/*
 * Battery measurement code for WM97xx
 *
 * based on tosa_battery.c
 *
 * Copyright (C) 2008 Marek Vasut <marek.vasut@gmail.com>
 *
 * 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_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);

        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_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);

        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_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);

        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_batt_pdata *pdata = power_supply_get_drvdata(bat_ps);

        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->desc->name, old_status,
                                        bat_status);
                power_supply_changed(bat_ps);
        }

        mutex_unlock(&work_lock);
}

static struct power_supply *bat_psy;
static struct power_supply_desc bat_psy_desc = {
        .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_psy);
}

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 wm97xx_bat_probe(struct platform_device *dev)
{
        int ret = 0;
        int props = 1;  /* POWER_SUPPLY_PROP_PRESENT */
        int i = 0;
        struct wm97xx_batt_pdata *pdata = dev->dev.platform_data;
        struct power_supply_config cfg = {};

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

        cfg.drv_data = pdata;

        if (dev->id != -1)
                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_psy_desc.name = "wm97xx-batt";
        } else
                bat_psy_desc.name = pdata->batt_name;

        bat_psy_desc.properties = prop;
        bat_psy_desc.num_properties = props;

        bat_psy = power_supply_register(&dev->dev, &bat_psy_desc, &cfg);
        if (!IS_ERR(bat_psy)) {
                schedule_work(&bat_work);
        } else {
                ret = PTR_ERR(bat_psy);
                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 wm97xx_bat_remove(struct platform_device *dev)
{
        struct wm97xx_batt_pdata *pdata = dev->dev.platform_data;

        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_psy);
        kfree(prop);
        return 0;
}

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

module_platform_driver(wm97xx_bat_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION("WM97xx battery driver");