wm97xx_battery.c

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/*
 * linux/drivers/power/wm97xx_battery.c
 *
 * Battery measurement code for WM97xx
 *
 * based on tosa_battery.c
 *
 * Copyright (C) 2008 Marek Vasut <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/wm97xx.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/slab.h>

static struct work_struct bat_work;
static DEFINE_MUTEX(work_lock);
static int bat_status = POWER_SUPPLY_STATUS_UNKNOWN;
static enum power_supply_property *prop;

static unsigned long wm97xx_read_bat(struct power_supply *bat_ps)
{
    struct wm97xx_pdata *wmdata = bat_ps->dev->parent->platform_data;
    struct wm97xx_batt_pdata *pdata = wmdata->batt_pdata;

    return wm97xx_read_aux_adc(dev_get_drvdata(bat_ps->dev->parent),
                    pdata->batt_aux) * pdata->batt_mult /
                    pdata->batt_div;
}

static unsigned long wm97xx_read_temp(struct power_supply *bat_ps)
{
    struct wm97xx_pdata *wmdata = bat_ps->dev->parent->platform_data;
    struct wm97xx_batt_pdata *pdata = wmdata->batt_pdata;

    return wm97xx_read_aux_adc(dev_get_drvdata(bat_ps->dev->parent),
                    pdata->temp_aux) * pdata->temp_mult /
                    pdata->temp_div;
}

static int wm97xx_bat_get_property(struct power_supply *bat_ps,
                enum power_supply_property psp,
                union power_supply_propval *val)
{
    struct wm97xx_pdata *wmdata = bat_ps->dev->parent->platform_data;
    struct wm97xx_batt_pdata *pdata = wmdata->batt_pdata;

    switch (psp) {
    case POWER_SUPPLY_PROP_STATUS:
        val->intval = bat_status;
        break;
    case POWER_SUPPLY_PROP_TECHNOLOGY:
        val->intval = pdata->batt_tech;
        break;
    case POWER_SUPPLY_PROP_VOLTAGE_NOW:
        if (pdata->batt_aux >= 0)
            val->intval = wm97xx_read_bat(bat_ps);
        else
            return -EINVAL;
        break;
    case POWER_SUPPLY_PROP_TEMP:
        if (pdata->temp_aux >= 0)
            val->intval = wm97xx_read_temp(bat_ps);
        else
            return -EINVAL;
        break;
    case POWER_SUPPLY_PROP_VOLTAGE_MAX:
        if (pdata->max_voltage >= 0)
            val->intval = pdata->max_voltage;
        else
            return -EINVAL;
        break;
    case POWER_SUPPLY_PROP_VOLTAGE_MIN:
        if (pdata->min_voltage >= 0)
            val->intval = pdata->min_voltage;
        else
            return -EINVAL;
        break;
    case POWER_SUPPLY_PROP_PRESENT:
        val->intval = 1;
        break;
    default:
        return -EINVAL;
    }
    return 0;
}

static void wm97xx_bat_external_power_changed(struct power_supply *bat_ps)
{
    schedule_work(&bat_work);
}

static void wm97xx_bat_update(struct power_supply *bat_ps)
{
    int old_status = bat_status;
    struct wm97xx_pdata *wmdata = bat_ps->dev->parent->platform_data;
    struct wm97xx_batt_pdata *pdata = wmdata->batt_pdata;

    mutex_lock(&work_lock);

    bat_status = (pdata->charge_gpio >= 0) ?
            (gpio_get_value(pdata->charge_gpio) ?
            POWER_SUPPLY_STATUS_DISCHARGING :
            POWER_SUPPLY_STATUS_CHARGING) :
            POWER_SUPPLY_STATUS_UNKNOWN;

    if (old_status != bat_status) {
        pr_debug("%s: %i -> %i\n", bat_ps->name, old_status,
                    bat_status);
        power_supply_changed(bat_ps);
    }

    mutex_unlock(&work_lock);
}

static struct power_supply bat_ps = {
    .type           = POWER_SUPPLY_TYPE_BATTERY,
    .get_property       = wm97xx_bat_get_property,
    .external_power_changed = wm97xx_bat_external_power_changed,
    .use_for_apm        = 1,
};

static void wm97xx_bat_work(struct work_struct *work)
{
    wm97xx_bat_update(&bat_ps);
}

static irqreturn_t wm97xx_chrg_irq(int irq, void *data)
{
    schedule_work(&bat_work);
    return IRQ_HANDLED;
}

#ifdef CONFIG_PM
static int wm97xx_bat_suspend(struct device *dev)
{
    flush_work(&bat_work);
    return 0;
}

static int wm97xx_bat_resume(struct device *dev)
{
    schedule_work(&bat_work);
    return 0;
}

static const struct dev_pm_ops wm97xx_bat_pm_ops = {
    .suspend    = wm97xx_bat_suspend,
    .resume     = wm97xx_bat_resume,
};
#endif

static int __devinit wm97xx_bat_probe(struct platform_device *dev)
{
    int ret = 0;
    int props = 1;  /* POWER_SUPPLY_PROP_PRESENT */
    int i = 0;
    struct wm97xx_pdata *wmdata = dev->dev.platform_data;
    struct wm97xx_batt_pdata *pdata;

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

    pdata = wmdata->batt_pdata;

    if (dev->id != -1)
        return -EINVAL;

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

    if (gpio_is_valid(pdata->charge_gpio)) {
        ret = gpio_request(pdata->charge_gpio, "BATT CHRG");
        if (ret)
            goto err;
        ret = gpio_direction_input(pdata->charge_gpio);
        if (ret)
            goto err2;
        ret = request_irq(gpio_to_irq(pdata->charge_gpio),
                wm97xx_chrg_irq, 0,
                "AC Detect", dev);
        if (ret)
            goto err2;
        props++;    /* POWER_SUPPLY_PROP_STATUS */
    }

    if (pdata->batt_tech >= 0)
        props++;    /* POWER_SUPPLY_PROP_TECHNOLOGY */
    if (pdata->temp_aux >= 0)
        props++;    /* POWER_SUPPLY_PROP_TEMP */
    if (pdata->batt_aux >= 0)
        props++;    /* POWER_SUPPLY_PROP_VOLTAGE_NOW */
    if (pdata->max_voltage >= 0)
        props++;    /* POWER_SUPPLY_PROP_VOLTAGE_MAX */
    if (pdata->min_voltage >= 0)
        props++;    /* POWER_SUPPLY_PROP_VOLTAGE_MIN */

    prop = kzalloc(props * sizeof(*prop), GFP_KERNEL);
    if (!prop) {
        ret = -ENOMEM;
        goto err3;
    }

    prop[i++] = POWER_SUPPLY_PROP_PRESENT;
    if (pdata->charge_gpio >= 0)
        prop[i++] = POWER_SUPPLY_PROP_STATUS;
    if (pdata->batt_tech >= 0)
        prop[i++] = POWER_SUPPLY_PROP_TECHNOLOGY;
    if (pdata->temp_aux >= 0)
        prop[i++] = POWER_SUPPLY_PROP_TEMP;
    if (pdata->batt_aux >= 0)
        prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_NOW;
    if (pdata->max_voltage >= 0)
        prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MAX;
    if (pdata->min_voltage >= 0)
        prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MIN;

    INIT_WORK(&bat_work, wm97xx_bat_work);

    if (!pdata->batt_name) {
        dev_info(&dev->dev, "Please consider setting proper battery "
                "name in platform definition file, falling "
                "back to name \"wm97xx-batt\"\n");
        bat_ps.name = "wm97xx-batt";
    } else
        bat_ps.name = pdata->batt_name;

    bat_ps.properties = prop;
    bat_ps.num_properties = props;

    ret = power_supply_register(&dev->dev, &bat_ps);
    if (!ret)
        schedule_work(&bat_work);
    else
        goto err4;

    return 0;
err4:
    kfree(prop);
err3:
    if (gpio_is_valid(pdata->charge_gpio))
        free_irq(gpio_to_irq(pdata->charge_gpio), dev);
err2:
    if (gpio_is_valid(pdata->charge_gpio))
        gpio_free(pdata->charge_gpio);
err:
    return ret;
}

static int __devexit wm97xx_bat_remove(struct platform_device *dev)
{
    struct wm97xx_pdata *wmdata = dev->dev.platform_data;
    struct wm97xx_batt_pdata *pdata = wmdata->batt_pdata;

    if (pdata && gpio_is_valid(pdata->charge_gpio)) {
        free_irq(gpio_to_irq(pdata->charge_gpio), dev);
        gpio_free(pdata->charge_gpio);
    }
    cancel_work_sync(&bat_work);
    power_supply_unregister(&bat_ps);
    kfree(prop);
    return 0;
}

static struct platform_driver wm97xx_bat_driver = {
    .driver = {
        .name   = "wm97xx-battery",
        .owner  = THIS_MODULE,
#ifdef CONFIG_PM
        .pm = &wm97xx_bat_pm_ops,
#endif
    },
    .probe      = wm97xx_bat_probe,
    .remove     = __devexit_p(wm97xx_bat_remove),
};

module_platform_driver(wm97xx_bat_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Vasut <[email protected]>");
MODULE_DESCRIPTION("WM97xx battery driver");