_REG_ALARM1                 0x01
#define LM80_REG_ALARM2                 0x02
#define LM80_REG_MASK1                  0x03
#define LM80_REG_MASK2                  0x04
#define LM80_REG_FANDIV                 0x05
#define LM80_REG_RES                    0x06

#define LM96080_REG_CONV_RATE           0x07
#define LM96080_REG_MAN_ID              0x3e
#define LM96080_REG_DEV_ID              0x3f


/*
 * Conversions. Rounding and limit checking is only done on the TO_REG
 * variants. Note that you should be a bit careful with which arguments
 * these macros are called: arguments may be evaluated more than once.
 * Fixing this is just not worth it.
 */

#define IN_TO_REG(val)          (clamp_val(((val) + 5) / 10, 0, 255))
#define IN_FROM_REG(val)        ((val) * 10)

static inline unsigned char FAN_TO_REG(unsigned rpm, unsigned div)
{
        if (rpm == 0)
                return 255;
        rpm = clamp_val(rpm, 1, 1000000);
        return clamp_val((1350000 + rpm * div / 2) / (rpm * div), 1, 254);
}

#define FAN_FROM_REG(val, div)  ((val) == 0 ? -1 : \
                                (val) == 255 ? 0 : 1350000/((div) * (val)))

static inline long TEMP_FROM_REG(u16 temp)
{
        long res;

        temp >>= 4;
        if (temp < 0x0800)
                res = 625 * (long) temp;
        else
                res = ((long) temp - 0x01000) * 625;

        return res / 10;
}

#define TEMP_LIMIT_FROM_REG(val)        (((val) > 0x80 ? \
        (val) - 0x100 : (val)) * 1000)

#define TEMP_LIMIT_TO_REG(val)          clamp_val((val) < 0 ? \
        ((val) - 500) / 1000 : ((val) + 500) / 1000, 0, 255)

#define DIV_FROM_REG(val)               (1 << (val))

/*
 * Client data (each client gets its own)
 */

struct lm80_data {
        struct device *hwmon_dev;
        struct mutex update_lock;
        char error;             /* !=0 if error occurred during last update */
        char valid;             /* !=0 if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        u8 in[7];               /* Register value */
        u8 in_max[7];           /* Register value */
        u8 in_min[7];           /* Register value */
        u8 fan[2];              /* Register value */
        u8 fan_min[2];          /* Register value */
        u8 fan_div[2];          /* Register encoding, shifted right */
        u16 temp;               /* Register values, shifted right */
        u8 temp_hot_max;        /* Register value */
        u8 temp_hot_hyst;       /* Register value */
        u8 temp_os_max;         /* Register value */
        u8 temp_os_hyst;        /* Register value */
        u16 alarms;             /* Register encoding, combined */
};

/*
 * Functions declaration
 */

static int lm80_probe(struct i2c_client *client,
                      const struct i2c_device_id *id);
static int lm80_detect(struct i2c_client *client, struct i2c_board_info *info);
static void lm80_init_client(struct i2c_client *client);
static int lm80_remove(struct i2c_client *client);
static struct lm80_data *lm80_update_device(struct device *dev);
static int lm80_read_value(struct i2c_client *client, u8 reg);
static int lm80_write_value(struct i2c_client *client, u8 reg, u8 value);

/*
 * Driver data (common to all clients)
 */

static const struct i2c_device_id lm80_id[] = {
        { "lm80", 0 },
        { "lm96080", 1 },
        { }
};
MODULE_DEVICE_TABLE(i2c, lm80_id);

static struct i2c_driver lm80_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "lm80",
        },
        .probe          = lm80_probe,
        .remove         = lm80_remove,
        .id_table       = lm80_id,
        .detect         = lm80_detect,
        .address_list   = normal_i2c,
};

/*
 * Sysfs stuff
 */

#define show_in(suffix, value) \
static ssize_t show_in_##suffix(struct device *dev, \
        struct device_attribute *attr, char *buf) \
{ \
        int nr = to_sensor_dev_attr(attr)->index; \
        struct lm80_data *data = lm80_update_device(dev); \
        if (IS_ERR(data)) \
                return PTR_ERR(data); \
        return sprintf(buf, "%d\n", IN_FROM_REG(data->value[nr])); \
}
show_in(min, in_min)
show_in(max, in_max)
show_in(input, in)

#define set_in(suffix, value, reg) \
static ssize_t set_in_##suffix(struct device *dev, \
        struct device_attribute *attr, const char *buf, size_t count) \
{ \
        int nr = to_sensor_dev_attr(attr)->index; \
        struct i2c_client *client = to_i2c_client(dev); \
        struct lm80_data *data = i2c_get_clientdata(client); \
        long val; \
        int err = kstrtol(buf, 10, &val); \
        if (err < 0) \
                return err; \
\
        mutex_lock(&data->update_lock);\
        data->value[nr] = IN_TO_REG(val); \
        lm80_write_value(client, reg(nr), data->value[nr]); \
        mutex_unlock(&data->update_lock);\
        return count; \
}
set_in(min, in_min, LM80_REG_IN_MIN)
set_in(max, in_max, LM80_REG_IN_MAX)

#define show_fan(suffix, value) \
static ssize_t show_fan_##suffix(struct device *dev, \
        struct device_attribute *attr, char *buf) \
{ \
        int nr = to_sensor_dev_attr(attr)->index; \
        struct lm80_data *data = lm80_update_device(dev); \
        if (IS_ERR(data)) \
                return PTR_ERR(data); \
        return sprintf(buf, "%d\n", FAN_FROM_REG(data->value[nr], \
                       DIV_FROM_REG(data->fan_div[nr]))); \
}
show_fan(min, fan_min)
show_fan(input, fan)

static ssize_t show_fan_div(struct device *dev, struct device_attribute *attr,
        char *buf)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct lm80_data *data = lm80_update_device(dev);
        if (IS_ERR(data))
                return PTR_ERR(data);
        return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[nr]));
}

static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
        const char *buf, size_t count)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct i2c_client *client = to_i2c_client(dev);
        struct lm80_data *data = i2c_get_clientdata(client);
        unsigned long val;
        int err = kstrtoul(buf, 10, &val);
        if (err < 0)
                return err;

        mutex_lock(&data->update_lock);
        data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
        lm80_write_value(client, LM80_REG_FAN_MIN(nr + 1), data->fan_min[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}

/*
 * Note: we save and restore the fan minimum here, because its value is
 * determined in part by the fan divisor.  This follows the principle of
 * least surprise; the user doesn't expect the fan minimum to change just
 * because the divisor changed.
 */
static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
        const char *buf, size_t count)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct i2c_client *client = to_i2c_client(dev);
        struct lm80_data *data = i2c_get_clientdata(client);
        unsigned long min, val;
        u8 reg;
        int err = kstrtoul(buf, 10, &val);
        if (err < 0)
                return err;

        /* Save fan_min */
        mutex_lock(&data->update_lock);
        min = FAN_FROM_REG(data->fan_min[nr],
                           DIV_FROM_REG(data->fan_div[nr]));

        switch (val) {
        case 1:
                data->fan_div[nr] = 0;
                break;
        case 2:
                data->fan_div[nr] = 1;
                break;
        case 4:
                data->fan_div[nr] = 2;
                break;
        case 8:
                data->fan_div[nr] = 3;
                break;
        default:
                dev_err(&client->dev,
                        "fan_div value %ld not supported. Choose one of 1, 2, 4 or 8!\n",
                        val);
                mutex_unlock(&data->update_lock);
                return -EINVAL;
        }

        reg = (lm80_read_value(client, LM80_REG_FANDIV) & ~(3 << (2 * (nr + 1))))
            | (data->fan_div[nr] << (2 * (nr + 1)));
        lm80_write_value(client, LM80_REG_FANDIV, reg);

        /* Restore fan_min */
        data->fan_min[nr] = FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));
        lm80_write_value(client, LM80_REG_FAN_MIN(nr + 1), data->fan_min[nr]);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t show_temp_input1(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct lm80_data *data = lm80_update_device(dev);
        if (IS_ERR(data))
                return PTR_ERR(data);
        return sprintf(buf, "%ld\n", TEMP_FROM_REG(data->temp));
}

#define show_temp(suffix, value) \
static ssize_t show_temp_##suffix(struct device *dev, \
        struct device_attribute *attr, char *buf) \
{ \
        struct lm80_data *data = lm80_update_device(dev); \
        if (IS_ERR(data)) \
                return PTR_ERR(data); \
        return sprintf(buf, "%d\n", TEMP_LIMIT_FROM_REG(data->value)); \
}
show_temp(hot_max, temp_hot_max);
show_temp(hot_hyst, temp_hot_hyst);
show_temp(os_max, temp_os_max);
show_temp(os_hyst, temp_os_hyst);

#define set_temp(suffix, value, reg) \
static ssize_t set_temp_##suffix(struct device *dev, \
        struct device_attribute *attr, const char *buf, size_t count) \
{ \
        struct i2c_client *client = to_i2c_client(dev); \
        struct lm80_data *data = i2c_get_clientdata(client); \
        long val; \
        int err = kstrtol(buf, 10, &val); \
        if (err < 0) \
                return err; \
\
        mutex_lock(&data->update_lock); \
        data->value = TEMP_LIMIT_TO_REG(val); \
        lm80_write_value(client, reg, data->value); \
        mutex_unlock(&data->update_lock); \
        return count; \
}
set_temp(hot_max, temp_hot_max, LM80_REG_TEMP_HOT_MAX);
set_temp(hot_hyst, temp_hot_hyst, LM80_REG_TEMP_HOT_HYST);
set_temp(os_max, temp_os_max, LM80_REG_TEMP_OS_MAX);
set_temp(os_hyst, temp_os_hyst, LM80_REG_TEMP_OS_HYST);

static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
                           char *buf)
{
        struct lm80_data *data = lm80_update_device(dev);
        if (IS_ERR(data))
                return PTR_ERR(data);
        return sprintf(buf, "%u\n", data->alarms);
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
                          char *buf)
{
        int bitnr = to_sensor_dev_attr(attr)->index;
        struct lm80_data *data = lm80_update_device(dev);
        if (IS_ERR(data))
                return PTR_ERR(data);
        return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}

static SENSOR_DEVICE_ATTR(in0_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 0);
static SENSOR_DEVICE_ATTR(in1_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 1);
static SENSOR_DEVICE_ATTR(in2_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 2);
static SENSOR_DEVICE_ATTR(in3_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 3);
static SENSOR_DEVICE_ATTR(in4_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 4);
static SENSOR_DEVICE_ATTR(in5_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 5);
static SENSOR_DEVICE_ATTR(in6_min, S_IWUSR | S_IRUGO,
                show_in_min, set_in_min, 6);
static SENSOR_DEVICE_ATTR(in0_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 0);
static SENSOR_DEVICE_ATTR(in1_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 1);
static SENSOR_DEVICE_ATTR(in2_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 2);
static SENSOR_DEVICE_ATTR(in3_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 3);
static SENSOR_DEVICE_ATTR(in4_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 4);
static SENSOR_DEVICE_ATTR(in5_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 5);
static SENSOR_DEVICE_ATTR(in6_max, S_IWUSR | S_IRUGO,
                show_in_max, set_in_max, 6);
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, show_in_input, NULL, 0);
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, show_in_input, NULL, 1);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, show_in_input, NULL, 2);
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, show_in_input, NULL, 3);
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, show_in_input, NULL, 4);
static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, show_in_input, NULL, 5);
static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, show_in_input, NULL, 6);
static SENSOR_DEVICE_ATTR(fan1_min, S_IWUSR | S_IRUGO,
                show_fan_min, set_fan_min, 0);
static SENSOR_DEVICE_ATTR(fan2_min, S_IWUSR | S_IRUGO,
                show_fan_min, set_fan_min, 1);
static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL, 0);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan_input, NULL, 1);
static SENSOR_DEVICE_ATTR(fan1_div, S_IWUSR | S_IRUGO,
                show_fan_div, set_fan_div, 0);
static SENSOR_DEVICE_ATTR(fan2_div, S_IWUSR | S_IRUGO,
                show_fan_div, set_fan_div, 1);
static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input1, NULL);
static DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_hot_max,
        set_temp_hot_max);
static DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_hot_hyst,
        set_temp_hot_hyst);
static DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp_os_max,
        set_temp_os_max);
static DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_os_hyst,
        set_temp_os_hyst);
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static SENSOR_DEVICE_ATTR(in0_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(in1_alarm, S_IRUGO, show_alarm, NULL, 1);
static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(in3_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(in4_alarm, S_IRUGO, show_alarm, NULL, 4);
static SENSOR_DEVICE_ATTR(in5_alarm, S_IRUGO, show_alarm, NULL, 5);
static SENSOR_DEVICE_ATTR(in6_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_alarm, NULL, 10);
static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_alarm, NULL, 11);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 8);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 13);

/*
 * Real code
 */

static struct attribute *lm80_attributes[] = {
        &sensor_dev_attr_in0_min.dev_attr.attr,
        &sensor_dev_attr_in1_min.dev_attr.attr,
        &sensor_dev_attr_in2_min.dev_attr.attr,
        &sensor_dev_attr_in3_min.dev_attr.attr,
        &sensor_dev_attr_in4_min.dev_attr.attr,
        &sensor_dev_attr_in5_min.dev_attr.attr,
        &sensor_dev_attr_in6_min.dev_attr.attr,
        &sensor_dev_attr_in0_max.dev_attr.attr,
        &sensor_dev_attr_in1_max.dev_attr.attr,
        &sensor_dev_attr_in2_max.dev_attr.attr,
        &sensor_dev_attr_in3_max.dev_attr.attr,
        &sensor_dev_attr_in4_max.dev_attr.attr,
        &sensor_dev_attr_in5_max.dev_attr.attr,
        &sensor_dev_attr_in6_max.dev_attr.attr,
        &sensor_dev_attr_in0_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_fan1_min.dev_attr.attr,
        &sensor_dev_attr_fan2_min.dev_attr.attr,
        &sensor_dev_attr_fan1_input.dev_attr.attr,
        &sensor_dev_attr_fan2_input.dev_attr.attr,
        &sensor_dev_attr_fan1_div.dev_attr.attr,
        &sensor_dev_attr_fan2_div.dev_attr.attr,
        &dev_attr_temp1_input.attr,
        &dev_attr_temp1_max.attr,
        &dev_attr_temp1_max_hyst.attr,
        &dev_attr_temp1_crit.attr,
        &dev_attr_temp1_crit_hyst.attr,
        &dev_attr_alarms.attr,
        &sensor_dev_attr_in0_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_alarm.dev_attr.attr,
        &sensor_dev_attr_in2_alarm.dev_attr.attr,
        &sensor_dev_attr_in3_alarm.dev_attr.attr,
        &sensor_dev_attr_in4_alarm.dev_attr.attr,
        &sensor_dev_attr_in5_alarm.dev_attr.attr,
        &sensor_dev_attr_in6_alarm.dev_attr.attr,
        &sensor_dev_attr_fan1_alarm.dev_attr.attr,
        &sensor_dev_attr_fan2_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
        NULL
};

static const struct attribute_group lm80_group = {
        .attrs = lm80_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm80_detect(struct i2c_client *client, struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int i, cur, man_id, dev_id;
        const char *name = NULL;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -ENODEV;

        /* First check for unused bits, common to both chip types */
        if ((lm80_read_value(client, LM80_REG_ALARM2) & 0xc0)
         || (lm80_read_value(client, LM80_REG_CONFIG) & 0x80))
                return -ENODEV;

        /*
         * The LM96080 has manufacturer and stepping/die rev registers so we
         * can just check that. The LM80 does not have such registers so we
         * have to use a more expensive trick.
         */
        man_id = lm80_read_value(client, LM96080_REG_MAN_ID);
        dev_id = lm80_read_value(client, LM96080_REG_DEV_ID);
        if (man_id == 0x01 && dev_id == 0x08) {
                /* Check more unused bits for confirmation */
                if (lm80_read_value(client, LM96080_REG_CONV_RATE) & 0xfe)
                        return -ENODEV;

                name = "lm96080";
        } else {
                /* Check 6-bit addressing */
                for (i = 0x2a; i <= 0x3d; i++) {
                        cur = i2c_smbus_read_byte_data(client, i);
                        if ((i2c_smbus_read_byte_data(client, i + 0x40) != cur)
                         || (i2c_smbus_read_byte_data(client, i + 0x80) != cur)
                         || (i2c_smbus_read_byte_data(client, i + 0xc0) != cur))
                                return -ENODEV;
                }

                name = "lm80";
        }

        strlcpy(info->type, name, I2C_NAME_SIZE);

        return 0;
}

static int lm80_probe(struct i2c_client *client,
                      const struct i2c_device_id *id)
{
        struct lm80_data *data;
        int err;

        data = devm_kzalloc(&client->dev, sizeof(struct lm80_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);

        /* Initialize the LM80 chip */
        lm80_init_client(client);

        /* A few vars need to be filled upon startup */
        data->fan_min[0] = lm80_read_value(client, LM80_REG_FAN_MIN(1));
        data->fan_min[1] = lm80_read_value(client, LM80_REG_FAN_MIN(2));

        /* Register sysfs hooks */
        err = sysfs_create_group(&client->dev.kobj, &lm80_group);
        if (err)
                return err;

        data->hwmon_dev = hwmon_device_register(&client->dev);
        if (IS_ERR(data->hwmon_dev)) {
                err = PTR_ERR(data->hwmon_dev);
                goto error_remove;
        }

        return 0;

error_remove:
        sysfs_remove_group(&client->dev.kobj, &lm80_group);
        return err;
}

static int lm80_remove(struct i2c_client *client)
{
        struct lm80_data *data = i2c_get_clientdata(client);

        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &lm80_group);

        return 0;
}

static int lm80_read_value(struct i2c_client *client, u8 reg)
{
        return i2c_smbus_read_byte_data(client, reg);
}

static int lm80_write_value(struct i2c_client *client, u8 reg, u8 value)
{
        return i2c_smbus_write_byte_data(client, reg, value);
}

/* Called when we have found a new LM80. */
static void lm80_init_client(struct i2c_client *client)
{
        /*
         * Reset all except Watchdog values and last conversion values
         * This sets fan-divs to 2, among others. This makes most other
         * initializations unnecessary
         */
        lm80_write_value(client, LM80_REG_CONFIG, 0x80);
        /* Set 11-bit temperature resolution */
        lm80_write_value(client, LM80_REG_RES, 0x08);

        /* Start monitoring */
        lm80_write_value(client, LM80_REG_CONFIG, 0x01);
}

static struct lm80_data *lm80_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lm80_data *data = i2c_get_clientdata(client);
        int i;
        int rv;
        int prev_rv;
        struct lm80_data *ret = data;

        mutex_lock(&data->update_lock);

        if (data->error)
                lm80_init_client(client);

        if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
                dev_dbg(&client->dev, "Starting lm80 update\n");
                for (i = 0; i <= 6; i++) {
                        rv = lm80_read_value(client, LM80_REG_IN(i));
                        if (rv < 0)
                                goto abort;
                        data->in[i] = rv;

                        rv = lm80_read_value(client, LM80_REG_IN_MIN(i));
                        if (rv < 0)
                                goto abort;
                        data->in_min[i] = rv;

                        rv = lm80_read_value(client, LM80_REG_IN_MAX(i));
                        if (rv < 0)
                                goto abort;
                        data->in_max[i] = rv;
                }

                rv = lm80_read_value(client, LM80_REG_FAN1);
                if (rv < 0)
                        goto abort;
                data->fan[0] = rv;

                rv = lm80_read_value(client, LM80_REG_FAN_MIN(1));
                if (rv < 0)
                        goto abort;
                data->fan_min[0] = rv;

                rv = lm80_read_value(client, LM80_REG_FAN2);
                if (rv < 0)
                        goto abort;
                data->fan[1] = rv;

                rv = lm80_read_value(client, LM80_REG_FAN_MIN(2));
                if (rv < 0)
                        goto abort;
                data->fan_min[1] = rv;

                prev_rv = rv = lm80_read_value(client, LM80_REG_TEMP);
                if (rv < 0)
                        goto abort;
                rv = lm80_read_value(client, LM80_REG_RES);
                if (rv < 0)
                        goto abort;
                data->temp = (prev_rv << 8) | (rv & 0xf0);

                rv = lm80_read_value(client, LM80_REG_TEMP_OS_MAX);
                if (rv < 0)
                        goto abort;
                data->temp_os_max = rv;

                rv = lm80_read_value(client, LM80_REG_TEMP_OS_HYST);
                if (rv < 0)
                        goto abort;
                data->temp_os_hyst = rv;

                rv = lm80_read_value(client, LM80_REG_TEMP_HOT_MAX);
                if (rv < 0)
                        goto abort;
                data->temp_hot_max = rv;

                rv = lm80_read_value(client, LM80_REG_TEMP_HOT_HYST);
                if (rv < 0)
                        goto abort;
                data->temp_hot_hyst = rv;

                rv = lm80_read_value(client, LM80_REG_FANDIV);
                if (rv < 0)
                        goto abort;
                data->fan_div[0] = (rv >> 2) & 0x03;
                data->fan_div[1] = (rv >> 4) & 0x03;

                prev_rv = rv = lm80_read_value(client, LM80_REG_ALARM1);
                if (rv < 0)
                        goto abort;
                rv = lm80_read_value(client, LM80_REG_ALARM2);
                if (rv < 0)
                        goto abort;
                data->alarms = prev_rv + (rv << 8);

                data->last_updated = jiffies;
                data->valid = 1;
                data->error = 0;
        }
        goto done;

abort:
        ret = ERR_PTR(rv);
        data->valid = 0;
        data->error = 1;

done:
        mutex_unlock(&data->update_lock);

        return ret;
}

module_i2c_driver(lm80_driver);

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
        "Philip Edelbrock <phil@netroedge.com>");
MODULE_DESCRIPTION("LM80 driver");
MODULE_LICENSE("GPL");