/*
   * Power supply driver for the goldfish emulator
   *
   * Copyright (C) 2008 Google, Inc.
   * Copyright (C) 2012 Intel, Inc.
   * Copyright (C) 2013 Intel, Inc.
   * Author: Mike Lockwood <lockwood@android.com>
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * 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.
   */
  
  #include <linux/module.h>
  #include <linux/err.h>
  #include <linux/platform_device.h>
  #include <linux/power_supply.h>
  #include <linux/types.h>
  #include <linux/pci.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  
  struct goldfish_battery_data {
  	void __iomem *reg_base;
  	int irq;
  	spinlock_t lock;
  
  	struct power_supply battery;
  	struct power_supply ac;
  };
  
  #define GOLDFISH_BATTERY_READ(data, addr) \
  	(readl(data->reg_base + addr))
  #define GOLDFISH_BATTERY_WRITE(data, addr, x) \
  	(writel(x, data->reg_base + addr))
  
  /*
   * Temporary variable used between goldfish_battery_probe() and
   * goldfish_battery_open().
   */
  static struct goldfish_battery_data *battery_data;
  
  enum {
  	/* status register */
  	BATTERY_INT_STATUS	    = 0x00,
  	/* set this to enable IRQ */
  	BATTERY_INT_ENABLE	    = 0x04,
  
  	BATTERY_AC_ONLINE       = 0x08,
  	BATTERY_STATUS          = 0x0C,
  	BATTERY_HEALTH          = 0x10,
  	BATTERY_PRESENT         = 0x14,
  	BATTERY_CAPACITY        = 0x18,
  
  	BATTERY_STATUS_CHANGED	= 1U << 0,
  	AC_STATUS_CHANGED	= 1U << 1,
  	BATTERY_INT_MASK        = BATTERY_STATUS_CHANGED | AC_STATUS_CHANGED,
  };
  
  
  static int goldfish_ac_get_property(struct power_supply *psy,
  			enum power_supply_property psp,
  			union power_supply_propval *val)
  {
  	struct goldfish_battery_data *data = container_of(psy,
  		struct goldfish_battery_data, ac);
  	int ret = 0;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = GOLDFISH_BATTERY_READ(data, BATTERY_AC_ONLINE);
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  	return ret;
  }
  
  static int goldfish_battery_get_property(struct power_supply *psy,
  				 enum power_supply_property psp,
  				 union power_supply_propval *val)
  {
  	struct goldfish_battery_data *data = container_of(psy,
  		struct goldfish_battery_data, battery);
  	int ret = 0;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:
  		val->intval = GOLDFISH_BATTERY_READ(data, BATTERY_STATUS);
  		break;
  	case POWER_SUPPLY_PROP_HEALTH:
  		val->intval = GOLDFISH_BATTERY_READ(data, BATTERY_HEALTH);
  		break;
  	case POWER_SUPPLY_PROP_PRESENT:
  		val->intval = GOLDFISH_BATTERY_READ(data, BATTERY_PRESENT);
  		break;
  	case POWER_SUPPLY_PROP_TECHNOLOGY:
  		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
  		break;
  	case POWER_SUPPLY_PROP_CAPACITY:
  		val->intval = GOLDFISH_BATTERY_READ(data, BATTERY_CAPACITY);
  		break;
  	default:
  		ret = -EINVAL;
  		break;
  	}
  
  	return ret;
  }
  
  static enum power_supply_property goldfish_battery_props[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_PRESENT,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_CAPACITY,
  };
  
  static enum power_supply_property goldfish_ac_props[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static irqreturn_t goldfish_battery_interrupt(int irq, void *dev_id)
  {
  	unsigned long irq_flags;
  	struct goldfish_battery_data *data = dev_id;
  	uint32_t status;
  
  	spin_lock_irqsave(&data->lock, irq_flags);
  
  	/* read status flags, which will clear the interrupt */
  	status = GOLDFISH_BATTERY_READ(data, BATTERY_INT_STATUS);
  	status &= BATTERY_INT_MASK;
  
  	if (status & BATTERY_STATUS_CHANGED)
  		power_supply_changed(&data->battery);
  	if (status & AC_STATUS_CHANGED)
  		power_supply_changed(&data->ac);
  
  	spin_unlock_irqrestore(&data->lock, irq_flags);
  	return status ? IRQ_HANDLED : IRQ_NONE;
  }
  
  
  static int goldfish_battery_probe(struct platform_device *pdev)
  {
  	int ret;
  	struct resource *r;
  	struct goldfish_battery_data *data;
  
  	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  	if (data == NULL)
  		return -ENOMEM;
  
  	spin_lock_init(&data->lock);
  
  	data->battery.properties = goldfish_battery_props;
  	data->battery.num_properties = ARRAY_SIZE(goldfish_battery_props);
  	data->battery.get_property = goldfish_battery_get_property;
  	data->battery.name = "battery";
  	data->battery.type = POWER_SUPPLY_TYPE_BATTERY;
  
  	data->ac.properties = goldfish_ac_props;
  	data->ac.num_properties = ARRAY_SIZE(goldfish_ac_props);
  	data->ac.get_property = goldfish_ac_get_property;
  	data->ac.name = "ac";
  	data->ac.type = POWER_SUPPLY_TYPE_MAINS;
  
  	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (r == NULL) {
  		dev_err(&pdev->dev, "platform_get_resource failed
  ");
  		return -ENODEV;
  	}
  
  	data->reg_base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
  	if (data->reg_base == NULL) {
  		dev_err(&pdev->dev, "unable to remap MMIO
  ");
  		return -ENOMEM;
  	}
  
  	data->irq = platform_get_irq(pdev, 0);
  	if (data->irq < 0) {
  		dev_err(&pdev->dev, "platform_get_irq failed
  ");
  		return -ENODEV;
  	}
  
  	ret = devm_request_irq(&pdev->dev, data->irq, goldfish_battery_interrupt,
  						IRQF_SHARED, pdev->name, data);
  	if (ret)
  		return ret;
  
  	ret = power_supply_register(&pdev->dev, &data->ac);
  	if (ret)
  		return ret;
  
  	ret = power_supply_register(&pdev->dev, &data->battery);
  	if (ret) {
  		power_supply_unregister(&data->ac);
  		return ret;
  	}
  
  	platform_set_drvdata(pdev, data);
  	battery_data = data;
  
  	GOLDFISH_BATTERY_WRITE(data, BATTERY_INT_ENABLE, BATTERY_INT_MASK);
  	return 0;
  }
  
  static int goldfish_battery_remove(struct platform_device *pdev)
  {
  	struct goldfish_battery_data *data = platform_get_drvdata(pdev);
  
  	power_supply_unregister(&data->battery);
  	power_supply_unregister(&data->ac);
  	battery_data = NULL;
  	return 0;
  }
  
  static struct platform_driver goldfish_battery_device = {
  	.probe		= goldfish_battery_probe,
  	.remove		= goldfish_battery_remove,
  	.driver = {
  		.name = "goldfish-battery"
  	}
  };
  module_platform_driver(goldfish_battery_device);
  
  MODULE_AUTHOR("Mike Lockwood lockwood@android.com");
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Battery driver for the Goldfish emulator");