/*
 * 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/debugfs.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/async.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/suspend.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/of_regulator.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/module.h>

#define CREATE_TRACE_POINTS
#include <trace/events/regulator.h>

#include "dummy.h"

#define rdev_crit(rdev, fmt, ...)                                       \
        pr_crit("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_err(rdev, fmt, ...)                                        \
        pr_err("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_warn(rdev, fmt, ...)                                       \
        pr_warn("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_info(rdev, fmt, ...)                                       \
        pr_info("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)
#define rdev_dbg(rdev, fmt, ...)                                        \
        pr_debug("%s: " fmt, rdev_get_name(rdev), ##__VA_ARGS__)

static DEFINE_MUTEX(regulator_list_mutex);
static LIST_HEAD(regulator_list);
static LIST_HEAD(regulator_map_list);
static LIST_HEAD(regulator_ena_gpio_list);
static bool has_full_constraints;
static bool board_wants_dummy_regulator;

static struct dentry *debugfs_root;

/*
 * struct regulator_map
 *
 * Used to provide symbolic supply names to devices.
 */
struct regulator_map {
        struct list_head list;
        const char *dev_name;   /* The dev_name() for the consumer */
        const char *supply;
        struct regulator_dev *regulator;
};

/*
 * struct regulator_enable_gpio
 *
 * Management for shared enable GPIO pin
 */
struct regulator_enable_gpio {
        struct list_head list;
        int gpio;
        u32 enable_count;       /* a number of enabled shared GPIO */
        u32 request_count;      /* a number of requested shared GPIO */
        unsigned int ena_gpio_invert:1;
};

/*
 * struct regulator
 *
 * One for each consumer device.
 */
struct regulator {
        struct device *dev;
        struct list_head list;
        unsigned int always_on:1;
        unsigned int bypass:1;
        int uA_load;
        int min_uV;
        int max_uV;
        char *supply_name;
        struct device_attribute dev_attr;
        struct regulator_dev *rdev;
        struct dentry *debugfs;
};

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);
static int _regulator_do_set_voltage(struct regulator_dev *rdev,
                                     int min_uV, int max_uV);
static struct regulator *create_regulator(struct regulator_dev *rdev,
                                          struct device *dev,
                                          const char *supply_name);

static const char *rdev_get_name(struct regulator_dev *rdev)
{
        if (rdev->constraints && rdev->constraints->name)
                return rdev->constraints->name;
        else if (rdev->desc->name)
                return rdev->desc->name;
        else
                return "";
}

/**
 * of_get_regulator - get a regulator device node based on supply name
 * @dev: Device pointer for the consumer (of regulator) device
 * @supply: regulator supply name
 *
 * Extract the regulator device node corresponding to the supply name.
 * returns the device node corresponding to the regulator if found, else
 * returns NULL.
 */
static struct device_node *of_get_regulator(struct device *dev, const char *supply)
{
        struct device_node *regnode = NULL;
        char prop_name[32]; /* 32 is max size of property name */

        dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);

        snprintf(prop_name, 32, "%s-supply", supply);
        regnode = of_parse_phandle(dev->of_node, prop_name, 0);

        if (!regnode) {
                dev_dbg(dev, "Looking up %s property in node %s failed",
                                prop_name, dev->of_node->full_name);
                return NULL;
        }
        return regnode;
}

static int _regulator_can_change_status(struct regulator_dev *rdev)
{
        if (!rdev->constraints)
                return 0;

        if (rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_STATUS)
                return 1;
        else
                return 0;
}

/* 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) {
                rdev_err(rdev, "no constraints\n");
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_VOLTAGE)) {
                rdev_err(rdev, "operation not allowed\n");
                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) {
                rdev_err(rdev, "unsupportable voltage range: %d-%duV\n",
                         *min_uV, *max_uV);
                return -EINVAL;
        }

        return 0;
}

/* Make sure we select a voltage that suits the needs of all
 * regulator consumers
 */
static int regulator_check_consumers(struct regulator_dev *rdev,
                                     int *min_uV, int *max_uV)
{
        struct regulator *regulator;

        list_for_each_entry(regulator, &rdev->consumer_list, list) {
                /*
                 * Assume consumers that didn't say anything are OK
                 * with anything in the constraint range.
                 */
                if (!regulator->min_uV && !regulator->max_uV)
                        continue;

                if (*max_uV > regulator->max_uV)
                        *max_uV = regulator->max_uV;
                if (*min_uV < regulator->min_uV)
                        *min_uV = regulator->min_uV;
        }

        if (*min_uV > *max_uV) {
                rdev_err(rdev, "Restricting voltage, %u-%uuV\n",
                        *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) {
                rdev_err(rdev, "no constraints\n");
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_CURRENT)) {
                rdev_err(rdev, "operation not allowed\n");
                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) {
                rdev_err(rdev, "unsupportable current range: %d-%duA\n",
                         *min_uA, *max_uA);
                return -EINVAL;
        }

        return 0;
}

/* operating mode constraint check */
static int regulator_mode_constrain(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:
                rdev_err(rdev, "invalid mode %x specified\n", *mode);
                return -EINVAL;
        }

        if (!rdev->constraints) {
                rdev_err(rdev, "no constraints\n");
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_MODE)) {
                rdev_err(rdev, "operation not allowed\n");
                return -EPERM;
        }

        /* The modes are bitmasks, the most power hungry modes having
         * the lowest values. If the requested mode isn't supported
         * try higher modes. */
        while (*mode) {
                if (rdev->constraints->valid_modes_mask & *mode)
                        return 0;
                *mode /= 2;
        }

        return -EINVAL;
}

/* dynamic regulator mode switching constraint check */
static int regulator_check_drms(struct regulator_dev *rdev)
{
        if (!rdev->constraints) {
                rdev_err(rdev, "no constraints\n");
                return -ENODEV;
        }
        if (!(rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS)) {
                rdev_err(rdev, "operation not allowed\n");
                return -EPERM;
        }
        return 0;
}

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);

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

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);
        ssize_t ret;

        mutex_lock(&rdev->mutex);
        ret = regulator_print_state(buf, _regulator_is_enabled(rdev));
        mutex_unlock(&rdev->mutex);

        return ret;
}
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;
        case REGULATOR_STATUS_BYPASS:
                label = "bypass";
                break;
        case REGULATOR_STATUS_UNDEFINED:
                label = "undefined";
                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);

static ssize_t regulator_bypass_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct regulator_dev *rdev = dev_get_drvdata(dev);
        const char *report;
        bool bypass;
        int ret;

        ret = rdev->desc->ops->get_bypass(rdev, &bypass);

        if (ret != 0)
                report = "unknown";
        else if (bypass)
                report = "enabled";
        else
                report = "disabled";

        return sprintf(buf, "%s\n", report);
}
static DEVICE_ATTR(bypass, 0444,
                   regulator_bypass_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->get_voltage_sel) ||
            !rdev->desc->ops->set_mode)
                return;

        /* get output voltage */
        output_uV = _regulator_get_voltage(rdev);
        if (output_uV <= 0)
                return;

        /* get input voltage */
        input_uV = 0;
        if (rdev->supply)
                input_uV = regulator_get_voltage(rdev->supply);
        if (input_uV <= 0)
                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_mode_constrain(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;

        /* If we have no suspend mode configration don't set anything;
         * only warn if the driver implements set_suspend_voltage or
         * set_suspend_mode callback.
         */
        if (!rstate->enabled && !rstate->disabled) {
                if (rdev->desc->ops->set_suspend_voltage ||
                    rdev->desc->ops->set_suspend_mode)
                        rdev_warn(rdev, "No configuration\n");
                return 0;
        }

        if (rstate->enabled && rstate->disabled) {
                rdev_err(rdev, "invalid configuration\n");
                return -EINVAL;
        }

        if (rstate->enabled && rdev->desc->ops->set_suspend_enable)
                ret = rdev->desc->ops->set_suspend_enable(rdev);
        else if (rstate->disabled && rdev->desc->ops->set_suspend_disable)
                ret = rdev->desc->ops->set_suspend_disable(rdev);
        else /* OK if set_suspend_enable or set_suspend_disable is NULL */
                ret = 0;

        if (ret < 0) {
                rdev_err(rdev, "failed to enabled/disable\n");
                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) {
                        rdev_err(rdev, "failed to set voltage\n");
                        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) {
                        rdev_err(rdev, "failed to set mode\n");
                        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[160] = "";
        int count = 0;
        int ret;

        if (constraints->min_uV && constraints->max_uV) {
                if (constraints->min_uV == constraints->max_uV)
                        count += sprintf(buf + count, "%d mV ",
                                         constraints->min_uV / 1000);
                else
                        count += sprintf(buf + count, "%d <--> %d mV ",
                                         constraints->min_uV / 1000,
                                         constraints->max_uV / 1000);
        }

        if (!constraints->min_uV ||
            constraints->min_uV != constraints->max_uV) {
                ret = _regulator_get_voltage(rdev);
                if (ret > 0)
                        count += sprintf(buf + count, "at %d mV ", ret / 1000);
        }

        if (constraints->uV_offset)
                count += sprintf(buf, "%dmV offset ",
                                 constraints->uV_offset / 1000);

        if (constraints->min_uA && constraints->max_uA) {
                if (constraints->min_uA == constraints->max_uA)
                        count += sprintf(buf + count, "%d mA ",
                                         constraints->min_uA / 1000);
                else
                        count += sprintf(buf + count, "%d <--> %d mA ",
                                         constraints->min_uA / 1000,
                                         constraints->max_uA / 1000);
        }

        if (!constraints->min_uA ||
            constraints->min_uA != constraints->max_uA) {
                ret = _regulator_get_current_limit(rdev);
                if (ret > 0)
                        count += sprintf(buf + count, "at %d mA ", ret / 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");

        if (!count)
                sprintf(buf, "no parameters");

        rdev_info(rdev, "%s\n", buf);

        if ((constraints->min_uV != constraints->max_uV) &&
            !(constraints->valid_ops_mask & REGULATOR_CHANGE_VOLTAGE))
                rdev_warn(rdev,
                          "Voltage range but no REGULATOR_CHANGE_VOLTAGE\n");
}

static int machine_constraints_voltage(struct regulator_dev *rdev,
        struct regulation_constraints *constraints)
{
        struct regulator_ops *ops = rdev->desc->ops;
        int ret;

        /* do we need to apply the constraint voltage */
        if (rdev->constraints->apply_uV &&
            rdev->constraints->min_uV == rdev->constraints->max_uV) {
                ret = _regulator_do_set_voltage(rdev,
                                                rdev->constraints->min_uV,
                                                rdev->constraints->max_uV);
                if (ret < 0) {
                        rdev_err(rdev, "failed to apply %duV constraint\n",
                                 rdev->constraints->min_uV);
                        return ret;
                }
        }

        /* 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))
                        return 0;

                /* else require explicit machine-level constraints */
                if (cmin <= 0 || cmax <= 0 || cmax < cmin) {
                        rdev_err(rdev, "invalid voltage constraints\n");
                        return -EINVAL;
                }

                /* 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) {
                        rdev_err(rdev,
                                 "unsupportable voltage constraints %u-%uuV\n",
                                 min_uV, max_uV);
                        return -EINVAL;
                }

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

        return 0;
}

static int _regulator_do_enable(struct regulator_dev *rdev);

/**
 * 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,
        const struct regulation_constraints *constraints)
{
        int ret = 0;
        struct regulator_ops *ops = rdev->desc->ops;

        if (constraints)
                rdev->constraints = kmemdup(constraints, sizeof(*constraints),
                                            GFP_KERNEL);
        else
                rdev->constraints = kzalloc(sizeof(*constraints),
                                            GFP_KERNEL);
        if (!rdev->constraints)
                return -ENOMEM;

        ret = machine_constraints_voltage(rdev, rdev->constraints);
        if (ret != 0)
                goto out;

        /* do we need to setup our suspend state */
        if (rdev->constraints->initial_state) {
                ret = suspend_prepare(rdev, rdev->constraints->initial_state);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set suspend state\n");
                        goto out;
                }
        }

        if (rdev->constraints->initial_mode) {
                if (!ops->set_mode) {
                        rdev_err(rdev, "no set_mode operation\n");
                        ret = -EINVAL;
                        goto out;
                }

                ret = ops->set_mode(rdev, rdev->constraints->initial_mode);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set initial mode: %d\n", 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 (rdev->constraints->always_on || rdev->constraints->boot_on) {
                ret = _regulator_do_enable(rdev);
                if (ret < 0 && ret != -EINVAL) {
                        rdev_err(rdev, "failed to enable\n");
                        goto out;
                }
        }

        if (rdev->constraints->ramp_delay && ops->set_ramp_delay) {
                ret = ops->set_ramp_delay(rdev, rdev->constraints->ramp_delay);
                if (ret < 0) {
                        rdev_err(rdev, "failed to set ramp_delay\n");
                        goto out;
                }
        }

        print_constraints(rdev);
        return 0;
out:
        kfree(rdev->constraints);
        rdev->constraints = NULL;

        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;

        rdev_info(rdev, "supplied by %s\n", rdev_get_name(supply_rdev));

        rdev->supply = create_regulator(supply_rdev, &rdev->dev, "SUPPLY");
        if (rdev->supply == NULL) {
                err = -ENOMEM;
                return err;
        }
        supply_rdev->open_count++;

        return 0;
}

/**
 * set_consumer_device_supply - Bind a regulator to a symbolic supply
 * @rdev:         regulator source
 * @consumer_dev_name: dev_name() string for device 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,
                                      const char *consumer_dev_name,
                                      const char *supply)
{
        struct regulator_map *node;
        int has_dev;

        if (supply == NULL)
                return -EINVAL;

        if (consumer_dev_name != NULL)
                has_dev = 1;
        else
                has_dev = 0;

        list_for_each_entry(node, &regulator_map_list, list) {
                if (node->dev_name && consumer_dev_name) {
                        if (strcmp(node->dev_name, consumer_dev_name) != 0)
                                continue;
                } else if (node->dev_name || consumer_dev_name) {
                        continue;
                }

                if (strcmp(node->supply, supply) != 0)
                        continue;

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

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

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

        if (has_dev) {
                node->dev_name = kstrdup(consumer_dev_name, GFP_KERNEL);
                if (node->dev_name == NULL) {
                        kfree(node);
                        return -ENOMEM;
                }
        }

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

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->dev_name);
                        kfree(node);
                }
        }
}

#define REG_STR_SIZE    64

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) {
                regulator->dev = dev;

                /* 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 overflow_err;

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

                err = sysfs_create_link(&rdev->dev.kobj, &dev->kobj,
                                        buf);
                if (err) {
                        rdev_warn(rdev, "could not add device link %s err %d\n",
                                  dev->kobj.name, err);
                        /* non-fatal */
                }
        } else {
                regulator->supply_name = kstrdup(supply_name, GFP_KERNEL);
                if (regulator->supply_name == NULL)
                        goto overflow_err;
        }

        regulator->debugfs = debugfs_create_dir(regulator->supply_name,
                                                rdev->debugfs);
        if (!regulator->debugfs) {
                rdev_warn(rdev, "Failed to create debugfs directory\n");
        } else {
                debugfs_create_u32("uA_load", 0444, regulator->debugfs,
                                   &regulator->uA_load);
                debugfs_create_u32("min_uV", 0444, regulator->debugfs,
                                   &regulator->min_uV);
                debugfs_create_u32("max_uV", 0444, regulator->debugfs,
                                   &regulator->max_uV);
        }

        /*
         * Check now if the regulator is an always on regulator - if
         * it is then we don't need to do nearly so much work for
         * enable/disable calls.
         */
        if (!_regulator_can_change_status(rdev) &&
            _regulator_is_enabled(rdev))
                regulator->always_on = true;

        mutex_unlock(&rdev->mutex);
        return regulator;
overflow_err:
        list_del(&regulator->list);
        kfree(regulator);
        mutex_unlock(&rdev->mutex);
        return NULL;
}

static int _regulator_get_enable_time(struct regulator_dev *rdev)
{
        if (!rdev->desc->ops->enable_time)
                return rdev->desc->enable_time;
        return rdev->desc->ops->enable_time(rdev);
}

static struct regulator_dev *regulator_dev_lookup(struct device *dev,
                                                  const char *supply,
                                                  int *ret)
{
        struct regulator_dev *r;
        struct device_node *node;
        struct regulator_map *map;
        const char *devname = NULL;

        /* first do a dt based lookup */
        if (dev && dev->of_node) {
                node = of_get_regulator(dev, supply);
                if (node) {
                        list_for_each_entry(r, &regulator_list, list)
                                if (r->dev.parent &&
                                        node == r->dev.of_node)
                                        return r;
                } else {
                        /*
                         * If we couldn't even get the node then it's
                         * not just that the device didn't register
                         * yet, there's no node and we'll never
                         * succeed.
                         */
                        *ret = -ENODEV;
                }
        }

        /* if not found, try doing it non-dt way */
        if (dev)
                devname = dev_name(dev);

        list_for_each_entry(r, &regulator_list, list)
                if (strcmp(rdev_get_name(r), supply) == 0)
                        return r;

        list_for_each_entry(map, &regulator_map_list, list) {
                /* If the mapping has a device set up it must match */
                if (map->dev_name &&
                    (!devname || strcmp(map->dev_name, devname)))
                        continue;

                if (strcmp(map->supply, supply) == 0)
                        return map->regulator;
        }


        return NULL;
}

/* Internal regulator request function */
static struct regulator *_regulator_get(struct device *dev, const char *id,
                                        int exclusive)
{
        struct regulator_dev *rdev;
        struct regulator *regulator = ERR_PTR(-EPROBE_DEFER);
        const char *devname = NULL;
        int ret = 0;

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

        if (dev)
                devname = dev_name(dev);

        mutex_lock(&regulator_list_mutex);

        rdev = regulator_dev_lookup(dev, id, &ret);
        if (rdev)
                goto found;

        /*
         * If we have return value from dev_lookup fail, we do not expect to
         * succeed, so, quit with appropriate error value
         */
        if (ret) {
                regulator = ERR_PTR(ret);
                goto out;
        }

        if (board_wants_dummy_regulator) {
                rdev = dummy_regulator_rdev;
                goto found;
        }

#ifdef CONFIG_REGULATOR_DUMMY
        if (!devname)
                devname = "deviceless";

        /* If the board didn't flag that it was fully constrained then
         * substitute in a dummy regulator so consumers can continue.
         */
        if (!has_full_constraints) {
                pr_warn("%s supply %s not found, using dummy regulator\n",
                        devname, id);
                rdev = dummy_regulator_rdev;
                goto found;
        }
#endif

        mutex_unlock(&regulator_list_mutex);
        return regulator;

found:
        if (rdev->exclusive) {
                regulator = ERR_PTR(-EPERM);
                goto out;
        }

        if (exclusive && rdev->open_count) {
                regulator = ERR_PTR(-EBUSY);
                goto out;
        }

        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);
                goto out;
        }

        rdev->open_count++;
        if (exclusive) {
                rdev->exclusive = 1;

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

out:
        mutex_unlock(&regulator_list_mutex);

        return regulator;
}

/**
 * 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)
{
        return _regulator_get(dev, id, 0);
}
EXPORT_SYMBOL_GPL(regulator_get);

static void devm_regulator_release(struct device *dev, void *res)
{
        regulator_put(*(struct regulator **)res);
}

/**
 * devm_regulator_get - Resource managed regulator_get()
 * @dev: device for regulator "consumer"
 * @id: Supply name or regulator ID.
 *
 * Managed regulator_get(). Regulators returned from this function are
 * automatically regulator_put() on driver detach. See regulator_get() for more
 * information.
 */
struct regulator *devm_regulator_get(struct device *dev, const char *id)
{
        struct regulator **ptr, *regulator;

        ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
        if (!ptr)
                return ERR_PTR(-ENOMEM);

        regulator = regulator_get(dev, id);
        if (!IS_ERR(regulator)) {
                *ptr = regulator;
                devres_add(dev, ptr);
        } else {
                devres_free(ptr);
        }

        return regulator;
}
EXPORT_SYMBOL_GPL(devm_regulator_get);

/**
 * regulator_get_exclusive - obtain exclusive access 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.  Other consumers will be
 * unable to obtain this reference is held and the use count for the
 * regulator will be initialised to reflect the current state of the
 * regulator.
 *
 * This is intended for use by consumers which cannot tolerate shared
 * use of the regulator such as those which need to force the
 * regulator off for correct operation of the hardware they are
 * controlling.
 *
 * 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_exclusive(struct device *dev, const char *id)
{
        return _regulator_get(dev, id, 1);
}
EXPORT_SYMBOL_GPL(regulator_get_exclusive);

/* regulator_list_mutex lock held by regulator_put() */
static void _regulator_put(struct regulator *regulator)
{
        struct regulator_dev *rdev;

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

        rdev = regulator->rdev;

        debugfs_remove_recursive(regulator->debugfs);

        /* remove any sysfs entries */
        if (regulator->dev)
                sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
        mutex_lock(&rdev->mutex);
        kfree(regulator->supply_name);
        list_del(&regulator->list);
        kfree(regulator);

        rdev->open_count--;
        rdev->exclusive = 0;
        mutex_unlock(&rdev->mutex);

        module_put(rdev->owner);
}

/**
 * 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)
{
        mutex_lock(&regulator_list_mutex);
        _regulator_put(regulator);
        mutex_unlock(&regulator_list_mutex);
}
EXPORT_SYMBOL_GPL(regulator_put);

static int devm_regulator_match(struct device *dev, void *res, void *data)
{
        struct regulator **r = res;
        if (!r || !*r) {
                WARN_ON(!r || !*r);
                return 0;
        }
        return *r == data;
}

/**
 * devm_regulator_put - Resource managed regulator_put()
 * @regulator: regulator to free
 *
 * Deallocate a regulator allocated with devm_regulator_get(). Normally
 * this function will not need to be called and the resource management
 * code will ensure that the resource is freed.
 */
void devm_regulator_put(struct regulator *regulator)
{
        int rc;

        rc = devres_release(regulator->dev, devm_regulator_release,
                            devm_regulator_match, regulator);
        if (rc != 0)
                WARN_ON(rc);
}
EXPORT_SYMBOL_GPL(devm_regulator_put);

/* Manage enable GPIO list. Same GPIO pin can be shared among regulators */
static int regulator_ena_gpio_request(struct regulator_dev *rdev,
                                const struct regulator_config *config)
{
        struct regulator_enable_gpio *pin;
        int ret;

        list_for_each_entry(pin, &regulator_ena_gpio_list, list) {
                if (pin->gpio == config->ena_gpio) {
                        rdev_dbg(rdev, "GPIO %d is already used\n",
                                config->ena_gpio);
                        goto update_ena_gpio_to_rdev;
                }
        }

        ret = gpio_request_one(config->ena_gpio,
                                GPIOF_DIR_OUT | config->ena_gpio_flags,
                                rdev_get_name(rdev));
        if (ret)
                return ret;

        pin = kzalloc(sizeof(struct regulator_enable_gpio), GFP_KERNEL);
        if (pin == NULL) {
                gpio_free(config->ena_gpio);
                return -ENOMEM;
        }

        pin->gpio = config->ena_gpio;
        pin->ena_gpio_invert = config->ena_gpio_invert;
        list_add(&pin->list, &regulator_ena_gpio_list);

update_ena_gpio_to_rdev:
        pin->request_count++;
        rdev->ena_pin = pin;
        return 0;
}

static void regulator_ena_gpio_free(struct regulator_dev *rdev)
{
        struct regulator_enable_gpio *pin, *n;

        if (!rdev->ena_pin)
                return;

        /* Free the GPIO only in case of no use */
        list_for_each_entry_safe(pin, n, &regulator_ena_gpio_list, list) {
                if (pin->gpio == rdev->ena_pin->gpio) {
                        if (pin->request_count <= 1) {
                                pin->request_count = 0;
                                gpio_free(pin->gpio);
                                list_del(&pin->list);
                                kfree(pin);
                        } else {
                                pin->request_count--;
                        }
                }
        }
}

/**
 * regulator_ena_gpio_ctrl - balance enable_count of each GPIO and actual GPIO pin control
 * @rdev: regulator_dev structure
 * @enable: enable GPIO at initial use?
 *
 * GPIO is enabled in case of initial use. (enable_count is 0)
 * GPIO is disabled when it is not shared any more. (enable_count <= 1)
 */
static int regulator_ena_gpio_ctrl(struct regulator_dev *rdev, bool enable)
{
        struct regulator_enable_gpio *pin = rdev->ena_pin;

        if (!pin)
                return -EINVAL;

        if (enable) {
                /* Enable GPIO at initial use */
                if (pin->enable_count == 0)
                        gpio_set_value_cansleep(pin->gpio,
                                                !pin->ena_gpio_invert);

                pin->enable_count++;
        } else {
                if (pin->enable_count > 1) {
                        pin->enable_count--;
                        return 0;
                }

                /* Disable GPIO if not used */
                if (pin->enable_count <= 1) {
                        gpio_set_value_cansleep(pin->gpio,
                                                pin->ena_gpio_invert);
                        pin->enable_count = 0;
                }
        }

        return 0;
}

static int _regulator_do_enable(struct regulator_dev *rdev)
{
        int ret, delay;

        /* Query before enabling in case configuration dependent.  */
        ret = _regulator_get_enable_time(rdev);
        if (ret >= 0) {
                delay = ret;
        } else {
                rdev_warn(rdev, "enable_time() failed: %d\n", ret);
                delay = 0;
        }

        trace_regulator_enable(rdev_get_name(rdev));

        if (rdev->ena_pin) {
                if (!rdev->ena_gpio_state) {
                        ret = regulator_ena_gpio_ctrl(rdev, true);
                        if (ret < 0)
                                return ret;
                        rdev->ena_gpio_state = 1;
                }
        } else if (rdev->desc->ops->enable) {
                ret = rdev->desc->ops->enable(rdev);
                if (ret < 0)
                        return ret;
        } else {
                return -EINVAL;
        }

        /* Allow the regulator to ramp; it would be useful to extend
         * this for bulk operations so that the regulators can ramp
         * together.  */
        trace_regulator_enable_delay(rdev_get_name(rdev));

        if (delay >= 1000) {
                mdelay(delay / 1000);
                udelay(delay % 1000);
        } else if (delay) {
                udelay(delay);
        }

        trace_regulator_enable_complete(rdev_get_name(rdev));

        return 0;
}

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

        /* check voltage and requested load before enabling */
        if (rdev->constraints &&
            (rdev->constraints->valid_ops_mask & REGULATOR_CHANGE_DRMS))
                drms_uA_update(rdev);

        if (rdev->use_count == 0) {
                /* The regulator may on if it's not switchable or left on */
                ret = _regulator_is_enabled(rdev);
                if (ret == -EINVAL || ret == 0) {
                        if (!_regulator_can_change_status(rdev))
                                return -EPERM;

                        ret = _regulator_do_enable(rdev);
                        if (ret < 0)
                                return ret;

                } else if (ret < 0) {
                        rdev_err(rdev, "is_enabled() failed: %d\n", ret);
                        return ret;
                }
                /* Fallthrough on positive return values - already enabled */
        }

        rdev->use_count++;

        return 0;
}

/**
 * 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;

        if (regulator->always_on)
                return 0;

        if (rdev->supply) {
                ret = regulator_enable(rdev->supply);
                if (ret != 0)
                        return ret;
        }

        mutex_lock(&rdev->mutex);
        ret = _regulator_enable(rdev);
        mutex_unlock(&rdev->mutex);

        if (ret != 0 && rdev->supply)
                regulator_disable(rdev->supply);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_enable);

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

        trace_regulator_disable(rdev_get_name(rdev));

        if (rdev->ena_pin) {
                if (rdev->ena_gpio_state) {
                        ret = regulator_ena_gpio_ctrl(rdev, false);
                        if (ret < 0)
                                return ret;
                        rdev->ena_gpio_state = 0;
                }

        } else if (rdev->desc->ops->disable) {
                ret = rdev->desc->ops->disable(rdev);
                if (ret != 0)
                        return ret;
        }

        trace_regulator_disable_complete(rdev_get_name(rdev));

        return 0;
}

/* 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_get_name(rdev)))
                return -EIO;

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

                /* we are last user */
                if (_regulator_can_change_status(rdev)) {
                        ret = _regulator_do_disable(rdev);
                        if (ret < 0) {
                                rdev_err(rdev, "failed to disable\n");
                                return ret;
                        }
                        _notifier_call_chain(rdev, REGULATOR_EVENT_DISABLE,
                                        NULL);
                }

                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;

        if (regulator->always_on)
                return 0;

        mutex_lock(&rdev->mutex);
        ret = _regulator_disable(rdev);
        mutex_unlock(&rdev->mutex);

        if (ret == 0 && rdev->supply)
                regulator_disable(rdev->supply);

        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;

        ret = _regulator_do_disable(rdev);
        if (ret < 0) {
                rdev_err(rdev, "failed to force disable\n");
                return ret;
        }

        _notifier_call_chain(rdev, REGULATOR_EVENT_FORCE_DISABLE |
                        REGULATOR_EVENT_DISABLE, NULL);

        return 0;
}

/**
 * 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)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

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

        if (rdev->supply)
                while (rdev->open_count--)
                        regulator_disable(rdev->supply);

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_force_disable);

static void regulator_disable_work(struct work_struct *work)
{
        struct regulator_dev *rdev = container_of(work, struct regulator_dev,
                                                  disable_work.work);
        int count, i, ret;

        mutex_lock(&rdev->mutex);

        BUG_ON(!rdev->deferred_disables);

        count = rdev->deferred_disables;
        rdev->deferred_disables = 0;

        for (i = 0; i < count; i++) {
                ret = _regulator_disable(rdev);
                if (ret != 0)
                        rdev_err(rdev, "Deferred disable failed: %d\n", ret);
        }

        mutex_unlock(&rdev->mutex);

        if (rdev->supply) {
                for (i = 0; i < count; i++) {
                        ret = regulator_disable(rdev->supply);
                        if (ret != 0) {
                                rdev_err(rdev,
                                         "Supply disable failed: %d\n", ret);
                        }
                }
        }
}

/**
 * regulator_disable_deferred - disable regulator output with delay
 * @regulator: regulator source
 * @ms: miliseconds until the regulator is disabled
 *
 * Execute regulator_disable() on the regulator after a delay.  This
 * is intended for use with devices that require some time to quiesce.
 *
 * 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_deferred(struct regulator *regulator, int ms)
{
        struct regulator_dev *rdev = regulator->rdev;
        int ret;

        if (regulator->always_on)
                return 0;

        if (!ms)
                return regulator_disable(regulator);

        mutex_lock(&rdev->mutex);
        rdev->deferred_disables++;
        mutex_unlock(&rdev->mutex);

        ret = schedule_delayed_work(&rdev->disable_work,
                                    msecs_to_jiffies(ms));
        if (ret < 0)
                return ret;
        else
                return 0;
}
EXPORT_SYMBOL_GPL(regulator_disable_deferred);

/**
 * regulator_is_enabled_regmap - standard is_enabled() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their is_enabled operation, saving some code.
 */
int regulator_is_enabled_regmap(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &val);
        if (ret != 0)
                return ret;

        if (rdev->desc->enable_is_inverted)
                return (val & rdev->desc->enable_mask) == 0;
        else
                return (val & rdev->desc->enable_mask) != 0;
}
EXPORT_SYMBOL_GPL(regulator_is_enabled_regmap);

/**
 * regulator_enable_regmap - standard enable() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their enable() operation, saving some code.
 */
int regulator_enable_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        if (rdev->desc->enable_is_inverted)
                val = 0;
        else
                val = rdev->desc->enable_mask;

        return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
                                  rdev->desc->enable_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_enable_regmap);

/**
 * regulator_disable_regmap - standard disable() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their disable() operation, saving some code.
 */
int regulator_disable_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        if (rdev->desc->enable_is_inverted)
                val = rdev->desc->enable_mask;
        else
                val = 0;

        return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
                                  rdev->desc->enable_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_disable_regmap);

static int _regulator_is_enabled(struct regulator_dev *rdev)
{
        /* A GPIO control always takes precedence */
        if (rdev->ena_pin)
                return rdev->ena_gpio_state;

        /* If we don't know then assume that the regulator is always on */
        if (!rdev->desc->ops->is_enabled)
                return 1;

        return rdev->desc->ops->is_enabled(rdev);
}

/**
 * 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.
 */