USB: use function attribute __maybe_unused

[linux-2.6/mini2440.git] / drivers / hwmon / it87.c

/*
    it87.c - Part of lm_sensors, Linux kernel modules for hardware
             monitoring.

    Supports: IT8705F  Super I/O chip w/LPC interface
              IT8712F  Super I/O chip w/LPC interface
              IT8716F  Super I/O chip w/LPC interface
              IT8718F  Super I/O chip w/LPC interface
              Sis950   A clone of the IT8705F

    Copyright (C) 2001 Chris Gauthron <chrisg@0-in.com> 
    Copyright (C) 2005-2006 Jean Delvare <khali@linux-fr.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/i2c-isa.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/hwmon-vid.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <asm/io.h>


static unsigned short isa_address;
enum chips { it87, it8712, it8716, it8718 };

#define REG     0x2e    /* The register to read/write */
#define DEV     0x07    /* Register: Logical device select */
#define VAL     0x2f    /* The value to read/write */
#define PME     0x04    /* The device with the fan registers in it */
#define GPIO    0x07    /* The device with the IT8718F VID value in it */
#define DEVID   0x20    /* Register: Device ID */
#define DEVREV  0x22    /* Register: Device Revision */

static inline int
superio_inb(int reg)
{
        outb(reg, REG);
        return inb(VAL);
}

static int superio_inw(int reg)
{
        int val;
        outb(reg++, REG);
        val = inb(VAL) << 8;
        outb(reg, REG);
        val |= inb(VAL);
        return val;
}

static inline void
superio_select(int ldn)
{
        outb(DEV, REG);
        outb(ldn, VAL);
}

static inline void
superio_enter(void)
{
        outb(0x87, REG);
        outb(0x01, REG);
        outb(0x55, REG);
        outb(0x55, REG);
}

static inline void
superio_exit(void)
{
        outb(0x02, REG);
        outb(0x02, VAL);
}

/* Logical device 4 registers */
#define IT8712F_DEVID 0x8712
#define IT8705F_DEVID 0x8705
#define IT8716F_DEVID 0x8716
#define IT8718F_DEVID 0x8718
#define IT87_ACT_REG  0x30
#define IT87_BASE_REG 0x60

/* Logical device 7 registers (IT8712F and later) */
#define IT87_SIO_PINX2_REG      0x2c    /* Pin selection */
#define IT87_SIO_VID_REG        0xfc    /* VID value */

/* Update battery voltage after every reading if true */
static int update_vbat;

/* Not all BIOSes properly configure the PWM registers */
static int fix_pwm_polarity;

/* Values read from Super-I/O config space */
static u16 chip_type;
static u8 vid_value;

/* Many IT87 constants specified below */

/* Length of ISA address segment */
#define IT87_EXTENT 8

/* Where are the ISA address/data registers relative to the base address */
#define IT87_ADDR_REG_OFFSET 5
#define IT87_DATA_REG_OFFSET 6

/*----- The IT87 registers -----*/

#define IT87_REG_CONFIG        0x00

#define IT87_REG_ALARM1        0x01
#define IT87_REG_ALARM2        0x02
#define IT87_REG_ALARM3        0x03

/* The IT8718F has the VID value in a different register, in Super-I/O
   configuration space. */
#define IT87_REG_VID           0x0a
/* Warning: register 0x0b is used for something completely different in
   new chips/revisions. I suspect only 16-bit tachometer mode will work
   for these. */
#define IT87_REG_FAN_DIV       0x0b
#define IT87_REG_FAN_16BIT     0x0c

/* Monitors: 9 voltage (0 to 7, battery), 3 temp (1 to 3), 3 fan (1 to 3) */

#define IT87_REG_FAN(nr)       (0x0d + (nr))
#define IT87_REG_FAN_MIN(nr)   (0x10 + (nr))
#define IT87_REG_FANX(nr)      (0x18 + (nr))
#define IT87_REG_FANX_MIN(nr)  (0x1b + (nr))
#define IT87_REG_FAN_MAIN_CTRL 0x13
#define IT87_REG_FAN_CTL       0x14
#define IT87_REG_PWM(nr)       (0x15 + (nr))

#define IT87_REG_VIN(nr)       (0x20 + (nr))
#define IT87_REG_TEMP(nr)      (0x29 + (nr))

#define IT87_REG_VIN_MAX(nr)   (0x30 + (nr) * 2)
#define IT87_REG_VIN_MIN(nr)   (0x31 + (nr) * 2)
#define IT87_REG_TEMP_HIGH(nr) (0x40 + (nr) * 2)
#define IT87_REG_TEMP_LOW(nr)  (0x41 + (nr) * 2)

#define IT87_REG_VIN_ENABLE    0x50
#define IT87_REG_TEMP_ENABLE   0x51

#define IT87_REG_CHIPID        0x58

#define IN_TO_REG(val)  (SENSORS_LIMIT((((val) + 8)/16),0,255))
#define IN_FROM_REG(val) ((val) * 16)

static inline u8 FAN_TO_REG(long rpm, int div)
{
        if (rpm == 0)
                return 255;
        rpm = SENSORS_LIMIT(rpm, 1, 1000000);
        return SENSORS_LIMIT((1350000 + rpm * div / 2) / (rpm * div), 1,
                             254);
}

static inline u16 FAN16_TO_REG(long rpm)
{
        if (rpm == 0)
                return 0xffff;
        return SENSORS_LIMIT((1350000 + rpm) / (rpm * 2), 1, 0xfffe);
}

#define FAN_FROM_REG(val,div) ((val)==0?-1:(val)==255?0:1350000/((val)*(div)))
/* The divider is fixed to 2 in 16-bit mode */
#define FAN16_FROM_REG(val) ((val)==0?-1:(val)==0xffff?0:1350000/((val)*2))

#define TEMP_TO_REG(val) (SENSORS_LIMIT(((val)<0?(((val)-500)/1000):\
                                        ((val)+500)/1000),-128,127))
#define TEMP_FROM_REG(val) (((val)>0x80?(val)-0x100:(val))*1000)

#define PWM_TO_REG(val)   ((val) >> 1)
#define PWM_FROM_REG(val) (((val)&0x7f) << 1)

static int DIV_TO_REG(int val)
{
        int answer = 0;
        while (answer < 7 && (val >>= 1))
                answer++;
        return answer;
}
#define DIV_FROM_REG(val) (1 << (val))

static const unsigned int pwm_freq[8] = {
        48000000 / 128,
        24000000 / 128,
        12000000 / 128,
        8000000 / 128,
        6000000 / 128,
        3000000 / 128,
        1500000 / 128,
        750000 / 128,
};


/* For each registered chip, we need to keep some data in memory.
   The structure is dynamically allocated. */
struct it87_data {
        struct i2c_client client;
        struct class_device *class_dev;
        enum chips type;

        struct mutex update_lock;
        char valid;             /* !=0 if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        u8 in[9];               /* Register value */
        u8 in_max[8];           /* Register value */
        u8 in_min[8];           /* Register value */
        u8 has_fan;             /* Bitfield, fans enabled */
        u16 fan[3];             /* Register values, possibly combined */
        u16 fan_min[3];         /* Register values, possibly combined */
        u8 temp[3];             /* Register value */
        u8 temp_high[3];        /* Register value */
        u8 temp_low[3];         /* Register value */
        u8 sensor;              /* Register value */
        u8 fan_div[3];          /* Register encoding, shifted right */
        u8 vid;                 /* Register encoding, combined */
        u8 vrm;
        u32 alarms;             /* Register encoding, combined */
        u8 fan_main_ctrl;       /* Register value */
        u8 fan_ctl;             /* Register value */
        u8 manual_pwm_ctl[3];   /* manual PWM value set by user */
};


static int it87_detect(struct i2c_adapter *adapter);
static int it87_detach_client(struct i2c_client *client);

static int it87_read_value(struct i2c_client *client, u8 reg);
static void it87_write_value(struct i2c_client *client, u8 reg, u8 value);
static struct it87_data *it87_update_device(struct device *dev);
static int it87_check_pwm(struct i2c_client *client);
static void it87_init_client(struct i2c_client *client, struct it87_data *data);


static struct i2c_driver it87_isa_driver = {
        .driver = {
                .owner  = THIS_MODULE,
                .name   = "it87-isa",
        },
        .attach_adapter = it87_detect,
        .detach_client  = it87_detach_client,
};


static ssize_t show_in(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", IN_FROM_REG(data->in[nr]));
}

static ssize_t show_in_min(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", IN_FROM_REG(data->in_min[nr]));
}

static ssize_t show_in_max(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", IN_FROM_REG(data->in_max[nr]));
}

static ssize_t set_in_min(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        unsigned long val = simple_strtoul(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->in_min[nr] = IN_TO_REG(val);
        it87_write_value(client, IT87_REG_VIN_MIN(nr), 
                        data->in_min[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_in_max(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        unsigned long val = simple_strtoul(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->in_max[nr] = IN_TO_REG(val);
        it87_write_value(client, IT87_REG_VIN_MAX(nr), 
                        data->in_max[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}

#define show_in_offset(offset)                                  \
static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO,          \
                show_in, NULL, offset);

#define limit_in_offset(offset)                                 \
static SENSOR_DEVICE_ATTR(in##offset##_min, S_IRUGO | S_IWUSR,  \
                show_in_min, set_in_min, offset);               \
static SENSOR_DEVICE_ATTR(in##offset##_max, S_IRUGO | S_IWUSR,  \
                show_in_max, set_in_max, offset);

show_in_offset(0);
limit_in_offset(0);
show_in_offset(1);
limit_in_offset(1);
show_in_offset(2);
limit_in_offset(2);
show_in_offset(3);
limit_in_offset(3);
show_in_offset(4);
limit_in_offset(4);
show_in_offset(5);
limit_in_offset(5);
show_in_offset(6);
limit_in_offset(6);
show_in_offset(7);
limit_in_offset(7);
show_in_offset(8);

/* 3 temperatures */
static ssize_t show_temp(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[nr]));
}
static ssize_t show_temp_max(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_high[nr]));
}
static ssize_t show_temp_min(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_low[nr]));
}
static ssize_t set_temp_max(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->temp_high[nr] = TEMP_TO_REG(val);
        it87_write_value(client, IT87_REG_TEMP_HIGH(nr), data->temp_high[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_temp_min(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->temp_low[nr] = TEMP_TO_REG(val);
        it87_write_value(client, IT87_REG_TEMP_LOW(nr), data->temp_low[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}
#define show_temp_offset(offset)                                        \
static SENSOR_DEVICE_ATTR(temp##offset##_input, S_IRUGO,                \
                show_temp, NULL, offset - 1);                           \
static SENSOR_DEVICE_ATTR(temp##offset##_max, S_IRUGO | S_IWUSR,        \
                show_temp_max, set_temp_max, offset - 1);               \
static SENSOR_DEVICE_ATTR(temp##offset##_min, S_IRUGO | S_IWUSR,        \
                show_temp_min, set_temp_min, offset - 1);

show_temp_offset(1);
show_temp_offset(2);
show_temp_offset(3);

static ssize_t show_sensor(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        u8 reg = data->sensor; /* In case the value is updated while we use it */
        
        if (reg & (1 << nr))
                return sprintf(buf, "3\n");  /* thermal diode */
        if (reg & (8 << nr))
                return sprintf(buf, "2\n");  /* thermistor */
        return sprintf(buf, "0\n");      /* disabled */
}
static ssize_t set_sensor(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);

        data->sensor &= ~(1 << nr);
        data->sensor &= ~(8 << nr);
        /* 3 = thermal diode; 2 = thermistor; 0 = disabled */
        if (val == 3)
            data->sensor |= 1 << nr;
        else if (val == 2)
            data->sensor |= 8 << nr;
        else if (val != 0) {
                mutex_unlock(&data->update_lock);
                return -EINVAL;
        }
        it87_write_value(client, IT87_REG_TEMP_ENABLE, data->sensor);
        mutex_unlock(&data->update_lock);
        return count;
}
#define show_sensor_offset(offset)                                      \
static SENSOR_DEVICE_ATTR(temp##offset##_type, S_IRUGO | S_IWUSR,       \
                show_sensor, set_sensor, offset - 1);

show_sensor_offset(1);
show_sensor_offset(2);
show_sensor_offset(3);

/* 3 Fans */
static ssize_t show_fan(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf,"%d\n", FAN_FROM_REG(data->fan[nr], 
                                DIV_FROM_REG(data->fan_div[nr])));
}
static ssize_t show_fan_min(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf,"%d\n",
                FAN_FROM_REG(data->fan_min[nr], DIV_FROM_REG(data->fan_div[nr])));
}
static ssize_t show_fan_div(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", DIV_FROM_REG(data->fan_div[nr]));
}
static ssize_t show_pwm_enable(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf,"%d\n", (data->fan_main_ctrl & (1 << nr)) ? 1 : 0);
}
static ssize_t show_pwm(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf,"%d\n", data->manual_pwm_ctl[nr]);
}
static ssize_t show_pwm_freq(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct it87_data *data = it87_update_device(dev);
        int index = (data->fan_ctl >> 4) & 0x07;

        return sprintf(buf, "%u\n", pwm_freq[index]);
}
static ssize_t set_fan_min(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);
        u8 reg;

        mutex_lock(&data->update_lock);
        reg = it87_read_value(client, IT87_REG_FAN_DIV);
        switch (nr) {
        case 0: data->fan_div[nr] = reg & 0x07; break;
        case 1: data->fan_div[nr] = (reg >> 3) & 0x07; break;
        case 2: data->fan_div[nr] = (reg & 0x40) ? 3 : 1; break;
        }

        data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
        it87_write_value(client, IT87_REG_FAN_MIN(nr), data->fan_min[nr]);
        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        unsigned long val = simple_strtoul(buf, NULL, 10);
        int min;
        u8 old;

        mutex_lock(&data->update_lock);
        old = it87_read_value(client, IT87_REG_FAN_DIV);

        /* Save fan min limit */
        min = FAN_FROM_REG(data->fan_min[nr], DIV_FROM_REG(data->fan_div[nr]));

        switch (nr) {
        case 0:
        case 1:
                data->fan_div[nr] = DIV_TO_REG(val);
                break;
        case 2:
                if (val < 8)
                        data->fan_div[nr] = 1;
                else
                        data->fan_div[nr] = 3;
        }
        val = old & 0x80;
        val |= (data->fan_div[0] & 0x07);
        val |= (data->fan_div[1] & 0x07) << 3;
        if (data->fan_div[2] == 3)
                val |= 0x1 << 6;
        it87_write_value(client, IT87_REG_FAN_DIV, val);

        /* Restore fan min limit */
        data->fan_min[nr] = FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));
        it87_write_value(client, IT87_REG_FAN_MIN(nr), data->fan_min[nr]);

        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_pwm_enable(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);

        if (val == 0) {
                int tmp;
                /* make sure the fan is on when in on/off mode */
                tmp = it87_read_value(client, IT87_REG_FAN_CTL);
                it87_write_value(client, IT87_REG_FAN_CTL, tmp | (1 << nr));
                /* set on/off mode */
                data->fan_main_ctrl &= ~(1 << nr);
                it87_write_value(client, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
        } else if (val == 1) {
                /* set SmartGuardian mode */
                data->fan_main_ctrl |= (1 << nr);
                it87_write_value(client, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
                /* set saved pwm value, clear FAN_CTLX PWM mode bit */
                it87_write_value(client, IT87_REG_PWM(nr), PWM_TO_REG(data->manual_pwm_ctl[nr]));
        } else {
                mutex_unlock(&data->update_lock);
                return -EINVAL;
        }

        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;

        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        if (val < 0 || val > 255)
                return -EINVAL;

        mutex_lock(&data->update_lock);
        data->manual_pwm_ctl[nr] = val;
        if (data->fan_main_ctrl & (1 << nr))
                it87_write_value(client, IT87_REG_PWM(nr), PWM_TO_REG(data->manual_pwm_ctl[nr]));
        mutex_unlock(&data->update_lock);
        return count;
}
static ssize_t set_pwm_freq(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        unsigned long val = simple_strtoul(buf, NULL, 10);
        int i;

        /* Search for the nearest available frequency */
        for (i = 0; i < 7; i++) {
                if (val > (pwm_freq[i] + pwm_freq[i+1]) / 2)
                        break;
        }

        mutex_lock(&data->update_lock);
        data->fan_ctl = it87_read_value(client, IT87_REG_FAN_CTL) & 0x8f;
        data->fan_ctl |= i << 4;
        it87_write_value(client, IT87_REG_FAN_CTL, data->fan_ctl);
        mutex_unlock(&data->update_lock);

        return count;
}

#define show_fan_offset(offset)                                 \
static SENSOR_DEVICE_ATTR(fan##offset##_input, S_IRUGO,         \
                show_fan, NULL, offset - 1);                    \
static SENSOR_DEVICE_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR, \
                show_fan_min, set_fan_min, offset - 1);         \
static SENSOR_DEVICE_ATTR(fan##offset##_div, S_IRUGO | S_IWUSR, \
                show_fan_div, set_fan_div, offset - 1);

show_fan_offset(1);
show_fan_offset(2);
show_fan_offset(3);

#define show_pwm_offset(offset)                                         \
static SENSOR_DEVICE_ATTR(pwm##offset##_enable, S_IRUGO | S_IWUSR,      \
                show_pwm_enable, set_pwm_enable, offset - 1);           \
static SENSOR_DEVICE_ATTR(pwm##offset, S_IRUGO | S_IWUSR,               \
                show_pwm, set_pwm, offset - 1);                         \
static DEVICE_ATTR(pwm##offset##_freq,                                  \
                (offset == 1 ? S_IRUGO | S_IWUSR : S_IRUGO),            \
                show_pwm_freq, (offset == 1 ? set_pwm_freq : NULL));

show_pwm_offset(1);
show_pwm_offset(2);
show_pwm_offset(3);

/* A different set of callbacks for 16-bit fans */
static ssize_t show_fan16(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;
        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", FAN16_FROM_REG(data->fan[nr]));
}

static ssize_t show_fan16_min(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;
        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%d\n", FAN16_FROM_REG(data->fan_min[nr]));
}

static ssize_t set_fan16_min(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
        int nr = sensor_attr->index;
        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int val = simple_strtol(buf, NULL, 10);

        mutex_lock(&data->update_lock);
        data->fan_min[nr] = FAN16_TO_REG(val);
        it87_write_value(client, IT87_REG_FAN_MIN(nr),
                         data->fan_min[nr] & 0xff);
        it87_write_value(client, IT87_REG_FANX_MIN(nr),
                         data->fan_min[nr] >> 8);
        mutex_unlock(&data->update_lock);
        return count;
}

/* We want to use the same sysfs file names as 8-bit fans, but we need
   different variable names, so we have to use SENSOR_ATTR instead of
   SENSOR_DEVICE_ATTR. */
#define show_fan16_offset(offset) \
static struct sensor_device_attribute sensor_dev_attr_fan##offset##_input16 \
        = SENSOR_ATTR(fan##offset##_input, S_IRUGO,             \
                show_fan16, NULL, offset - 1);                  \
static struct sensor_device_attribute sensor_dev_attr_fan##offset##_min16 \
        = SENSOR_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR,     \
                show_fan16_min, set_fan16_min, offset - 1)

show_fan16_offset(1);
show_fan16_offset(2);
show_fan16_offset(3);

/* Alarms */
static ssize_t show_alarms(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%u\n", data->alarms);
}
static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

static ssize_t
show_vrm_reg(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%u\n", data->vrm);
}
static ssize_t
store_vrm_reg(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        u32 val;

        val = simple_strtoul(buf, NULL, 10);
        data->vrm = val;

        return count;
}
static DEVICE_ATTR(vrm, S_IRUGO | S_IWUSR, show_vrm_reg, store_vrm_reg);

static ssize_t
show_vid_reg(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct it87_data *data = it87_update_device(dev);
        return sprintf(buf, "%ld\n", (long) vid_from_reg(data->vid, data->vrm));
}
static DEVICE_ATTR(cpu0_vid, S_IRUGO, show_vid_reg, NULL);

static struct attribute *it87_attributes[] = {
        &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_in7_input.dev_attr.attr,
        &sensor_dev_attr_in8_input.dev_attr.attr,
        &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_in7_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_in7_max.dev_attr.attr,

        &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_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp2_max.dev_attr.attr,
        &sensor_dev_attr_temp3_max.dev_attr.attr,
        &sensor_dev_attr_temp1_min.dev_attr.attr,
        &sensor_dev_attr_temp2_min.dev_attr.attr,
        &sensor_dev_attr_temp3_min.dev_attr.attr,
        &sensor_dev_attr_temp1_type.dev_attr.attr,
        &sensor_dev_attr_temp2_type.dev_attr.attr,
        &sensor_dev_attr_temp3_type.dev_attr.attr,

        &dev_attr_alarms.attr,
        NULL
};

static const struct attribute_group it87_group = {
        .attrs = it87_attributes,
};

static struct attribute *it87_attributes_opt[] = {
        &sensor_dev_attr_fan1_input16.dev_attr.attr,
        &sensor_dev_attr_fan1_min16.dev_attr.attr,
        &sensor_dev_attr_fan2_input16.dev_attr.attr,
        &sensor_dev_attr_fan2_min16.dev_attr.attr,
        &sensor_dev_attr_fan3_input16.dev_attr.attr,
        &sensor_dev_attr_fan3_min16.dev_attr.attr,

        &sensor_dev_attr_fan1_input.dev_attr.attr,
        &sensor_dev_attr_fan1_min.dev_attr.attr,
        &sensor_dev_attr_fan1_div.dev_attr.attr,
        &sensor_dev_attr_fan2_input.dev_attr.attr,
        &sensor_dev_attr_fan2_min.dev_attr.attr,
        &sensor_dev_attr_fan2_div.dev_attr.attr,
        &sensor_dev_attr_fan3_input.dev_attr.attr,
        &sensor_dev_attr_fan3_min.dev_attr.attr,
        &sensor_dev_attr_fan3_div.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_pwm1.dev_attr.attr,
        &sensor_dev_attr_pwm2.dev_attr.attr,
        &sensor_dev_attr_pwm3.dev_attr.attr,

        &dev_attr_vrm.attr,
        &dev_attr_cpu0_vid.attr,
        NULL
};

static const struct attribute_group it87_group_opt = {
        .attrs = it87_attributes_opt,
};

/* SuperIO detection - will change isa_address if a chip is found */
static int __init it87_find(unsigned short *address)
{
        int err = -ENODEV;

        superio_enter();
        chip_type = superio_inw(DEVID);
        if (chip_type != IT8712F_DEVID
         && chip_type != IT8716F_DEVID
         && chip_type != IT8718F_DEVID
         && chip_type != IT8705F_DEVID)
                goto exit;

        superio_select(PME);
        if (!(superio_inb(IT87_ACT_REG) & 0x01)) {
                pr_info("it87: Device not activated, skipping\n");
                goto exit;
        }

        *address = superio_inw(IT87_BASE_REG) & ~(IT87_EXTENT - 1);
        if (*address == 0) {
                pr_info("it87: Base address not set, skipping\n");
                goto exit;
        }

        err = 0;
        pr_info("it87: Found IT%04xF chip at 0x%x, revision %d\n",
                chip_type, *address, superio_inb(DEVREV) & 0x0f);

        /* Read GPIO config and VID value from LDN 7 (GPIO) */
        if (chip_type != IT8705F_DEVID) {
                int reg;

                superio_select(GPIO);
                if (chip_type == it8718)
                        vid_value = superio_inb(IT87_SIO_VID_REG);

                reg = superio_inb(IT87_SIO_PINX2_REG);
                if (reg & (1 << 0))
                        pr_info("it87: in3 is VCC (+5V)\n");
                if (reg & (1 << 1))
                        pr_info("it87: in7 is VCCH (+5V Stand-By)\n");
        }

exit:
        superio_exit();
        return err;
}

/* This function is called by i2c_probe */
static int it87_detect(struct i2c_adapter *adapter)
{
        struct i2c_client *new_client;
        struct it87_data *data;
        int err = 0;
        const char *name;
        int enable_pwm_interface;

        /* Reserve the ISA region */
        if (!request_region(isa_address, IT87_EXTENT,
                            it87_isa_driver.driver.name)){
                err = -EBUSY;
                goto ERROR0;
        }

        if (!(data = kzalloc(sizeof(struct it87_data), GFP_KERNEL))) {
                err = -ENOMEM;
                goto ERROR1;
        }

        new_client = &data->client;
        i2c_set_clientdata(new_client, data);
        new_client->addr = isa_address;
        new_client->adapter = adapter;
        new_client->driver = &it87_isa_driver;

        /* Now, we do the remaining detection. */
        if ((it87_read_value(new_client, IT87_REG_CONFIG) & 0x80)
         || it87_read_value(new_client, IT87_REG_CHIPID) != 0x90) {
                err = -ENODEV;
                goto ERROR2;
        }

        /* Determine the chip type. */
        switch (chip_type) {
        case IT8712F_DEVID:
                data->type = it8712;
                name = "it8712";
                break;
        case IT8716F_DEVID:
                data->type = it8716;
                name = "it8716";
                break;
        case IT8718F_DEVID:
                data->type = it8718;
                name = "it8718";
                break;
        default:
                data->type = it87;
                name = "it87";
        }

        /* Fill in the remaining client fields and put it into the global list */
        strlcpy(new_client->name, name, I2C_NAME_SIZE);
        mutex_init(&data->update_lock);

        /* Tell the I2C layer a new client has arrived */
        if ((err = i2c_attach_client(new_client)))
                goto ERROR2;

        /* Check PWM configuration */
        enable_pwm_interface = it87_check_pwm(new_client);

        /* Initialize the IT87 chip */
        it87_init_client(new_client, data);

        /* Register sysfs hooks */
        if ((err = sysfs_create_group(&new_client->dev.kobj, &it87_group)))
                goto ERROR3;

        /* Do not create fan files for disabled fans */
        if (data->type == it8716 || data->type == it8718) {
                /* 16-bit tachometers */
                if (data->has_fan & (1 << 0)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan1_input16.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan1_min16.dev_attr)))
                                goto ERROR4;
                }
                if (data->has_fan & (1 << 1)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan2_input16.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan2_min16.dev_attr)))
                                goto ERROR4;
                }
                if (data->has_fan & (1 << 2)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan3_input16.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan3_min16.dev_attr)))
                                goto ERROR4;
                }
        } else {
                /* 8-bit tachometers with clock divider */
                if (data->has_fan & (1 << 0)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan1_input.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan1_min.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan1_div.dev_attr)))
                                goto ERROR4;
                }
                if (data->has_fan & (1 << 1)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan2_input.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan2_min.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan2_div.dev_attr)))
                                goto ERROR4;
                }
                if (data->has_fan & (1 << 2)) {
                        if ((err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan3_input.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan3_min.dev_attr))
                         || (err = device_create_file(&new_client->dev,
                             &sensor_dev_attr_fan3_div.dev_attr)))
                                goto ERROR4;
                }
        }

        if (enable_pwm_interface) {
                if ((err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm1_enable.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm2_enable.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm3_enable.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm1.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm2.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &sensor_dev_attr_pwm3.dev_attr))
                 || (err = device_create_file(&new_client->dev,
                     &dev_attr_pwm1_freq))
                 || (err = device_create_file(&new_client->dev,
                     &dev_attr_pwm2_freq))
                 || (err = device_create_file(&new_client->dev,
                     &dev_attr_pwm3_freq)))
                        goto ERROR4;
        }

        if (data->type == it8712 || data->type == it8716
         || data->type == it8718) {
                data->vrm = vid_which_vrm();
                /* VID reading from Super-I/O config space if available */
                data->vid = vid_value;
                if ((err = device_create_file(&new_client->dev,
                     &dev_attr_vrm))
                 || (err = device_create_file(&new_client->dev,
                     &dev_attr_cpu0_vid)))
                        goto ERROR4;
        }

        data->class_dev = hwmon_device_register(&new_client->dev);
        if (IS_ERR(data->class_dev)) {
                err = PTR_ERR(data->class_dev);
                goto ERROR4;
        }

        return 0;

ERROR4:
        sysfs_remove_group(&new_client->dev.kobj, &it87_group);
        sysfs_remove_group(&new_client->dev.kobj, &it87_group_opt);
ERROR3:
        i2c_detach_client(new_client);
ERROR2:
        kfree(data);
ERROR1:
        release_region(isa_address, IT87_EXTENT);
ERROR0:
        return err;
}

static int it87_detach_client(struct i2c_client *client)
{
        struct it87_data *data = i2c_get_clientdata(client);
        int err;

        hwmon_device_unregister(data->class_dev);
        sysfs_remove_group(&client->dev.kobj, &it87_group);
        sysfs_remove_group(&client->dev.kobj, &it87_group_opt);

        if ((err = i2c_detach_client(client)))
                return err;

        release_region(client->addr, IT87_EXTENT);
        kfree(data);

        return 0;
}

/* Must be called with data->update_lock held, except during initialization.
   We ignore the IT87 BUSY flag at this moment - it could lead to deadlocks,
   would slow down the IT87 access and should not be necessary. */
static int it87_read_value(struct i2c_client *client, u8 reg)
{
        outb_p(reg, client->addr + IT87_ADDR_REG_OFFSET);
        return inb_p(client->addr + IT87_DATA_REG_OFFSET);
}

/* Must be called with data->update_lock held, except during initialization.
   We ignore the IT87 BUSY flag at this moment - it could lead to deadlocks,
   would slow down the IT87 access and should not be necessary. */
static void it87_write_value(struct i2c_client *client, u8 reg, u8 value)
{
        outb_p(reg, client->addr + IT87_ADDR_REG_OFFSET);
        outb_p(value, client->addr + IT87_DATA_REG_OFFSET);
}

/* Return 1 if and only if the PWM interface is safe to use */
static int it87_check_pwm(struct i2c_client *client)
{
        /* Some BIOSes fail to correctly configure the IT87 fans. All fans off
         * and polarity set to active low is sign that this is the case so we
         * disable pwm control to protect the user. */
        int tmp = it87_read_value(client, IT87_REG_FAN_CTL);
        if ((tmp & 0x87) == 0) {
                if (fix_pwm_polarity) {
                        /* The user asks us to attempt a chip reconfiguration.
                         * This means switching to active high polarity and
                         * inverting all fan speed values. */
                        int i;
                        u8 pwm[3];

                        for (i = 0; i < 3; i++)
                                pwm[i] = it87_read_value(client,
                                                         IT87_REG_PWM(i));

                        /* If any fan is in automatic pwm mode, the polarity
                         * might be correct, as suspicious as it seems, so we
                         * better don't change anything (but still disable the
                         * PWM interface). */
                        if (!((pwm[0] | pwm[1] | pwm[2]) & 0x80)) {
                                dev_info(&client->dev, "Reconfiguring PWM to "
                                         "active high polarity\n");
                                it87_write_value(client, IT87_REG_FAN_CTL,
                                                 tmp | 0x87);
                                for (i = 0; i < 3; i++)
                                        it87_write_value(client,
                                                         IT87_REG_PWM(i),
                                                         0x7f & ~pwm[i]);
                                return 1;
                        }

                        dev_info(&client->dev, "PWM configuration is "
                                 "too broken to be fixed\n");
                }

                dev_info(&client->dev, "Detected broken BIOS "
                         "defaults, disabling PWM interface\n");
                return 0;
        } else if (fix_pwm_polarity) {
                dev_info(&client->dev, "PWM configuration looks "
                         "sane, won't touch\n");
        }

        return 1;
}

/* Called when we have found a new IT87. */
static void it87_init_client(struct i2c_client *client, struct it87_data *data)
{
        int tmp, i;

        /* initialize to sane defaults:
         * - if the chip is in manual pwm mode, this will be overwritten with
         *   the actual settings on the chip (so in this case, initialization
         *   is not needed)
         * - if in automatic or on/off mode, we could switch to manual mode,
         *   read the registers and set manual_pwm_ctl accordingly, but currently
         *   this is not implemented, so we initialize to something sane */
        for (i = 0; i < 3; i++) {
                data->manual_pwm_ctl[i] = 0xff;
        }

        /* Some chips seem to have default value 0xff for all limit
         * registers. For low voltage limits it makes no sense and triggers
         * alarms, so change to 0 instead. For high temperature limits, it
         * means -1 degree C, which surprisingly doesn't trigger an alarm,
         * but is still confusing, so change to 127 degrees C. */
        for (i = 0; i < 8; i++) {
                tmp = it87_read_value(client, IT87_REG_VIN_MIN(i));
                if (tmp == 0xff)
                        it87_write_value(client, IT87_REG_VIN_MIN(i), 0);
        }
        for (i = 0; i < 3; i++) {
                tmp = it87_read_value(client, IT87_REG_TEMP_HIGH(i));
                if (tmp == 0xff)
                        it87_write_value(client, IT87_REG_TEMP_HIGH(i), 127);
        }

        /* Check if temperature channnels are reset manually or by some reason */
        tmp = it87_read_value(client, IT87_REG_TEMP_ENABLE);
        if ((tmp & 0x3f) == 0) {
                /* Temp1,Temp3=thermistor; Temp2=thermal diode */
                tmp = (tmp & 0xc0) | 0x2a;
                it87_write_value(client, IT87_REG_TEMP_ENABLE, tmp);
        }
        data->sensor = tmp;

        /* Check if voltage monitors are reset manually or by some reason */
        tmp = it87_read_value(client, IT87_REG_VIN_ENABLE);
        if ((tmp & 0xff) == 0) {
                /* Enable all voltage monitors */
                it87_write_value(client, IT87_REG_VIN_ENABLE, 0xff);
        }

        /* Check if tachometers are reset manually or by some reason */
        data->fan_main_ctrl = it87_read_value(client, IT87_REG_FAN_MAIN_CTRL);
        if ((data->fan_main_ctrl & 0x70) == 0) {
                /* Enable all fan tachometers */
                data->fan_main_ctrl |= 0x70;
                it87_write_value(client, IT87_REG_FAN_MAIN_CTRL, data->fan_main_ctrl);
        }
        data->has_fan = (data->fan_main_ctrl >> 4) & 0x07;

        /* Set tachometers to 16-bit mode if needed */
        if (data->type == it8716 || data->type == it8718) {
                tmp = it87_read_value(client, IT87_REG_FAN_16BIT);
                if (~tmp & 0x07 & data->has_fan) {
                        dev_dbg(&client->dev,
                                "Setting fan1-3 to 16-bit mode\n");
                        it87_write_value(client, IT87_REG_FAN_16BIT,
                                         tmp | 0x07);
                }
        }

        /* Set current fan mode registers and the default settings for the
         * other mode registers */
        for (i = 0; i < 3; i++) {
                if (data->fan_main_ctrl & (1 << i)) {
                        /* pwm mode */
                        tmp = it87_read_value(client, IT87_REG_PWM(i));
                        if (tmp & 0x80) {
                                /* automatic pwm - not yet implemented, but
                                 * leave the settings made by the BIOS alone
                                 * until a change is requested via the sysfs
                                 * interface */
                        } else {
                                /* manual pwm */
                                data->manual_pwm_ctl[i] = PWM_FROM_REG(tmp);
                        }
                }
        }

        /* Start monitoring */
        it87_write_value(client, IT87_REG_CONFIG,
                         (it87_read_value(client, IT87_REG_CONFIG) & 0x36)
                         | (update_vbat ? 0x41 : 0x01));
}

static struct it87_data *it87_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct it87_data *data = i2c_get_clientdata(client);
        int i;

        mutex_lock(&data->update_lock);

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

                if (update_vbat) {
                        /* Cleared after each update, so reenable.  Value
                          returned by this read will be previous value */       
                        it87_write_value(client, IT87_REG_CONFIG,
                           it87_read_value(client, IT87_REG_CONFIG) | 0x40);
                }
                for (i = 0; i <= 7; i++) {
                        data->in[i] =
                            it87_read_value(client, IT87_REG_VIN(i));
                        data->in_min[i] =
                            it87_read_value(client, IT87_REG_VIN_MIN(i));
                        data->in_max[i] =
                            it87_read_value(client, IT87_REG_VIN_MAX(i));
                }
                /* in8 (battery) has no limit registers */
                data->in[8] =
                    it87_read_value(client, IT87_REG_VIN(8));

                for (i = 0; i < 3; i++) {
                        /* Skip disabled fans */
                        if (!(data->has_fan & (1 << i)))
                                continue;

                        data->fan_min[i] =
                            it87_read_value(client, IT87_REG_FAN_MIN(i));
                        data->fan[i] = it87_read_value(client,
                                       IT87_REG_FAN(i));
                        /* Add high byte if in 16-bit mode */
                        if (data->type == it8716 || data->type == it8718) {
                                data->fan[i] |= it87_read_value(client,
                                                IT87_REG_FANX(i)) << 8;
                                data->fan_min[i] |= it87_read_value(client,
                                                IT87_REG_FANX_MIN(i)) << 8;
                        }
                }
                for (i = 0; i < 3; i++) {
                        data->temp[i] =
                            it87_read_value(client, IT87_REG_TEMP(i));
                        data->temp_high[i] =
                            it87_read_value(client, IT87_REG_TEMP_HIGH(i));
                        data->temp_low[i] =
                            it87_read_value(client, IT87_REG_TEMP_LOW(i));
                }

                /* Newer chips don't have clock dividers */
                if ((data->has_fan & 0x07) && data->type != it8716
                 && data->type != it8718) {
                        i = it87_read_value(client, IT87_REG_FAN_DIV);
                        data->fan_div[0] = i & 0x07;
                        data->fan_div[1] = (i >> 3) & 0x07;
                        data->fan_div[2] = (i & 0x40) ? 3 : 1;
                }

                data->alarms =
                        it87_read_value(client, IT87_REG_ALARM1) |
                        (it87_read_value(client, IT87_REG_ALARM2) << 8) |
                        (it87_read_value(client, IT87_REG_ALARM3) << 16);
                data->fan_main_ctrl = it87_read_value(client, IT87_REG_FAN_MAIN_CTRL);
                data->fan_ctl = it87_read_value(client, IT87_REG_FAN_CTL);

                data->sensor = it87_read_value(client, IT87_REG_TEMP_ENABLE);
                /* The 8705 does not have VID capability */
                if (data->type == it8712 || data->type == it8716) {
                        data->vid = it87_read_value(client, IT87_REG_VID);
                        /* The older IT8712F revisions had only 5 VID pins,
                           but we assume it is always safe to read 6 bits. */
                        data->vid &= 0x3f;
                }
                data->last_updated = jiffies;
                data->valid = 1;
        }

        mutex_unlock(&data->update_lock);

        return data;
}

static int __init sm_it87_init(void)
{
        int res;

        if ((res = it87_find(&isa_address)))
                return res;
        return i2c_isa_add_driver(&it87_isa_driver);
}

static void __exit sm_it87_exit(void)
{
        i2c_isa_del_driver(&it87_isa_driver);
}


MODULE_AUTHOR("Chris Gauthron <chrisg@0-in.com>, "
              "Jean Delvare <khali@linux-fr.org>");
MODULE_DESCRIPTION("IT8705F/8712F/8716F/8718F, SiS950 driver");
module_param(update_vbat, bool, 0);
MODULE_PARM_DESC(update_vbat, "Update vbat if set else return powerup value");
module_param(fix_pwm_polarity, bool, 0);
MODULE_PARM_DESC(fix_pwm_polarity, "Force PWM polarity to active high (DANGEROUS)");
MODULE_LICENSE("GPL");

module_init(sm_it87_init);
module_exit(sm_it87_exit);