/*
 * Hardware monitoring driver for PMBus devices
 *
 * Copyright (c) 2010, 2011 Ericsson AB.
 * Copyright (c) 2012 Guenter Roeck
 *
 * 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"

/*
 * Number of additional attribute pointers to allocate
 * with each call to krealloc
 */
#define PMBUS_ATTR_ALLOC_SIZE   32

/*
 * 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_TEMP_BASE     (PB_STATUS_FAN34_BASE + PMBUS_PAGES)
#define PB_STATUS_INPUT_BASE    (PB_STATUS_TEMP_BASE + PMBUS_PAGES)
#define PB_STATUS_VMON_BASE     (PB_STATUS_INPUT_BASE + 1)

#define PB_NUM_STATUS_REG       (PB_STATUS_VMON_BASE + 1)

#define PMBUS_NAME_SIZE         24

struct pmbus_sensor {
        struct pmbus_sensor *next;
        char name[PMBUS_NAME_SIZE];     /* sysfs sensor name */
        struct 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 */
};
#define to_pmbus_sensor(_attr) \
        container_of(_attr, struct pmbus_sensor, attribute)

struct pmbus_boolean {
        char name[PMBUS_NAME_SIZE];     /* sysfs boolean name */
        struct sensor_device_attribute attribute;
        struct pmbus_sensor *s1;
        struct pmbus_sensor *s2;
};
#define to_pmbus_boolean(_attr) \
        container_of(_attr, struct pmbus_boolean, attribute)

struct pmbus_label {
        char name[PMBUS_NAME_SIZE];     /* sysfs label name */
        struct device_attribute attribute;
        char label[PMBUS_NAME_SIZE];    /* label */
};
#define to_pmbus_label(_attr) \
        container_of(_attr, struct pmbus_label, attribute)

struct pmbus_data {
        struct device *dev;
        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_group group;

        struct pmbus_sensor *sensors;

        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 status_register;

        u8 currpage;
};

void pmbus_clear_cache(struct i2c_client *client)
{
        struct pmbus_data *data = i2c_get_clientdata(client);

        data->valid = false;
}
EXPORT_SYMBOL_GPL(pmbus_clear_cache);

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)
{
        struct pmbus_data *data = i2c_get_clientdata(client);
        int status, status2;

        status = _pmbus_read_byte_data(client, -1, data->status_register);
        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;
}

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

        rv = func(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;
}

bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg)
{
        return pmbus_check_register(client, _pmbus_read_byte_data, page, reg);
}
EXPORT_SYMBOL_GPL(pmbus_check_byte_register);

bool pmbus_check_word_register(struct i2c_client *client, int page, int reg)
{
        return pmbus_check_register(client, _pmbus_read_word_data, page, reg);
}
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_status {
        u32 func;
        u16 base;
        u16 reg;
} pmbus_status[] = {
        { PMBUS_HAVE_STATUS_VOUT, PB_STATUS_VOUT_BASE, PMBUS_STATUS_VOUT },
        { PMBUS_HAVE_STATUS_IOUT, PB_STATUS_IOUT_BASE, PMBUS_STATUS_IOUT },
        { PMBUS_HAVE_STATUS_TEMP, PB_STATUS_TEMP_BASE,
          PMBUS_STATUS_TEMPERATURE },
        { PMBUS_HAVE_STATUS_FAN12, PB_STATUS_FAN_BASE, PMBUS_STATUS_FAN_12 },
        { PMBUS_HAVE_STATUS_FAN34, PB_STATUS_FAN34_BASE, PMBUS_STATUS_FAN_34 },
};

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;
        struct pmbus_sensor *sensor;

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

                for (i = 0; i < info->pages; i++) {
                        data->status[PB_STATUS_BASE + i]
                            = _pmbus_read_byte_data(client, i,
                                                    data->status_register);
                        for (j = 0; j < ARRAY_SIZE(pmbus_status); j++) {
                                struct _pmbus_status *s = &pmbus_status[j];

                                if (!(info->func[i] & s->func))
                                        continue;
                                data->status[s->base + i]
                                        = _pmbus_read_byte_data(client, i,
                                                                s->reg);
                        }
                }

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

                if (info->func[0] & PMBUS_HAVE_STATUS_VMON)
                        data->status[PB_STATUS_VMON_BASE]
                          = _pmbus_read_byte_data(client, 0,
                                                  PMBUS_VIRT_STATUS_VMON);

                for (sensor = data->sensors; sensor; sensor = sensor->next) {
                        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 = clamp_val(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.
 * The mask is in the lower 8 bits, the register index is in bits 8..23.
 *
 * The associated pmbus_boolean structure contains optional pointers to two
 * sensor attributes. If specified, those attributes are compared against each
 * other to determine if a limit has been exceeded.
 *
 * If the sensor attribute pointers are NULL, the function returns true if
 * (status[reg] & mask) is true.
 *
 * If sensor attribute pointers are provided, 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 attribute pointers 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, struct pmbus_boolean *b,
                             int index)
{
        struct pmbus_sensor *s1 = b->s1;
        struct pmbus_sensor *s2 = b->s2;
        u16 reg = (index >> 8) & 0xffff;
        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 if (!s1 || !s2) {
                BUG();
                return 0;
        } else {
                long v1, v2;

                if (s1->data < 0)
                        return s1->data;
                if (s2->data < 0)
                        return s2->data;

                v1 = pmbus_reg2data(data, s1);
                v2 = pmbus_reg2data(data, s2);
                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_boolean *boolean = to_pmbus_boolean(attr);
        struct pmbus_data *data = pmbus_update_device(dev);
        int val;

        val = pmbus_get_boolean(data, boolean, 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 *devattr, char *buf)
{
        struct pmbus_data *data = pmbus_update_device(dev);
        struct pmbus_sensor *sensor = to_pmbus_sensor(devattr);

        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 i2c_client *client = to_i2c_client(dev);
        struct pmbus_data *data = i2c_get_clientdata(client);
        struct pmbus_sensor *sensor = to_pmbus_sensor(devattr);
        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
                sensor->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 pmbus_label *label = to_pmbus_label(da);

        return snprintf(buf, PAGE_SIZE, "%s\n", label->label);
}

static int pmbus_add_attribute(struct pmbus_data *data, struct attribute *attr)
{
        if (data->num_attributes >= data->max_attributes - 1) {
                int new_max_attrs = data->max_attributes + PMBUS_ATTR_ALLOC_SIZE;
                void *new_attrs = krealloc(data->group.attrs,
                                           new_max_attrs * sizeof(void *),
                                           GFP_KERNEL);
                if (!new_attrs)
                        return -ENOMEM;
                data->group.attrs = new_attrs;
                data->max_attributes = new_max_attrs;
        }

        data->group.attrs[data->num_attributes++] = attr;
        data->group.attrs[data->num_attributes] = NULL;
        return 0;
}

static void pmbus_dev_attr_init(struct device_attribute *dev_attr,
                                const char *name,
                                umode_t mode,
                                ssize_t (*show)(struct device *dev,
                                                struct device_attribute *attr,
                                                char *buf),
                                ssize_t (*store)(struct device *dev,
                                                 struct device_attribute *attr,
                                                 const char *buf, size_t count))
{
        sysfs_attr_init(&dev_attr->attr);
        dev_attr->attr.name = name;
        dev_attr->attr.mode = mode;
        dev_attr->show = show;
        dev_attr->store = store;
}

static void pmbus_attr_init(struct sensor_device_attribute *a,
                            const char *name,
                            umode_t mode,
                            ssize_t (*show)(struct device *dev,
                                            struct device_attribute *attr,
                                            char *buf),
                            ssize_t (*store)(struct device *dev,
                                             struct device_attribute *attr,
                                             const char *buf, size_t count),
                            int idx)
{
        pmbus_dev_attr_init(&a->dev_attr, name, mode, show, store);
        a->index = idx;
}

static int pmbus_add_boolean(struct pmbus_data *data,
                             const char *name, const char *type, int seq,
                             struct pmbus_sensor *s1,
                             struct pmbus_sensor *s2,
                             u16 reg, u8 mask)
{
        struct pmbus_boolean *boolean;
        struct sensor_device_attribute *a;

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

        a = &boolean->attribute;

        snprintf(boolean->name, sizeof(boolean->name), "%s%d_%s",
                 name, seq, type);
        boolean->s1 = s1;
        boolean->s2 = s2;
        pmbus_attr_init(a, boolean->name, S_IRUGO, pmbus_show_boolean, NULL,
                        (reg << 8) | mask);

        return pmbus_add_attribute(data, &a->dev_attr.attr);
}

static struct pmbus_sensor *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;
        struct device_attribute *a;

        sensor = devm_kzalloc(data->dev, sizeof(*sensor), GFP_KERNEL);
        if (!sensor)
                return NULL;
        a = &sensor->attribute;

        snprintf(sensor->name, sizeof(sensor->name), "%s%d_%s",
                 name, seq, type);
        sensor->page = page;
        sensor->reg = reg;
        sensor->class = class;
        sensor->update = update;
        pmbus_dev_attr_init(a, sensor->name,
                            readonly ? S_IRUGO : S_IRUGO | S_IWUSR,
                            pmbus_show_sensor, pmbus_set_sensor);

        if (pmbus_add_attribute(data, &a->attr))
                return NULL;

        sensor->next = data->sensors;
        data->sensors = sensor;

        return sensor;
}

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

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

        a = &label->attribute;

        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_dev_attr_init(a, label->name, S_IRUGO, pmbus_show_label, NULL);
        return pmbus_add_attribute(data, &a->attr);
}

/*
 * 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 */
        u16 sbit;               /* Alarm attribute status bit */
        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 */
};

/*
 * The pmbus_sensor_attr structure describes one sensor attribute. This
 * description includes a reference to the associated limit attributes.
 */
struct pmbus_sensor_attr {
        u16 reg;                        /* sensor register */
        u8 gbit;                        /* generic status bit */
        u8 nlimit;                      /* # of limit registers */
        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 */
        const struct pmbus_limit_attr *limit;/* limit registers */
};

/*
 * Add a set of limit attributes and, if supported, the associated
 * alarm attributes.
 * returns 0 if no alarm register found, 1 if an alarm register was found,
 * < 0 on errors.
 */
static int 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,
                                 struct pmbus_sensor *base,
                                 const struct pmbus_sensor_attr *attr)
{
        const struct pmbus_limit_attr *l = attr->limit;
        int nlimit = attr->nlimit;
        int have_alarm = 0;
        int i, ret;
        struct pmbus_sensor *curr;

        for (i = 0; i < nlimit; i++) {
                if (pmbus_check_word_register(client, page, l->reg)) {
                        curr = pmbus_add_sensor(data, name, l->attr, index,
                                                page, l->reg, attr->class,
                                                attr->update || l->update,
                                                false);
                        if (!curr)
                                return -ENOMEM;
                        if (l->sbit && (info->func[page] & attr->sfunc)) {
                                ret = pmbus_add_boolean(data, name,
                                        l->alarm, index,
                                        attr->compare ?  l->low ? curr : base
                                                      : NULL,
                                        attr->compare ? l->low ? base : curr
                                                      : NULL,
                                        attr->sbase + page, l->sbit);
                                if (ret)
                                        return ret;
                                have_alarm = 1;
                        }
                }
                l++;
        }
        return have_alarm;
}

static int 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)
{
        struct pmbus_sensor *base;
        int ret;

        if (attr->label) {
                ret = pmbus_add_label(data, name, index, attr->label,
                                      attr->paged ? page + 1 : 0);
                if (ret)
                        return ret;
        }
        base = pmbus_add_sensor(data, name, "input", index, page, attr->reg,
                                attr->class, true, true);
        if (!base)
                return -ENOMEM;
        if (attr->sfunc) {

                ret = pmbus_add_limit_attrs(client, data, info, name,
                                            index, page, base, attr);
                if (ret < 0)
                        return ret;
                /*
                 * 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 (!ret && attr->gbit &&
                    pmbus_check_byte_register(client, page,
                                              data->status_register)) {
                        ret = pmbus_add_boolean(data, name, "alarm", index,
                                                NULL, NULL,
                                                PB_STATUS_BASE + page,
                                                attr->gbit);
                        if (ret)
                                return ret;
                }
        }
        return 0;
}

static int 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;
        int ret;

        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;
                        ret = pmbus_add_sensor_attrs_one(client, data, info,
                                                         name, index, page,
                                                         attrs);
                        if (ret)
                                return ret;
                        index++;
                }
                attrs++;
        }
        return 0;
}

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 vmon_limit_attrs[] = {
        {
                .reg = PMBUS_VIRT_VMON_UV_WARN_LIMIT,
                .attr = "min",
                .alarm = "min_alarm",
                .sbit = PB_VOLTAGE_UV_WARNING,
        }, {
                .reg = PMBUS_VIRT_VMON_UV_FAULT_LIMIT,
                .attr = "lcrit",
                .alarm = "lcrit_alarm",
                .sbit = PB_VOLTAGE_UV_FAULT,
        }, {
                .reg = PMBUS_VIRT_VMON_OV_WARN_LIMIT,
                .attr = "max",
                .alarm = "max_alarm",
                .sbit = PB_VOLTAGE_OV_WARNING,
        }, {
                .reg = PMBUS_VIRT_VMON_OV_FAULT_LIMIT,
                .attr = "crit",
                .alarm = "crit_alarm",
                .sbit = PB_VOLTAGE_OV_FAULT,
        }
};

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_VIRT_READ_VMON,
                .class = PSC_VOLTAGE_IN,
                .label = "vmon",
                .func = PMBUS_HAVE_VMON,
                .sfunc = PMBUS_HAVE_STATUS_VMON,
                .sbase = PB_STATUS_VMON_BASE,
                .limit = vmon_limit_attrs,
                .nlimit = ARRAY_SIZE(vmon_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 int 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;
        int ret;

        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;

                        if (pmbus_add_sensor(data, "fan", "input", index,
                                             page, pmbus_fan_registers[f],
                                             PSC_FAN, true, true) == NULL)
                                return -ENOMEM;

                        /*
                         * 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;
                                ret = pmbus_add_boolean(data, "fan",
                                        "alarm", index, NULL, NULL, base,
                                        PB_FAN_FAN1_WARNING >> (f & 1));
                                if (ret)
                                        return ret;
                                ret = pmbus_add_boolean(data, "fan",
                                        "fault", index, NULL, NULL, base,
                                        PB_FAN_FAN1_FAULT >> (f & 1));
                                if (ret)
                                        return ret;
                        }
                        index++;
                }
        }
        return 0;
}

static int pmbus_find_attributes(struct i2c_client *client,
                                 struct pmbus_data *data)
{
        int ret;

        /* Voltage sensors */
        ret = pmbus_add_sensor_attrs(client, data, "in", voltage_attributes,
                                     ARRAY_SIZE(voltage_attributes));
        if (ret)
                return ret;

        /* Current sensors */
        ret = pmbus_add_sensor_attrs(client, data, "curr", current_attributes,
                                     ARRAY_SIZE(current_attributes));
        if (ret)
                return ret;

        /* Power sensors */
        ret = pmbus_add_sensor_attrs(client, data, "power", power_attributes,
                                     ARRAY_SIZE(power_attributes));
        if (ret)
                return ret;

        /* Temperature sensors */
        ret = pmbus_add_sensor_attrs(client, data, "temp", temp_attributes,
                                     ARRAY_SIZE(temp_attributes));
        if (ret)
                return ret;

        /* Fans */
        ret = pmbus_add_fan_attributes(client, data);
        return ret;
}

/*
 * 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;
                }
        }

        pmbus_clear_fault_page(client, 0);
        return 0;
}

static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
                             struct pmbus_driver_info *info)
{
        struct device *dev = &client->dev;
        int ret;

        /*
         * Some PMBus chips don't support PMBUS_STATUS_BYTE, so try
         * to use PMBUS_STATUS_WORD instead if that is the case.
         * Bail out if both registers are not supported.
         */
        data->status_register = PMBUS_STATUS_BYTE;
        ret = i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE);
        if (ret < 0 || ret == 0xff) {
                data->status_register = PMBUS_STATUS_WORD;
                ret = i2c_smbus_read_word_data(client, PMBUS_STATUS_WORD);
                if (ret < 0 || ret == 0xffff) {
                        dev_err(dev, "PMBus status register not found\n");
                        return -ENODEV;
                }
        }

        pmbus_clear_faults(client);

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

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

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

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

        if (!info)
                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(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

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

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

        ret = pmbus_init_common(client, data, info);
        if (ret < 0)
                return ret;

        ret = pmbus_find_attributes(client, data);
        if (ret)
                goto out_kfree;

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

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

out_hwmon_device_register:
        sysfs_remove_group(&dev->kobj, &data->group);
out_kfree:
        kfree(data->group.attrs);
        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);
        kfree(data->group.attrs);
        return 0;
}
EXPORT_SYMBOL_GPL(pmbus_do_remove);

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