virtual.c

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/*
 * reg-virtual-consumer.c
 *
 * Copyright 2008 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <[email protected]>
 *
 * 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/err.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/module.h>

struct virtual_consumer_data {
    struct mutex lock;
    struct regulator *regulator;
    bool enabled;
    int min_uV;
    int max_uV;
    int min_uA;
    int max_uA;
    unsigned int mode;
};

static void update_voltage_constraints(struct device *dev,
                       struct virtual_consumer_data *data)
{
    int ret;

    if (data->min_uV && data->max_uV
        && data->min_uV <= data->max_uV) {
        dev_dbg(dev, "Requesting %d-%duV\n",
            data->min_uV, data->max_uV);
        ret = regulator_set_voltage(data->regulator,
                    data->min_uV, data->max_uV);
        if (ret != 0) {
            dev_err(dev,
                "regulator_set_voltage() failed: %d\n", ret);
            return;
        }
    }

    if (data->min_uV && data->max_uV && !data->enabled) {
        dev_dbg(dev, "Enabling regulator\n");
        ret = regulator_enable(data->regulator);
        if (ret == 0)
            data->enabled = true;
        else
            dev_err(dev, "regulator_enable() failed: %d\n",
                ret);
    }

    if (!(data->min_uV && data->max_uV) && data->enabled) {
        dev_dbg(dev, "Disabling regulator\n");
        ret = regulator_disable(data->regulator);
        if (ret == 0)
            data->enabled = false;
        else
            dev_err(dev, "regulator_disable() failed: %d\n",
                ret);
    }
}

static void update_current_limit_constraints(struct device *dev,
                      struct virtual_consumer_data *data)
{
    int ret;

    if (data->max_uA
        && data->min_uA <= data->max_uA) {
        dev_dbg(dev, "Requesting %d-%duA\n",
            data->min_uA, data->max_uA);
        ret = regulator_set_current_limit(data->regulator,
                    data->min_uA, data->max_uA);
        if (ret != 0) {
            dev_err(dev,
                "regulator_set_current_limit() failed: %d\n",
                ret);
            return;
        }
    }

    if (data->max_uA && !data->enabled) {
        dev_dbg(dev, "Enabling regulator\n");
        ret = regulator_enable(data->regulator);
        if (ret == 0)
            data->enabled = true;
        else
            dev_err(dev, "regulator_enable() failed: %d\n",
                ret);
    }

    if (!(data->min_uA && data->max_uA) && data->enabled) {
        dev_dbg(dev, "Disabling regulator\n");
        ret = regulator_disable(data->regulator);
        if (ret == 0)
            data->enabled = false;
        else
            dev_err(dev, "regulator_disable() failed: %d\n",
                ret);
    }
}

static ssize_t show_min_uV(struct device *dev,
               struct device_attribute *attr, char *buf)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    return sprintf(buf, "%d\n", data->min_uV);
}

static ssize_t set_min_uV(struct device *dev, struct device_attribute *attr,
              const char *buf, size_t count)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    long val;

    if (kstrtol(buf, 10, &val) != 0)
        return count;

    mutex_lock(&data->lock);

    data->min_uV = val;
    update_voltage_constraints(dev, data);

    mutex_unlock(&data->lock);

    return count;
}

static ssize_t show_max_uV(struct device *dev,
               struct device_attribute *attr, char *buf)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    return sprintf(buf, "%d\n", data->max_uV);
}

static ssize_t set_max_uV(struct device *dev, struct device_attribute *attr,
              const char *buf, size_t count)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    long val;

    if (kstrtol(buf, 10, &val) != 0)
        return count;

    mutex_lock(&data->lock);

    data->max_uV = val;
    update_voltage_constraints(dev, data);

    mutex_unlock(&data->lock);

    return count;
}

static ssize_t show_min_uA(struct device *dev,
               struct device_attribute *attr, char *buf)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    return sprintf(buf, "%d\n", data->min_uA);
}

static ssize_t set_min_uA(struct device *dev, struct device_attribute *attr,
              const char *buf, size_t count)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    long val;

    if (kstrtol(buf, 10, &val) != 0)
        return count;

    mutex_lock(&data->lock);

    data->min_uA = val;
    update_current_limit_constraints(dev, data);

    mutex_unlock(&data->lock);

    return count;
}

static ssize_t show_max_uA(struct device *dev,
               struct device_attribute *attr, char *buf)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    return sprintf(buf, "%d\n", data->max_uA);
}

static ssize_t set_max_uA(struct device *dev, struct device_attribute *attr,
              const char *buf, size_t count)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    long val;

    if (kstrtol(buf, 10, &val) != 0)
        return count;

    mutex_lock(&data->lock);

    data->max_uA = val;
    update_current_limit_constraints(dev, data);

    mutex_unlock(&data->lock);

    return count;
}

static ssize_t show_mode(struct device *dev,
             struct device_attribute *attr, char *buf)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);

    switch (data->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");
    default:
        return sprintf(buf, "unknown\n");
    }
}

static ssize_t set_mode(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct virtual_consumer_data *data = dev_get_drvdata(dev);
    unsigned int mode;
    int ret;

    /*
     * sysfs_streq() doesn't need the \n's, but we add them so the strings
     * will be shared with show_mode(), above.
     */
    if (sysfs_streq(buf, "fast\n"))
        mode = REGULATOR_MODE_FAST;
    else if (sysfs_streq(buf, "normal\n"))
        mode = REGULATOR_MODE_NORMAL;
    else if (sysfs_streq(buf, "idle\n"))
        mode = REGULATOR_MODE_IDLE;
    else if (sysfs_streq(buf, "standby\n"))
        mode = REGULATOR_MODE_STANDBY;
    else {
        dev_err(dev, "Configuring invalid mode\n");
        return count;
    }

    mutex_lock(&data->lock);
    ret = regulator_set_mode(data->regulator, mode);
    if (ret == 0)
        data->mode = mode;
    else
        dev_err(dev, "Failed to configure mode: %d\n", ret);
    mutex_unlock(&data->lock);

    return count;
}

static DEVICE_ATTR(min_microvolts, 0666, show_min_uV, set_min_uV);
static DEVICE_ATTR(max_microvolts, 0666, show_max_uV, set_max_uV);
static DEVICE_ATTR(min_microamps, 0666, show_min_uA, set_min_uA);
static DEVICE_ATTR(max_microamps, 0666, show_max_uA, set_max_uA);
static DEVICE_ATTR(mode, 0666, show_mode, set_mode);

static struct attribute *regulator_virtual_attributes[] = {
    &dev_attr_min_microvolts.attr,
    &dev_attr_max_microvolts.attr,
    &dev_attr_min_microamps.attr,
    &dev_attr_max_microamps.attr,
    &dev_attr_mode.attr,
    NULL
};

static const struct attribute_group regulator_virtual_attr_group = {
    .attrs  = regulator_virtual_attributes,
};

static int __devinit regulator_virtual_probe(struct platform_device *pdev)
{
    char *reg_id = pdev->dev.platform_data;
    struct virtual_consumer_data *drvdata;
    int ret;

    drvdata = devm_kzalloc(&pdev->dev, sizeof(struct virtual_consumer_data),
                   GFP_KERNEL);
    if (drvdata == NULL)
        return -ENOMEM;

    mutex_init(&drvdata->lock);

    drvdata->regulator = devm_regulator_get(&pdev->dev, reg_id);
    if (IS_ERR(drvdata->regulator)) {
        ret = PTR_ERR(drvdata->regulator);
        dev_err(&pdev->dev, "Failed to obtain supply '%s': %d\n",
            reg_id, ret);
        return ret;
    }

    ret = sysfs_create_group(&pdev->dev.kobj,
                 &regulator_virtual_attr_group);
    if (ret != 0) {
        dev_err(&pdev->dev,
            "Failed to create attribute group: %d\n", ret);
        return ret;
    }

    drvdata->mode = regulator_get_mode(drvdata->regulator);

    platform_set_drvdata(pdev, drvdata);

    return 0;
}

static int __devexit regulator_virtual_remove(struct platform_device *pdev)
{
    struct virtual_consumer_data *drvdata = platform_get_drvdata(pdev);

    sysfs_remove_group(&pdev->dev.kobj, &regulator_virtual_attr_group);

    if (drvdata->enabled)
        regulator_disable(drvdata->regulator);

    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver regulator_virtual_consumer_driver = {
    .probe      = regulator_virtual_probe,
    .remove     = __devexit_p(regulator_virtual_remove),
    .driver     = {
        .name       = "reg-virt-consumer",
        .owner      = THIS_MODULE,
    },
};

module_platform_driver(regulator_virtual_consumer_driver);

MODULE_AUTHOR("Mark Brown <[email protected]>");
MODULE_DESCRIPTION("Virtual regulator consumer");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:reg-virt-consumer");