/*
   *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   *  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(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
  ");
  		return -EINVAL;
  	}
  
  	if (!gpio_is_valid(pdata->gpio)) {
  		dev_err(&pdev->dev, "Invalid gpio pin
  ");
  		return -EINVAL;
  	}
  
  	gpio_charger = kzalloc(sizeof(*gpio_charger), GFP_KERNEL);

  	if (!gpio_charger) {
  		dev_err(&pdev->dev, "Failed to alloc driver structure
  ");
  		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
  ", ret);
  		goto err_free;
  	}
  	ret = gpio_direction_input(pdata->gpio);
  	if (ret) {
  		dev_err(&pdev->dev, "Failed to set gpio to input: %d
  ", 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
  ",
  			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
  ", 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 <lars@metafoo.de>");
  MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:gpio-charger");