/*
   * linux/drivers/power/wm97xx_battery.c
   *
   * 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_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
  ", 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_pdata *wmdata = dev->dev.platform_data;
  	struct wm97xx_batt_pdata *pdata;

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

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

  	if (!pdata) {

  		dev_err(&dev->dev, "No platform_data supplied
  ");

  		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\"
  ");

  		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, NULL);
  	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_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_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");