Merge branch 'drm-intel-next' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt...

[linux-2.6/mini2440.git] / drivers / regulator / core.c

/*
 * core.c  --  Voltage/Current Regulator framework.
 *
 * Copyright 2007, 2008 Wolfson Microelectronics PLC.
 * Copyright 2008 SlimLogic Ltd.
 *
 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/suspend.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>

#define REGULATOR_VERSION "0.5"

static DEFINE_MUTEX(regulator_list_mutex);
static LIST_HEAD(regulator_list);
static LIST_HEAD(regulator_map_list);
static int has_full_constraints;

/*
 * struct regulator_map
 *
 * Used to provide symbolic supply names to devices.
 */
struct regulator_map {
        struct list_head list;
        struct device *dev;
        const char *supply;
        struct regulator_dev *regulator;
};

/*
 * struct regulator
 *
 * One for each consumer device.
 */
struct regulator {
        struct device *dev;
        struct list_head list;
        int uA_load;
        int min_uV;
        int max_uV;
        char *supply_name;
        struct device_attribute dev_attr;
        struct regulator_dev *rdev;
};

static int _regulator_is_enabled(struct regulator_dev *rdev);
static int _regulator_disable(struct regulator_dev *rdev);
static int _regulator_get_voltage(struct regulator_dev *rdev);
static int _regulator_get_current_limit(struct regulator_dev *rdev);
static unsigned int _regulator_get_mode(struct regulator_dev *rdev);
static void _notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data);

/* gets the regulator for a given consumer device */
static struct regulator *get_device_regulator(struct device *dev)
{
        struct regulator *regulator = NULL;
        struct regulator_dev *rdev;

        mutex_lock(&regulator_list_mutex);
        list_for_each_entry(rdev, &regulator_list, list) {
                mutex_lock(&rdev->mutex);
                list_for_each_entry(regulator, &rdev->consumer_list, list) {
                        if (regulator->dev == dev) {
                                mutex_unlock(&rdev->mutex);
                                mutex_unlock(&regulator_list_mutex);
                                return regulator;
                        }
                }
                mutex_unlock(&rdev->mutex);
        }
        mutex_unlock(&regulator_list_mutex);
        return NULL;
}

/* Platform voltage constraint check */
static int regulator_check_voltage(struct regulator_dev *rdev,
                                   int *min_uV, int *max_uV)
{
        BUG_ON(*min_uV > *max_uV);

        if (!rdev->constraints) {
                printk(KERN_ERR "%s: no constraints for %s\n", __func__,
                       rdev->desc->name);
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_VOLTAGE)) {
                printk(KERN_ERR "%s: operation not allowed for %s\n",
                       __func__, rdev->desc->name);
                return -EPERM;
        }

        if (*max_uV > rdev->constraints->max_uV)
                *max_uV = rdev->constraints->max_uV;
        if (*min_uV < rdev->constraints->min_uV)
                *min_uV = rdev->constraints->min_uV;

        if (*min_uV > *max_uV)
                return -EINVAL;

        return 0;
}

/* current constraint check */
static int regulator_check_current_limit(struct regulator_dev *rdev,
                                        int *min_uA, int *max_uA)
{
        BUG_ON(*min_uA > *max_uA);

        if (!rdev->constraints) {
                printk(KERN_ERR "%s: no constraints for %s\n", __func__,
                       rdev->desc->name);
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_CURRENT)) {
                printk(KERN_ERR "%s: operation not allowed for %s\n",
                       __func__, rdev->desc->name);
                return -EPERM;
        }

        if (*max_uA > rdev->constraints->max_uA)
                *max_uA = rdev->constraints->max_uA;
        if (*min_uA < rdev->constraints->min_uA)
                *min_uA = rdev->constraints->min_uA;

        if (*min_uA > *max_uA)
                return -EINVAL;

        return 0;
}

/* operating mode constraint check */
static int regulator_check_mode(struct regulator_dev *rdev, int mode)
{
        switch (mode) {
        case REGULATOR_MODE_FAST:
        case REGULATOR_MODE_NORMAL:
        case REGULATOR_MODE_IDLE:
        case REGULATOR_MODE_STANDBY:
                break;
        default:
                return -EINVAL;
        }

        if (!rdev->constraints) {
                printk(KERN_ERR "%s: no constraints for %s\n", __func__,
                       rdev->desc->name);
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_MODE)) {
                printk(KERN_ERR "%s: operation not allowed for %s\n",
                       __func__, rdev->desc->name);
                return -EPERM;
        }
        if (!(rdev->constraints->valid_modes_mask & mode)) {
                printk(KERN_ERR "%s: invalid mode %x for %s\n",
                       __func__, mode, rdev->desc->name);
                return -EINVAL;
        }
        return 0;
}

/* dynamic regulator mode switching constraint check */
static int regulator_check_drms(struct regulator_dev *rdev)
{
        if (!rdev->constraints) {
                printk(KERN_ERR "%s: no constraints for %s\n", __func__,
                       rdev->desc->name);
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS)) {
                printk(KERN_ERR "%s: operation not allowed for %s\n",
                       __func__, rdev->desc->name);
                return -EPERM;
        }
        return 0;
}

static ssize_t device_requested_uA_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct regulator *regulator;

        regulator = get_device_regulator(dev);
        if (regulator == NULL)
                return 0;

        return sprintf(buf, "%d\n", regulator->uA_load);
}

static ssize_t regulator_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        ssize_t ret;

        mutex_lock(&rdev->mutex);
        ret = sprintf(buf, "%d\n", _regulator_get_voltage(rdev));
        mutex_unlock(&rdev->mutex);

        return ret;
}
static DEVICE_ATTR(microvolts, 0444, regulator_uV_show, NULL);

static ssize_t regulator_uA_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", _regulator_get_current_limit(rdev));
}
static DEVICE_ATTR(microamps, 0444, regulator_uA_show, NULL);

static ssize_t regulator_name_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        const char *name;

        if (rdev->constraints->name)
                name = rdev->constraints->name;
        else if (rdev->desc->name)
                name = rdev->desc->name;
        else
                name = "";

        return sprintf(buf, "%s\n", name);
}

static ssize_t regulator_print_opmode(char *buf, int mode)
{
        switch (mode) {
        case REGULATOR_MODE_FAST:
                return sprintf(buf, "fast\n");
        case REGULATOR_MODE_NORMAL:
                return sprintf(buf, "normal\n");
        case REGULATOR_MODE_IDLE:
                return sprintf(buf, "idle\n");
        case REGULATOR_MODE_STANDBY:
                return sprintf(buf, "standby\n");
        }
        return sprintf(buf, "unknown\n");
}

static ssize_t regulator_opmode_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf, _regulator_get_mode(rdev));
}
static DEVICE_ATTR(opmode, 0444, regulator_opmode_show, NULL);

static ssize_t regulator_print_state(char *buf, int state)
{
        if (state > 0)
                return sprintf(buf, "enabled\n");
        else if (state == 0)
                return sprintf(buf, "disabled\n");
        else
                return sprintf(buf, "unknown\n");
}

static ssize_t regulator_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf, _regulator_is_enabled(rdev));
}
static DEVICE_ATTR(state, 0444, regulator_state_show, NULL);

static ssize_t regulator_status_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        int status;
        char *label;

        status = rdev->desc->ops->get_status(rdev);
        if (status < 0)
                return status;

        switch (status) {
        case REGULATOR_STATUS_OFF:
                label = "off";
                break;
        case REGULATOR_STATUS_ON:
                label = "on";
                break;
        case REGULATOR_STATUS_ERROR:
                label = "error";
                break;
        case REGULATOR_STATUS_FAST:
                label = "fast";
                break;
        case REGULATOR_STATUS_NORMAL:
                label = "normal";
                break;
        case REGULATOR_STATUS_IDLE:
                label = "idle";
                break;
        case REGULATOR_STATUS_STANDBY:
                label = "standby";
                break;
        default:
                return -ERANGE;
        }

        return sprintf(buf, "%s\n", label);
}
static DEVICE_ATTR(status, 0444, regulator_status_show, NULL);

static ssize_t regulator_min_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->min_uA);
}
static DEVICE_ATTR(min_microamps, 0444, regulator_min_uA_show, NULL);

static ssize_t regulator_max_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->max_uA);
}
static DEVICE_ATTR(max_microamps, 0444, regulator_max_uA_show, NULL);

static ssize_t regulator_min_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->min_uV);
}
static DEVICE_ATTR(min_microvolts, 0444, regulator_min_uV_show, NULL);

static ssize_t regulator_max_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        if (!rdev->constraints)
                return sprintf(buf, "constraint not defined\n");

        return sprintf(buf, "%d\n", rdev->constraints->max_uV);
}
static DEVICE_ATTR(max_microvolts, 0444, regulator_max_uV_show, NULL);

static ssize_t regulator_total_uA_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        struct regulator *regulator;
        int uA = 0;

        mutex_lock(&rdev->mutex);
        list_for_each_entry(regulator, &rdev->consumer_list, list)
            uA += regulator->uA_load;
        mutex_unlock(&rdev->mutex);
        return sprintf(buf, "%d\n", uA);
}
static DEVICE_ATTR(requested_microamps, 0444, regulator_total_uA_show, NULL);

static ssize_t regulator_num_users_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        return sprintf(buf, "%d\n", rdev->use_count);
}

static ssize_t regulator_type_show(struct device *dev,
                                  struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        switch (rdev->desc->type) {
        case REGULATOR_VOLTAGE:
                return sprintf(buf, "voltage\n");
        case REGULATOR_CURRENT:
                return sprintf(buf, "current\n");
        }
        return sprintf(buf, "unknown\n");
}

static ssize_t regulator_suspend_mem_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_mem.uV);
}
static DEVICE_ATTR(suspend_mem_microvolts, 0444,
                regulator_suspend_mem_uV_show, NULL);

static ssize_t regulator_suspend_disk_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_disk.uV);
}
static DEVICE_ATTR(suspend_disk_microvolts, 0444,
                regulator_suspend_disk_uV_show, NULL);

static ssize_t regulator_suspend_standby_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", rdev->constraints->state_standby.uV);
}
static DEVICE_ATTR(suspend_standby_microvolts, 0444,
                regulator_suspend_standby_uV_show, NULL);

static ssize_t regulator_suspend_mem_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_mem.mode);
}
static DEVICE_ATTR(suspend_mem_mode, 0444,
                regulator_suspend_mem_mode_show, NULL);

static ssize_t regulator_suspend_disk_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_disk.mode);
}
static DEVICE_ATTR(suspend_disk_mode, 0444,
                regulator_suspend_disk_mode_show, NULL);

static ssize_t regulator_suspend_standby_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_opmode(buf,
                rdev->constraints->state_standby.mode);
}
static DEVICE_ATTR(suspend_standby_mode, 0444,
                regulator_suspend_standby_mode_show, NULL);

static ssize_t regulator_suspend_mem_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_mem.enabled);
}
static DEVICE_ATTR(suspend_mem_state, 0444,
                regulator_suspend_mem_state_show, NULL);

static ssize_t regulator_suspend_disk_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_disk.enabled);
}
static DEVICE_ATTR(suspend_disk_state, 0444,
                regulator_suspend_disk_state_show, NULL);

static ssize_t regulator_suspend_standby_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);

        return regulator_print_state(buf,
                        rdev->constraints->state_standby.enabled);
}
static DEVICE_ATTR(suspend_standby_state, 0444,
                regulator_suspend_standby_state_show, NULL);


/*
 * These are the only attributes are present for all regulators.
 * Other attributes are a function of regulator functionality.
 */
static struct device_attribute regulator_dev_attrs[] = {
        __ATTR(name, 0444, regulator_name_show, NULL),
        __ATTR(num_users, 0444, regulator_num_users_show, NULL),
        __ATTR(type, 0444, regulator_type_show, NULL),
        __ATTR_NULL,
};

static void regulator_dev_release(struct device *dev)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        kfree(rdev);
}

static struct class regulator_class = {
        .name = "regulator",
        .dev_release = regulator_dev_release,
        .dev_attrs = regulator_dev_attrs,
};

/* Calculate the new optimum regulator operating mode based on the new total
 * consumer load. All locks held by caller */
static void drms_uA_update(struct regulator_dev *rdev)
{
        struct regulator *sibling;
        int current_uA = 0, output_uV, input_uV, err;
        unsigned int mode;

        err = regulator_check_drms(rdev);
        if (err < 0 || !rdev->desc->ops->get_optimum_mode ||
            !rdev->desc->ops->get_voltage || !rdev->desc->ops->set_mode)
                return;

        /* get output voltage */
        output_uV = rdev->desc->ops->get_voltage(rdev);
        if (output_uV <= 0)
                return;

        /* get input voltage */
        if (rdev->supply && rdev->supply->desc->ops->get_voltage)
                input_uV = rdev->supply->desc->ops->get_voltage(rdev->supply);
        else
                input_uV = rdev->constraints->input_uV;
        if (input_uV <= 0)
                return;

        /* calc total requested load */
        list_for_each_entry(sibling, &rdev->consumer_list, list)
            current_uA += sibling->uA_load;

        /* now get the optimum mode for our new total regulator load */
        mode = rdev->desc->ops->get_optimum_mode(rdev, input_uV,
                                                  output_uV, current_uA);

        /* check the new mode is allowed */
        err = regulator_check_mode(rdev, mode);
        if (err == 0)
                rdev->desc->ops->set_mode(rdev, mode);
}

static int suspend_set_state(struct regulator_dev *rdev,
        struct regulator_state *rstate)
{
        int ret = 0;

        /* enable & disable are mandatory for suspend control */
        if (!rdev->desc->ops->set_suspend_enable ||
                !rdev->desc->ops->set_suspend_disable) {
                printk(KERN_ERR "%s: no way to set suspend state\n",
                        __func__);
                return -EINVAL;
        }

        if (rstate->enabled)
                ret = rdev->desc->ops->set_suspend_enable(rdev);
        else
                ret = rdev->desc->ops->set_suspend_disable(rdev);
        if (ret < 0) {
                printk(KERN_ERR "%s: failed to enabled/disable\n", __func__);
                return ret;
        }

        if (rdev->desc->ops->set_suspend_voltage && rstate->uV > 0) {
                ret = rdev->desc->ops->set_suspend_voltage(rdev, rstate->uV);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to set voltage\n",
                                __func__);
                        return ret;
                }
        }

        if (rdev->desc->ops->set_suspend_mode && rstate->mode > 0) {
                ret = rdev->desc->ops->set_suspend_mode(rdev, rstate->mode);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to set mode\n", __func__);
                        return ret;
                }
        }
        return ret;
}

/* locks held by caller */
static int suspend_prepare(struct regulator_dev *rdev, suspend_state_t state)
{
        if (!rdev->constraints)
                return -EINVAL;

        switch (state) {
        case PM_SUSPEND_STANDBY:
                return suspend_set_state(rdev,
                        &rdev->constraints->state_standby);
        case PM_SUSPEND_MEM:
                return suspend_set_state(rdev,
                        &rdev->constraints->state_mem);
        case PM_SUSPEND_MAX:
                return suspend_set_state(rdev,
                        &rdev->constraints->state_disk);
        default:
                return -EINVAL;
        }
}

static void print_constraints(struct regulator_dev *rdev)
{
        struct regulation_constraints *constraints = rdev->constraints;
        char buf[80];
        int count;

        if (rdev->desc->type == REGULATOR_VOLTAGE) {
                if (constraints->min_uV == constraints->max_uV)
                        count = sprintf(buf, "%d mV ",
                                        constraints->min_uV / 1000);
                else
                        count = sprintf(buf, "%d <--> %d mV ",
                                        constraints->min_uV / 1000,
                                        constraints->max_uV / 1000);
        } else {
                if (constraints->min_uA == constraints->max_uA)
                        count = sprintf(buf, "%d mA ",
                                        constraints->min_uA / 1000);
                else
                        count = sprintf(buf, "%d <--> %d mA ",
                                        constraints->min_uA / 1000,
                                        constraints->max_uA / 1000);
        }
        if (constraints->valid_modes_mask & REGULATOR_MODE_FAST)
                count += sprintf(buf + count, "fast ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_NORMAL)
                count += sprintf(buf + count, "normal ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_IDLE)
                count += sprintf(buf + count, "idle ");
        if (constraints->valid_modes_mask & REGULATOR_MODE_STANDBY)
                count += sprintf(buf + count, "standby");

        printk(KERN_INFO "regulator: %s: %s\n", rdev->desc->name, buf);
}

/**
 * set_machine_constraints - sets regulator constraints
 * @rdev: regulator source
 * @constraints: constraints to apply
 *
 * Allows platform initialisation code to define and constrain
 * regulator circuits e.g. valid voltage/current ranges, etc.  NOTE:
 * Constraints *must* be set by platform code in order for some
 * regulator operations to proceed i.e. set_voltage, set_current_limit,
 * set_mode.
 */
static int set_machine_constraints(struct regulator_dev *rdev,
        struct regulation_constraints *constraints)
{
        int ret = 0;
        const char *name;
        struct regulator_ops *ops = rdev->desc->ops;

        if (constraints->name)
                name = constraints->name;
        else if (rdev->desc->name)
                name = rdev->desc->name;
        else
                name = "regulator";

        /* constrain machine-level voltage specs to fit
         * the actual range supported by this regulator.
         */
        if (ops->list_voltage && rdev->desc->n_voltages) {
                int     count = rdev->desc->n_voltages;
                int     i;
                int     min_uV = INT_MAX;
                int     max_uV = INT_MIN;
                int     cmin = constraints->min_uV;
                int     cmax = constraints->max_uV;

                /* it's safe to autoconfigure fixed-voltage supplies
                   and the constraints are used by list_voltage. */
                if (count == 1 && !cmin) {
                        cmin = 1;
                        cmax = INT_MAX;
                        constraints->min_uV = cmin;
                        constraints->max_uV = cmax;
                }

                /* voltage constraints are optional */
                if ((cmin == 0) && (cmax == 0))
                        goto out;

                /* else require explicit machine-level constraints */
                if (cmin <= 0 || cmax <= 0 || cmax < cmin) {
                        pr_err("%s: %s '%s' voltage constraints\n",
                                       __func__, "invalid", name);
                        ret = -EINVAL;
                        goto out;
                }

                /* initial: [cmin..cmax] valid, [min_uV..max_uV] not */
                for (i = 0; i < count; i++) {
                        int     value;

                        value = ops->list_voltage(rdev, i);
                        if (value <= 0)
                                continue;

                        /* maybe adjust [min_uV..max_uV] */
                        if (value >= cmin && value < min_uV)
                                min_uV = value;
                        if (value <= cmax && value > max_uV)
                                max_uV = value;
                }

                /* final: [min_uV..max_uV] valid iff constraints valid */
                if (max_uV < min_uV) {
                        pr_err("%s: %s '%s' voltage constraints\n",
                                       __func__, "unsupportable", name);
                        ret = -EINVAL;
                        goto out;
                }

                /* use regulator's subset of machine constraints */
                if (constraints->min_uV < min_uV) {
                        pr_debug("%s: override '%s' %s, %d -> %d\n",
                                       __func__, name, "min_uV",
                                        constraints->min_uV, min_uV);
                        constraints->min_uV = min_uV;
                }
                if (constraints->max_uV > max_uV) {
                        pr_debug("%s: override '%s' %s, %d -> %d\n",
                                       __func__, name, "max_uV",
                                        constraints->max_uV, max_uV);
                        constraints->max_uV = max_uV;
                }
        }

        rdev->constraints = constraints;

        /* do we need to apply the constraint voltage */
        if (rdev->constraints->apply_uV &&
                rdev->constraints->min_uV == rdev->constraints->max_uV &&
                ops->set_voltage) {
                ret = ops->set_voltage(rdev,
                        rdev->constraints->min_uV, rdev->constraints->max_uV);
                        if (ret < 0) {
                                printk(KERN_ERR "%s: failed to apply %duV constraint to %s\n",
                                       __func__,
                                       rdev->constraints->min_uV, name);
                                rdev->constraints = NULL;
                                goto out;
                        }
        }

        /* do we need to setup our suspend state */
        if (constraints->initial_state) {
                ret = suspend_prepare(rdev, constraints->initial_state);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to set suspend state for %s\n",
                               __func__, name);
                        rdev->constraints = NULL;
                        goto out;
                }
        }

        if (constraints->initial_mode) {
                if (!ops->set_mode) {
                        printk(KERN_ERR "%s: no set_mode operation for %s\n",
                               __func__, name);
                        ret = -EINVAL;
                        goto out;
                }

                ret = ops->set_mode(rdev, constraints->initial_mode);
                if (ret < 0) {
                        printk(KERN_ERR
                               "%s: failed to set initial mode for %s: %d\n",
                               __func__, name, ret);
                        goto out;
                }
        }

        /* If the constraints say the regulator should be on at this point
         * and we have control then make sure it is enabled.
         */
        if ((constraints->always_on || constraints->boot_on) && ops->enable) {
                ret = ops->enable(rdev);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to enable %s\n",
                               __func__, name);
                        rdev->constraints = NULL;
                        goto out;
                }
        }

        print_constraints(rdev);
out:
        return ret;
}

/**
 * set_supply - set regulator supply regulator
 * @rdev: regulator name
 * @supply_rdev: supply regulator name
 *
 * Called by platform initialisation code to set the supply regulator for this
 * regulator. This ensures that a regulators supply will also be enabled by the
 * core if it's child is enabled.
 */
static int set_supply(struct regulator_dev *rdev,
        struct regulator_dev *supply_rdev)
{
        int err;

        err = sysfs_create_link(&rdev->dev.kobj, &supply_rdev->dev.kobj,
                                "supply");
        if (err) {
                printk(KERN_ERR
                       "%s: could not add device link %s err %d\n",
                       __func__, supply_rdev->dev.kobj.name, err);
                       goto out;
        }
        rdev->supply = supply_rdev;
        list_add(&rdev->slist, &supply_rdev->supply_list);
out:
        return err;
}

/**
 * set_consumer_device_supply: Bind a regulator to a symbolic supply
 * @rdev:         regulator source
 * @consumer_dev: device the supply applies to
 * @supply:       symbolic name for supply
 *
 * Allows platform initialisation code to map physical regulator
 * sources to symbolic names for supplies for use by devices.  Devices
 * should use these symbolic names to request regulators, avoiding the
 * need to provide board-specific regulator names as platform data.
 */
static int set_consumer_device_supply(struct regulator_dev *rdev,
        struct device *consumer_dev, const char *supply)
{
        struct regulator_map *node;

        if (supply == NULL)
                return -EINVAL;

        list_for_each_entry(node, &regulator_map_list, list) {
                if (consumer_dev != node->dev)
                        continue;
                if (strcmp(node->supply, supply) != 0)
                        continue;

                dev_dbg(consumer_dev, "%s/%s is '%s' supply; fail %s/%s\n",
                                dev_name(&node->regulator->dev),
                                node->regulator->desc->name,
                                supply,
                                dev_name(&rdev->dev), rdev->desc->name);
                return -EBUSY;
        }

        node = kmalloc(sizeof(struct regulator_map), GFP_KERNEL);
        if (node == NULL)
                return -ENOMEM;

        node->regulator = rdev;
        node->dev = consumer_dev;
        node->supply = supply;

        list_add(&node->list, &regulator_map_list);
        return 0;
}

static void unset_consumer_device_supply(struct regulator_dev *rdev,
        struct device *consumer_dev)
{
        struct regulator_map *node, *n;

        list_for_each_entry_safe(node, n, &regulator_map_list, list) {
                if (rdev == node->regulator &&
                        consumer_dev == node->dev) {
                        list_del(&node->list);
                        kfree(node);
                        return;
                }
        }
}

static void unset_regulator_supplies(struct regulator_dev *rdev)
{
        struct regulator_map *node, *n;

        list_for_each_entry_safe(node, n, &regulator_map_list, list) {
                if (rdev == node->regulator) {
                        list_del(&node->list);
                        kfree(node);
                        return;
                }
        }
}

#define REG_STR_SIZE    32

static struct regulator *create_regulator(struct regulator_dev *rdev,
                                          struct device *dev,
                                          const char *supply_name)
{
        struct regulator *regulator;
        char buf[REG_STR_SIZE];
        int err, size;

        regulator = kzalloc(sizeof(*regulator), GFP_KERNEL);
        if (regulator == NULL)
                return NULL;

        mutex_lock(&rdev->mutex);
        regulator->rdev = rdev;
        list_add(&regulator->list, &rdev->consumer_list);

        if (dev) {
                /* create a 'requested_microamps_name' sysfs entry */
                size = scnprintf(buf, REG_STR_SIZE, "microamps_requested_%s",
                        supply_name);
                if (size >= REG_STR_SIZE)
                        goto overflow_err;

                regulator->dev = dev;
                regulator->dev_attr.attr.name = kstrdup(buf, GFP_KERNEL);
                if (regulator->dev_attr.attr.name == NULL)
                        goto attr_name_err;

                regulator->dev_attr.attr.owner = THIS_MODULE;
                regulator->dev_attr.attr.mode = 0444;
                regulator->dev_attr.show = device_requested_uA_show;
                err = device_create_file(dev, &regulator->dev_attr);
                if (err < 0) {
                        printk(KERN_WARNING "%s: could not add regulator_dev"
                                " load sysfs\n", __func__);
                        goto attr_name_err;
                }

                /* also add a link to the device sysfs entry */
                size = scnprintf(buf, REG_STR_SIZE, "%s-%s",
                                 dev->kobj.name, supply_name);
                if (size >= REG_STR_SIZE)
                        goto attr_err;

                regulator->supply_name = kstrdup(buf, GFP_KERNEL);
                if (regulator->supply_name == NULL)
                        goto attr_err;

                err = sysfs_create_link(&rdev->dev.kobj, &dev->kobj,
                                        buf);
                if (err) {
                        printk(KERN_WARNING
                               "%s: could not add device link %s err %d\n",
                               __func__, dev->kobj.name, err);
                        device_remove_file(dev, &regulator->dev_attr);
                        goto link_name_err;
                }
        }
        mutex_unlock(&rdev->mutex);
        return regulator;
link_name_err:
        kfree(regulator->supply_name);
attr_err:
        device_remove_file(regulator->dev, &regulator->dev_attr);
attr_name_err:
        kfree(regulator->dev_attr.attr.name);
overflow_err:
        list_del(&regulator->list);
        kfree(regulator);
        mutex_unlock(&rdev->mutex);
        return NULL;
}

/**
 * regulator_get - lookup and obtain a reference to a regulator.
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Returns a struct regulator corresponding to the regulator producer,
 * or IS_ERR() condition containing errno.
 *
 * Use of supply names configured via regulator_set_device_supply() is
 * strongly encouraged.  It is recommended that the supply name used
 * should match the name used for the supply and/or the relevant
 * device pins in the datasheet.
 */
struct regulator *regulator_get(struct device *dev, const char *id)
{
        struct regulator_dev *rdev;
        struct regulator_map *map;
        struct regulator *regulator = ERR_PTR(-ENODEV);

        if (id == NULL) {
                printk(KERN_ERR "regulator: get() with no identifier\n");
                return regulator;
        }

        mutex_lock(&regulator_list_mutex);

        list_for_each_entry(map, &regulator_map_list, list) {
                if (dev == map->dev &&
                    strcmp(map->supply, id) == 0) {
                        rdev = map->regulator;
                        goto found;
                }
        }
        mutex_unlock(&regulator_list_mutex);
        return regulator;

found:
        if (!try_module_get(rdev->owner))
                goto out;

        regulator = create_regulator(rdev, dev, id);
        if (regulator == NULL) {
                regulator = ERR_PTR(-ENOMEM);
                module_put(rdev->owner);
        }

out:
        mutex_unlock(&regulator_list_mutex);
        return regulator;
}
EXPORT_SYMBOL_GPL(regulator_get);

/**
 * regulator_put - "free" the regulator source
 * @regulator: regulator source
 *
 * Note: drivers must ensure that all regulator_enable calls made on this
 * regulator source are balanced by regulator_disable calls prior to calling
 * this function.
 */
void regulator_put(struct regulator *regulator)
{
        struct regulator_dev *rdev;

        if (regulator == NULL || IS_ERR(regulator))
                return;

        mutex_lock(&regulator_list_mutex);
        rdev = regulator->rdev;

        /* remove any sysfs entries */
        if (regulator->dev) {
                sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
                kfree(regulator->supply_name);
                device_remove_file(regulator->dev, &regulator->dev_attr);
                kfree(regulator->dev_attr.attr.name);
        }
        list_del(&regulator->list);
        kfree(regulator);

        module_put(rdev->owner);
        mutex_unlock(&regulator_list_mutex);
}
EXPORT_SYMBOL_GPL(regulator_put);

/* locks held by regulator_enable() */
static int _regulator_enable(struct regulator_dev *rdev)
{
        int ret = -EINVAL;

        if (!rdev->constraints) {
                printk(KERN_ERR "%s: %s has no constraints\n",
                       __func__, rdev->desc->name);
                return ret;
        }

        /* do we need to enable the supply regulator first */
        if (rdev->supply) {
                ret = _regulator_enable(rdev->supply);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to enable %s: %d\n",
                               __func__, rdev->desc->name, ret);
                        return ret;
                }
        }

        /* check voltage and requested load before enabling */
        if (rdev->desc->ops->enable) {

                if (rdev->constraints &&
                        (rdev->constraints->valid_ops_mask &
                        REGULATOR_CHANGE_DRMS))
                        drms_uA_update(rdev);

                ret = rdev->desc->ops->enable(rdev);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to enable %s: %d\n",
                               __func__, rdev->desc->name, ret);
                        return ret;
                }
                rdev->use_count++;
                return ret;
        }

        return ret;
}

/**
 * regulator_enable - enable regulator output
 * @regulator: regulator source
 *
 * Request that the regulator be enabled with the regulator output at
 * the predefined voltage or current value.  Calls to regulator_enable()
 * must be balanced with calls to regulator_disable().
 *
 * NOTE: the output value can be set by other drivers, boot loader or may be
 * hardwired in the regulator.
 */
int regulator_enable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret = 0;

        mutex_lock(&rdev->mutex);
        ret = _regulator_enable(rdev);
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_enable);

/* locks held by regulator_disable() */
static int _regulator_disable(struct regulator_dev *rdev)
{
        int ret = 0;

        if (WARN(rdev->use_count <= 0,
                        "unbalanced disables for %s\n",
                        rdev->desc->name))
                return -EIO;

        /* are we the last user and permitted to disable ? */
        if (rdev->use_count == 1 && !rdev->constraints->always_on) {

                /* we are last user */
                if (rdev->desc->ops->disable) {
                        ret = rdev->desc->ops->disable(rdev);
                        if (ret < 0) {
                                printk(KERN_ERR "%s: failed to disable %s\n",
                                       __func__, rdev->desc->name);
                                return ret;
                        }
                }

                /* decrease our supplies ref count and disable if required */
                if (rdev->supply)
                        _regulator_disable(rdev->supply);

                rdev->use_count = 0;
        } else if (rdev->use_count > 1) {

                if (rdev->constraints &&
                        (rdev->constraints->valid_ops_mask &
                        REGULATOR_CHANGE_DRMS))
                        drms_uA_update(rdev);

                rdev->use_count--;
        }
        return ret;
}

/**
 * regulator_disable - disable regulator output
 * @regulator: regulator source
 *
 * Disable the regulator output voltage or current.  Calls to
 * regulator_enable() must be balanced with calls to
 * regulator_disable().
 *
 * NOTE: this will only disable the regulator output if no other consumer
 * devices have it enabled, the regulator device supports disabling and
 * machine constraints permit this operation.
 */
int regulator_disable(struct regulator *regulator)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret = 0;

        mutex_lock(&rdev->mutex);
        ret = _regulator_disable(rdev);
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_disable);

/* locks held by regulator_force_disable() */
static int _regulator_force_disable(struct regulator_dev *rdev)
{
        int ret = 0;

        /* force disable */
        if (rdev->desc->ops->disable) {
                /* ah well, who wants to live forever... */
                ret = rdev->desc->ops->disable(rdev);
                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to force disable %s\n",
                               __func__, rdev->desc->name);
                        return ret;
                }
                /* notify other consumers that power has been forced off */
                _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE,
                        NULL);
        }

        /* decrease our supplies ref count and disable if required */
        if (rdev->supply)
                _regulator_disable(rdev->supply);

        rdev->use_count = 0;
        return ret;
}

/**
 * regulator_force_disable - force disable regulator output
 * @regulator: regulator source
 *
 * Forcibly disable the regulator output voltage or current.
 * NOTE: this *will* disable the regulator output even if other consumer
 * devices have it enabled. This should be used for situations when device
 * damage will likely occur if the regulator is not disabled (e.g. over temp).
 */
int regulator_force_disable(struct regulator *regulator)
{
        int ret;

        mutex_lock(&regulator->rdev->mutex);
        regulator->uA_load = 0;
        ret = _regulator_force_disable(regulator->rdev);
        mutex_unlock(&regulator->rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_force_disable);

static int _regulator_is_enabled(struct regulator_dev *rdev)
{
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->is_enabled) {
                ret = -EINVAL;
                goto out;
        }

        ret = rdev->desc->ops->is_enabled(rdev);
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}

/**
 * regulator_is_enabled - is the regulator output enabled
 * @regulator: regulator source
 *
 * Returns positive if the regulator driver backing the source/client
 * has requested that the device be enabled, zero if it hasn't, else a
 * negative errno code.
 *
 * Note that the device backing this regulator handle can have multiple
 * users, so it might be enabled even if regulator_enable() was never
 * called for this particular source.
 */
int regulator_is_enabled(struct regulator *regulator)
{
        return _regulator_is_enabled(regulator->rdev);
}
EXPORT_SYMBOL_GPL(regulator_is_enabled);

/**
 * regulator_count_voltages - count regulator_list_voltage() selectors
 * @regulator: regulator source
 *
 * Returns number of selectors, or negative errno.  Selectors are
 * numbered starting at zero, and typically correspond to bitfields
 * in hardware registers.
 */
int regulator_count_voltages(struct regulator *regulator)
{
        struct regulator_dev    *rdev = regulator->rdev;

        return rdev->desc->n_voltages ? : -EINVAL;
}
EXPORT_SYMBOL_GPL(regulator_count_voltages);

/**
 * regulator_list_voltage - enumerate supported voltages
 * @regulator: regulator source
 * @selector: identify voltage to list
 * Context: can sleep
 *
 * Returns a voltage that can be passed to @regulator_set_voltage(),
 * zero if this selector code can't be used on this sytem, or a
 * negative errno.
 */
int regulator_list_voltage(struct regulator *regulator, unsigned selector)
{
        struct regulator_dev    *rdev = regulator->rdev;
        struct regulator_ops    *ops = rdev->desc->ops;
        int                     ret;

        if (!ops->list_voltage || selector >= rdev->desc->n_voltages)
                return -EINVAL;

        mutex_lock(&rdev->mutex);
        ret = ops->list_voltage(rdev, selector);
        mutex_unlock(&rdev->mutex);

        if (ret > 0) {
                if (ret < rdev->constraints->min_uV)
                        ret = 0;
                else if (ret > rdev->constraints->max_uV)
                        ret = 0;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_list_voltage);

/**
 * regulator_set_voltage - set regulator output voltage
 * @regulator: regulator source
 * @min_uV: Minimum required voltage in uV
 * @max_uV: Maximum acceptable voltage in uV
 *
 * Sets a voltage regulator to the desired output voltage. This can be set
 * during any regulator state. IOW, regulator can be disabled or enabled.
 *
 * If the regulator is enabled then the voltage will change to the new value
 * immediately otherwise if the regulator is disabled the regulator will
 * output at the new voltage when enabled.
 *
 * NOTE: If the regulator is shared between several devices then the lowest
 * request voltage that meets the system constraints will be used.
 * Regulator system constraints must be set for this regulator before
 * calling this function otherwise this call will fail.
 */
int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->set_voltage) {
                ret = -EINVAL;
                goto out;
        }

        /* constraints check */
        ret = regulator_check_voltage(rdev, &min_uV, &max_uV);
        if (ret < 0)
                goto out;
        regulator->min_uV = min_uV;
        regulator->max_uV = max_uV;
        ret = rdev->desc->ops->set_voltage(rdev, min_uV, max_uV);

out:
        _notifier_call_chain(rdev, REGULATOR_EVENT_VOLTAGE_CHANGE, NULL);
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_voltage);

static int _regulator_get_voltage(struct regulator_dev *rdev)
{
        /* sanity check */
        if (rdev->desc->ops->get_voltage)
                return rdev->desc->ops->get_voltage(rdev);
        else
                return -EINVAL;
}

/**
 * regulator_get_voltage - get regulator output voltage
 * @regulator: regulator source
 *
 * This returns the current regulator voltage in uV.
 *
 * NOTE: If the regulator is disabled it will return the voltage value. This
 * function should not be used to determine regulator state.
 */
int regulator_get_voltage(struct regulator *regulator)
{
        int ret;

        mutex_lock(&regulator->rdev->mutex);

        ret = _regulator_get_voltage(regulator->rdev);

        mutex_unlock(&regulator->rdev->mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_get_voltage);

/**
 * regulator_set_current_limit - set regulator output current limit
 * @regulator: regulator source
 * @min_uA: Minimuum supported current in uA
 * @max_uA: Maximum supported current in uA
 *
 * Sets current sink to the desired output current. This can be set during
 * any regulator state. IOW, regulator can be disabled or enabled.
 *
 * If the regulator is enabled then the current will change to the new value
 * immediately otherwise if the regulator is disabled the regulator will
 * output at the new current when enabled.
 *
 * NOTE: Regulator system constraints must be set for this regulator before
 * calling this function otherwise this call will fail.
 */
int regulator_set_current_limit(struct regulator *regulator,
                               int min_uA, int max_uA)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->set_current_limit) {
                ret = -EINVAL;
                goto out;
        }

        /* constraints check */
        ret = regulator_check_current_limit(rdev, &min_uA, &max_uA);
        if (ret < 0)
                goto out;

        ret = rdev->desc->ops->set_current_limit(rdev, min_uA, max_uA);
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_current_limit);

static int _regulator_get_current_limit(struct regulator_dev *rdev)
{
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->get_current_limit) {
                ret = -EINVAL;
                goto out;
        }

        ret = rdev->desc->ops->get_current_limit(rdev);
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}

/**
 * regulator_get_current_limit - get regulator output current
 * @regulator: regulator source
 *
 * This returns the current supplied by the specified current sink in uA.
 *
 * NOTE: If the regulator is disabled it will return the current value. This
 * function should not be used to determine regulator state.
 */
int regulator_get_current_limit(struct regulator *regulator)
{
        return _regulator_get_current_limit(regulator->rdev);
}
EXPORT_SYMBOL_GPL(regulator_get_current_limit);

/**
 * regulator_set_mode - set regulator operating mode
 * @regulator: regulator source
 * @mode: operating mode - one of the REGULATOR_MODE constants
 *
 * Set regulator operating mode to increase regulator efficiency or improve
 * regulation performance.
 *
 * NOTE: Regulator system constraints must be set for this regulator before
 * calling this function otherwise this call will fail.
 */
int regulator_set_mode(struct regulator *regulator, unsigned int mode)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->set_mode) {
                ret = -EINVAL;
                goto out;
        }

        /* constraints check */
        ret = regulator_check_mode(rdev, mode);
        if (ret < 0)
                goto out;

        ret = rdev->desc->ops->set_mode(rdev, mode);
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_mode);

static unsigned int _regulator_get_mode(struct regulator_dev *rdev)
{
        int ret;

        mutex_lock(&rdev->mutex);

        /* sanity check */
        if (!rdev->desc->ops->get_mode) {
                ret = -EINVAL;
                goto out;
        }

        ret = rdev->desc->ops->get_mode(rdev);
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}

/**
 * regulator_get_mode - get regulator operating mode
 * @regulator: regulator source
 *
 * Get the current regulator operating mode.
 */
unsigned int regulator_get_mode(struct regulator *regulator)
{
        return _regulator_get_mode(regulator->rdev);
}
EXPORT_SYMBOL_GPL(regulator_get_mode);

/**
 * regulator_set_optimum_mode - set regulator optimum operating mode
 * @regulator: regulator source
 * @uA_load: load current
 *
 * Notifies the regulator core of a new device load. This is then used by
 * DRMS (if enabled by constraints) to set the most efficient regulator
 * operating mode for the new regulator loading.
 *
 * Consumer devices notify their supply regulator of the maximum power
 * they will require (can be taken from device datasheet in the power
 * consumption tables) when they change operational status and hence power
 * state. Examples of operational state changes that can affect power
 * consumption are :-
 *
 *    o Device is opened / closed.
 *    o Device I/O is about to begin or has just finished.
 *    o Device is idling in between work.
 *
 * This information is also exported via sysfs to userspace.
 *
 * DRMS will sum the total requested load on the regulator and change
 * to the most efficient operating mode if platform constraints allow.
 *
 * Returns the new regulator mode or error.
 */
int regulator_set_optimum_mode(struct regulator *regulator, int uA_load)
{
        struct regulator_dev *rdev = regulator->rdev;
        struct regulator *consumer;
        int ret, output_uV, input_uV, total_uA_load = 0;
        unsigned int mode;

        mutex_lock(&rdev->mutex);

        regulator->uA_load = uA_load;
        ret = regulator_check_drms(rdev);
        if (ret < 0)
                goto out;
        ret = -EINVAL;

        /* sanity check */
        if (!rdev->desc->ops->get_optimum_mode)
                goto out;

        /* get output voltage */
        output_uV = rdev->desc->ops->get_voltage(rdev);
        if (output_uV <= 0) {
                printk(KERN_ERR "%s: invalid output voltage found for %s\n",
                        __func__, rdev->desc->name);
                goto out;
        }

        /* get input voltage */
        if (rdev->supply && rdev->supply->desc->ops->get_voltage)
                input_uV = rdev->supply->desc->ops->get_voltage(rdev->supply);
        else
                input_uV = rdev->constraints->input_uV;
        if (input_uV <= 0) {
                printk(KERN_ERR "%s: invalid input voltage found for %s\n",
                        __func__, rdev->desc->name);
                goto out;
        }

        /* calc total requested load for this regulator */
        list_for_each_entry(consumer, &rdev->consumer_list, list)
            total_uA_load += consumer->uA_load;

        mode = rdev->desc->ops->get_optimum_mode(rdev,
                                                 input_uV, output_uV,
                                                 total_uA_load);
        ret = regulator_check_mode(rdev, mode);
        if (ret < 0) {
                printk(KERN_ERR "%s: failed to get optimum mode for %s @"
                        " %d uA %d -> %d uV\n", __func__, rdev->desc->name,
                        total_uA_load, input_uV, output_uV);
                goto out;
        }

        ret = rdev->desc->ops->set_mode(rdev, mode);
        if (ret < 0) {
                printk(KERN_ERR "%s: failed to set optimum mode %x for %s\n",
                        __func__, mode, rdev->desc->name);
                goto out;
        }
        ret = mode;
out:
        mutex_unlock(&rdev->mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_optimum_mode);

/**
 * regulator_register_notifier - register regulator event notifier
 * @regulator: regulator source
 * @nb: notifier block
 *
 * Register notifier block to receive regulator events.
 */
int regulator_register_notifier(struct regulator *regulator,
                              struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&regulator->rdev->notifier,
                                                nb);
}
EXPORT_SYMBOL_GPL(regulator_register_notifier);

/**
 * regulator_unregister_notifier - unregister regulator event notifier
 * @regulator: regulator source
 * @nb: notifier block
 *
 * Unregister regulator event notifier block.
 */
int regulator_unregister_notifier(struct regulator *regulator,
                                struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&regulator->rdev->notifier,
                                                  nb);
}
EXPORT_SYMBOL_GPL(regulator_unregister_notifier);

/* notify regulator consumers and downstream regulator consumers.
 * Note mutex must be held by caller.
 */
static void _notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data)
{
        struct regulator_dev *_rdev;

        /* call rdev chain first */
        blocking_notifier_call_chain(&rdev->notifier, event, NULL);

        /* now notify regulator we supply */
        list_for_each_entry(_rdev, &rdev->supply_list, slist) {
          mutex_lock(&_rdev->mutex);
          _notifier_call_chain(_rdev, event, data);
          mutex_unlock(&_rdev->mutex);
        }
}

/**
 * regulator_bulk_get - get multiple regulator consumers
 *
 * @dev:           Device to supply
 * @num_consumers: Number of consumers to register
 * @consumers:     Configuration of consumers; clients are stored here.
 *
 * @return 0 on success, an errno on failure.
 *
 * This helper function allows drivers to get several regulator
 * consumers in one operation.  If any of the regulators cannot be
 * acquired then any regulators that were allocated will be freed
 * before returning to the caller.
 */
int regulator_bulk_get(struct device *dev, int num_consumers,
                       struct regulator_bulk_data *consumers)
{
        int i;
        int ret;

        for (i = 0; i < num_consumers; i++)
                consumers[i].consumer = NULL;

        for (i = 0; i < num_consumers; i++) {
                consumers[i].consumer = regulator_get(dev,
                                                      consumers[i].supply);
                if (IS_ERR(consumers[i].consumer)) {
                        dev_err(dev, "Failed to get supply '%s'\n",
                                consumers[i].supply);
                        ret = PTR_ERR(consumers[i].consumer);
                        consumers[i].consumer = NULL;
                        goto err;
                }
        }

        return 0;

err:
        for (i = 0; i < num_consumers && consumers[i].consumer; i++)
                regulator_put(consumers[i].consumer);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_bulk_get);

/**
 * regulator_bulk_enable - enable multiple regulator consumers
 *
 * @num_consumers: Number of consumers
 * @consumers:     Consumer data; clients are stored here.
 * @return         0 on success, an errno on failure
 *
 * This convenience API allows consumers to enable multiple regulator
 * clients in a single API call.  If any consumers cannot be enabled
 * then any others that were enabled will be disabled again prior to
 * return.
 */
int regulator_bulk_enable(int num_consumers,
                          struct regulator_bulk_data *consumers)
{
        int i;
        int ret;

        for (i = 0; i < num_consumers; i++) {
                ret = regulator_enable(consumers[i].consumer);
                if (ret != 0)
                        goto err;
        }

        return 0;

err:
        printk(KERN_ERR "Failed to enable %s\n", consumers[i].supply);
        for (i = 0; i < num_consumers; i++)
                regulator_disable(consumers[i].consumer);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_bulk_enable);

/**
 * regulator_bulk_disable - disable multiple regulator consumers
 *
 * @num_consumers: Number of consumers
 * @consumers:     Consumer data; clients are stored here.
 * @return         0 on success, an errno on failure
 *
 * This convenience API allows consumers to disable multiple regulator
 * clients in a single API call.  If any consumers cannot be enabled
 * then any others that were disabled will be disabled again prior to
 * return.
 */
int regulator_bulk_disable(int num_consumers,
                           struct regulator_bulk_data *consumers)
{
        int i;
        int ret;

        for (i = 0; i < num_consumers; i++) {
                ret = regulator_disable(consumers[i].consumer);
                if (ret != 0)
                        goto err;
        }

        return 0;

err:
        printk(KERN_ERR "Failed to disable %s\n", consumers[i].supply);
        for (i = 0; i < num_consumers; i++)
                regulator_enable(consumers[i].consumer);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_bulk_disable);

/**
 * regulator_bulk_free - free multiple regulator consumers
 *
 * @num_consumers: Number of consumers
 * @consumers:     Consumer data; clients are stored here.
 *
 * This convenience API allows consumers to free multiple regulator
 * clients in a single API call.
 */
void regulator_bulk_free(int num_consumers,
                         struct regulator_bulk_data *consumers)
{
        int i;

        for (i = 0; i < num_consumers; i++) {
                regulator_put(consumers[i].consumer);
                consumers[i].consumer = NULL;
        }
}
EXPORT_SYMBOL_GPL(regulator_bulk_free);

/**
 * regulator_notifier_call_chain - call regulator event notifier
 * @rdev: regulator source
 * @event: notifier block
 * @data: callback-specific data.
 *
 * Called by regulator drivers to notify clients a regulator event has
 * occurred. We also notify regulator clients downstream.
 * Note lock must be held by caller.
 */
int regulator_notifier_call_chain(struct regulator_dev *rdev,
                                  unsigned long event, void *data)
{
        _notifier_call_chain(rdev, event, data);
        return NOTIFY_DONE;

}
EXPORT_SYMBOL_GPL(regulator_notifier_call_chain);

/*
 * To avoid cluttering sysfs (and memory) with useless state, only
 * create attributes that can be meaningfully displayed.
 */
static int add_regulator_attributes(struct regulator_dev *rdev)
{
        struct device           *dev = &rdev->dev;
        struct regulator_ops    *ops = rdev->desc->ops;
        int                     status = 0;

        /* some attributes need specific methods to be displayed */
        if (ops->get_voltage) {
                status = device_create_file(dev, &dev_attr_microvolts);
                if (status < 0)
                        return status;
        }
        if (ops->get_current_limit) {
                status = device_create_file(dev, &dev_attr_microamps);
                if (status < 0)
                        return status;
        }
        if (ops->get_mode) {
                status = device_create_file(dev, &dev_attr_opmode);
                if (status < 0)
                        return status;
        }
        if (ops->is_enabled) {
                status = device_create_file(dev, &dev_attr_state);
                if (status < 0)
                        return status;
        }
        if (ops->get_status) {
                status = device_create_file(dev, &dev_attr_status);
                if (status < 0)
                        return status;
        }

        /* some attributes are type-specific */
        if (rdev->desc->type == REGULATOR_CURRENT) {
                status = device_create_file(dev, &dev_attr_requested_microamps);
                if (status < 0)
                        return status;
        }

        /* all the other attributes exist to support constraints;
         * don't show them if there are no constraints, or if the
         * relevant supporting methods are missing.
         */
        if (!rdev->constraints)
                return status;

        /* constraints need specific supporting methods */
        if (ops->set_voltage) {
                status = device_create_file(dev, &dev_attr_min_microvolts);
                if (status < 0)
                        return status;
                status = device_create_file(dev, &dev_attr_max_microvolts);
                if (status < 0)
                        return status;
        }
        if (ops->set_current_limit) {
                status = device_create_file(dev, &dev_attr_min_microamps);
                if (status < 0)
                        return status;
                status = device_create_file(dev, &dev_attr_max_microamps);
                if (status < 0)
                        return status;
        }

        /* suspend mode constraints need multiple supporting methods */
        if (!(ops->set_suspend_enable && ops->set_suspend_disable))
                return status;

        status = device_create_file(dev, &dev_attr_suspend_standby_state);
        if (status < 0)
                return status;
        status = device_create_file(dev, &dev_attr_suspend_mem_state);
        if (status < 0)
                return status;
        status = device_create_file(dev, &dev_attr_suspend_disk_state);
        if (status < 0)
                return status;

        if (ops->set_suspend_voltage) {
                status = device_create_file(dev,
                                &dev_attr_suspend_standby_microvolts);
                if (status < 0)
                        return status;
                status = device_create_file(dev,
                                &dev_attr_suspend_mem_microvolts);
                if (status < 0)
                        return status;
                status = device_create_file(dev,
                                &dev_attr_suspend_disk_microvolts);
                if (status < 0)
                        return status;
        }

        if (ops->set_suspend_mode) {
                status = device_create_file(dev,
                                &dev_attr_suspend_standby_mode);
                if (status < 0)
                        return status;
                status = device_create_file(dev,
                                &dev_attr_suspend_mem_mode);
                if (status < 0)
                        return status;
                status = device_create_file(dev,
                                &dev_attr_suspend_disk_mode);
                if (status < 0)
                        return status;
        }

        return status;
}

/**
 * regulator_register - register regulator
 * @regulator_desc: regulator to register
 * @dev: struct device for the regulator
 * @init_data: platform provided init data, passed through by driver
 * @driver_data: private regulator data
 *
 * Called by regulator drivers to register a regulator.
 * Returns 0 on success.
 */
struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
        struct device *dev, struct regulator_init_data *init_data,
        void *driver_data)
{
        static atomic_t regulator_no = ATOMIC_INIT(0);
        struct regulator_dev *rdev;
        int ret, i;

        if (regulator_desc == NULL)
                return ERR_PTR(-EINVAL);

        if (regulator_desc->name == NULL || regulator_desc->ops == NULL)
                return ERR_PTR(-EINVAL);

        if (regulator_desc->type != REGULATOR_VOLTAGE &&
            regulator_desc->type != REGULATOR_CURRENT)
                return ERR_PTR(-EINVAL);

        if (!init_data)
                return ERR_PTR(-EINVAL);

        rdev = kzalloc(sizeof(struct regulator_dev), GFP_KERNEL);
        if (rdev == NULL)
                return ERR_PTR(-ENOMEM);

        mutex_lock(&regulator_list_mutex);

        mutex_init(&rdev->mutex);
        rdev->reg_data = driver_data;
        rdev->owner = regulator_desc->owner;
        rdev->desc = regulator_desc;
        INIT_LIST_HEAD(&rdev->consumer_list);
        INIT_LIST_HEAD(&rdev->supply_list);
        INIT_LIST_HEAD(&rdev->list);
        INIT_LIST_HEAD(&rdev->slist);
        BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier);

        /* preform any regulator specific init */
        if (init_data->regulator_init) {
                ret = init_data->regulator_init(rdev->reg_data);
                if (ret < 0)
                        goto clean;
        }

        /* register with sysfs */
        rdev->dev.class = &regulator_class;
        rdev->dev.parent = dev;
        dev_set_name(&rdev->dev, "regulator.%d",
                     atomic_inc_return(&regulator_no) - 1);
        ret = device_register(&rdev->dev);
        if (ret != 0)
                goto clean;

        dev_set_drvdata(&rdev->dev, rdev);

        /* set regulator constraints */
        ret = set_machine_constraints(rdev, &init_data->constraints);
        if (ret < 0)
                goto scrub;

        /* add attributes supported by this regulator */
        ret = add_regulator_attributes(rdev);
        if (ret < 0)
                goto scrub;

        /* set supply regulator if it exists */
        if (init_data->supply_regulator_dev) {
                ret = set_supply(rdev,
                        dev_get_drvdata(init_data->supply_regulator_dev));
                if (ret < 0)
                        goto scrub;
        }

        /* add consumers devices */
        for (i = 0; i < init_data->num_consumer_supplies; i++) {
                ret = set_consumer_device_supply(rdev,
                        init_data->consumer_supplies[i].dev,
                        init_data->consumer_supplies[i].supply);
                if (ret < 0) {
                        for (--i; i >= 0; i--)
                                unset_consumer_device_supply(rdev,
                                        init_data->consumer_supplies[i].dev);
                        goto scrub;
                }
        }

        list_add(&rdev->list, &regulator_list);
out:
        mutex_unlock(&regulator_list_mutex);
        return rdev;

scrub:
        device_unregister(&rdev->dev);
        /* device core frees rdev */
        rdev = ERR_PTR(ret);
        goto out;

clean:
        kfree(rdev);
        rdev = ERR_PTR(ret);
        goto out;
}
EXPORT_SYMBOL_GPL(regulator_register);

/**
 * regulator_unregister - unregister regulator
 * @rdev: regulator to unregister
 *
 * Called by regulator drivers to unregister a regulator.
 */
void regulator_unregister(struct regulator_dev *rdev)
{
        if (rdev == NULL)
                return;

        mutex_lock(&regulator_list_mutex);
        unset_regulator_supplies(rdev);
        list_del(&rdev->list);
        if (rdev->supply)
                sysfs_remove_link(&rdev->dev.kobj, "supply");
        device_unregister(&rdev->dev);
        mutex_unlock(&regulator_list_mutex);
}
EXPORT_SYMBOL_GPL(regulator_unregister);

/**
 * regulator_suspend_prepare - prepare regulators for system wide suspend
 * @state: system suspend state
 *
 * Configure each regulator with it's suspend operating parameters for state.
 * This will usually be called by machine suspend code prior to supending.
 */
int regulator_suspend_prepare(suspend_state_t state)
{
        struct regulator_dev *rdev;
        int ret = 0;

        /* ON is handled by regulator active state */
        if (state == PM_SUSPEND_ON)
                return -EINVAL;

        mutex_lock(&regulator_list_mutex);
        list_for_each_entry(rdev, &regulator_list, list) {

                mutex_lock(&rdev->mutex);
                ret = suspend_prepare(rdev, state);
                mutex_unlock(&rdev->mutex);

                if (ret < 0) {
                        printk(KERN_ERR "%s: failed to prepare %s\n",
                                __func__, rdev->desc->name);
                        goto out;
                }
        }
out:
        mutex_unlock(&regulator_list_mutex);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_suspend_prepare);

/**
 * regulator_has_full_constraints - the system has fully specified constraints
 *
 * Calling this function will cause the regulator API to disable all
 * regulators which have a zero use count and don't have an always_on
 * constraint in a late_initcall.
 *
 * The intention is that this will become the default behaviour in a
 * future kernel release so users are encouraged to use this facility
 * now.
 */
void regulator_has_full_constraints(void)
{
        has_full_constraints = 1;
}
EXPORT_SYMBOL_GPL(regulator_has_full_constraints);

/**
 * rdev_get_drvdata - get rdev regulator driver data
 * @rdev: regulator
 *
 * Get rdev regulator driver private data. This call can be used in the
 * regulator driver context.
 */
void *rdev_get_drvdata(struct regulator_dev *rdev)
{
        return rdev->reg_data;
}
EXPORT_SYMBOL_GPL(rdev_get_drvdata);

/**
 * regulator_get_drvdata - get regulator driver data
 * @regulator: regulator
 *
 * Get regulator driver private data. This call can be used in the consumer
 * driver context when non API regulator specific functions need to be called.
 */
void *regulator_get_drvdata(struct regulator *regulator)
{
        return regulator->rdev->reg_data;
}
EXPORT_SYMBOL_GPL(regulator_get_drvdata);

/**
 * regulator_set_drvdata - set regulator driver data
 * @regulator: regulator
 * @data: data
 */
void regulator_set_drvdata(struct regulator *regulator, void *data)
{
        regulator->rdev->reg_data = data;
}
EXPORT_SYMBOL_GPL(regulator_set_drvdata);

/**
 * regulator_get_id - get regulator ID
 * @rdev: regulator
 */
int rdev_get_id(struct regulator_dev *rdev)
{
        return rdev->desc->id;
}
EXPORT_SYMBOL_GPL(rdev_get_id);

struct device *rdev_get_dev(struct regulator_dev *rdev)
{
        return &rdev->dev;
}
EXPORT_SYMBOL_GPL(rdev_get_dev);

void *regulator_get_init_drvdata(struct regulator_init_data *reg_init_data)
{
        return reg_init_data->driver_data;
}
EXPORT_SYMBOL_GPL(regulator_get_init_drvdata);

static int __init regulator_init(void)
{
        printk(KERN_INFO "regulator: core version %s\n", REGULATOR_VERSION);
        return class_register(&regulator_class);
}

/* init early to allow our consumers to complete system booting */
core_initcall(regulator_init);

static int __init regulator_init_complete(void)
{
        struct regulator_dev *rdev;
        struct regulator_ops *ops;
        struct regulation_constraints *c;
        int enabled, ret;
        const char *name;

        mutex_lock(&regulator_list_mutex);

        /* If we have a full configuration then disable any regulators
         * which are not in use or always_on.  This will become the
         * default behaviour in the future.
         */
        list_for_each_entry(rdev, &regulator_list, list) {
                ops = rdev->desc->ops;
                c = rdev->constraints;

                if (c->name)
                        name = c->name;
                else if (rdev->desc->name)
                        name = rdev->desc->name;
                else
                        name = "regulator";

                if (!ops->disable || c->always_on)
                        continue;

                mutex_lock(&rdev->mutex);

                if (rdev->use_count)
                        goto unlock;

                /* If we can't read the status assume it's on. */
                if (ops->is_enabled)
                        enabled = ops->is_enabled(rdev);
                else
                        enabled = 1;

                if (!enabled)
                        goto unlock;

                if (has_full_constraints) {
                        /* We log since this may kill the system if it
                         * goes wrong. */
                        printk(KERN_INFO "%s: disabling %s\n",
                               __func__, name);
                        ret = ops->disable(rdev);
                        if (ret != 0) {
                                printk(KERN_ERR
                                       "%s: couldn't disable %s: %d\n",
                                       __func__, name, ret);
                        }
                } else {
                        /* The intention is that in future we will
                         * assume that full constraints are provided
                         * so warn even if we aren't going to do
                         * anything here.
                         */
                        printk(KERN_WARNING
                               "%s: incomplete constraints, leaving %s on\n",
                               __func__, name);
                }

unlock:
                mutex_unlock(&rdev->mutex);
        }

        mutex_unlock(&regulator_list_mutex);

        return 0;
}
late_initcall(regulator_init_complete);