/*
 * asb100.c - Part of lm_sensors, Linux kernel modules for hardware
 *            monitoring
 *
 * Copyright (C) 2004 Mark M. Hoffman <mhoffman@lightlink.com>
 *
 * (derived from w83781d.c)
 *
 * Copyright (C) 1998 - 2003  Frodo Looijaard <frodol@dds.nl>,
 *                            Philip Edelbrock <phil@netroedge.com>, and
 *                            Mark Studebaker <mdsxyz123@yahoo.com>
 *
 * 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.
 */

/*
 * This driver supports the hardware sensor chips: Asus ASB100 and
 * ASB100-A "BACH".
 *
 * ASB100-A supports pwm1, while plain ASB100 does not.  There is no known
 * way for the driver to tell which one is there.
 *
 * Chip         #vin    #fanin  #pwm    #temp   wchipid vendid  i2c     ISA
 * asb100       7       3       1       4       0x31    0x0694  yes     no
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/hwmon-vid.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/mutex.h>
#include "lm75.h"

/* I2C addresses to scan */
static const unsigned short normal_i2c[] = { 0x2d, I2C_CLIENT_END };

static unsigned short force_subclients[4];
module_param_array(force_subclients, short, NULL, 0);
MODULE_PARM_DESC(force_subclients,
        "List of subclient addresses: {bus, clientaddr, subclientaddr1, subclientaddr2}");

/* Voltage IN registers 0-6 */
#define ASB100_REG_IN(nr)       (0x20 + (nr))
#define ASB100_REG_IN_MAX(nr)   (0x2b + (nr * 2))
#define ASB100_REG_IN_MIN(nr)   (0x2c + (nr * 2))

/* FAN IN registers 1-3 */
#define ASB100_REG_FAN(nr)      (0x28 + (nr))
#define ASB100_REG_FAN_MIN(nr)  (0x3b + (nr))

/* TEMPERATURE registers 1-4 */
static const u16 asb100_reg_temp[]      = {0, 0x27, 0x150, 0x250, 0x17};
static const u16 asb100_reg_temp_max[]  = {0, 0x39, 0x155, 0x255, 0x18};
static const u16 asb100_reg_temp_hyst[] = {0, 0x3a, 0x153, 0x253, 0x19};

#define ASB100_REG_TEMP(nr) (asb100_reg_temp[nr])
#define ASB100_REG_TEMP_MAX(nr) (asb100_reg_temp_max[nr])
#define ASB100_REG_TEMP_HYST(nr) (asb100_reg_temp_hyst[nr])

#define ASB100_REG_TEMP2_CONFIG 0x0152
#define ASB100_REG_TEMP3_CONFIG 0x0252


#define ASB100_REG_CONFIG       0x40
#define ASB100_REG_ALARM1       0x41
#define ASB100_REG_ALARM2       0x42
#define ASB100_REG_SMIM1        0x43
#define ASB100_REG_SMIM2        0x44
#define ASB100_REG_VID_FANDIV   0x47
#define ASB100_REG_I2C_ADDR     0x48
#define ASB100_REG_CHIPID       0x49
#define ASB100_REG_I2C_SUBADDR  0x4a
#define ASB100_REG_PIN          0x4b
#define ASB100_REG_IRQ          0x4c
#define ASB100_REG_BANK         0x4e
#define ASB100_REG_CHIPMAN      0x4f

#define ASB100_REG_WCHIPID      0x58

/* bit 7 -> enable, bits 0-3 -> duty cycle */
#define ASB100_REG_PWM1         0x59

/*
 * CONVERSIONS
 * Rounding and limit checking is only done on the TO_REG variants.
 */

/* These constants are a guess, consistent w/ w83781d */
#define ASB100_IN_MIN           0
#define ASB100_IN_MAX           4080

/*
 * IN: 1/1000 V (0V to 4.08V)
 * REG: 16mV/bit
 */
static u8 IN_TO_REG(unsigned val)
{
        unsigned nval = clamp_val(val, ASB100_IN_MIN, ASB100_IN_MAX);
        return (nval + 8) / 16;
}

static unsigned IN_FROM_REG(u8 reg)
{
        return reg * 16;
}

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

static int FAN_FROM_REG(u8 val, int div)
{
        return val == 0 ? -1 : val == 255 ? 0 : 1350000 / (val * div);
}

/* These constants are a guess, consistent w/ w83781d */
#define ASB100_TEMP_MIN         -128000
#define ASB100_TEMP_MAX         127000

/*
 * TEMP: 0.001C/bit (-128C to +127C)
 * REG: 1C/bit, two's complement
 */
static u8 TEMP_TO_REG(long temp)
{
        int ntemp = clamp_val(temp, ASB100_TEMP_MIN, ASB100_TEMP_MAX);
        ntemp += (ntemp < 0 ? -500 : 500);
        return (u8)(ntemp / 1000);
}

static int TEMP_FROM_REG(u8 reg)
{
        return (s8)reg * 1000;
}

/*
 * PWM: 0 - 255 per sensors documentation
 * REG: (6.25% duty cycle per bit)
 */
static u8 ASB100_PWM_TO_REG(int pwm)
{
        pwm = clamp_val(pwm, 0, 255);
        return (u8)(pwm / 16);
}

static int ASB100_PWM_FROM_REG(u8 reg)
{
        return reg * 16;
}

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

/*
 * FAN DIV: 1, 2, 4, or 8 (defaults to 2)
 * REG: 0, 1, 2, or 3 (respectively) (defaults to 1)
 */
static u8 DIV_TO_REG(long val)
{
        return val == 8 ? 3 : val == 4 ? 2 : val == 1 ? 0 : 1;
}

/*
 * For each registered client, we need to keep some data in memory. That
 * data is pointed to by client->data. The structure itself is
 * dynamically allocated, at the same time the client itself is allocated.
 */
struct asb100_data {
        struct device *hwmon_dev;
        struct mutex lock;

        struct mutex update_lock;
        unsigned long last_updated;     /* In jiffies */

        /* array of 2 pointers to subclients */
        struct i2c_client *lm75[2];

        char valid;             /* !=0 if following fields are valid */
        u8 in[7];               /* Register value */
        u8 in_max[7];           /* Register value */
        u8 in_min[7];           /* Register value */
        u8 fan[3];              /* Register value */
        u8 fan_min[3];          /* Register value */
        u16 temp[4];            /* Register value (0 and 3 are u8 only) */
        u16 temp_max[4];        /* Register value (0 and 3 are u8 only) */
        u16 temp_hyst[4];       /* Register value (0 and 3 are u8 only) */
        u8 fan_div[3];          /* Register encoding, right justified */
        u8 pwm;                 /* Register encoding */
        u8 vid;                 /* Register encoding, combined */
        u32 alarms;             /* Register encoding, combined */
        u8 vrm;
};

static int asb100_read_value(struct i2c_client *client, u16 reg);
static void asb100_write_value(struct i2c_client *client, u16 reg, u16 val);

static int asb100_probe(struct i2c_client *client,
                        const struct i2c_device_id *id);
static int asb100_detect(struct i2c_client *client,
                         struct i2c_board_info *info);
static int asb100_remove(struct i2c_client *client);
static struct asb100_data *asb100_update_device(struct device *dev);
static void asb100_init_client(struct i2c_client *client);

static const struct i2c_device_id asb100_id[] = {
        { "asb100", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, asb100_id);

static struct i2c_driver asb100_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "asb100",
        },
        .probe          = asb100_probe,
        .remove         = asb100_remove,
        .id_table       = asb100_id,
        .detect         = asb100_detect,
        .address_list   = normal_i2c,
};

/* 7 Voltages */
#define show_in_reg(reg) \
static ssize_t show_##reg(struct device *dev, struct device_attribute *attr, \
                char *buf) \
{ \
        int nr = to_sensor_dev_attr(attr)->index; \
        struct asb100_data *data = asb100_update_device(dev); \
        return sprintf(buf, "%d\n", IN_FROM_REG(data->reg[nr])); \
}

show_in_reg(in)
show_in_reg(in_min)
show_in_reg(in_max)

#define set_in_reg(REG, reg) \
static ssize_t set_in_##reg(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 asb100_data *data = i2c_get_clientdata(client); \
        unsigned long val; \
        int err = kstrtoul(buf, 10, &val); \
        if (err) \
                return err; \
        mutex_lock(&data->update_lock); \
        data->in_##reg[nr] = IN_TO_REG(val); \
        asb100_write_value(client, ASB100_REG_IN_##REG(nr), \
                data->in_##reg[nr]); \
        mutex_unlock(&data->update_lock); \
        return count; \
}

set_in_reg(MIN, min)
set_in_reg(MAX, max)

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

sysfs_in(0);
sysfs_in(1);
sysfs_in(2);
sysfs_in(3);
sysfs_in(4);
sysfs_in(5);
sysfs_in(6);

/* 3 Fans */
static ssize_t show_fan(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct asb100_data *data = asb100_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)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct asb100_data *data = asb100_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)
{
        int nr = to_sensor_dev_attr(attr)->index;
        struct asb100_data *data = asb100_update_device(dev);
        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 asb100_data *data = i2c_get_clientdata(client);
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;

        mutex_lock(&data->update_lock);
        data->fan_min[nr] = FAN_TO_REG(val, DIV_FROM_REG(data->fan_div[nr]));
        asb100_write_value(client, ASB100_REG_FAN_MIN(nr), 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 asb100_data *data = i2c_get_clientdata(client);
        unsigned long min;
        int reg;
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;

        mutex_lock(&data->update_lock);

        min = FAN_FROM_REG(data->fan_min[nr],
                        DIV_FROM_REG(data->fan_div[nr]));
        data->fan_div[nr] = DIV_TO_REG(val);

        switch (nr) {
        case 0: /* fan 1 */
                reg = asb100_read_value(client, ASB100_REG_VID_FANDIV);
                reg = (reg & 0xcf) | (data->fan_div[0] << 4);
                asb100_write_value(client, ASB100_REG_VID_FANDIV, reg);
                break;

        case 1: /* fan 2 */
                reg = asb100_read_value(client, ASB100_REG_VID_FANDIV);
                reg = (reg & 0x3f) | (data->fan_div[1] << 6);
                asb100_write_value(client, ASB100_REG_VID_FANDIV, reg);
                break;

        case 2: /* fan 3 */
                reg = asb100_read_value(client, ASB100_REG_PIN);
                reg = (reg & 0x3f) | (data->fan_div[2] << 6);
                asb100_write_value(client, ASB100_REG_PIN, reg);
                break;
        }

        data->fan_min[nr] =
                FAN_TO_REG(min, DIV_FROM_REG(data->fan_div[nr]));
        asb100_write_value(client, ASB100_REG_FAN_MIN(nr), data->fan_min[nr]);

        mutex_unlock(&data->update_lock);

        return count;
}

#define sysfs_fan(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)

sysfs_fan(1);
sysfs_fan(2);
sysfs_fan(3);

/* 4 Temp. Sensors */
static int sprintf_temp_from_reg(u16 reg, char *buf, int nr)
{
        int ret = 0;

        switch (nr) {
        case 1: case 2:
                ret = sprintf(buf, "%d\n", LM75_TEMP_FROM_REG(reg));
                break;
        case 0: case 3: default:
                ret = sprintf(buf, "%d\n", TEMP_FROM_REG(reg));
                break;
        }
        return ret;
}

#define show_temp_reg(reg) \
static ssize_t show_##reg(struct device *dev, struct device_attribute *attr, \
                char *buf) \
{ \
        int nr = to_sensor_dev_attr(attr)->index; \
        struct asb100_data *data = asb100_update_device(dev); \
        return sprintf_temp_from_reg(data->reg[nr], buf, nr); \
}

show_temp_reg(temp);
show_temp_reg(temp_max);
show_temp_reg(temp_hyst);

#define set_temp_reg(REG, reg) \
static ssize_t set_##reg(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 asb100_data *data = i2c_get_clientdata(client); \
        long val; \
        int err = kstrtol(buf, 10, &val); \
        if (err) \
                return err; \
        mutex_lock(&data->update_lock); \
        switch (nr) { \
        case 1: case 2: \
                data->reg[nr] = LM75_TEMP_TO_REG(val); \
                break; \
        case 0: case 3: default: \
                data->reg[nr] = TEMP_TO_REG(val); \
                break; \
        } \
        asb100_write_value(client, ASB100_REG_TEMP_##REG(nr+1), \
                        data->reg[nr]); \
        mutex_unlock(&data->update_lock); \
        return count; \
}

set_temp_reg(MAX, temp_max);
set_temp_reg(HYST, temp_hyst);

#define sysfs_temp(num) \
static SENSOR_DEVICE_ATTR(temp##num##_input, S_IRUGO, \
                show_temp, NULL, num - 1); \
static SENSOR_DEVICE_ATTR(temp##num##_max, S_IRUGO | S_IWUSR, \
                show_temp_max, set_temp_max, num - 1); \
static SENSOR_DEVICE_ATTR(temp##num##_max_hyst, S_IRUGO | S_IWUSR, \
                show_temp_hyst, set_temp_hyst, num - 1)

sysfs_temp(1);
sysfs_temp(2);
sysfs_temp(3);
sysfs_temp(4);

/* VID */
static ssize_t show_vid(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct asb100_data *data = asb100_update_device(dev);
        return sprintf(buf, "%d\n", vid_from_reg(data->vid, data->vrm));
}

static DEVICE_ATTR(cpu0_vid, S_IRUGO, show_vid, NULL);

/* VRM */
static ssize_t show_vrm(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct asb100_data *data = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n", data->vrm);
}

static ssize_t set_vrm(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct asb100_data *data = dev_get_drvdata(dev);
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;
        data->vrm = val;
        return count;
}

/* Alarms */
static DEVICE_ATTR(vrm, S_IRUGO | S_IWUSR, show_vrm, set_vrm);

static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct asb100_data *data = asb100_update_device(dev);
        return sprintf(buf, "%u\n", data->alarms);
}

static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        int bitnr = to_sensor_dev_attr(attr)->index;
        struct asb100_data *data = asb100_update_device(dev);
        return sprintf(buf, "%u\n", (data->alarms >> bitnr) & 1);
}
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, 8);
static SENSOR_DEVICE_ATTR(fan1_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(fan2_alarm, S_IRUGO, show_alarm, NULL, 7);
static SENSOR_DEVICE_ATTR(fan3_alarm, S_IRUGO, show_alarm, NULL, 11);
static SENSOR_DEVICE_ATTR(temp1_alarm, S_IRUGO, show_alarm, NULL, 4);
static SENSOR_DEVICE_ATTR(temp2_alarm, S_IRUGO, show_alarm, NULL, 5);
static SENSOR_DEVICE_ATTR(temp3_alarm, S_IRUGO, show_alarm, NULL, 13);

/* 1 PWM */
static ssize_t show_pwm1(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        struct asb100_data *data = asb100_update_device(dev);
        return sprintf(buf, "%d\n", ASB100_PWM_FROM_REG(data->pwm & 0x0f));
}

static ssize_t set_pwm1(struct device *dev, struct device_attribute *attr,
                const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct asb100_data *data = i2c_get_clientdata(client);
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;

        mutex_lock(&data->update_lock);
        data->pwm &= 0x80; /* keep the enable bit */
        data->pwm |= (0x0f & ASB100_PWM_TO_REG(val));
        asb100_write_value(client, ASB100_REG_PWM1, data->pwm);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_pwm_enable1(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct asb100_data *data = asb100_update_device(dev);
        return sprintf(buf, "%d\n", (data->pwm & 0x80) ? 1 : 0);
}

static ssize_t set_pwm_enable1(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct asb100_data *data = i2c_get_clientdata(client);
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;

        mutex_lock(&data->update_lock);
        data->pwm &= 0x0f; /* keep the duty cycle bits */
        data->pwm |= (val ? 0x80 : 0x00);
        asb100_write_value(client, ASB100_REG_PWM1, data->pwm);
        mutex_unlock(&data->update_lock);
        return count;
}

static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm1, set_pwm1);
static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
                show_pwm_enable1, set_pwm_enable1);

static struct attribute *asb100_attributes[] = {
        &sensor_dev_attr_in0_input.dev_attr.attr,
        &sensor_dev_attr_in0_min.dev_attr.attr,
        &sensor_dev_attr_in0_max.dev_attr.attr,
        &sensor_dev_attr_in1_input.dev_attr.attr,
        &sensor_dev_attr_in1_min.dev_attr.attr,
        &sensor_dev_attr_in1_max.dev_attr.attr,
        &sensor_dev_attr_in2_input.dev_attr.attr,
        &sensor_dev_attr_in2_min.dev_attr.attr,
        &sensor_dev_attr_in2_max.dev_attr.attr,
        &sensor_dev_attr_in3_input.dev_attr.attr,
        &sensor_dev_attr_in3_min.dev_attr.attr,
        &sensor_dev_attr_in3_max.dev_attr.attr,
        &sensor_dev_attr_in4_input.dev_attr.attr,
        &sensor_dev_attr_in4_min.dev_attr.attr,
        &sensor_dev_attr_in4_max.dev_attr.attr,
        &sensor_dev_attr_in5_input.dev_attr.attr,
        &sensor_dev_attr_in5_min.dev_attr.attr,
        &sensor_dev_attr_in5_max.dev_attr.attr,
        &sensor_dev_attr_in6_input.dev_attr.attr,
        &sensor_dev_attr_in6_min.dev_attr.attr,
        &sensor_dev_attr_in6_max.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_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
        &sensor_dev_attr_temp2_input.dev_attr.attr,
        &sensor_dev_attr_temp2_max.dev_attr.attr,
        &sensor_dev_attr_temp2_max_hyst.dev_attr.attr,
        &sensor_dev_attr_temp3_input.dev_attr.attr,
        &sensor_dev_attr_temp3_max.dev_attr.attr,
        &sensor_dev_attr_temp3_max_hyst.dev_attr.attr,
        &sensor_dev_attr_temp4_input.dev_attr.attr,
        &sensor_dev_attr_temp4_max.dev_attr.attr,
        &sensor_dev_attr_temp4_max_hyst.dev_attr.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_fan1_alarm.dev_attr.attr,
        &sensor_dev_attr_fan2_alarm.dev_attr.attr,
        &sensor_dev_attr_fan3_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_alarm.dev_attr.attr,
        &sensor_dev_attr_temp3_alarm.dev_attr.attr,

        &dev_attr_cpu0_vid.attr,
        &dev_attr_vrm.attr,
        &dev_attr_alarms.attr,
        &dev_attr_pwm1.attr,
        &dev_attr_pwm1_enable.attr,

        NULL
};

static const struct attribute_group asb100_group = {
        .attrs = asb100_attributes,
};

static int asb100_detect_subclients(struct i2c_client *client)
{
        int i, id, err;
        int address = client->addr;
        unsigned short sc_addr[2];
        struct asb100_data *data = i2c_get_clientdata(client);
        struct i2c_adapter *adapter = client->adapter;

        id = i2c_adapter_id(adapter);

        if (force_subclients[0] == id && force_subclients[1] == address) {
                for (i = 2; i <= 3; i++) {
                        if (force_subclients[i] < 0x48 ||
                            force_subclients[i] > 0x4f) {
                                dev_err(&client->dev,
                                        "invalid subclient address %d; must be 0x48-0x4f\n",
                                        force_subclients[i]);
                                err = -ENODEV;
                                goto ERROR_SC_2;
                        }
                }
                asb100_write_value(client, ASB100_REG_I2C_SUBADDR,
                                        (force_subclients[2] & 0x07) |
                                        ((force_subclients[3] & 0x07) << 4));
                sc_addr[0] = force_subclients[2];
                sc_addr[1] = force_subclients[3];
        } else {
                int val = asb100_read_value(client, ASB100_REG_I2C_SUBADDR);
                sc_addr[0] = 0x48 + (val & 0x07);
                sc_addr[1] = 0x48 + ((val >> 4) & 0x07);
        }

        if (sc_addr[0] == sc_addr[1]) {
                dev_err(&client->dev,
                        "duplicate addresses 0x%x for subclients\n",
                        sc_addr[0]);
                err = -ENODEV;
                goto ERROR_SC_2;
        }

        data->lm75[0] = i2c_new_dummy(adapter, sc_addr[0]);
        if (!data->lm75[0]) {
                dev_err(&client->dev,
                        "subclient %d registration at address 0x%x failed.\n",
                        1, sc_addr[0]);
                err = -ENOMEM;
                goto ERROR_SC_2;
        }

        data->lm75[1] = i2c_new_dummy(adapter, sc_addr[1]);
        if (!data->lm75[1]) {
                dev_err(&client->dev,
                        "subclient %d registration at address 0x%x failed.\n",
                        2, sc_addr[1]);
                err = -ENOMEM;
                goto ERROR_SC_3;
        }

        return 0;

/* Undo inits in case of errors */
ERROR_SC_3:
        i2c_unregister_device(data->lm75[0]);
ERROR_SC_2:
        return err;
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int asb100_detect(struct i2c_client *client,
                         struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int val1, val2;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
                pr_debug("detect failed, smbus byte data not supported!\n");
                return -ENODEV;
        }

        val1 = i2c_smbus_read_byte_data(client, ASB100_REG_BANK);
        val2 = i2c_smbus_read_byte_data(client, ASB100_REG_CHIPMAN);

        /* If we're in bank 0 */
        if ((!(val1 & 0x07)) &&
                        /* Check for ASB100 ID (low byte) */
                        (((!(val1 & 0x80)) && (val2 != 0x94)) ||
                        /* Check for ASB100 ID (high byte ) */
                        ((val1 & 0x80) && (val2 != 0x06)))) {
                pr_debug("detect failed, bad chip id 0x%02x!\n", val2);
                return -ENODEV;
        }

        /* Put it now into bank 0 and Vendor ID High Byte */
        i2c_smbus_write_byte_data(client, ASB100_REG_BANK,
                (i2c_smbus_read_byte_data(client, ASB100_REG_BANK) & 0x78)
                | 0x80);

        /* Determine the chip type. */
        val1 = i2c_smbus_read_byte_data(client, ASB100_REG_WCHIPID);
        val2 = i2c_smbus_read_byte_data(client, ASB100_REG_CHIPMAN);

        if (val1 != 0x31 || val2 != 0x06)
                return -ENODEV;

        strlcpy(info->type, "asb100", I2C_NAME_SIZE);

        return 0;
}

static int asb100_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        int err;
        struct asb100_data *data;

        data = devm_kzalloc(&client->dev, sizeof(struct asb100_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

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

        /* Attach secondary lm75 clients */
        err = asb100_detect_subclients(client);
        if (err)
                return err;

        /* Initialize the chip */
        asb100_init_client(client);

        /* A few vars need to be filled upon startup */
        data->fan_min[0] = asb100_read_value(client, ASB100_REG_FAN_MIN(0));
        data->fan_min[1] = asb100_read_value(client, ASB100_REG_FAN_MIN(1));
        data->fan_min[2] = asb100_read_value(client, ASB100_REG_FAN_MIN(2));

        /* Register sysfs hooks */
        err = sysfs_create_group(&client->dev.kobj, &asb100_group);
        if (err)
                goto ERROR3;

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

        return 0;

ERROR4:
        sysfs_remove_group(&client->dev.kobj, &asb100_group);
ERROR3:
        i2c_unregister_device(data->lm75[1]);
        i2c_unregister_device(data->lm75[0]);
        return err;
}

static int asb100_remove(struct i2c_client *client)
{
        struct asb100_data *data = i2c_get_clientdata(client);

        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &asb100_group);

        i2c_unregister_device(data->lm75[1]);
        i2c_unregister_device(data->lm75[0]);

        return 0;
}

/*
 * The SMBus locks itself, usually, but nothing may access the chip between
 * bank switches.
 */
static int asb100_read_value(struct i2c_client *client, u16 reg)
{
        struct asb100_data *data = i2c_get_clientdata(client);
        struct i2c_client *cl;
        int res, bank;

        mutex_lock(&data->lock);

        bank = (reg >> 8) & 0x0f;
        if (bank > 2)
                /* switch banks */
                i2c_smbus_write_byte_data(client, ASB100_REG_BANK, bank);

        if (bank == 0 || bank > 2) {
                res = i2c_smbus_read_byte_data(client, reg & 0xff);
        } else {
                /* switch to subclient */
                cl = data->lm75[bank - 1];

                /* convert from ISA to LM75 I2C addresses */
                switch (reg & 0xff) {
                case 0x50: /* TEMP */
                        res = i2c_smbus_read_word_swapped(cl, 0);
                        break;
                case 0x52: /* CONFIG */
                        res = i2c_smbus_read_byte_data(cl, 1);
                        break;
                case 0x53: /* HYST */
                        res = i2c_smbus_read_word_swapped(cl, 2);
                        break;
                case 0x55: /* MAX */
                default:
                        res = i2c_smbus_read_word_swapped(cl, 3);
                        break;
                }
        }

        if (bank > 2)
                i2c_smbus_write_byte_data(client, ASB100_REG_BANK, 0);

        mutex_unlock(&data->lock);

        return res;
}

static void asb100_write_value(struct i2c_client *client, u16 reg, u16 value)
{
        struct asb100_data *data = i2c_get_clientdata(client);
        struct i2c_client *cl;
        int bank;

        mutex_lock(&data->lock);

        bank = (reg >> 8) & 0x0f;
        if (bank > 2)
                /* switch banks */
                i2c_smbus_write_byte_data(client, ASB100_REG_BANK, bank);

        if (bank == 0 || bank > 2) {
                i2c_smbus_write_byte_data(client, reg & 0xff, value & 0xff);
        } else {
                /* switch to subclient */
                cl = data->lm75[bank - 1];

                /* convert from ISA to LM75 I2C addresses */
                switch (reg & 0xff) {
                case 0x52: /* CONFIG */
                        i2c_smbus_write_byte_data(cl, 1, value & 0xff);
                        break;
                case 0x53: /* HYST */
                        i2c_smbus_write_word_swapped(cl, 2, value);
                        break;
                case 0x55: /* MAX */
                        i2c_smbus_write_word_swapped(cl, 3, value);
                        break;
                }
        }

        if (bank > 2)
                i2c_smbus_write_byte_data(client, ASB100_REG_BANK, 0);

        mutex_unlock(&data->lock);
}

static void asb100_init_client(struct i2c_client *client)
{
        struct asb100_data *data = i2c_get_clientdata(client);

        data->vrm = vid_which_vrm();

        /* Start monitoring */
        asb100_write_value(client, ASB100_REG_CONFIG,
                (asb100_read_value(client, ASB100_REG_CONFIG) & 0xf7) | 0x01);
}

static struct asb100_data *asb100_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct asb100_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) {

                dev_dbg(&client->dev, "starting device update...\n");

                /* 7 voltage inputs */
                for (i = 0; i < 7; i++) {
                        data->in[i] = asb100_read_value(client,
                                ASB100_REG_IN(i));
                        data->in_min[i] = asb100_read_value(client,
                                ASB100_REG_IN_MIN(i));
                        data->in_max[i] = asb100_read_value(client,
                                ASB100_REG_IN_MAX(i));
                }

                /* 3 fan inputs */
                for (i = 0; i < 3; i++) {
                        data->fan[i] = asb100_read_value(client,
                                        ASB100_REG_FAN(i));
                        data->fan_min[i] = asb100_read_value(client,
                                        ASB100_REG_FAN_MIN(i));
                }

                /* 4 temperature inputs */
                for (i = 1; i <= 4; i++) {
                        data->temp[i-1] = asb100_read_value(client,
                                        ASB100_REG_TEMP(i));
                        data->temp_max[i-1] = asb100_read_value(client,
                                        ASB100_REG_TEMP_MAX(i));
                        data->temp_hyst[i-1] = asb100_read_value(client,
                                        ASB100_REG_TEMP_HYST(i));
                }

                /* VID and fan divisors */
                i = asb100_read_value(client, ASB100_REG_VID_FANDIV);
                data->vid = i & 0x0f;
                data->vid |= (asb100_read_value(client,
                                ASB100_REG_CHIPID) & 0x01) << 4;
                data->fan_div[0] = (i >> 4) & 0x03;
                data->fan_div[1] = (i >> 6) & 0x03;
                data->fan_div[2] = (asb100_read_value(client,
                                ASB100_REG_PIN) >> 6) & 0x03;

                /* PWM */
                data->pwm = asb100_read_value(client, ASB100_REG_PWM1);

                /* alarms */
                data->alarms = asb100_read_value(client, ASB100_REG_ALARM1) +
                        (asb100_read_value(client, ASB100_REG_ALARM2) << 8);

                data->last_updated = jiffies;
                data->valid = 1;

                dev_dbg(&client->dev, "... device update complete\n");
        }

        mutex_unlock(&data->update_lock);

        return data;
}

module_i2c_driver(asb100_driver);

MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
MODULE_DESCRIPTION("ASB100 Bach driver");
MODULE_LICENSE("GPL");