gpio-charger.c

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/*
 *  Copyright (C) 2010, Lars-Peter Clausen <[email protected]>
 *  Driver for chargers which report their online status through a GPIO pin
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>

#include <linux/power/gpio-charger.h>

struct gpio_charger {
    const struct gpio_charger_platform_data *pdata;
    unsigned int irq;

    struct power_supply charger;
};

static irqreturn_t gpio_charger_irq(int irq, void *devid)
{
    struct power_supply *charger = devid;

    power_supply_changed(charger);

    return IRQ_HANDLED;
}

static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
{
    return container_of(psy, struct gpio_charger, charger);
}

static int gpio_charger_get_property(struct power_supply *psy,
        enum power_supply_property psp, union power_supply_propval *val)
{
    struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
    const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;

    switch (psp) {
    case POWER_SUPPLY_PROP_ONLINE:
        val->intval = gpio_get_value_cansleep(pdata->gpio);
        val->intval ^= pdata->gpio_active_low;
        break;
    default:
        return -EINVAL;
    }

    return 0;
}

static enum power_supply_property gpio_charger_properties[] = {
    POWER_SUPPLY_PROP_ONLINE,
};

static int __devinit gpio_charger_probe(struct platform_device *pdev)
{
    const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
    struct gpio_charger *gpio_charger;
    struct power_supply *charger;
    int ret;
    int irq;

    if (!pdata) {
        dev_err(&pdev->dev, "No platform data\n");
        return -EINVAL;
    }

    if (!gpio_is_valid(pdata->gpio)) {
        dev_err(&pdev->dev, "Invalid gpio pin\n");
        return -EINVAL;
    }

    gpio_charger = kzalloc(sizeof(*gpio_charger), GFP_KERNEL);
    if (!gpio_charger) {
        dev_err(&pdev->dev, "Failed to alloc driver structure\n");
        return -ENOMEM;
    }

    charger = &gpio_charger->charger;

    charger->name = pdata->name ? pdata->name : "gpio-charger";
    charger->type = pdata->type;
    charger->properties = gpio_charger_properties;
    charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
    charger->get_property = gpio_charger_get_property;
    charger->supplied_to = pdata->supplied_to;
    charger->num_supplicants = pdata->num_supplicants;

    ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
    if (ret) {
        dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
        goto err_free;
    }
    ret = gpio_direction_input(pdata->gpio);
    if (ret) {
        dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
        goto err_gpio_free;
    }

    gpio_charger->pdata = pdata;

    ret = power_supply_register(&pdev->dev, charger);
    if (ret < 0) {
        dev_err(&pdev->dev, "Failed to register power supply: %d\n",
            ret);
        goto err_gpio_free;
    }

    irq = gpio_to_irq(pdata->gpio);
    if (irq > 0) {
        ret = request_any_context_irq(irq, gpio_charger_irq,
                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                dev_name(&pdev->dev), charger);
        if (ret < 0)
            dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
        else
            gpio_charger->irq = irq;
    }

    platform_set_drvdata(pdev, gpio_charger);

    return 0;

err_gpio_free:
    gpio_free(pdata->gpio);
err_free:
    kfree(gpio_charger);
    return ret;
}

static int __devexit gpio_charger_remove(struct platform_device *pdev)
{
    struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);

    if (gpio_charger->irq)
        free_irq(gpio_charger->irq, &gpio_charger->charger);

    power_supply_unregister(&gpio_charger->charger);

    gpio_free(gpio_charger->pdata->gpio);

    platform_set_drvdata(pdev, NULL);
    kfree(gpio_charger);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int gpio_charger_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);

    power_supply_changed(&gpio_charger->charger);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops, NULL, gpio_charger_resume);

static struct platform_driver gpio_charger_driver = {
    .probe = gpio_charger_probe,
    .remove = __devexit_p(gpio_charger_remove),
    .driver = {
        .name = "gpio-charger",
        .owner = THIS_MODULE,
        .pm = &gpio_charger_pm_ops,
    },
};

module_platform_driver(gpio_charger_driver);

MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-charger");