gpio-regulator.c

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/*
 * gpio-regulator.c
 *
 * Copyright 2011 Heiko Stuebner <[email protected]>
 *
 * based on fixed.c
 *
 * Copyright 2008 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <[email protected]>
 *
 * Copyright (c) 2009 Nokia Corporation
 * Roger Quadros <[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.
 *
 * This is useful for systems with mixed controllable and
 * non-controllable regulators, as well as for allowing testing on
 * systems with no controllable regulators.
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/gpio-regulator.h>
#include <linux/gpio.h>
#include <linux/slab.h>

struct gpio_regulator_data {
    struct regulator_desc desc;
    struct regulator_dev *dev;

    struct gpio *gpios;
    int nr_gpios;

    struct gpio_regulator_state *states;
    int nr_states;

    int state;
};

static int gpio_regulator_get_value(struct regulator_dev *dev)
{
    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
    int ptr;

    for (ptr = 0; ptr < data->nr_states; ptr++)
        if (data->states[ptr].gpios == data->state)
            return data->states[ptr].value;

    return -EINVAL;
}

static int gpio_regulator_set_voltage(struct regulator_dev *dev,
                    int min_uV, int max_uV,
                    unsigned *selector)
{
    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
    int ptr, target = 0, state, best_val = INT_MAX;

    for (ptr = 0; ptr < data->nr_states; ptr++)
        if (data->states[ptr].value < best_val &&
            data->states[ptr].value >= min_uV &&
            data->states[ptr].value <= max_uV) {
            target = data->states[ptr].gpios;
            best_val = data->states[ptr].value;
            if (selector)
                *selector = ptr;
        }

    if (best_val == INT_MAX)
        return -EINVAL;

    for (ptr = 0; ptr < data->nr_gpios; ptr++) {
        state = (target & (1 << ptr)) >> ptr;
        gpio_set_value(data->gpios[ptr].gpio, state);
    }
    data->state = target;

    return 0;
}

static int gpio_regulator_list_voltage(struct regulator_dev *dev,
                      unsigned selector)
{
    struct gpio_regulator_data *data = rdev_get_drvdata(dev);

    if (selector >= data->nr_states)
        return -EINVAL;

    return data->states[selector].value;
}

static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
                    int min_uA, int max_uA)
{
    struct gpio_regulator_data *data = rdev_get_drvdata(dev);
    int ptr, target = 0, state, best_val = 0;

    for (ptr = 0; ptr < data->nr_states; ptr++)
        if (data->states[ptr].value > best_val &&
            data->states[ptr].value >= min_uA &&
            data->states[ptr].value <= max_uA) {
            target = data->states[ptr].gpios;
            best_val = data->states[ptr].value;
        }

    if (best_val == 0)
        return -EINVAL;

    for (ptr = 0; ptr < data->nr_gpios; ptr++) {
        state = (target & (1 << ptr)) >> ptr;
        gpio_set_value(data->gpios[ptr].gpio, state);
    }
    data->state = target;

    return 0;
}

static struct regulator_ops gpio_regulator_voltage_ops = {
    .get_voltage = gpio_regulator_get_value,
    .set_voltage = gpio_regulator_set_voltage,
    .list_voltage = gpio_regulator_list_voltage,
};

static struct regulator_ops gpio_regulator_current_ops = {
    .get_current_limit = gpio_regulator_get_value,
    .set_current_limit = gpio_regulator_set_current_limit,
};

static int __devinit gpio_regulator_probe(struct platform_device *pdev)
{
    struct gpio_regulator_config *config = pdev->dev.platform_data;
    struct gpio_regulator_data *drvdata;
    struct regulator_config cfg = { };
    int ptr, ret, state;

    drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
                   GFP_KERNEL);
    if (drvdata == NULL) {
        dev_err(&pdev->dev, "Failed to allocate device data\n");
        return -ENOMEM;
    }

    drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
    if (drvdata->desc.name == NULL) {
        dev_err(&pdev->dev, "Failed to allocate supply name\n");
        ret = -ENOMEM;
        goto err;
    }

    drvdata->gpios = kmemdup(config->gpios,
                 config->nr_gpios * sizeof(struct gpio),
                 GFP_KERNEL);
    if (drvdata->gpios == NULL) {
        dev_err(&pdev->dev, "Failed to allocate gpio data\n");
        ret = -ENOMEM;
        goto err_name;
    }

    drvdata->states = kmemdup(config->states,
                  config->nr_states *
                     sizeof(struct gpio_regulator_state),
                  GFP_KERNEL);
    if (drvdata->states == NULL) {
        dev_err(&pdev->dev, "Failed to allocate state data\n");
        ret = -ENOMEM;
        goto err_memgpio;
    }
    drvdata->nr_states = config->nr_states;

    drvdata->desc.owner = THIS_MODULE;
    drvdata->desc.enable_time = config->startup_delay;

    /* handle regulator type*/
    switch (config->type) {
    case REGULATOR_VOLTAGE:
        drvdata->desc.type = REGULATOR_VOLTAGE;
        drvdata->desc.ops = &gpio_regulator_voltage_ops;
        drvdata->desc.n_voltages = config->nr_states;
        break;
    case REGULATOR_CURRENT:
        drvdata->desc.type = REGULATOR_CURRENT;
        drvdata->desc.ops = &gpio_regulator_current_ops;
        break;
    default:
        dev_err(&pdev->dev, "No regulator type set\n");
        ret = -EINVAL;
        goto err_memgpio;
        break;
    }

    drvdata->nr_gpios = config->nr_gpios;
    ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
    if (ret) {
        dev_err(&pdev->dev,
           "Could not obtain regulator setting GPIOs: %d\n", ret);
        goto err_memstate;
    }

    /* build initial state from gpio init data. */
    state = 0;
    for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
        if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
            state |= (1 << ptr);
    }
    drvdata->state = state;

    cfg.dev = &pdev->dev;
    cfg.init_data = config->init_data;
    cfg.driver_data = drvdata;

    if (config->enable_gpio >= 0)
        cfg.ena_gpio = config->enable_gpio;
    cfg.ena_gpio_invert = !config->enable_high;
    if (config->enabled_at_boot) {
        if (config->enable_high)
            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
        else
            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
    } else {
        if (config->enable_high)
            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
        else
            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
    }

    drvdata->dev = regulator_register(&drvdata->desc, &cfg);
    if (IS_ERR(drvdata->dev)) {
        ret = PTR_ERR(drvdata->dev);
        dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
        goto err_stategpio;
    }

    platform_set_drvdata(pdev, drvdata);

    return 0;

err_stategpio:
    gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
err_memstate:
    kfree(drvdata->states);
err_memgpio:
    kfree(drvdata->gpios);
err_name:
    kfree(drvdata->desc.name);
err:
    return ret;
}

static int __devexit gpio_regulator_remove(struct platform_device *pdev)
{
    struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);

    regulator_unregister(drvdata->dev);

    gpio_free_array(drvdata->gpios, drvdata->nr_gpios);

    kfree(drvdata->states);
    kfree(drvdata->gpios);

    kfree(drvdata->desc.name);

    return 0;
}

static struct platform_driver gpio_regulator_driver = {
    .probe      = gpio_regulator_probe,
    .remove     = __devexit_p(gpio_regulator_remove),
    .driver     = {
        .name       = "gpio-regulator",
        .owner      = THIS_MODULE,
    },
};

static int __init gpio_regulator_init(void)
{
    return platform_driver_register(&gpio_regulator_driver);
}
subsys_initcall(gpio_regulator_init);

static void __exit gpio_regulator_exit(void)
{
    platform_driver_unregister(&gpio_regulator_driver);
}
module_exit(gpio_regulator_exit);

MODULE_AUTHOR("Heiko Stuebner <[email protected]>");
MODULE_DESCRIPTION("gpio voltage regulator");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-regulator");