sched: Add wrapper for checking task_struct::on_rq

[linux-2.6/btrfs-unstable.git] / drivers / hwmon / emc2103.c

/*
 * emc2103.c - Support for SMSC EMC2103
 * Copyright (c) 2010 SMSC
 *
 * 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 scanned */
static const unsigned short normal_i2c[] = { 0x2E, I2C_CLIENT_END };

static const u8 REG_TEMP[4] = { 0x00, 0x02, 0x04, 0x06 };
static const u8 REG_TEMP_MIN[4] = { 0x3c, 0x38, 0x39, 0x3a };
static const u8 REG_TEMP_MAX[4] = { 0x34, 0x30, 0x31, 0x32 };

#define REG_CONF1               0x20
#define REG_TEMP_MAX_ALARM      0x24
#define REG_TEMP_MIN_ALARM      0x25
#define REG_FAN_CONF1           0x42
#define REG_FAN_TARGET_LO       0x4c
#define REG_FAN_TARGET_HI       0x4d
#define REG_FAN_TACH_HI         0x4e
#define REG_FAN_TACH_LO         0x4f
#define REG_PRODUCT_ID          0xfd
#define REG_MFG_ID              0xfe

/* equation 4 from datasheet: rpm = (3932160 * multipler) / count */
#define FAN_RPM_FACTOR          3932160

/*
 * 2103-2 and 2103-4's 3rd temperature sensor can be connected to two diodes
 * in anti-parallel mode, and in this configuration both can be read
 * independently (so we have 4 temperature inputs).  The device can't
 * detect if it's connected in this mode, so we have to manually enable
 * it.  Default is to leave the device in the state it's already in (-1).
 * This parameter allows APD mode to be optionally forced on or off
 */
static int apd = -1;
module_param(apd, bint, 0);
MODULE_PARM_DESC(init, "Set to zero to disable anti-parallel diode mode");

struct temperature {
        s8      degrees;
        u8      fraction;       /* 0-7 multiples of 0.125 */
};

struct emc2103_data {
        struct device           *hwmon_dev;
        struct mutex            update_lock;
        bool                    valid;          /* registers are valid */
        bool                    fan_rpm_control;
        int                     temp_count;     /* num of temp sensors */
        unsigned long           last_updated;   /* in jiffies */
        struct temperature      temp[4];        /* internal + 3 external */
        s8                      temp_min[4];    /* no fractional part */
        s8                      temp_max[4];    /* no fractional part */
        u8                      temp_min_alarm;
        u8                      temp_max_alarm;
        u8                      fan_multiplier;
        u16                     fan_tach;
        u16                     fan_target;
};

static int read_u8_from_i2c(struct i2c_client *client, u8 i2c_reg, u8 *output)
{
        int status = i2c_smbus_read_byte_data(client, i2c_reg);
        if (status < 0) {
                dev_warn(&client->dev, "reg 0x%02x, err %d\n",
                        i2c_reg, status);
        } else {
                *output = status;
        }
        return status;
}

static void read_temp_from_i2c(struct i2c_client *client, u8 i2c_reg,
                               struct temperature *temp)
{
        u8 degrees, fractional;

        if (read_u8_from_i2c(client, i2c_reg, &degrees) < 0)
                return;

        if (read_u8_from_i2c(client, i2c_reg + 1, &fractional) < 0)
                return;

        temp->degrees = degrees;
        temp->fraction = (fractional & 0xe0) >> 5;
}

static void read_fan_from_i2c(struct i2c_client *client, u16 *output,
                              u8 hi_addr, u8 lo_addr)
{
        u8 high_byte, lo_byte;

        if (read_u8_from_i2c(client, hi_addr, &high_byte) < 0)
                return;

        if (read_u8_from_i2c(client, lo_addr, &lo_byte) < 0)
                return;

        *output = ((u16)high_byte << 5) | (lo_byte >> 3);
}

static void write_fan_target_to_i2c(struct i2c_client *client, u16 new_target)
{
        u8 high_byte = (new_target & 0x1fe0) >> 5;
        u8 low_byte = (new_target & 0x001f) << 3;
        i2c_smbus_write_byte_data(client, REG_FAN_TARGET_LO, low_byte);
        i2c_smbus_write_byte_data(client, REG_FAN_TARGET_HI, high_byte);
}

static void read_fan_config_from_i2c(struct i2c_client *client)

{
        struct emc2103_data *data = i2c_get_clientdata(client);
        u8 conf1;

        if (read_u8_from_i2c(client, REG_FAN_CONF1, &conf1) < 0)
                return;

        data->fan_multiplier = 1 << ((conf1 & 0x60) >> 5);
        data->fan_rpm_control = (conf1 & 0x80) != 0;
}

static struct emc2103_data *emc2103_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct emc2103_data *data = i2c_get_clientdata(client);

        mutex_lock(&data->update_lock);

        if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
            || !data->valid) {
                int i;

                for (i = 0; i < data->temp_count; i++) {
                        read_temp_from_i2c(client, REG_TEMP[i], &data->temp[i]);
                        read_u8_from_i2c(client, REG_TEMP_MIN[i],
                                &data->temp_min[i]);
                        read_u8_from_i2c(client, REG_TEMP_MAX[i],
                                &data->temp_max[i]);
                }

                read_u8_from_i2c(client, REG_TEMP_MIN_ALARM,
                        &data->temp_min_alarm);
                read_u8_from_i2c(client, REG_TEMP_MAX_ALARM,
                        &data->temp_max_alarm);

                read_fan_from_i2c(client, &data->fan_tach,
                        REG_FAN_TACH_HI, REG_FAN_TACH_LO);
                read_fan_from_i2c(client, &data->fan_target,
                        REG_FAN_TARGET_HI, REG_FAN_TARGET_LO);
                read_fan_config_from_i2c(client);

                data->last_updated = jiffies;
                data->valid = true;
        }

        mutex_unlock(&data->update_lock);

        return data;
}

static ssize_t
show_temp(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        int millidegrees = data->temp[nr].degrees * 1000
                + data->temp[nr].fraction * 125;
        return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
show_temp_min(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        int millidegrees = data->temp_min[nr] * 1000;
        return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
show_temp_max(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        int millidegrees = data->temp_max[nr] * 1000;
        return sprintf(buf, "%d\n", millidegrees);
}

static ssize_t
show_temp_fault(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        bool fault = (data->temp[nr].degrees == -128);
        return sprintf(buf, "%d\n", fault ? 1 : 0);
}

static ssize_t
show_temp_min_alarm(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        bool alarm = data->temp_min_alarm & (1 << nr);
        return sprintf(buf, "%d\n", alarm ? 1 : 0);
}

static ssize_t
show_temp_max_alarm(struct device *dev, struct device_attribute *da, char *buf)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct emc2103_data *data = emc2103_update_device(dev);
        bool alarm = data->temp_max_alarm & (1 << nr);
        return sprintf(buf, "%d\n", alarm ? 1 : 0);
}

static ssize_t set_temp_min(struct device *dev, struct device_attribute *da,
                            const char *buf, size_t count)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct i2c_client *client = to_i2c_client(dev);
        struct emc2103_data *data = i2c_get_clientdata(client);
        long val;

        int result = kstrtol(buf, 10, &val);
        if (result < 0)
                return result;

        val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -63, 127);

        mutex_lock(&data->update_lock);
        data->temp_min[nr] = val;
        i2c_smbus_write_byte_data(client, REG_TEMP_MIN[nr], val);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t set_temp_max(struct device *dev, struct device_attribute *da,
                            const char *buf, size_t count)
{
        int nr = to_sensor_dev_attr(da)->index;
        struct i2c_client *client = to_i2c_client(dev);
        struct emc2103_data *data = i2c_get_clientdata(client);
        long val;

        int result = kstrtol(buf, 10, &val);
        if (result < 0)
                return result;

        val = clamp_val(DIV_ROUND_CLOSEST(val, 1000), -63, 127);

        mutex_lock(&data->update_lock);
        data->temp_max[nr] = val;
        i2c_smbus_write_byte_data(client, REG_TEMP_MAX[nr], val);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t
show_fan(struct device *dev, struct device_attribute *da, char *buf)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        int rpm = 0;
        if (data->fan_tach != 0)
                rpm = (FAN_RPM_FACTOR * data->fan_multiplier) / data->fan_tach;
        return sprintf(buf, "%d\n", rpm);
}

static ssize_t
show_fan_div(struct device *dev, struct device_attribute *da, char *buf)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        int fan_div = 8 / data->fan_multiplier;
        return sprintf(buf, "%d\n", fan_div);
}

/*
 * Note: we also update the fan target here, because its value is
 * determined in part by the fan clock divider.  This follows the principle
 * of least surprise; the user doesn't expect the fan target to change just
 * because the divider changed.
 */
static ssize_t set_fan_div(struct device *dev, struct device_attribute *da,
                           const char *buf, size_t count)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        struct i2c_client *client = to_i2c_client(dev);
        int new_range_bits, old_div = 8 / data->fan_multiplier;
        long new_div;

        int status = kstrtol(buf, 10, &new_div);
        if (status < 0)
                return status;

        if (new_div == old_div) /* No change */
                return count;

        switch (new_div) {
        case 1:
                new_range_bits = 3;
                break;
        case 2:
                new_range_bits = 2;
                break;
        case 4:
                new_range_bits = 1;
                break;
        case 8:
                new_range_bits = 0;
                break;
        default:
                return -EINVAL;
        }

        mutex_lock(&data->update_lock);

        status = i2c_smbus_read_byte_data(client, REG_FAN_CONF1);
        if (status < 0) {
                dev_dbg(&client->dev, "reg 0x%02x, err %d\n",
                        REG_FAN_CONF1, status);
                mutex_unlock(&data->update_lock);
                return status;
        }
        status &= 0x9F;
        status |= (new_range_bits << 5);
        i2c_smbus_write_byte_data(client, REG_FAN_CONF1, status);

        data->fan_multiplier = 8 / new_div;

        /* update fan target if high byte is not disabled */
        if ((data->fan_target & 0x1fe0) != 0x1fe0) {
                u16 new_target = (data->fan_target * old_div) / new_div;
                data->fan_target = min(new_target, (u16)0x1fff);
                write_fan_target_to_i2c(client, data->fan_target);
        }

        /* invalidate data to force re-read from hardware */
        data->valid = false;

        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t
show_fan_target(struct device *dev, struct device_attribute *da, char *buf)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        int rpm = 0;

        /* high byte of 0xff indicates disabled so return 0 */
        if ((data->fan_target != 0) && ((data->fan_target & 0x1fe0) != 0x1fe0))
                rpm = (FAN_RPM_FACTOR * data->fan_multiplier)
                        / data->fan_target;

        return sprintf(buf, "%d\n", rpm);
}

static ssize_t set_fan_target(struct device *dev, struct device_attribute *da,
                              const char *buf, size_t count)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        struct i2c_client *client = to_i2c_client(dev);
        unsigned long rpm_target;

        int result = kstrtoul(buf, 10, &rpm_target);
        if (result < 0)
                return result;

        /* Datasheet states 16384 as maximum RPM target (table 3.2) */
        rpm_target = clamp_val(rpm_target, 0, 16384);

        mutex_lock(&data->update_lock);

        if (rpm_target == 0)
                data->fan_target = 0x1fff;
        else
                data->fan_target = clamp_val(
                        (FAN_RPM_FACTOR * data->fan_multiplier) / rpm_target,
                        0, 0x1fff);

        write_fan_target_to_i2c(client, data->fan_target);

        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t
show_fan_fault(struct device *dev, struct device_attribute *da, char *buf)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        bool fault = ((data->fan_tach & 0x1fe0) == 0x1fe0);
        return sprintf(buf, "%d\n", fault ? 1 : 0);
}

static ssize_t
show_pwm_enable(struct device *dev, struct device_attribute *da, char *buf)
{
        struct emc2103_data *data = emc2103_update_device(dev);
        return sprintf(buf, "%d\n", data->fan_rpm_control ? 3 : 0);
}

static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *da,
                              const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct emc2103_data *data = i2c_get_clientdata(client);
        long new_value;
        u8 conf_reg;

        int result = kstrtol(buf, 10, &new_value);
        if (result < 0)
                return result;

        mutex_lock(&data->update_lock);
        switch (new_value) {
        case 0:
                data->fan_rpm_control = false;
                break;
        case 3:
                data->fan_rpm_control = true;
                break;
        default:
                count = -EINVAL;
                goto err;
        }

        result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
        if (result) {
                count = result;
                goto err;
        }

        if (data->fan_rpm_control)
                conf_reg |= 0x80;
        else
                conf_reg &= ~0x80;

        i2c_smbus_write_byte_data(client, REG_FAN_CONF1, conf_reg);
err:
        mutex_unlock(&data->update_lock);
        return count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO | S_IWUSR, show_temp_min,
        set_temp_min, 0);
static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO | S_IWUSR, show_temp_max,
        set_temp_max, 0);
static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, show_temp_fault, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_temp_min_alarm,
        NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_temp_max_alarm,
        NULL, 0);

static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO | S_IWUSR, show_temp_min,
        set_temp_min, 1);
static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO | S_IWUSR, show_temp_max,
        set_temp_max, 1);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_temp_fault, NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_temp_min_alarm,
        NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_temp_max_alarm,
        NULL, 1);

static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO | S_IWUSR, show_temp_min,
        set_temp_min, 2);
static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO | S_IWUSR, show_temp_max,
        set_temp_max, 2);
static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_temp_fault, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_temp_min_alarm,
        NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_temp_max_alarm,
        NULL, 2);

static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO | S_IWUSR, show_temp_min,
        set_temp_min, 3);
static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO | S_IWUSR, show_temp_max,
        set_temp_max, 3);
static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_temp_fault, NULL, 3);
static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_temp_min_alarm,
        NULL, 3);
static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_temp_max_alarm,
        NULL, 3);

static DEVICE_ATTR(fan1_input, S_IRUGO, show_fan, NULL);
static DEVICE_ATTR(fan1_div, S_IRUGO | S_IWUSR, show_fan_div, set_fan_div);
static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_fan_target,
        set_fan_target);
static DEVICE_ATTR(fan1_fault, S_IRUGO, show_fan_fault, NULL);

static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR, show_pwm_enable,
        set_pwm_enable);

/* sensors present on all models */
static struct attribute *emc2103_attributes[] = {
        &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_fault.dev_attr.attr,
        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_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_fault.dev_attr.attr,
        &sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
        &dev_attr_fan1_input.attr,
        &dev_attr_fan1_div.attr,
        &dev_attr_fan1_target.attr,
        &dev_attr_fan1_fault.attr,
        &dev_attr_pwm1_enable.attr,
        NULL
};

/* extra temperature sensors only present on 2103-2 and 2103-4 */
static struct attribute *emc2103_attributes_temp3[] = {
        &sensor_dev_attr_temp3_input.dev_attr.attr,
        &sensor_dev_attr_temp3_min.dev_attr.attr,
        &sensor_dev_attr_temp3_max.dev_attr.attr,
        &sensor_dev_attr_temp3_fault.dev_attr.attr,
        &sensor_dev_attr_temp3_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
        NULL
};

/* extra temperature sensors only present on 2103-2 and 2103-4 in APD mode */
static struct attribute *emc2103_attributes_temp4[] = {
        &sensor_dev_attr_temp4_input.dev_attr.attr,
        &sensor_dev_attr_temp4_min.dev_attr.attr,
        &sensor_dev_attr_temp4_max.dev_attr.attr,
        &sensor_dev_attr_temp4_fault.dev_attr.attr,
        &sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
        NULL
};

static const struct attribute_group emc2103_group = {
        .attrs = emc2103_attributes,
};

static const struct attribute_group emc2103_temp3_group = {
        .attrs = emc2103_attributes_temp3,
};

static const struct attribute_group emc2103_temp4_group = {
        .attrs = emc2103_attributes_temp4,
};

static int
emc2103_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        struct emc2103_data *data;
        int status;

        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -EIO;

        data = devm_kzalloc(&client->dev, sizeof(struct emc2103_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

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

        /* 2103-2 and 2103-4 have 3 external diodes, 2103-1 has 1 */
        status = i2c_smbus_read_byte_data(client, REG_PRODUCT_ID);
        if (status == 0x24) {
                /* 2103-1 only has 1 external diode */
                data->temp_count = 2;
        } else {
                /* 2103-2 and 2103-4 have 3 or 4 external diodes */
                status = i2c_smbus_read_byte_data(client, REG_CONF1);
                if (status < 0) {
                        dev_dbg(&client->dev, "reg 0x%02x, err %d\n", REG_CONF1,
                                status);
                        return status;
                }

                /* detect current state of hardware */
                data->temp_count = (status & 0x01) ? 4 : 3;

                /* force APD state if module parameter is set */
                if (apd == 0) {
                        /* force APD mode off */
                        data->temp_count = 3;
                        status &= ~(0x01);
                        i2c_smbus_write_byte_data(client, REG_CONF1, status);
                } else if (apd == 1) {
                        /* force APD mode on */
                        data->temp_count = 4;
                        status |= 0x01;
                        i2c_smbus_write_byte_data(client, REG_CONF1, status);
                }
        }

        /* Register sysfs hooks */
        status = sysfs_create_group(&client->dev.kobj, &emc2103_group);
        if (status)
                return status;

        if (data->temp_count >= 3) {
                status = sysfs_create_group(&client->dev.kobj,
                        &emc2103_temp3_group);
                if (status)
                        goto exit_remove;
        }

        if (data->temp_count == 4) {
                status = sysfs_create_group(&client->dev.kobj,
                        &emc2103_temp4_group);
                if (status)
                        goto exit_remove_temp3;
        }

        data->hwmon_dev = hwmon_device_register(&client->dev);
        if (IS_ERR(data->hwmon_dev)) {
                status = PTR_ERR(data->hwmon_dev);
                goto exit_remove_temp4;
        }

        dev_info(&client->dev, "%s: sensor '%s'\n",
                 dev_name(data->hwmon_dev), client->name);

        return 0;

exit_remove_temp4:
        if (data->temp_count == 4)
                sysfs_remove_group(&client->dev.kobj, &emc2103_temp4_group);
exit_remove_temp3:
        if (data->temp_count >= 3)
                sysfs_remove_group(&client->dev.kobj, &emc2103_temp3_group);
exit_remove:
        sysfs_remove_group(&client->dev.kobj, &emc2103_group);
        return status;
}

static int emc2103_remove(struct i2c_client *client)
{
        struct emc2103_data *data = i2c_get_clientdata(client);

        hwmon_device_unregister(data->hwmon_dev);

        if (data->temp_count == 4)
                sysfs_remove_group(&client->dev.kobj, &emc2103_temp4_group);

        if (data->temp_count >= 3)
                sysfs_remove_group(&client->dev.kobj, &emc2103_temp3_group);

        sysfs_remove_group(&client->dev.kobj, &emc2103_group);

        return 0;
}

static const struct i2c_device_id emc2103_ids[] = {
        { "emc2103", 0, },
        { /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, emc2103_ids);

/* Return 0 if detection is successful, -ENODEV otherwise */
static int
emc2103_detect(struct i2c_client *new_client, struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;
        int manufacturer, product;

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

        manufacturer = i2c_smbus_read_byte_data(new_client, REG_MFG_ID);
        if (manufacturer != 0x5D)
                return -ENODEV;

        product = i2c_smbus_read_byte_data(new_client, REG_PRODUCT_ID);
        if ((product != 0x24) && (product != 0x26))
                return -ENODEV;

        strlcpy(info->type, "emc2103", I2C_NAME_SIZE);

        return 0;
}

static struct i2c_driver emc2103_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "emc2103",
        },
        .probe          = emc2103_probe,
        .remove         = emc2103_remove,
        .id_table       = emc2103_ids,
        .detect         = emc2103_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(emc2103_driver);

MODULE_AUTHOR("Steve Glendinning <steve.glendinning@shawell.net>");
MODULE_DESCRIPTION("SMSC EMC2103 hwmon driver");
MODULE_LICENSE("GPL");