smm665.c

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/*
 * 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>
#include <linux/jiffies.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_swapped() instead.
     * We could also try to use i2c_master_recv(),
     * but that is not always supported.
     */
    rv = i2c_smbus_read_word_swapped(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).
     */
    radc = (rv >> 11) & 0x0f;
    if (radc != adc) {
        dev_dbg(&client->dev, "Unexpected RADC: Expected %d got %d",
            adc, radc);
        return -EIO;
    }

    return rv & SMM665_ADC_MASK;
}

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;

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

    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)
        return -ENOMEM;

    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);
    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);

    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,
};

module_i2c_driver(smm665_driver);

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