pmbus_core.c

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/*
 * Hardware monitoring driver for PMBus devices
 *
 * Copyright (c) 2010, 2011 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; 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/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/jiffies.h>
#include <linux/i2c/pmbus.h>
#include "pmbus.h"

/*
 * Constants needed to determine number of sensors, booleans, and labels.
 */
#define PMBUS_MAX_INPUT_SENSORS     22  /* 10*volt, 7*curr, 5*power */
#define PMBUS_VOUT_SENSORS_PER_PAGE 9   /* input, min, max, lcrit,
                           crit, lowest, highest, avg,
                           reset */
#define PMBUS_IOUT_SENSORS_PER_PAGE 8   /* input, min, max, crit,
                           lowest, highest, avg,
                           reset */
#define PMBUS_POUT_SENSORS_PER_PAGE 7   /* input, cap, max, crit,
                         * highest, avg, reset
                         */
#define PMBUS_MAX_SENSORS_PER_FAN   1   /* input */
#define PMBUS_MAX_SENSORS_PER_TEMP  9   /* input, min, max, lcrit,
                         * crit, lowest, highest, avg,
                         * reset
                         */

#define PMBUS_MAX_INPUT_BOOLEANS    7   /* v: min_alarm, max_alarm,
                           lcrit_alarm, crit_alarm;
                           c: alarm, crit_alarm;
                           p: crit_alarm */
#define PMBUS_VOUT_BOOLEANS_PER_PAGE    4   /* min_alarm, max_alarm,
                           lcrit_alarm, crit_alarm */
#define PMBUS_IOUT_BOOLEANS_PER_PAGE    3   /* alarm, lcrit_alarm,
                           crit_alarm */
#define PMBUS_POUT_BOOLEANS_PER_PAGE    3   /* cap_alarm, alarm, crit_alarm
                         */
#define PMBUS_MAX_BOOLEANS_PER_FAN  2   /* alarm, fault */
#define PMBUS_MAX_BOOLEANS_PER_TEMP 4   /* min_alarm, max_alarm,
                           lcrit_alarm, crit_alarm */

#define PMBUS_MAX_INPUT_LABELS      4   /* vin, vcap, iin, pin */

/*
 * status, status_vout, status_iout, status_fans, status_fan34, and status_temp
 * are paged. status_input is unpaged.
 */
#define PB_NUM_STATUS_REG   (PMBUS_PAGES * 6 + 1)

/*
 * Index into status register array, per status register group
 */
#define PB_STATUS_BASE      0
#define PB_STATUS_VOUT_BASE (PB_STATUS_BASE + PMBUS_PAGES)
#define PB_STATUS_IOUT_BASE (PB_STATUS_VOUT_BASE + PMBUS_PAGES)
#define PB_STATUS_FAN_BASE  (PB_STATUS_IOUT_BASE + PMBUS_PAGES)
#define PB_STATUS_FAN34_BASE    (PB_STATUS_FAN_BASE + PMBUS_PAGES)
#define PB_STATUS_INPUT_BASE    (PB_STATUS_FAN34_BASE + PMBUS_PAGES)
#define PB_STATUS_TEMP_BASE (PB_STATUS_INPUT_BASE + 1)

#define PMBUS_NAME_SIZE     24

struct pmbus_sensor {
    char name[PMBUS_NAME_SIZE]; /* sysfs sensor name */
    struct sensor_device_attribute attribute;
    u8 page;        /* page number */
    u16 reg;        /* register */
    enum pmbus_sensor_classes class;    /* sensor class */
    bool update;        /* runtime sensor update needed */
    int data;       /* Sensor data.
                   Negative if there was a read error */
};

struct pmbus_boolean {
    char name[PMBUS_NAME_SIZE]; /* sysfs boolean name */
    struct sensor_device_attribute attribute;
};

struct pmbus_label {
    char name[PMBUS_NAME_SIZE]; /* sysfs label name */
    struct sensor_device_attribute attribute;
    char label[PMBUS_NAME_SIZE];    /* label */
};

struct pmbus_data {
    struct device *hwmon_dev;

    u32 flags;      /* from platform data */

    int exponent;       /* linear mode: exponent for output voltages */

    const struct pmbus_driver_info *info;

    int max_attributes;
    int num_attributes;
    struct attribute **attributes;
    struct attribute_group group;

    /*
     * Sensors cover both sensor and limit registers.
     */
    int max_sensors;
    int num_sensors;
    struct pmbus_sensor *sensors;
    /*
     * Booleans are used for alarms.
     * Values are determined from status registers.
     */
    int max_booleans;
    int num_booleans;
    struct pmbus_boolean *booleans;
    /*
     * Labels are used to map generic names (e.g., "in1")
     * to PMBus specific names (e.g., "vin" or "vout1").
     */
    int max_labels;
    int num_labels;
    struct pmbus_label *labels;

    struct mutex update_lock;
    bool valid;
    unsigned long last_updated; /* in jiffies */

    /*
     * A single status register covers multiple attributes,
     * so we keep them all together.
     */
    u8 status[PB_NUM_STATUS_REG];

    u8 currpage;
};

int pmbus_set_page(struct i2c_client *client, u8 page)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    int rv = 0;
    int newpage;

    if (page != data->currpage) {
        rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
        newpage = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
        if (newpage != page)
            rv = -EIO;
        else
            data->currpage = page;
    }
    return rv;
}
EXPORT_SYMBOL_GPL(pmbus_set_page);

int pmbus_write_byte(struct i2c_client *client, int page, u8 value)
{
    int rv;

    if (page >= 0) {
        rv = pmbus_set_page(client, page);
        if (rv < 0)
            return rv;
    }

    return i2c_smbus_write_byte(client, value);
}
EXPORT_SYMBOL_GPL(pmbus_write_byte);

/*
 * _pmbus_write_byte() is similar to pmbus_write_byte(), but checks if
 * a device specific mapping funcion exists and calls it if necessary.
 */
static int _pmbus_write_byte(struct i2c_client *client, int page, u8 value)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    const struct pmbus_driver_info *info = data->info;
    int status;

    if (info->write_byte) {
        status = info->write_byte(client, page, value);
        if (status != -ENODATA)
            return status;
    }
    return pmbus_write_byte(client, page, value);
}

int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg, u16 word)
{
    int rv;

    rv = pmbus_set_page(client, page);
    if (rv < 0)
        return rv;

    return i2c_smbus_write_word_data(client, reg, word);
}
EXPORT_SYMBOL_GPL(pmbus_write_word_data);

/*
 * _pmbus_write_word_data() is similar to pmbus_write_word_data(), but checks if
 * a device specific mapping function exists and calls it if necessary.
 */
static int _pmbus_write_word_data(struct i2c_client *client, int page, int reg,
                  u16 word)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    const struct pmbus_driver_info *info = data->info;
    int status;

    if (info->write_word_data) {
        status = info->write_word_data(client, page, reg, word);
        if (status != -ENODATA)
            return status;
    }
    if (reg >= PMBUS_VIRT_BASE)
        return -ENXIO;
    return pmbus_write_word_data(client, page, reg, word);
}

int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg)
{
    int rv;

    rv = pmbus_set_page(client, page);
    if (rv < 0)
        return rv;

    return i2c_smbus_read_word_data(client, reg);
}
EXPORT_SYMBOL_GPL(pmbus_read_word_data);

/*
 * _pmbus_read_word_data() is similar to pmbus_read_word_data(), but checks if
 * a device specific mapping function exists and calls it if necessary.
 */
static int _pmbus_read_word_data(struct i2c_client *client, int page, int reg)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    const struct pmbus_driver_info *info = data->info;
    int status;

    if (info->read_word_data) {
        status = info->read_word_data(client, page, reg);
        if (status != -ENODATA)
            return status;
    }
    if (reg >= PMBUS_VIRT_BASE)
        return -ENXIO;
    return pmbus_read_word_data(client, page, reg);
}

int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg)
{
    int rv;

    if (page >= 0) {
        rv = pmbus_set_page(client, page);
        if (rv < 0)
            return rv;
    }

    return i2c_smbus_read_byte_data(client, reg);
}
EXPORT_SYMBOL_GPL(pmbus_read_byte_data);

/*
 * _pmbus_read_byte_data() is similar to pmbus_read_byte_data(), but checks if
 * a device specific mapping function exists and calls it if necessary.
 */
static int _pmbus_read_byte_data(struct i2c_client *client, int page, int reg)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    const struct pmbus_driver_info *info = data->info;
    int status;

    if (info->read_byte_data) {
        status = info->read_byte_data(client, page, reg);
        if (status != -ENODATA)
            return status;
    }
    return pmbus_read_byte_data(client, page, reg);
}

static void pmbus_clear_fault_page(struct i2c_client *client, int page)
{
    _pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
}

void pmbus_clear_faults(struct i2c_client *client)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    int i;

    for (i = 0; i < data->info->pages; i++)
        pmbus_clear_fault_page(client, i);
}
EXPORT_SYMBOL_GPL(pmbus_clear_faults);

static int pmbus_check_status_cml(struct i2c_client *client)
{
    int status, status2;

    status = _pmbus_read_byte_data(client, -1, PMBUS_STATUS_BYTE);
    if (status < 0 || (status & PB_STATUS_CML)) {
        status2 = _pmbus_read_byte_data(client, -1, PMBUS_STATUS_CML);
        if (status2 < 0 || (status2 & PB_CML_FAULT_INVALID_COMMAND))
            return -EIO;
    }
    return 0;
}

bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg)
{
    int rv;
    struct pmbus_data *data = i2c_get_clientdata(client);

    rv = _pmbus_read_byte_data(client, page, reg);
    if (rv >= 0 && !(data->flags & PMBUS_SKIP_STATUS_CHECK))
        rv = pmbus_check_status_cml(client);
    pmbus_clear_fault_page(client, -1);
    return rv >= 0;
}
EXPORT_SYMBOL_GPL(pmbus_check_byte_register);

bool pmbus_check_word_register(struct i2c_client *client, int page, int reg)
{
    int rv;
    struct pmbus_data *data = i2c_get_clientdata(client);

    rv = _pmbus_read_word_data(client, page, reg);
    if (rv >= 0 && !(data->flags & PMBUS_SKIP_STATUS_CHECK))
        rv = pmbus_check_status_cml(client);
    pmbus_clear_fault_page(client, -1);
    return rv >= 0;
}
EXPORT_SYMBOL_GPL(pmbus_check_word_register);

const struct pmbus_driver_info *pmbus_get_driver_info(struct i2c_client *client)
{
    struct pmbus_data *data = i2c_get_clientdata(client);

    return data->info;
}
EXPORT_SYMBOL_GPL(pmbus_get_driver_info);

static struct pmbus_data *pmbus_update_device(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct pmbus_data *data = i2c_get_clientdata(client);
    const struct pmbus_driver_info *info = data->info;

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

        for (i = 0; i < info->pages; i++)
            data->status[PB_STATUS_BASE + i]
                = _pmbus_read_byte_data(client, i,
                            PMBUS_STATUS_BYTE);
        for (i = 0; i < info->pages; i++) {
            if (!(info->func[i] & PMBUS_HAVE_STATUS_VOUT))
                continue;
            data->status[PB_STATUS_VOUT_BASE + i]
              = _pmbus_read_byte_data(client, i, PMBUS_STATUS_VOUT);
        }
        for (i = 0; i < info->pages; i++) {
            if (!(info->func[i] & PMBUS_HAVE_STATUS_IOUT))
                continue;
            data->status[PB_STATUS_IOUT_BASE + i]
              = _pmbus_read_byte_data(client, i, PMBUS_STATUS_IOUT);
        }
        for (i = 0; i < info->pages; i++) {
            if (!(info->func[i] & PMBUS_HAVE_STATUS_TEMP))
                continue;
            data->status[PB_STATUS_TEMP_BASE + i]
              = _pmbus_read_byte_data(client, i,
                          PMBUS_STATUS_TEMPERATURE);
        }
        for (i = 0; i < info->pages; i++) {
            if (!(info->func[i] & PMBUS_HAVE_STATUS_FAN12))
                continue;
            data->status[PB_STATUS_FAN_BASE + i]
              = _pmbus_read_byte_data(client, i,
                          PMBUS_STATUS_FAN_12);
        }

        for (i = 0; i < info->pages; i++) {
            if (!(info->func[i] & PMBUS_HAVE_STATUS_FAN34))
                continue;
            data->status[PB_STATUS_FAN34_BASE + i]
              = _pmbus_read_byte_data(client, i,
                          PMBUS_STATUS_FAN_34);
        }

        if (info->func[0] & PMBUS_HAVE_STATUS_INPUT)
            data->status[PB_STATUS_INPUT_BASE]
              = _pmbus_read_byte_data(client, 0,
                          PMBUS_STATUS_INPUT);

        for (i = 0; i < data->num_sensors; i++) {
            struct pmbus_sensor *sensor = &data->sensors[i];

            if (!data->valid || sensor->update)
                sensor->data
                    = _pmbus_read_word_data(client,
                                sensor->page,
                                sensor->reg);
        }
        pmbus_clear_faults(client);
        data->last_updated = jiffies;
        data->valid = 1;
    }
    mutex_unlock(&data->update_lock);
    return data;
}

/*
 * Convert linear sensor values to milli- or micro-units
 * depending on sensor type.
 */
static long pmbus_reg2data_linear(struct pmbus_data *data,
                  struct pmbus_sensor *sensor)
{
    s16 exponent;
    s32 mantissa;
    long val;

    if (sensor->class == PSC_VOLTAGE_OUT) { /* LINEAR16 */
        exponent = data->exponent;
        mantissa = (u16) sensor->data;
    } else {                /* LINEAR11 */
        exponent = ((s16)sensor->data) >> 11;
        mantissa = ((s16)((sensor->data & 0x7ff) << 5)) >> 5;
    }

    val = mantissa;

    /* scale result to milli-units for all sensors except fans */
    if (sensor->class != PSC_FAN)
        val = val * 1000L;

    /* scale result to micro-units for power sensors */
    if (sensor->class == PSC_POWER)
        val = val * 1000L;

    if (exponent >= 0)
        val <<= exponent;
    else
        val >>= -exponent;

    return val;
}

/*
 * Convert direct sensor values to milli- or micro-units
 * depending on sensor type.
 */
static long pmbus_reg2data_direct(struct pmbus_data *data,
                  struct pmbus_sensor *sensor)
{
    long val = (s16) sensor->data;
    long m, b, R;

    m = data->info->m[sensor->class];
    b = data->info->b[sensor->class];
    R = data->info->R[sensor->class];

    if (m == 0)
        return 0;

    /* X = 1/m * (Y * 10^-R - b) */
    R = -R;
    /* scale result to milli-units for everything but fans */
    if (sensor->class != PSC_FAN) {
        R += 3;
        b *= 1000;
    }

    /* scale result to micro-units for power sensors */
    if (sensor->class == PSC_POWER) {
        R += 3;
        b *= 1000;
    }

    while (R > 0) {
        val *= 10;
        R--;
    }
    while (R < 0) {
        val = DIV_ROUND_CLOSEST(val, 10);
        R++;
    }

    return (val - b) / m;
}

/*
 * Convert VID sensor values to milli- or micro-units
 * depending on sensor type.
 * We currently only support VR11.
 */
static long pmbus_reg2data_vid(struct pmbus_data *data,
                   struct pmbus_sensor *sensor)
{
    long val = sensor->data;

    if (val < 0x02 || val > 0xb2)
        return 0;
    return DIV_ROUND_CLOSEST(160000 - (val - 2) * 625, 100);
}

static long pmbus_reg2data(struct pmbus_data *data, struct pmbus_sensor *sensor)
{
    long val;

    switch (data->info->format[sensor->class]) {
    case direct:
        val = pmbus_reg2data_direct(data, sensor);
        break;
    case vid:
        val = pmbus_reg2data_vid(data, sensor);
        break;
    case linear:
    default:
        val = pmbus_reg2data_linear(data, sensor);
        break;
    }
    return val;
}

#define MAX_MANTISSA    (1023 * 1000)
#define MIN_MANTISSA    (511 * 1000)

static u16 pmbus_data2reg_linear(struct pmbus_data *data,
                 enum pmbus_sensor_classes class, long val)
{
    s16 exponent = 0, mantissa;
    bool negative = false;

    /* simple case */
    if (val == 0)
        return 0;

    if (class == PSC_VOLTAGE_OUT) {
        /* LINEAR16 does not support negative voltages */
        if (val < 0)
            return 0;

        /*
         * For a static exponents, we don't have a choice
         * but to adjust the value to it.
         */
        if (data->exponent < 0)
            val <<= -data->exponent;
        else
            val >>= data->exponent;
        val = DIV_ROUND_CLOSEST(val, 1000);
        return val & 0xffff;
    }

    if (val < 0) {
        negative = true;
        val = -val;
    }

    /* Power is in uW. Convert to mW before converting. */
    if (class == PSC_POWER)
        val = DIV_ROUND_CLOSEST(val, 1000L);

    /*
     * For simplicity, convert fan data to milli-units
     * before calculating the exponent.
     */
    if (class == PSC_FAN)
        val = val * 1000;

    /* Reduce large mantissa until it fits into 10 bit */
    while (val >= MAX_MANTISSA && exponent < 15) {
        exponent++;
        val >>= 1;
    }
    /* Increase small mantissa to improve precision */
    while (val < MIN_MANTISSA && exponent > -15) {
        exponent--;
        val <<= 1;
    }

    /* Convert mantissa from milli-units to units */
    mantissa = DIV_ROUND_CLOSEST(val, 1000);

    /* Ensure that resulting number is within range */
    if (mantissa > 0x3ff)
        mantissa = 0x3ff;

    /* restore sign */
    if (negative)
        mantissa = -mantissa;

    /* Convert to 5 bit exponent, 11 bit mantissa */
    return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
}

static u16 pmbus_data2reg_direct(struct pmbus_data *data,
                 enum pmbus_sensor_classes class, long val)
{
    long m, b, R;

    m = data->info->m[class];
    b = data->info->b[class];
    R = data->info->R[class];

    /* Power is in uW. Adjust R and b. */
    if (class == PSC_POWER) {
        R -= 3;
        b *= 1000;
    }

    /* Calculate Y = (m * X + b) * 10^R */
    if (class != PSC_FAN) {
        R -= 3;     /* Adjust R and b for data in milli-units */
        b *= 1000;
    }
    val = val * m + b;

    while (R > 0) {
        val *= 10;
        R--;
    }
    while (R < 0) {
        val = DIV_ROUND_CLOSEST(val, 10);
        R++;
    }

    return val;
}

static u16 pmbus_data2reg_vid(struct pmbus_data *data,
                  enum pmbus_sensor_classes class, long val)
{
    val = SENSORS_LIMIT(val, 500, 1600);

    return 2 + DIV_ROUND_CLOSEST((1600 - val) * 100, 625);
}

static u16 pmbus_data2reg(struct pmbus_data *data,
              enum pmbus_sensor_classes class, long val)
{
    u16 regval;

    switch (data->info->format[class]) {
    case direct:
        regval = pmbus_data2reg_direct(data, class, val);
        break;
    case vid:
        regval = pmbus_data2reg_vid(data, class, val);
        break;
    case linear:
    default:
        regval = pmbus_data2reg_linear(data, class, val);
        break;
    }
    return regval;
}

/*
 * Return boolean calculated from converted data.
 * <index> defines a status register index and mask, and optionally
 * two sensor indexes.
 * The upper half-word references the two sensors,
 * two sensor indices.
 * The upper half-word references the two optional sensors,
 * the lower half word references status register and mask.
 * The function returns true if (status[reg] & mask) is true and,
 * if specified, if v1 >= v2.
 * To determine if an object exceeds upper limits, specify <v, limit>.
 * To determine if an object exceeds lower limits, specify <limit, v>.
 *
 * For booleans created with pmbus_add_boolean_reg(), only the lower 16 bits of
 * index are set. s1 and s2 (the sensor index values) are zero in this case.
 * The function returns true if (status[reg] & mask) is true.
 *
 * If the boolean was created with pmbus_add_boolean_cmp(), a comparison against
 * a specified limit has to be performed to determine the boolean result.
 * In this case, the function returns true if v1 >= v2 (where v1 and v2 are
 * sensor values referenced by sensor indices s1 and s2).
 *
 * To determine if an object exceeds upper limits, specify <s1,s2> = <v,limit>.
 * To determine if an object exceeds lower limits, specify <s1,s2> = <limit,v>.
 *
 * If a negative value is stored in any of the referenced registers, this value
 * reflects an error code which will be returned.
 */
static int pmbus_get_boolean(struct pmbus_data *data, int index)
{
    u8 s1 = (index >> 24) & 0xff;
    u8 s2 = (index >> 16) & 0xff;
    u8 reg = (index >> 8) & 0xff;
    u8 mask = index & 0xff;
    int ret, status;
    u8 regval;

    status = data->status[reg];
    if (status < 0)
        return status;

    regval = status & mask;
    if (!s1 && !s2)
        ret = !!regval;
    else {
        long v1, v2;
        struct pmbus_sensor *sensor1, *sensor2;

        sensor1 = &data->sensors[s1];
        if (sensor1->data < 0)
            return sensor1->data;
        sensor2 = &data->sensors[s2];
        if (sensor2->data < 0)
            return sensor2->data;

        v1 = pmbus_reg2data(data, sensor1);
        v2 = pmbus_reg2data(data, sensor2);
        ret = !!(regval && v1 >= v2);
    }
    return ret;
}

static ssize_t pmbus_show_boolean(struct device *dev,
                  struct device_attribute *da, char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct pmbus_data *data = pmbus_update_device(dev);
    int val;

    val = pmbus_get_boolean(data, attr->index);
    if (val < 0)
        return val;
    return snprintf(buf, PAGE_SIZE, "%d\n", val);
}

static ssize_t pmbus_show_sensor(struct device *dev,
                 struct device_attribute *da, char *buf)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
    struct pmbus_data *data = pmbus_update_device(dev);
    struct pmbus_sensor *sensor;

    sensor = &data->sensors[attr->index];
    if (sensor->data < 0)
        return sensor->data;

    return snprintf(buf, PAGE_SIZE, "%ld\n", pmbus_reg2data(data, sensor));
}

static ssize_t pmbus_set_sensor(struct device *dev,
                struct device_attribute *devattr,
                const char *buf, size_t count)
{
    struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
    struct i2c_client *client = to_i2c_client(dev);
    struct pmbus_data *data = i2c_get_clientdata(client);
    struct pmbus_sensor *sensor = &data->sensors[attr->index];
    ssize_t rv = count;
    long val = 0;
    int ret;
    u16 regval;

    if (kstrtol(buf, 10, &val) < 0)
        return -EINVAL;

    mutex_lock(&data->update_lock);
    regval = pmbus_data2reg(data, sensor->class, val);
    ret = _pmbus_write_word_data(client, sensor->page, sensor->reg, regval);
    if (ret < 0)
        rv = ret;
    else
        data->sensors[attr->index].data = regval;
    mutex_unlock(&data->update_lock);
    return rv;
}

static ssize_t pmbus_show_label(struct device *dev,
                struct device_attribute *da, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct pmbus_data *data = i2c_get_clientdata(client);
    struct sensor_device_attribute *attr = to_sensor_dev_attr(da);

    return snprintf(buf, PAGE_SIZE, "%s\n",
            data->labels[attr->index].label);
}

#define PMBUS_ADD_ATTR(data, _name, _idx, _mode, _type, _show, _set)    \
do {                                    \
    struct sensor_device_attribute *a               \
        = &data->_type##s[data->num_##_type##s].attribute;      \
    BUG_ON(data->num_attributes >= data->max_attributes);       \
    sysfs_attr_init(&a->dev_attr.attr);             \
    a->dev_attr.attr.name = _name;                  \
    a->dev_attr.attr.mode = _mode;                  \
    a->dev_attr.show = _show;                   \
    a->dev_attr.store = _set;                   \
    a->index = _idx;                        \
    data->attributes[data->num_attributes] = &a->dev_attr.attr; \
    data->num_attributes++;                     \
} while (0)

#define PMBUS_ADD_GET_ATTR(data, _name, _type, _idx)            \
    PMBUS_ADD_ATTR(data, _name, _idx, S_IRUGO, _type,       \
               pmbus_show_##_type,  NULL)

#define PMBUS_ADD_SET_ATTR(data, _name, _type, _idx)            \
    PMBUS_ADD_ATTR(data, _name, _idx, S_IWUSR | S_IRUGO, _type, \
               pmbus_show_##_type, pmbus_set_##_type)

static void pmbus_add_boolean(struct pmbus_data *data,
                  const char *name, const char *type, int seq,
                  int idx)
{
    struct pmbus_boolean *boolean;

    BUG_ON(data->num_booleans >= data->max_booleans);

    boolean = &data->booleans[data->num_booleans];

    snprintf(boolean->name, sizeof(boolean->name), "%s%d_%s",
         name, seq, type);
    PMBUS_ADD_GET_ATTR(data, boolean->name, boolean, idx);
    data->num_booleans++;
}

static void pmbus_add_boolean_reg(struct pmbus_data *data,
                  const char *name, const char *type,
                  int seq, int reg, int bit)
{
    pmbus_add_boolean(data, name, type, seq, (reg << 8) | bit);
}

static void pmbus_add_boolean_cmp(struct pmbus_data *data,
                  const char *name, const char *type,
                  int seq, int i1, int i2, int reg, int mask)
{
    pmbus_add_boolean(data, name, type, seq,
              (i1 << 24) | (i2 << 16) | (reg << 8) | mask);
}

static void pmbus_add_sensor(struct pmbus_data *data,
                 const char *name, const char *type, int seq,
                 int page, int reg, enum pmbus_sensor_classes class,
                 bool update, bool readonly)
{
    struct pmbus_sensor *sensor;

    BUG_ON(data->num_sensors >= data->max_sensors);

    sensor = &data->sensors[data->num_sensors];
    snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
         name, seq, type);
    sensor->page = page;
    sensor->reg = reg;
    sensor->class = class;
    sensor->update = update;
    if (readonly)
        PMBUS_ADD_GET_ATTR(data, sensor->name, sensor,
                   data->num_sensors);
    else
        PMBUS_ADD_SET_ATTR(data, sensor->name, sensor,
                   data->num_sensors);
    data->num_sensors++;
}

static void pmbus_add_label(struct pmbus_data *data,
                const char *name, int seq,
                const char *lstring, int index)
{
    struct pmbus_label *label;

    BUG_ON(data->num_labels >= data->max_labels);

    label = &data->labels[data->num_labels];
    snprintf(label->name, sizeof(label->name), "%s%d_label", name, seq);
    if (!index)
        strncpy(label->label, lstring, sizeof(label->label) - 1);
    else
        snprintf(label->label, sizeof(label->label), "%s%d", lstring,
             index);

    PMBUS_ADD_GET_ATTR(data, label->name, label, data->num_labels);
    data->num_labels++;
}

/*
 * Determine maximum number of sensors, booleans, and labels.
 * To keep things simple, only make a rough high estimate.
 */
static void pmbus_find_max_attr(struct i2c_client *client,
                struct pmbus_data *data)
{
    const struct pmbus_driver_info *info = data->info;
    int page, max_sensors, max_booleans, max_labels;

    max_sensors = PMBUS_MAX_INPUT_SENSORS;
    max_booleans = PMBUS_MAX_INPUT_BOOLEANS;
    max_labels = PMBUS_MAX_INPUT_LABELS;

    for (page = 0; page < info->pages; page++) {
        if (info->func[page] & PMBUS_HAVE_VOUT) {
            max_sensors += PMBUS_VOUT_SENSORS_PER_PAGE;
            max_booleans += PMBUS_VOUT_BOOLEANS_PER_PAGE;
            max_labels++;
        }
        if (info->func[page] & PMBUS_HAVE_IOUT) {
            max_sensors += PMBUS_IOUT_SENSORS_PER_PAGE;
            max_booleans += PMBUS_IOUT_BOOLEANS_PER_PAGE;
            max_labels++;
        }
        if (info->func[page] & PMBUS_HAVE_POUT) {
            max_sensors += PMBUS_POUT_SENSORS_PER_PAGE;
            max_booleans += PMBUS_POUT_BOOLEANS_PER_PAGE;
            max_labels++;
        }
        if (info->func[page] & PMBUS_HAVE_FAN12) {
            max_sensors += 2 * PMBUS_MAX_SENSORS_PER_FAN;
            max_booleans += 2 * PMBUS_MAX_BOOLEANS_PER_FAN;
        }
        if (info->func[page] & PMBUS_HAVE_FAN34) {
            max_sensors += 2 * PMBUS_MAX_SENSORS_PER_FAN;
            max_booleans += 2 * PMBUS_MAX_BOOLEANS_PER_FAN;
        }
        if (info->func[page] & PMBUS_HAVE_TEMP) {
            max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
            max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
        }
        if (info->func[page] & PMBUS_HAVE_TEMP2) {
            max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
            max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
        }
        if (info->func[page] & PMBUS_HAVE_TEMP3) {
            max_sensors += PMBUS_MAX_SENSORS_PER_TEMP;
            max_booleans += PMBUS_MAX_BOOLEANS_PER_TEMP;
        }
    }
    data->max_sensors = max_sensors;
    data->max_booleans = max_booleans;
    data->max_labels = max_labels;
    data->max_attributes = max_sensors + max_booleans + max_labels;
}

/*
 * Search for attributes. Allocate sensors, booleans, and labels as needed.
 */

/*
 * The pmbus_limit_attr structure describes a single limit attribute
 * and its associated alarm attribute.
 */
struct pmbus_limit_attr {
    u16 reg;        /* Limit register */
    bool update;        /* True if register needs updates */
    bool low;       /* True if low limit; for limits with compare
                   functions only */
    const char *attr;   /* Attribute name */
    const char *alarm;  /* Alarm attribute name */
    u32 sbit;       /* Alarm attribute status bit */
};

/*
 * The pmbus_sensor_attr structure describes one sensor attribute. This
 * description includes a reference to the associated limit attributes.
 */
struct pmbus_sensor_attr {
    u8 reg;             /* sensor register */
    enum pmbus_sensor_classes class;/* sensor class */
    const char *label;      /* sensor label */
    bool paged;         /* true if paged sensor */
    bool update;            /* true if update needed */
    bool compare;           /* true if compare function needed */
    u32 func;           /* sensor mask */
    u32 sfunc;          /* sensor status mask */
    int sbase;          /* status base register */
    u32 gbit;           /* generic status bit */
    const struct pmbus_limit_attr *limit;/* limit registers */
    int nlimit;         /* # of limit registers */
};

/*
 * Add a set of limit attributes and, if supported, the associated
 * alarm attributes.
 */
static bool pmbus_add_limit_attrs(struct i2c_client *client,
                  struct pmbus_data *data,
                  const struct pmbus_driver_info *info,
                  const char *name, int index, int page,
                  int cbase,
                  const struct pmbus_sensor_attr *attr)
{
    const struct pmbus_limit_attr *l = attr->limit;
    int nlimit = attr->nlimit;
    bool have_alarm = false;
    int i, cindex;

    for (i = 0; i < nlimit; i++) {
        if (pmbus_check_word_register(client, page, l->reg)) {
            cindex = data->num_sensors;
            pmbus_add_sensor(data, name, l->attr, index, page,
                     l->reg, attr->class,
                     attr->update || l->update,
                     false);
            if (l->sbit && (info->func[page] & attr->sfunc)) {
                if (attr->compare) {
                    pmbus_add_boolean_cmp(data, name,
                        l->alarm, index,
                        l->low ? cindex : cbase,
                        l->low ? cbase : cindex,
                        attr->sbase + page, l->sbit);
                } else {
                    pmbus_add_boolean_reg(data, name,
                        l->alarm, index,
                        attr->sbase + page, l->sbit);
                }
                have_alarm = true;
            }
        }
        l++;
    }
    return have_alarm;
}

static void pmbus_add_sensor_attrs_one(struct i2c_client *client,
                       struct pmbus_data *data,
                       const struct pmbus_driver_info *info,
                       const char *name,
                       int index, int page,
                       const struct pmbus_sensor_attr *attr)
{
    bool have_alarm;
    int cbase = data->num_sensors;

    if (attr->label)
        pmbus_add_label(data, name, index, attr->label,
                attr->paged ? page + 1 : 0);
    pmbus_add_sensor(data, name, "input", index, page, attr->reg,
             attr->class, true, true);
    if (attr->sfunc) {
        have_alarm = pmbus_add_limit_attrs(client, data, info, name,
                           index, page, cbase, attr);
        /*
         * Add generic alarm attribute only if there are no individual
         * alarm attributes, if there is a global alarm bit, and if
         * the generic status register for this page is accessible.
         */
        if (!have_alarm && attr->gbit &&
            pmbus_check_byte_register(client, page, PMBUS_STATUS_BYTE))
            pmbus_add_boolean_reg(data, name, "alarm", index,
                          PB_STATUS_BASE + page,
                          attr->gbit);
    }
}

static void pmbus_add_sensor_attrs(struct i2c_client *client,
                   struct pmbus_data *data,
                   const char *name,
                   const struct pmbus_sensor_attr *attrs,
                   int nattrs)
{
    const struct pmbus_driver_info *info = data->info;
    int index, i;

    index = 1;
    for (i = 0; i < nattrs; i++) {
        int page, pages;

        pages = attrs->paged ? info->pages : 1;
        for (page = 0; page < pages; page++) {
            if (!(info->func[page] & attrs->func))
                continue;
            pmbus_add_sensor_attrs_one(client, data, info, name,
                           index, page, attrs);
            index++;
        }
        attrs++;
    }
}

static const struct pmbus_limit_attr vin_limit_attrs[] = {
    {
        .reg = PMBUS_VIN_UV_WARN_LIMIT,
        .attr = "min",
        .alarm = "min_alarm",
        .sbit = PB_VOLTAGE_UV_WARNING,
    }, {
        .reg = PMBUS_VIN_UV_FAULT_LIMIT,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_VOLTAGE_UV_FAULT,
    }, {
        .reg = PMBUS_VIN_OV_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_VOLTAGE_OV_WARNING,
    }, {
        .reg = PMBUS_VIN_OV_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_VOLTAGE_OV_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_VIN_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_VIN_MIN,
        .update = true,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_VIN_MAX,
        .update = true,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_VIN_HISTORY,
        .attr = "reset_history",
    },
};

static const struct pmbus_limit_attr vout_limit_attrs[] = {
    {
        .reg = PMBUS_VOUT_UV_WARN_LIMIT,
        .attr = "min",
        .alarm = "min_alarm",
        .sbit = PB_VOLTAGE_UV_WARNING,
    }, {
        .reg = PMBUS_VOUT_UV_FAULT_LIMIT,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_VOLTAGE_UV_FAULT,
    }, {
        .reg = PMBUS_VOUT_OV_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_VOLTAGE_OV_WARNING,
    }, {
        .reg = PMBUS_VOUT_OV_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_VOLTAGE_OV_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_VOUT_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_VOUT_MIN,
        .update = true,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_VOUT_MAX,
        .update = true,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_VOUT_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_sensor_attr voltage_attributes[] = {
    {
        .reg = PMBUS_READ_VIN,
        .class = PSC_VOLTAGE_IN,
        .label = "vin",
        .func = PMBUS_HAVE_VIN,
        .sfunc = PMBUS_HAVE_STATUS_INPUT,
        .sbase = PB_STATUS_INPUT_BASE,
        .gbit = PB_STATUS_VIN_UV,
        .limit = vin_limit_attrs,
        .nlimit = ARRAY_SIZE(vin_limit_attrs),
    }, {
        .reg = PMBUS_READ_VCAP,
        .class = PSC_VOLTAGE_IN,
        .label = "vcap",
        .func = PMBUS_HAVE_VCAP,
    }, {
        .reg = PMBUS_READ_VOUT,
        .class = PSC_VOLTAGE_OUT,
        .label = "vout",
        .paged = true,
        .func = PMBUS_HAVE_VOUT,
        .sfunc = PMBUS_HAVE_STATUS_VOUT,
        .sbase = PB_STATUS_VOUT_BASE,
        .gbit = PB_STATUS_VOUT_OV,
        .limit = vout_limit_attrs,
        .nlimit = ARRAY_SIZE(vout_limit_attrs),
    }
};

/* Current attributes */

static const struct pmbus_limit_attr iin_limit_attrs[] = {
    {
        .reg = PMBUS_IIN_OC_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_IIN_OC_WARNING,
    }, {
        .reg = PMBUS_IIN_OC_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_IIN_OC_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_IIN_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_IIN_MIN,
        .update = true,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_IIN_MAX,
        .update = true,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_IIN_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_limit_attr iout_limit_attrs[] = {
    {
        .reg = PMBUS_IOUT_OC_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_IOUT_OC_WARNING,
    }, {
        .reg = PMBUS_IOUT_UC_FAULT_LIMIT,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_IOUT_UC_FAULT,
    }, {
        .reg = PMBUS_IOUT_OC_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_IOUT_OC_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_IOUT_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_IOUT_MIN,
        .update = true,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_IOUT_MAX,
        .update = true,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_IOUT_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_sensor_attr current_attributes[] = {
    {
        .reg = PMBUS_READ_IIN,
        .class = PSC_CURRENT_IN,
        .label = "iin",
        .func = PMBUS_HAVE_IIN,
        .sfunc = PMBUS_HAVE_STATUS_INPUT,
        .sbase = PB_STATUS_INPUT_BASE,
        .limit = iin_limit_attrs,
        .nlimit = ARRAY_SIZE(iin_limit_attrs),
    }, {
        .reg = PMBUS_READ_IOUT,
        .class = PSC_CURRENT_OUT,
        .label = "iout",
        .paged = true,
        .func = PMBUS_HAVE_IOUT,
        .sfunc = PMBUS_HAVE_STATUS_IOUT,
        .sbase = PB_STATUS_IOUT_BASE,
        .gbit = PB_STATUS_IOUT_OC,
        .limit = iout_limit_attrs,
        .nlimit = ARRAY_SIZE(iout_limit_attrs),
    }
};

/* Power attributes */

static const struct pmbus_limit_attr pin_limit_attrs[] = {
    {
        .reg = PMBUS_PIN_OP_WARN_LIMIT,
        .attr = "max",
        .alarm = "alarm",
        .sbit = PB_PIN_OP_WARNING,
    }, {
        .reg = PMBUS_VIRT_READ_PIN_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_PIN_MAX,
        .update = true,
        .attr = "input_highest",
    }, {
        .reg = PMBUS_VIRT_RESET_PIN_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_limit_attr pout_limit_attrs[] = {
    {
        .reg = PMBUS_POUT_MAX,
        .attr = "cap",
        .alarm = "cap_alarm",
        .sbit = PB_POWER_LIMITING,
    }, {
        .reg = PMBUS_POUT_OP_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_POUT_OP_WARNING,
    }, {
        .reg = PMBUS_POUT_OP_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_POUT_OP_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_POUT_AVG,
        .update = true,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_POUT_MAX,
        .update = true,
        .attr = "input_highest",
    }, {
        .reg = PMBUS_VIRT_RESET_POUT_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_sensor_attr power_attributes[] = {
    {
        .reg = PMBUS_READ_PIN,
        .class = PSC_POWER,
        .label = "pin",
        .func = PMBUS_HAVE_PIN,
        .sfunc = PMBUS_HAVE_STATUS_INPUT,
        .sbase = PB_STATUS_INPUT_BASE,
        .limit = pin_limit_attrs,
        .nlimit = ARRAY_SIZE(pin_limit_attrs),
    }, {
        .reg = PMBUS_READ_POUT,
        .class = PSC_POWER,
        .label = "pout",
        .paged = true,
        .func = PMBUS_HAVE_POUT,
        .sfunc = PMBUS_HAVE_STATUS_IOUT,
        .sbase = PB_STATUS_IOUT_BASE,
        .limit = pout_limit_attrs,
        .nlimit = ARRAY_SIZE(pout_limit_attrs),
    }
};

/* Temperature atributes */

static const struct pmbus_limit_attr temp_limit_attrs[] = {
    {
        .reg = PMBUS_UT_WARN_LIMIT,
        .low = true,
        .attr = "min",
        .alarm = "min_alarm",
        .sbit = PB_TEMP_UT_WARNING,
    }, {
        .reg = PMBUS_UT_FAULT_LIMIT,
        .low = true,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_TEMP_UT_FAULT,
    }, {
        .reg = PMBUS_OT_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_TEMP_OT_WARNING,
    }, {
        .reg = PMBUS_OT_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_TEMP_OT_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_TEMP_MIN,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_TEMP_AVG,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_TEMP_MAX,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_TEMP_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_limit_attr temp_limit_attrs2[] = {
    {
        .reg = PMBUS_UT_WARN_LIMIT,
        .low = true,
        .attr = "min",
        .alarm = "min_alarm",
        .sbit = PB_TEMP_UT_WARNING,
    }, {
        .reg = PMBUS_UT_FAULT_LIMIT,
        .low = true,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_TEMP_UT_FAULT,
    }, {
        .reg = PMBUS_OT_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_TEMP_OT_WARNING,
    }, {
        .reg = PMBUS_OT_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_TEMP_OT_FAULT,
    }, {
        .reg = PMBUS_VIRT_READ_TEMP2_MIN,
        .attr = "lowest",
    }, {
        .reg = PMBUS_VIRT_READ_TEMP2_AVG,
        .attr = "average",
    }, {
        .reg = PMBUS_VIRT_READ_TEMP2_MAX,
        .attr = "highest",
    }, {
        .reg = PMBUS_VIRT_RESET_TEMP2_HISTORY,
        .attr = "reset_history",
    }
};

static const struct pmbus_limit_attr temp_limit_attrs3[] = {
    {
        .reg = PMBUS_UT_WARN_LIMIT,
        .low = true,
        .attr = "min",
        .alarm = "min_alarm",
        .sbit = PB_TEMP_UT_WARNING,
    }, {
        .reg = PMBUS_UT_FAULT_LIMIT,
        .low = true,
        .attr = "lcrit",
        .alarm = "lcrit_alarm",
        .sbit = PB_TEMP_UT_FAULT,
    }, {
        .reg = PMBUS_OT_WARN_LIMIT,
        .attr = "max",
        .alarm = "max_alarm",
        .sbit = PB_TEMP_OT_WARNING,
    }, {
        .reg = PMBUS_OT_FAULT_LIMIT,
        .attr = "crit",
        .alarm = "crit_alarm",
        .sbit = PB_TEMP_OT_FAULT,
    }
};

static const struct pmbus_sensor_attr temp_attributes[] = {
    {
        .reg = PMBUS_READ_TEMPERATURE_1,
        .class = PSC_TEMPERATURE,
        .paged = true,
        .update = true,
        .compare = true,
        .func = PMBUS_HAVE_TEMP,
        .sfunc = PMBUS_HAVE_STATUS_TEMP,
        .sbase = PB_STATUS_TEMP_BASE,
        .gbit = PB_STATUS_TEMPERATURE,
        .limit = temp_limit_attrs,
        .nlimit = ARRAY_SIZE(temp_limit_attrs),
    }, {
        .reg = PMBUS_READ_TEMPERATURE_2,
        .class = PSC_TEMPERATURE,
        .paged = true,
        .update = true,
        .compare = true,
        .func = PMBUS_HAVE_TEMP2,
        .sfunc = PMBUS_HAVE_STATUS_TEMP,
        .sbase = PB_STATUS_TEMP_BASE,
        .gbit = PB_STATUS_TEMPERATURE,
        .limit = temp_limit_attrs2,
        .nlimit = ARRAY_SIZE(temp_limit_attrs2),
    }, {
        .reg = PMBUS_READ_TEMPERATURE_3,
        .class = PSC_TEMPERATURE,
        .paged = true,
        .update = true,
        .compare = true,
        .func = PMBUS_HAVE_TEMP3,
        .sfunc = PMBUS_HAVE_STATUS_TEMP,
        .sbase = PB_STATUS_TEMP_BASE,
        .gbit = PB_STATUS_TEMPERATURE,
        .limit = temp_limit_attrs3,
        .nlimit = ARRAY_SIZE(temp_limit_attrs3),
    }
};

static const int pmbus_fan_registers[] = {
    PMBUS_READ_FAN_SPEED_1,
    PMBUS_READ_FAN_SPEED_2,
    PMBUS_READ_FAN_SPEED_3,
    PMBUS_READ_FAN_SPEED_4
};

static const int pmbus_fan_config_registers[] = {
    PMBUS_FAN_CONFIG_12,
    PMBUS_FAN_CONFIG_12,
    PMBUS_FAN_CONFIG_34,
    PMBUS_FAN_CONFIG_34
};

static const int pmbus_fan_status_registers[] = {
    PMBUS_STATUS_FAN_12,
    PMBUS_STATUS_FAN_12,
    PMBUS_STATUS_FAN_34,
    PMBUS_STATUS_FAN_34
};

static const u32 pmbus_fan_flags[] = {
    PMBUS_HAVE_FAN12,
    PMBUS_HAVE_FAN12,
    PMBUS_HAVE_FAN34,
    PMBUS_HAVE_FAN34
};

static const u32 pmbus_fan_status_flags[] = {
    PMBUS_HAVE_STATUS_FAN12,
    PMBUS_HAVE_STATUS_FAN12,
    PMBUS_HAVE_STATUS_FAN34,
    PMBUS_HAVE_STATUS_FAN34
};

/* Fans */
static void pmbus_add_fan_attributes(struct i2c_client *client,
                     struct pmbus_data *data)
{
    const struct pmbus_driver_info *info = data->info;
    int index = 1;
    int page;

    for (page = 0; page < info->pages; page++) {
        int f;

        for (f = 0; f < ARRAY_SIZE(pmbus_fan_registers); f++) {
            int regval;

            if (!(info->func[page] & pmbus_fan_flags[f]))
                break;

            if (!pmbus_check_word_register(client, page,
                               pmbus_fan_registers[f]))
                break;

            /*
             * Skip fan if not installed.
             * Each fan configuration register covers multiple fans,
             * so we have to do some magic.
             */
            regval = _pmbus_read_byte_data(client, page,
                pmbus_fan_config_registers[f]);
            if (regval < 0 ||
                (!(regval & (PB_FAN_1_INSTALLED >> ((f & 1) * 4)))))
                continue;

            pmbus_add_sensor(data, "fan", "input", index, page,
                     pmbus_fan_registers[f], PSC_FAN, true,
                     true);

            /*
             * Each fan status register covers multiple fans,
             * so we have to do some magic.
             */
            if ((info->func[page] & pmbus_fan_status_flags[f]) &&
                pmbus_check_byte_register(client,
                    page, pmbus_fan_status_registers[f])) {
                int base;

                if (f > 1)  /* fan 3, 4 */
                    base = PB_STATUS_FAN34_BASE + page;
                else
                    base = PB_STATUS_FAN_BASE + page;
                pmbus_add_boolean_reg(data, "fan", "alarm",
                    index, base,
                    PB_FAN_FAN1_WARNING >> (f & 1));
                pmbus_add_boolean_reg(data, "fan", "fault",
                    index, base,
                    PB_FAN_FAN1_FAULT >> (f & 1));
            }
            index++;
        }
    }
}

static void pmbus_find_attributes(struct i2c_client *client,
                  struct pmbus_data *data)
{
    /* Voltage sensors */
    pmbus_add_sensor_attrs(client, data, "in", voltage_attributes,
                   ARRAY_SIZE(voltage_attributes));

    /* Current sensors */
    pmbus_add_sensor_attrs(client, data, "curr", current_attributes,
                   ARRAY_SIZE(current_attributes));

    /* Power sensors */
    pmbus_add_sensor_attrs(client, data, "power", power_attributes,
                   ARRAY_SIZE(power_attributes));

    /* Temperature sensors */
    pmbus_add_sensor_attrs(client, data, "temp", temp_attributes,
                   ARRAY_SIZE(temp_attributes));

    /* Fans */
    pmbus_add_fan_attributes(client, data);
}

/*
 * Identify chip parameters.
 * This function is called for all chips.
 */
static int pmbus_identify_common(struct i2c_client *client,
                 struct pmbus_data *data)
{
    int vout_mode = -1;

    if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE))
        vout_mode = _pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);
    if (vout_mode >= 0 && vout_mode != 0xff) {
        /*
         * Not all chips support the VOUT_MODE command,
         * so a failure to read it is not an error.
         */
        switch (vout_mode >> 5) {
        case 0: /* linear mode      */
            if (data->info->format[PSC_VOLTAGE_OUT] != linear)
                return -ENODEV;

            data->exponent = ((s8)(vout_mode << 3)) >> 3;
            break;
        case 1: /* VID mode         */
            if (data->info->format[PSC_VOLTAGE_OUT] != vid)
                return -ENODEV;
            break;
        case 2: /* direct mode      */
            if (data->info->format[PSC_VOLTAGE_OUT] != direct)
                return -ENODEV;
            break;
        default:
            return -ENODEV;
        }
    }

    /* Determine maximum number of sensors, booleans, and labels */
    pmbus_find_max_attr(client, data);
    pmbus_clear_fault_page(client, 0);
    return 0;
}

int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
           struct pmbus_driver_info *info)
{
    const struct pmbus_platform_data *pdata = client->dev.platform_data;
    struct pmbus_data *data;
    int ret;

    if (!info) {
        dev_err(&client->dev, "Missing chip information");
        return -ENODEV;
    }

    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
                     | I2C_FUNC_SMBUS_BYTE_DATA
                     | I2C_FUNC_SMBUS_WORD_DATA))
        return -ENODEV;

    data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
    if (!data) {
        dev_err(&client->dev, "No memory to allocate driver data\n");
        return -ENOMEM;
    }

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

    /* Bail out if PMBus status register does not exist. */
    if (i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE) < 0) {
        dev_err(&client->dev, "PMBus status register not found\n");
        return -ENODEV;
    }

    if (pdata)
        data->flags = pdata->flags;
    data->info = info;

    pmbus_clear_faults(client);

    if (info->identify) {
        ret = (*info->identify)(client, info);
        if (ret < 0) {
            dev_err(&client->dev, "Chip identification failed\n");
            return ret;
        }
    }

    if (info->pages <= 0 || info->pages > PMBUS_PAGES) {
        dev_err(&client->dev, "Bad number of PMBus pages: %d\n",
            info->pages);
        return -ENODEV;
    }

    ret = pmbus_identify_common(client, data);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to identify chip capabilities\n");
        return ret;
    }

    ret = -ENOMEM;
    data->sensors = devm_kzalloc(&client->dev, sizeof(struct pmbus_sensor)
                     * data->max_sensors, GFP_KERNEL);
    if (!data->sensors) {
        dev_err(&client->dev, "No memory to allocate sensor data\n");
        return -ENOMEM;
    }

    data->booleans = devm_kzalloc(&client->dev, sizeof(struct pmbus_boolean)
                 * data->max_booleans, GFP_KERNEL);
    if (!data->booleans) {
        dev_err(&client->dev, "No memory to allocate boolean data\n");
        return -ENOMEM;
    }

    data->labels = devm_kzalloc(&client->dev, sizeof(struct pmbus_label)
                    * data->max_labels, GFP_KERNEL);
    if (!data->labels) {
        dev_err(&client->dev, "No memory to allocate label data\n");
        return -ENOMEM;
    }

    data->attributes = devm_kzalloc(&client->dev, sizeof(struct attribute *)
                    * data->max_attributes, GFP_KERNEL);
    if (!data->attributes) {
        dev_err(&client->dev, "No memory to allocate attribute data\n");
        return -ENOMEM;
    }

    pmbus_find_attributes(client, data);

    /*
     * If there are no attributes, something is wrong.
     * Bail out instead of trying to register nothing.
     */
    if (!data->num_attributes) {
        dev_err(&client->dev, "No attributes found\n");
        return -ENODEV;
    }

    /* Register sysfs hooks */
    data->group.attrs = data->attributes;
    ret = sysfs_create_group(&client->dev.kobj, &data->group);
    if (ret) {
        dev_err(&client->dev, "Failed to create sysfs entries\n");
        return ret;
    }
    data->hwmon_dev = hwmon_device_register(&client->dev);
    if (IS_ERR(data->hwmon_dev)) {
        ret = PTR_ERR(data->hwmon_dev);
        dev_err(&client->dev, "Failed to register hwmon device\n");
        goto out_hwmon_device_register;
    }
    return 0;

out_hwmon_device_register:
    sysfs_remove_group(&client->dev.kobj, &data->group);
    return ret;
}
EXPORT_SYMBOL_GPL(pmbus_do_probe);

int pmbus_do_remove(struct i2c_client *client)
{
    struct pmbus_data *data = i2c_get_clientdata(client);
    hwmon_device_unregister(data->hwmon_dev);
    sysfs_remove_group(&client->dev.kobj, &data->group);
    return 0;
}
EXPORT_SYMBOL_GPL(pmbus_do_remove);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus core driver");
MODULE_LICENSE("GPL");