/*
   * max8903_charger.c - Maxim 8903 USB/Adapter Charger Driver
   *
   * Copyright (C) 2011 Samsung Electronics
   * MyungJoo Ham <myungjoo.ham@samsung.com>
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  
  #include <linux/gpio.h>
  #include <linux/interrupt.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/power_supply.h>
  #include <linux/platform_device.h>
  #include <linux/power/max8903_charger.h>
  
  struct max8903_data {
  	struct max8903_pdata pdata;
  	struct device *dev;
  	struct power_supply psy;
  	bool fault;
  	bool usb_in;
  	bool ta_in;
  };
  
  static enum power_supply_property max8903_charger_props[] = {
  	POWER_SUPPLY_PROP_STATUS, /* Charger status output */
  	POWER_SUPPLY_PROP_ONLINE, /* External power source */
  	POWER_SUPPLY_PROP_HEALTH, /* Fault or OK */
  };
  
  static int max8903_get_property(struct power_supply *psy,
  		enum power_supply_property psp,
  		union power_supply_propval *val)
  {
  	struct max8903_data *data = container_of(psy,
  			struct max8903_data, psy);
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:
  		val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
  		if (data->pdata.chg) {
  			if (gpio_get_value(data->pdata.chg) == 0)
  				val->intval = POWER_SUPPLY_STATUS_CHARGING;
  			else if (data->usb_in || data->ta_in)
  				val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  			else
  				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  		}
  		break;
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = 0;
  		if (data->usb_in || data->ta_in)
  			val->intval = 1;
  		break;
  	case POWER_SUPPLY_PROP_HEALTH:
  		val->intval = POWER_SUPPLY_HEALTH_GOOD;
  		if (data->fault)
  			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
  		break;
  	default:
  		return -EINVAL;
  	}
  	return 0;
  }
  
  static irqreturn_t max8903_dcin(int irq, void *_data)
  {
  	struct max8903_data *data = _data;
  	struct max8903_pdata *pdata = &data->pdata;
  	bool ta_in;
  	enum power_supply_type old_type;
  
  	ta_in = gpio_get_value(pdata->dok) ? false : true;
  
  	if (ta_in == data->ta_in)
  		return IRQ_HANDLED;
  
  	data->ta_in = ta_in;
  
  	/* Set Current-Limit-Mode 1:DC 0:USB */
  	if (pdata->dcm)
  		gpio_set_value(pdata->dcm, ta_in ? 1 : 0);
  
  	/* Charger Enable / Disable (cen is negated) */
  	if (pdata->cen)
  		gpio_set_value(pdata->cen, ta_in ? 0 :
  				(data->usb_in ? 0 : 1));
  
  	dev_dbg(data->dev, "TA(DC-IN) Charger %s.
  ", ta_in ?
  			"Connected" : "Disconnected");
  
  	old_type = data->psy.type;
  
  	if (data->ta_in)
  		data->psy.type = POWER_SUPPLY_TYPE_MAINS;
  	else if (data->usb_in)
  		data->psy.type = POWER_SUPPLY_TYPE_USB;
  	else
  		data->psy.type = POWER_SUPPLY_TYPE_BATTERY;
  
  	if (old_type != data->psy.type)
  		power_supply_changed(&data->psy);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t max8903_usbin(int irq, void *_data)
  {
  	struct max8903_data *data = _data;
  	struct max8903_pdata *pdata = &data->pdata;
  	bool usb_in;
  	enum power_supply_type old_type;
  
  	usb_in = gpio_get_value(pdata->uok) ? false : true;
  
  	if (usb_in == data->usb_in)
  		return IRQ_HANDLED;
  
  	data->usb_in = usb_in;
  
  	/* Do not touch Current-Limit-Mode */
  
  	/* Charger Enable / Disable (cen is negated) */
  	if (pdata->cen)
  		gpio_set_value(pdata->cen, usb_in ? 0 :
  				(data->ta_in ? 0 : 1));
  
  	dev_dbg(data->dev, "USB Charger %s.
  ", usb_in ?
  			"Connected" : "Disconnected");
  
  	old_type = data->psy.type;
  
  	if (data->ta_in)
  		data->psy.type = POWER_SUPPLY_TYPE_MAINS;
  	else if (data->usb_in)
  		data->psy.type = POWER_SUPPLY_TYPE_USB;
  	else
  		data->psy.type = POWER_SUPPLY_TYPE_BATTERY;
  
  	if (old_type != data->psy.type)
  		power_supply_changed(&data->psy);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t max8903_fault(int irq, void *_data)
  {
  	struct max8903_data *data = _data;
  	struct max8903_pdata *pdata = &data->pdata;
  	bool fault;
  
  	fault = gpio_get_value(pdata->flt) ? false : true;
  
  	if (fault == data->fault)
  		return IRQ_HANDLED;
  
  	data->fault = fault;
  
  	if (fault)
  		dev_err(data->dev, "Charger suffers a fault and stops.
  ");
  	else
  		dev_err(data->dev, "Charger recovered from a fault.
  ");
  
  	return IRQ_HANDLED;
  }
  
  static int max8903_probe(struct platform_device *pdev)
  {
  	struct max8903_data *data;
  	struct device *dev = &pdev->dev;
  	struct max8903_pdata *pdata = pdev->dev.platform_data;
  	int ret = 0;
  	int gpio;
  	int ta_in = 0;
  	int usb_in = 0;
  
  	data = devm_kzalloc(dev, sizeof(struct max8903_data), GFP_KERNEL);
  	if (data == NULL) {
  		dev_err(dev, "Cannot allocate memory.
  ");
  		return -ENOMEM;
  	}
  	memcpy(&data->pdata, pdata, sizeof(struct max8903_pdata));
  	data->dev = dev;
  	platform_set_drvdata(pdev, data);
  
  	if (pdata->dc_valid == false && pdata->usb_valid == false) {
  		dev_err(dev, "No valid power sources.
  ");
  		ret = -EINVAL;
  		goto err;
  	}
  
  	if (pdata->dc_valid) {
  		if (pdata->dok && gpio_is_valid(pdata->dok) &&
  				pdata->dcm && gpio_is_valid(pdata->dcm)) {
  			gpio = pdata->dok; /* PULL_UPed Interrupt */
  			ta_in = gpio_get_value(gpio) ? 0 : 1;
  
  			gpio = pdata->dcm; /* Output */
  			gpio_set_value(gpio, ta_in);
  		} else {
  			dev_err(dev, "When DC is wired, DOK and DCM should"
  					" be wired as well.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	} else {
  		if (pdata->dcm) {
  			if (gpio_is_valid(pdata->dcm))
  				gpio_set_value(pdata->dcm, 0);
  			else {
  				dev_err(dev, "Invalid pin: dcm.
  ");
  				ret = -EINVAL;
  				goto err;
  			}
  		}
  	}
  
  	if (pdata->usb_valid) {
  		if (pdata->uok && gpio_is_valid(pdata->uok)) {
  			gpio = pdata->uok;
  			usb_in = gpio_get_value(gpio) ? 0 : 1;
  		} else {
  			dev_err(dev, "When USB is wired, UOK should be wired."
  					"as well.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	}
  
  	if (pdata->cen) {
  		if (gpio_is_valid(pdata->cen)) {
  			gpio_set_value(pdata->cen, (ta_in || usb_in) ? 0 : 1);
  		} else {
  			dev_err(dev, "Invalid pin: cen.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	}
  
  	if (pdata->chg) {
  		if (!gpio_is_valid(pdata->chg)) {
  			dev_err(dev, "Invalid pin: chg.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	}
  
  	if (pdata->flt) {
  		if (!gpio_is_valid(pdata->flt)) {
  			dev_err(dev, "Invalid pin: flt.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	}
  
  	if (pdata->usus) {
  		if (!gpio_is_valid(pdata->usus)) {
  			dev_err(dev, "Invalid pin: usus.
  ");
  			ret = -EINVAL;
  			goto err;
  		}
  	}
  
  	data->fault = false;
  	data->ta_in = ta_in;
  	data->usb_in = usb_in;
  
  	data->psy.name = "max8903_charger";
  	data->psy.type = (ta_in) ? POWER_SUPPLY_TYPE_MAINS :
  			((usb_in) ? POWER_SUPPLY_TYPE_USB :
  			 POWER_SUPPLY_TYPE_BATTERY);
  	data->psy.get_property = max8903_get_property;
  	data->psy.properties = max8903_charger_props;
  	data->psy.num_properties = ARRAY_SIZE(max8903_charger_props);
  
  	ret = power_supply_register(dev, &data->psy);
  	if (ret) {
  		dev_err(dev, "failed: power supply register.
  ");
  		goto err;
  	}
  
  	if (pdata->dc_valid) {
  		ret = request_threaded_irq(gpio_to_irq(pdata->dok),
  				NULL, max8903_dcin,
  				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
  				"MAX8903 DC IN", data);
  		if (ret) {
  			dev_err(dev, "Cannot request irq %d for DC (%d)
  ",
  					gpio_to_irq(pdata->dok), ret);
  			goto err_psy;
  		}
  	}
  
  	if (pdata->usb_valid) {
  		ret = request_threaded_irq(gpio_to_irq(pdata->uok),
  				NULL, max8903_usbin,
  				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
  				"MAX8903 USB IN", data);
  		if (ret) {
  			dev_err(dev, "Cannot request irq %d for USB (%d)
  ",
  					gpio_to_irq(pdata->uok), ret);
  			goto err_dc_irq;
  		}
  	}
  
  	if (pdata->flt) {
  		ret = request_threaded_irq(gpio_to_irq(pdata->flt),
  				NULL, max8903_fault,
  				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
  				"MAX8903 Fault", data);
  		if (ret) {
  			dev_err(dev, "Cannot request irq %d for Fault (%d)
  ",
  					gpio_to_irq(pdata->flt), ret);
  			goto err_usb_irq;
  		}
  	}
  
  	return 0;
  
  err_usb_irq:
  	if (pdata->usb_valid)
  		free_irq(gpio_to_irq(pdata->uok), data);
  err_dc_irq:
  	if (pdata->dc_valid)
  		free_irq(gpio_to_irq(pdata->dok), data);
  err_psy:
  	power_supply_unregister(&data->psy);
  err:
  	return ret;
  }
  
  static int max8903_remove(struct platform_device *pdev)
  {
  	struct max8903_data *data = platform_get_drvdata(pdev);
  
  	if (data) {
  		struct max8903_pdata *pdata = &data->pdata;
  
  		if (pdata->flt)
  			free_irq(gpio_to_irq(pdata->flt), data);
  		if (pdata->usb_valid)
  			free_irq(gpio_to_irq(pdata->uok), data);
  		if (pdata->dc_valid)
  			free_irq(gpio_to_irq(pdata->dok), data);
  		power_supply_unregister(&data->psy);
  	}
  
  	return 0;
  }
  
  static struct platform_driver max8903_driver = {
  	.probe	= max8903_probe,
  	.remove	= max8903_remove,
  	.driver = {
  		.name	= "max8903-charger",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver(max8903_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("MAX8903 Charger Driver");
  MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
  MODULE_ALIAS("platform:max8903-charger");