/*
 * Driver for SMM665 Power Controller / Monitor
 *
 * Copyright (C) 2010 Ericsson AB.
 *
 * 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; version 2 of the License.
 *
 * This driver should also work for SMM465, SMM764, and SMM766, but is untested
 * for those chips. Only monitoring functionality is implemented.
 *
 * Datasheets:
 * http://www.summitmicro.com/prod_select/summary/SMM665/SMM665B_2089_20.pdf
 * http://www.summitmicro.com/prod_select/summary/SMM766B/SMM766B_2122.pdf
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/delay.h>

/* Internal reference voltage (VREF, x 1000 */
#define SMM665_VREF_ADC_X1000   1250

/* module parameters */
static int vref = SMM665_VREF_ADC_X1000;
module_param(vref, int, 0);
MODULE_PARM_DESC(vref, "Reference voltage in mV");

enum chips { smm465, smm665, smm665c, smm764, smm766 };

/*
 * ADC channel addresses
 */
#define SMM665_MISC16_ADC_DATA_A        0x00
#define SMM665_MISC16_ADC_DATA_B        0x01
#define SMM665_MISC16_ADC_DATA_C        0x02
#define SMM665_MISC16_ADC_DATA_D        0x03
#define SMM665_MISC16_ADC_DATA_E        0x04
#define SMM665_MISC16_ADC_DATA_F        0x05
#define SMM665_MISC16_ADC_DATA_VDD      0x06
#define SMM665_MISC16_ADC_DATA_12V      0x07
#define SMM665_MISC16_ADC_DATA_INT_TEMP 0x08
#define SMM665_MISC16_ADC_DATA_AIN1     0x09
#define SMM665_MISC16_ADC_DATA_AIN2     0x0a

/*
 * Command registers
 */
#define SMM665_MISC8_CMD_STS            0x80
#define SMM665_MISC8_STATUS1            0x81
#define SMM665_MISC8_STATUSS2           0x82
#define SMM665_MISC8_IO_POLARITY        0x83
#define SMM665_MISC8_PUP_POLARITY       0x84
#define SMM665_MISC8_ADOC_STATUS1       0x85
#define SMM665_MISC8_ADOC_STATUS2       0x86
#define SMM665_MISC8_WRITE_PROT         0x87
#define SMM665_MISC8_STS_TRACK          0x88

/*
 * Configuration registers and register groups
 */
#define SMM665_ADOC_ENABLE              0x0d
#define SMM665_LIMIT_BASE               0x80    /* First limit register */

/*
 * Limit register bit masks
 */
#define SMM665_TRIGGER_RST              0x8000
#define SMM665_TRIGGER_HEALTHY          0x4000
#define SMM665_TRIGGER_POWEROFF         0x2000
#define SMM665_TRIGGER_SHUTDOWN         0x1000
#define SMM665_ADC_MASK                 0x03ff

#define smm665_is_critical(lim) ((lim) & (SMM665_TRIGGER_RST \
                                        | SMM665_TRIGGER_POWEROFF \
                                        | SMM665_TRIGGER_SHUTDOWN))
/*
 * Fault register bit definitions
 * Values are merged from status registers 1/2,
 * with status register 1 providing the upper 8 bits.
 */
#define SMM665_FAULT_A          0x0001
#define SMM665_FAULT_B          0x0002
#define SMM665_FAULT_C          0x0004
#define SMM665_FAULT_D          0x0008
#define SMM665_FAULT_E          0x0010
#define SMM665_FAULT_F          0x0020
#define SMM665_FAULT_VDD        0x0040
#define SMM665_FAULT_12V        0x0080
#define SMM665_FAULT_TEMP       0x0100
#define SMM665_FAULT_AIN1       0x0200
#define SMM665_FAULT_AIN2       0x0400

/*
 * I2C Register addresses
 *
 * The configuration register needs to be the configured base register.
 * The command/status register address is derived from it.
 */
#define SMM665_REGMASK          0x78
#define SMM665_CMDREG_BASE      0x48
#define SMM665_CONFREG_BASE     0x50

/*
 *  Equations given by chip manufacturer to calculate voltage/temperature values
 *  vref = Reference voltage on VREF_ADC pin (module parameter)
 *  adc  = 10bit ADC value read back from registers
 */

/* Voltage A-F and VDD */
#define SMM665_VMON_ADC_TO_VOLTS(adc)  ((adc) * vref / 256)

/* Voltage 12VIN */
#define SMM665_12VIN_ADC_TO_VOLTS(adc) ((adc) * vref * 3 / 256)

/* Voltage AIN1, AIN2 */
#define SMM665_AIN_ADC_TO_VOLTS(adc)   ((adc) * vref / 512)

/* Temp Sensor */
#define SMM665_TEMP_ADC_TO_CELSIUS(adc) ((adc) <= 511) ?                   \
                                         ((int)(adc) * 1000 / 4) :         \
                                         (((int)(adc) - 0x400) * 1000 / 4)

#define SMM665_NUM_ADC          11

/*
 * Chip dependent ADC conversion time, in uS
 */
#define SMM665_ADC_WAIT_SMM665  70
#define SMM665_ADC_WAIT_SMM766  185

struct smm665_data {
        enum chips type;
        int conversion_time;            /* ADC conversion time */
        struct device *hwmon_dev;
        struct mutex update_lock;
        bool valid;
        unsigned long last_updated;     /* in jiffies */
        u16 adc[SMM665_NUM_ADC];        /* adc values (raw) */
        u16 faults;                     /* fault status */
        /* The following values are in mV */
        int critical_min_limit[SMM665_NUM_ADC];
        int alarm_min_limit[SMM665_NUM_ADC];
        int critical_max_limit[SMM665_NUM_ADC];
        int alarm_max_limit[SMM665_NUM_ADC];
        struct i2c_client *cmdreg;
};

/*
 * smm665_read16()
 *
 * Read 16 bit value from <reg>, <reg+1>. Upper 8 bits are in <reg>.
 */
static int smm665_read16(struct i2c_client *client, int reg)
{
        int rv, val;

        rv = i2c_smbus_read_byte_data(client, reg);
        if (rv < 0)
                return rv;
        val = rv << 8;
        rv = i2c_smbus_read_byte_data(client, reg + 1);
        if (rv < 0)
                return rv;
        val |= rv;
        return val;
}

/*
 * Read adc value.
 */
static int smm665_read_adc(struct smm665_data *data, int adc)
{
        struct i2c_client *client = data->cmdreg;
        int rv;
        int radc;

        /*
         * Algorithm for reading ADC, per SMM665 datasheet
         *
         *  {[S][addr][W][Ack]} {[offset][Ack]} {[S][addr][R][Nack]}
         * [wait conversion time]
         *  {[S][addr][R][Ack]} {[datahi][Ack]} {[datalo][Ack][P]}
         *
         * To implement the first part of this exchange,
         * do a full read transaction and expect a failure/Nack.
         * This sets up the address pointer on the SMM665
         * and starts the ADC conversion.
         * Then do a two-byte read transaction.
         */
        rv = i2c_smbus_read_byte_data(client, adc << 3);
        if (rv != -ENXIO) {
                /*
                 * We expect ENXIO to reflect NACK
                 * (per Documentation/i2c/fault-codes).
                 * Everything else is an error.
                 */
                dev_dbg(&client->dev,
                        "Unexpected return code %d when setting ADC index", rv);
                return (rv < 0) ? rv : -EIO;
        }

        udelay(data->conversion_time);

        /*
         * Now read two bytes.
         *
         * Neither i2c_smbus_read_byte() nor
         * i2c_smbus_read_block_data() worked here,
         * so use i2c_smbus_read_word_data() instead.
         * We could also try to use i2c_master_recv(),
         * but that is not always supported.
         */
        rv = i2c_smbus_read_word_data(client, 0);
        if (rv < 0) {
                dev_dbg(&client->dev, "Failed to read ADC value: error %d", rv);
                return -1;
        }
        /*
         * Validate/verify readback adc channel (in bit 11..14).
         * High byte is in lower 8 bit of rv, so only shift by 3.
         */
        radc = (rv >> 3) & 0x0f;
        if (radc != adc) {
                dev_dbg(&client->dev, "Unexpected RADC: Expected %d got %d",
                        adc, radc);
                return -EIO;
        }
        /*
         * Chip replies with H/L, while SMBus expects L/H.
         * Thus, byte order is reversed, and we have to swap
         * the result.
         */
        rv = swab16(rv) & SMM665_ADC_MASK;

        return rv;
}

static struct smm665_data *smm665_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct smm665_data *data = i2c_get_clientdata(client);
        struct smm665_data *ret = data;

        mutex_lock(&data->update_lock);

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

                /*
                 * read status registers
                 */
                val = smm665_read16(client, SMM665_MISC8_STATUS1);
                if (unlikely(val < 0)) {
                        ret = ERR_PTR(val);
                        goto abort;
                }
                data->faults = val;

                /* Read adc registers */
                for (i = 0; i < SMM665_NUM_ADC; i++) {
                        val = smm665_read_adc(data, i);
                        if (unlikely(val < 0)) {
                                ret = ERR_PTR(val);
                                goto abort;
                        }
                        data->adc[i] = val;
                }
                data->last_updated = jiffies;
                data->valid = 1;
        }
abort:
        mutex_unlock(&data->update_lock);
        return ret;
}

/* Return converted value from given adc */
static int smm665_convert(u16 adcval, int index)
{
        int val = 0;

        switch (index) {
        case SMM665_MISC16_ADC_DATA_12V:
                val = SMM665_12VIN_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
                break;

        case SMM665_MISC16_ADC_DATA_VDD:
        case SMM665_MISC16_ADC_DATA_A:
        case SMM665_MISC16_ADC_DATA_B:
        case SMM665_MISC16_ADC_DATA_C:
        case SMM665_MISC16_ADC_DATA_D:
        case SMM665_MISC16_ADC_DATA_E:
        case SMM665_MISC16_ADC_DATA_F:
                val = SMM665_VMON_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
                break;

        case SMM665_MISC16_ADC_DATA_AIN1:
        case SMM665_MISC16_ADC_DATA_AIN2:
                val = SMM665_AIN_ADC_TO_VOLTS(adcval & SMM665_ADC_MASK);
                break;

        case SMM665_MISC16_ADC_DATA_INT_TEMP:
                val = SMM665_TEMP_ADC_TO_CELSIUS(adcval & SMM665_ADC_MASK);
                break;

        default:
                /* If we get here, the developer messed up */
                WARN_ON_ONCE(1);
                break;
        }

        return val;
}

static int smm665_get_min(struct device *dev, int index)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct smm665_data *data = i2c_get_clientdata(client);

        return data->alarm_min_limit[index];
}

static int smm665_get_max(struct device *dev, int index)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct smm665_data *data = i2c_get_clientdata(client);

        return data->alarm_max_limit[index];
}

static int smm665_get_lcrit(struct device *dev, int index)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct smm665_data *data = i2c_get_clientdata(client);

        return data->critical_min_limit[index];
}

static int smm665_get_crit(struct device *dev, int index)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct smm665_data *data = i2c_get_clientdata(client);

        return data->critical_max_limit[index];
}

static ssize_t smm665_show_crit_alarm(struct device *dev,
                                      struct device_attribute *da, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct smm665_data *data = smm665_update_device(dev);
        int val = 0;

        if (IS_ERR(data))
                return PTR_ERR(data);

        if (data->faults & (1 << attr->index))
                val = 1;

        return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

static ssize_t smm665_show_input(struct device *dev,
                                 struct device_attribute *da, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct smm665_data *data = smm665_update_device(dev);
        int adc = attr->index;
        int val;

        if (IS_ERR(data))
                return PTR_ERR(data);

        val = smm665_convert(data->adc[adc], adc);
        return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

#define SMM665_SHOW(what) \
  static ssize_t smm665_show_##what(struct device *dev, \
                                    struct device_attribute *da, char *buf) \
{ \
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da); \
        const int val = smm665_get_##what(dev, attr->index); \
        return snprintf(buf, PAGE_SIZE, "%d\n", val); \
}

SMM665_SHOW(min);
SMM665_SHOW(max);
SMM665_SHOW(lcrit);
SMM665_SHOW(crit);

/* These macros are used below in constructing device attribute objects
 * for use with sysfs_create_group() to make a sysfs device file
 * for each register.
 */

#define SMM665_ATTR(name, type, cmd_idx) \
        static SENSOR_DEVICE_ATTR(name##_##type, S_IRUGO, \
                                  smm665_show_##type, NULL, cmd_idx)

/* Construct a sensor_device_attribute structure for each register */

/* Input voltages */
SMM665_ATTR(in1, input, SMM665_MISC16_ADC_DATA_12V);
SMM665_ATTR(in2, input, SMM665_MISC16_ADC_DATA_VDD);
SMM665_ATTR(in3, input, SMM665_MISC16_ADC_DATA_A);
SMM665_ATTR(in4, input, SMM665_MISC16_ADC_DATA_B);
SMM665_ATTR(in5, input, SMM665_MISC16_ADC_DATA_C);
SMM665_ATTR(in6, input, SMM665_MISC16_ADC_DATA_D);
SMM665_ATTR(in7, input, SMM665_MISC16_ADC_DATA_E);
SMM665_ATTR(in8, input, SMM665_MISC16_ADC_DATA_F);
SMM665_ATTR(in9, input, SMM665_MISC16_ADC_DATA_AIN1);
SMM665_ATTR(in10, input, SMM665_MISC16_ADC_DATA_AIN2);

/* Input voltages min */
SMM665_ATTR(in1, min, SMM665_MISC16_ADC_DATA_12V);
SMM665_ATTR(in2, min, SMM665_MISC16_ADC_DATA_VDD);
SMM665_ATTR(in3, min, SMM665_MISC16_ADC_DATA_A);
SMM665_ATTR(in4, min, SMM665_MISC16_ADC_DATA_B);
SMM665_ATTR(in5, min, SMM665_MISC16_ADC_DATA_C);
SMM665_ATTR(in6, min, SMM665_MISC16_ADC_DATA_D);
SMM665_ATTR(in7, min, SMM665_MISC16_ADC_DATA_E);
SMM665_ATTR(in8, min, SMM665_MISC16_ADC_DATA_F);
SMM665_ATTR(in9, min, SMM665_MISC16_ADC_DATA_AIN1);
SMM665_ATTR(in10, min, SMM665_MISC16_ADC_DATA_AIN2);

/* Input voltages max */
SMM665_ATTR(in1, max, SMM665_MISC16_ADC_DATA_12V);
SMM665_ATTR(in2, max, SMM665_MISC16_ADC_DATA_VDD);
SMM665_ATTR(in3, max, SMM665_MISC16_ADC_DATA_A);
SMM665_ATTR(in4, max, SMM665_MISC16_ADC_DATA_B);
SMM665_ATTR(in5, max, SMM665_MISC16_ADC_DATA_C);
SMM665_ATTR(in6, max, SMM665_MISC16_ADC_DATA_D);
SMM665_ATTR(in7, max, SMM665_MISC16_ADC_DATA_E);
SMM665_ATTR(in8, max, SMM665_MISC16_ADC_DATA_F);
SMM665_ATTR(in9, max, SMM665_MISC16_ADC_DATA_AIN1);
SMM665_ATTR(in10, max, SMM665_MISC16_ADC_DATA_AIN2);

/* Input voltages lcrit */
SMM665_ATTR(in1, lcrit, SMM665_MISC16_ADC_DATA_12V);
SMM665_ATTR(in2, lcrit, SMM665_MISC16_ADC_DATA_VDD);
SMM665_ATTR(in3, lcrit, SMM665_MISC16_ADC_DATA_A);
SMM665_ATTR(in4, lcrit, SMM665_MISC16_ADC_DATA_B);
SMM665_ATTR(in5, lcrit, SMM665_MISC16_ADC_DATA_C);
SMM665_ATTR(in6, lcrit, SMM665_MISC16_ADC_DATA_D);
SMM665_ATTR(in7, lcrit, SMM665_MISC16_ADC_DATA_E);
SMM665_ATTR(in8, lcrit, SMM665_MISC16_ADC_DATA_F);
SMM665_ATTR(in9, lcrit, SMM665_MISC16_ADC_DATA_AIN1);
SMM665_ATTR(in10, lcrit, SMM665_MISC16_ADC_DATA_AIN2);

/* Input voltages crit */
SMM665_ATTR(in1, crit, SMM665_MISC16_ADC_DATA_12V);
SMM665_ATTR(in2, crit, SMM665_MISC16_ADC_DATA_VDD);
SMM665_ATTR(in3, crit, SMM665_MISC16_ADC_DATA_A);
SMM665_ATTR(in4, crit, SMM665_MISC16_ADC_DATA_B);
SMM665_ATTR(in5, crit, SMM665_MISC16_ADC_DATA_C);
SMM665_ATTR(in6, crit, SMM665_MISC16_ADC_DATA_D);
SMM665_ATTR(in7, crit, SMM665_MISC16_ADC_DATA_E);
SMM665_ATTR(in8, crit, SMM665_MISC16_ADC_DATA_F);
SMM665_ATTR(in9, crit, SMM665_MISC16_ADC_DATA_AIN1);
SMM665_ATTR(in10, crit, SMM665_MISC16_ADC_DATA_AIN2);

/* critical alarms */
SMM665_ATTR(in1, crit_alarm, SMM665_FAULT_12V);
SMM665_ATTR(in2, crit_alarm, SMM665_FAULT_VDD);
SMM665_ATTR(in3, crit_alarm, SMM665_FAULT_A);
SMM665_ATTR(in4, crit_alarm, SMM665_FAULT_B);
SMM665_ATTR(in5, crit_alarm, SMM665_FAULT_C);
SMM665_ATTR(in6, crit_alarm, SMM665_FAULT_D);
SMM665_ATTR(in7, crit_alarm, SMM665_FAULT_E);
SMM665_ATTR(in8, crit_alarm, SMM665_FAULT_F);
SMM665_ATTR(in9, crit_alarm, SMM665_FAULT_AIN1);
SMM665_ATTR(in10, crit_alarm, SMM665_FAULT_AIN2);

/* Temperature */
SMM665_ATTR(temp1, input, SMM665_MISC16_ADC_DATA_INT_TEMP);
SMM665_ATTR(temp1, min, SMM665_MISC16_ADC_DATA_INT_TEMP);
SMM665_ATTR(temp1, max, SMM665_MISC16_ADC_DATA_INT_TEMP);
SMM665_ATTR(temp1, lcrit, SMM665_MISC16_ADC_DATA_INT_TEMP);
SMM665_ATTR(temp1, crit, SMM665_MISC16_ADC_DATA_INT_TEMP);
SMM665_ATTR(temp1, crit_alarm, SMM665_FAULT_TEMP);

/*
 * Finally, construct an array of pointers to members of the above objects,
 * as required for sysfs_create_group()
 */
static struct attribute *smm665_attributes[] = {
        &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_in1_lcrit.dev_attr.attr,
        &sensor_dev_attr_in1_crit.dev_attr.attr,
        &sensor_dev_attr_in1_crit_alarm.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_in2_lcrit.dev_attr.attr,
        &sensor_dev_attr_in2_crit.dev_attr.attr,
        &sensor_dev_attr_in2_crit_alarm.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_in3_lcrit.dev_attr.attr,
        &sensor_dev_attr_in3_crit.dev_attr.attr,
        &sensor_dev_attr_in3_crit_alarm.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_in4_lcrit.dev_attr.attr,
        &sensor_dev_attr_in4_crit.dev_attr.attr,
        &sensor_dev_attr_in4_crit_alarm.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_in5_lcrit.dev_attr.attr,
        &sensor_dev_attr_in5_crit.dev_attr.attr,
        &sensor_dev_attr_in5_crit_alarm.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_in6_lcrit.dev_attr.attr,
        &sensor_dev_attr_in6_crit.dev_attr.attr,
        &sensor_dev_attr_in6_crit_alarm.dev_attr.attr,

        &sensor_dev_attr_in7_input.dev_attr.attr,
        &sensor_dev_attr_in7_min.dev_attr.attr,
        &sensor_dev_attr_in7_max.dev_attr.attr,
        &sensor_dev_attr_in7_lcrit.dev_attr.attr,
        &sensor_dev_attr_in7_crit.dev_attr.attr,
        &sensor_dev_attr_in7_crit_alarm.dev_attr.attr,

        &sensor_dev_attr_in8_input.dev_attr.attr,
        &sensor_dev_attr_in8_min.dev_attr.attr,
        &sensor_dev_attr_in8_max.dev_attr.attr,
        &sensor_dev_attr_in8_lcrit.dev_attr.attr,
        &sensor_dev_attr_in8_crit.dev_attr.attr,
        &sensor_dev_attr_in8_crit_alarm.dev_attr.attr,

        &sensor_dev_attr_in9_input.dev_attr.attr,
        &sensor_dev_attr_in9_min.dev_attr.attr,
        &sensor_dev_attr_in9_max.dev_attr.attr,
        &sensor_dev_attr_in9_lcrit.dev_attr.attr,
        &sensor_dev_attr_in9_crit.dev_attr.attr,
        &sensor_dev_attr_in9_crit_alarm.dev_attr.attr,

        &sensor_dev_attr_in10_input.dev_attr.attr,
        &sensor_dev_attr_in10_min.dev_attr.attr,
        &sensor_dev_attr_in10_max.dev_attr.attr,
        &sensor_dev_attr_in10_lcrit.dev_attr.attr,
        &sensor_dev_attr_in10_crit.dev_attr.attr,
        &sensor_dev_attr_in10_crit_alarm.dev_attr.attr,

        &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_lcrit.dev_attr.attr,
        &sensor_dev_attr_temp1_crit.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,

        NULL,
};

static const struct attribute_group smm665_group = {
        .attrs = smm665_attributes,
};

static int smm665_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        struct i2c_adapter *adapter = client->adapter;
        struct smm665_data *data;
        int i, ret;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
                                     | I2C_FUNC_SMBUS_WORD_DATA))
                return -ENODEV;

        if (i2c_smbus_read_byte_data(client, SMM665_ADOC_ENABLE) < 0)
                return -ENODEV;

        ret = -ENOMEM;
        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                goto out_return;

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

        data->type = id->driver_data;
        data->cmdreg = i2c_new_dummy(adapter, (client->addr & ~SMM665_REGMASK)
                                     | SMM665_CMDREG_BASE);
        if (!data->cmdreg)
                goto out_kfree;

        switch (data->type) {
        case smm465:
        case smm665:
                data->conversion_time = SMM665_ADC_WAIT_SMM665;
                break;
        case smm665c:
        case smm764:
        case smm766:
                data->conversion_time = SMM665_ADC_WAIT_SMM766;
                break;
        }

        ret = -ENODEV;
        if (i2c_smbus_read_byte_data(data->cmdreg, SMM665_MISC8_CMD_STS) < 0)
                goto out_unregister;

        /*
         * Read limits.
         *
         * Limit registers start with register SMM665_LIMIT_BASE.
         * Each channel uses 8 registers, providing four limit values
         * per channel. Each limit value requires two registers, with the
         * high byte in the first register and the low byte in the second
         * register. The first two limits are under limit values, followed
         * by two over limit values.
         *
         * Limit register order matches the ADC register order, so we use
         * ADC register defines throughout the code to index limit registers.
         *
         * We save the first retrieved value both as "critical" and "alarm"
         * value. The second value overwrites either the critical or the
         * alarm value, depending on its configuration. This ensures that both
         * critical and alarm values are initialized, even if both registers are
         * configured as critical or non-critical.
         */
        for (i = 0; i < SMM665_NUM_ADC; i++) {
                int val;

                val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8);
                if (unlikely(val < 0))
                        goto out_unregister;
                data->critical_min_limit[i] = data->alarm_min_limit[i]
                  = smm665_convert(val, i);
                val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 2);
                if (unlikely(val < 0))
                        goto out_unregister;
                if (smm665_is_critical(val))
                        data->critical_min_limit[i] = smm665_convert(val, i);
                else
                        data->alarm_min_limit[i] = smm665_convert(val, i);
                val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 4);
                if (unlikely(val < 0))
                        goto out_unregister;
                data->critical_max_limit[i] = data->alarm_max_limit[i]
                  = smm665_convert(val, i);
                val = smm665_read16(client, SMM665_LIMIT_BASE + i * 8 + 6);
                if (unlikely(val < 0))
                        goto out_unregister;
                if (smm665_is_critical(val))
                        data->critical_max_limit[i] = smm665_convert(val, i);
                else
                        data->alarm_max_limit[i] = smm665_convert(val, i);
        }

        /* Register sysfs hooks */
        ret = sysfs_create_group(&client->dev.kobj, &smm665_group);
        if (ret)
                goto out_unregister;

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

        return 0;

out_remove_group:
        sysfs_remove_group(&client->dev.kobj, &smm665_group);
out_unregister:
        i2c_unregister_device(data->cmdreg);
out_kfree:
        kfree(data);
out_return:
        return ret;
}

static int smm665_remove(struct i2c_client *client)
{
        struct smm665_data *data = i2c_get_clientdata(client);

        i2c_unregister_device(data->cmdreg);
        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &smm665_group);

        kfree(data);

        return 0;
}

static const struct i2c_device_id smm665_id[] = {
        {"smm465", smm465},
        {"smm665", smm665},
        {"smm665c", smm665c},
        {"smm764", smm764},
        {"smm766", smm766},
        {}
};

MODULE_DEVICE_TABLE(i2c, smm665_id);

/* This is the driver that will be inserted */
static struct i2c_driver smm665_driver = {
        .driver = {
                   .name = "smm665",
                   },
        .probe = smm665_probe,
        .remove = smm665_remove,
        .id_table = smm665_id,
};

static int __init smm665_init(void)
{
        return i2c_add_driver(&smm665_driver);
}

static void __exit smm665_exit(void)
{
        i2c_del_driver(&smm665_driver);
}

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("SMM665 driver");
MODULE_LICENSE("GPL");

module_init(smm665_init);
module_exit(smm665_exit);