/*
   * Generic battery driver code using IIO
   * Copyright (C) 2012, Anish Kumar <anish198519851985@gmail.com>
   * based on jz4740-battery.c
   * based on s3c_adc_battery.c
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file COPYING in the main directory of this archive for
   * more details.
   *
   */
  #include <linux/interrupt.h>
  #include <linux/platform_device.h>
  #include <linux/power_supply.h>
  #include <linux/gpio.h>
  #include <linux/err.h>
  #include <linux/timer.h>
  #include <linux/jiffies.h>
  #include <linux/errno.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/iio/consumer.h>
  #include <linux/iio/types.h>
  #include <linux/power/generic-adc-battery.h>
  
  #define JITTER_DEFAULT 10 /* hope 10ms is enough */
  
  enum gab_chan_type {
  	GAB_VOLTAGE = 0,
  	GAB_CURRENT,
  	GAB_POWER,
  	GAB_MAX_CHAN_TYPE
  };
  
  /*
   * gab_chan_name suggests the standard channel names for commonly used
   * channel types.
   */
  static const char *const gab_chan_name[] = {
  	[GAB_VOLTAGE]	= "voltage",
  	[GAB_CURRENT]	= "current",
  	[GAB_POWER]		= "power",
  };
  
  struct gab {

  	struct power_supply		*psy;
  	struct power_supply_desc	psy_desc;

  	struct iio_channel	*channel[GAB_MAX_CHAN_TYPE];
  	struct gab_platform_data	*pdata;
  	struct delayed_work bat_work;
  	int	level;
  	int	status;
  	bool cable_plugged;
  };
  
  static struct gab *to_generic_bat(struct power_supply *psy)
  {

  	return power_supply_get_drvdata(psy);

  }
  
  static void gab_ext_power_changed(struct power_supply *psy)
  {
  	struct gab *adc_bat = to_generic_bat(psy);
  
  	schedule_delayed_work(&adc_bat->bat_work, msecs_to_jiffies(0));
  }
  
  static const enum power_supply_property gab_props[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
  	POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN,
  	POWER_SUPPLY_PROP_CHARGE_NOW,
  	POWER_SUPPLY_PROP_VOLTAGE_NOW,
  	POWER_SUPPLY_PROP_CURRENT_NOW,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
  	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
  	POWER_SUPPLY_PROP_MODEL_NAME,
  };
  
  /*
   * This properties are set based on the received platform data and this
   * should correspond one-to-one with enum chan_type.
   */
  static const enum power_supply_property gab_dyn_props[] = {
  	POWER_SUPPLY_PROP_VOLTAGE_NOW,
  	POWER_SUPPLY_PROP_CURRENT_NOW,
  	POWER_SUPPLY_PROP_POWER_NOW,
  };
  
  static bool gab_charge_finished(struct gab *adc_bat)
  {
  	struct gab_platform_data *pdata = adc_bat->pdata;
  	bool ret = gpio_get_value(pdata->gpio_charge_finished);
  	bool inv = pdata->gpio_inverted;
  
  	if (!gpio_is_valid(pdata->gpio_charge_finished))
  		return false;
  	return ret ^ inv;
  }
  
  static int gab_get_status(struct gab *adc_bat)
  {
  	struct gab_platform_data *pdata = adc_bat->pdata;
  	struct power_supply_info *bat_info;
  
  	bat_info = &pdata->battery_info;
  	if (adc_bat->level == bat_info->charge_full_design)
  		return POWER_SUPPLY_STATUS_FULL;
  	return adc_bat->status;
  }
  
  static enum gab_chan_type gab_prop_to_chan(enum power_supply_property psp)
  {
  	switch (psp) {
  	case POWER_SUPPLY_PROP_POWER_NOW:
  		return GAB_POWER;
  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  		return GAB_VOLTAGE;
  	case POWER_SUPPLY_PROP_CURRENT_NOW:
  		return GAB_CURRENT;
  	default:
  		WARN_ON(1);
  		break;
  	}
  	return GAB_POWER;
  }
  
  static int read_channel(struct gab *adc_bat, enum power_supply_property psp,
  		int *result)
  {
  	int ret;
  	int chan_index;
  
  	chan_index = gab_prop_to_chan(psp);
  	ret = iio_read_channel_processed(adc_bat->channel[chan_index],
  			result);
  	if (ret < 0)
  		pr_err("read channel error
  ");
  	return ret;
  }
  
  static int gab_get_property(struct power_supply *psy,
  		enum power_supply_property psp, union power_supply_propval *val)
  {
  	struct gab *adc_bat;
  	struct gab_platform_data *pdata;
  	struct power_supply_info *bat_info;
  	int result = 0;
  	int ret = 0;
  
  	adc_bat = to_generic_bat(psy);
  	if (!adc_bat) {

  		dev_err(&psy->dev, "no battery infos ?!
  ");

  		return -EINVAL;
  	}
  	pdata = adc_bat->pdata;
  	bat_info = &pdata->battery_info;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:

  		val->intval = gab_get_status(adc_bat);

  		break;
  	case POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN:
  		val->intval = 0;
  		break;
  	case POWER_SUPPLY_PROP_CHARGE_NOW:
  		val->intval = pdata->cal_charge(result);
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  	case POWER_SUPPLY_PROP_CURRENT_NOW:
  	case POWER_SUPPLY_PROP_POWER_NOW:
  		ret = read_channel(adc_bat, psp, &result);
  		if (ret < 0)
  			goto err;
  		val->intval = result;
  		break;
  	case POWER_SUPPLY_PROP_TECHNOLOGY:
  		val->intval = bat_info->technology;
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
  		val->intval = bat_info->voltage_min_design;
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
  		val->intval = bat_info->voltage_max_design;
  		break;
  	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
  		val->intval = bat_info->charge_full_design;
  		break;
  	case POWER_SUPPLY_PROP_MODEL_NAME:
  		val->strval = bat_info->name;
  		break;
  	default:
  		return -EINVAL;
  	}
  err:
  	return ret;
  }
  
  static void gab_work(struct work_struct *work)
  {
  	struct gab *adc_bat;
  	struct gab_platform_data *pdata;
  	struct delayed_work *delayed_work;
  	bool is_plugged;
  	int status;

  	delayed_work = to_delayed_work(work);

  	adc_bat = container_of(delayed_work, struct gab, bat_work);
  	pdata = adc_bat->pdata;
  	status = adc_bat->status;

  	is_plugged = power_supply_am_i_supplied(adc_bat->psy);

  	adc_bat->cable_plugged = is_plugged;
  
  	if (!is_plugged)
  		adc_bat->status =  POWER_SUPPLY_STATUS_DISCHARGING;
  	else if (gab_charge_finished(adc_bat))
  		adc_bat->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
  	else
  		adc_bat->status = POWER_SUPPLY_STATUS_CHARGING;
  
  	if (status != adc_bat->status)

  		power_supply_changed(adc_bat->psy);

  }
  
  static irqreturn_t gab_charged(int irq, void *dev_id)
  {
  	struct gab *adc_bat = dev_id;
  	struct gab_platform_data *pdata = adc_bat->pdata;
  	int delay;
  
  	delay = pdata->jitter_delay ? pdata->jitter_delay : JITTER_DEFAULT;
  	schedule_delayed_work(&adc_bat->bat_work,
  			msecs_to_jiffies(delay));
  	return IRQ_HANDLED;
  }

  static int gab_probe(struct platform_device *pdev)

  {
  	struct gab *adc_bat;

  	struct power_supply_desc *psy_desc;
  	struct power_supply_config psy_cfg = {};

  	struct gab_platform_data *pdata = pdev->dev.platform_data;
  	enum power_supply_property *properties;
  	int ret = 0;
  	int chan;
  	int index = 0;
  
  	adc_bat = devm_kzalloc(&pdev->dev, sizeof(*adc_bat), GFP_KERNEL);
  	if (!adc_bat) {
  		dev_err(&pdev->dev, "failed to allocate memory
  ");
  		return -ENOMEM;
  	}

  	psy_cfg.drv_data = adc_bat;
  	psy_desc = &adc_bat->psy_desc;
  	psy_desc->name = pdata->battery_info.name;

  
  	/* bootup default values for the battery */
  	adc_bat->cable_plugged = false;
  	adc_bat->status = POWER_SUPPLY_STATUS_DISCHARGING;

  	psy_desc->type = POWER_SUPPLY_TYPE_BATTERY;
  	psy_desc->get_property = gab_get_property;
  	psy_desc->external_power_changed = gab_ext_power_changed;

  	adc_bat->pdata = pdata;

  	/*
  	 * copying the static properties and allocating extra memory for holding
  	 * the extra configurable properties received from platform data.
  	 */

  	psy_desc->properties = kcalloc(ARRAY_SIZE(gab_props) +

  					ARRAY_SIZE(gab_chan_name),

  					sizeof(*psy_desc->properties),
  					GFP_KERNEL);
  	if (!psy_desc->properties) {

  		ret = -ENOMEM;
  		goto first_mem_fail;
  	}

  	memcpy(psy_desc->properties, gab_props, sizeof(gab_props));

  	properties = (enum power_supply_property *)

  			((char *)psy_desc->properties + sizeof(gab_props));

  
  	/*
  	 * getting channel from iio and copying the battery properties
  	 * based on the channel supported by consumer device.
  	 */
  	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {

  		adc_bat->channel[chan] = iio_channel_get(&pdev->dev,
  							 gab_chan_name[chan]);

  		if (IS_ERR(adc_bat->channel[chan])) {
  			ret = PTR_ERR(adc_bat->channel[chan]);

  			adc_bat->channel[chan] = NULL;

  		} else {
  			/* copying properties for supported channels only */

  			memcpy(properties + sizeof(*(psy_desc->properties)) * index,

  					&gab_dyn_props[chan],
  					sizeof(gab_dyn_props[chan]));
  			index++;
  		}
  	}
  
  	/* none of the channels are supported so let's bail out */

  	if (index == 0) {
  		ret = -ENODEV;

  		goto second_mem_fail;

  	}

  
  	/*
  	 * Total number of properties is equal to static properties
  	 * plus the dynamic properties.Some properties may not be set
  	 * as come channels may be not be supported by the device.So
  	 * we need to take care of that.
  	 */

  	psy_desc->num_properties = ARRAY_SIZE(gab_props) + index;

  	adc_bat->psy = power_supply_register(&pdev->dev, psy_desc, &psy_cfg);
  	if (IS_ERR(adc_bat->psy)) {
  		ret = PTR_ERR(adc_bat->psy);

  		goto err_reg_fail;

  	}

  
  	INIT_DELAYED_WORK(&adc_bat->bat_work, gab_work);
  
  	if (gpio_is_valid(pdata->gpio_charge_finished)) {
  		int irq;
  		ret = gpio_request(pdata->gpio_charge_finished, "charged");
  		if (ret)
  			goto gpio_req_fail;
  
  		irq = gpio_to_irq(pdata->gpio_charge_finished);
  		ret = request_any_context_irq(irq, gab_charged,
  				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
  				"battery charged", adc_bat);

  		if (ret < 0)

  			goto err_gpio;
  	}
  
  	platform_set_drvdata(pdev, adc_bat);
  
  	/* Schedule timer to check current status */
  	schedule_delayed_work(&adc_bat->bat_work,
  			msecs_to_jiffies(0));
  	return 0;
  
  err_gpio:
  	gpio_free(pdata->gpio_charge_finished);
  gpio_req_fail:

  	power_supply_unregister(adc_bat->psy);

  err_reg_fail:

  	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
  		if (adc_bat->channel[chan])
  			iio_channel_release(adc_bat->channel[chan]);
  	}

  second_mem_fail:

  	kfree(psy_desc->properties);

  first_mem_fail:
  	return ret;
  }

  static int gab_remove(struct platform_device *pdev)

  {
  	int chan;
  	struct gab *adc_bat = platform_get_drvdata(pdev);
  	struct gab_platform_data *pdata = adc_bat->pdata;

  	power_supply_unregister(adc_bat->psy);

  
  	if (gpio_is_valid(pdata->gpio_charge_finished)) {
  		free_irq(gpio_to_irq(pdata->gpio_charge_finished), adc_bat);
  		gpio_free(pdata->gpio_charge_finished);
  	}

  	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
  		if (adc_bat->channel[chan])
  			iio_channel_release(adc_bat->channel[chan]);
  	}

  	kfree(adc_bat->psy_desc.properties);

  	cancel_delayed_work(&adc_bat->bat_work);
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int gab_suspend(struct device *dev)
  {
  	struct gab *adc_bat = dev_get_drvdata(dev);
  
  	cancel_delayed_work_sync(&adc_bat->bat_work);
  	adc_bat->status = POWER_SUPPLY_STATUS_UNKNOWN;
  	return 0;
  }
  
  static int gab_resume(struct device *dev)
  {
  	struct gab *adc_bat = dev_get_drvdata(dev);
  	struct gab_platform_data *pdata = adc_bat->pdata;
  	int delay;
  
  	delay = pdata->jitter_delay ? pdata->jitter_delay : JITTER_DEFAULT;
  
  	/* Schedule timer to check current status */
  	schedule_delayed_work(&adc_bat->bat_work,
  			msecs_to_jiffies(delay));
  	return 0;
  }
  
  static const struct dev_pm_ops gab_pm_ops = {
  	.suspend        = gab_suspend,
  	.resume         = gab_resume,
  };
  
  #define GAB_PM_OPS       (&gab_pm_ops)
  #else
  #define GAB_PM_OPS       (NULL)
  #endif
  
  static struct platform_driver gab_driver = {
  	.driver		= {
  		.name	= "generic-adc-battery",

  		.pm	= GAB_PM_OPS
  	},
  	.probe		= gab_probe,

  	.remove		= gab_remove,

  };
  module_platform_driver(gab_driver);
  
  MODULE_AUTHOR("anish kumar <anish198519851985@gmail.com>");
  MODULE_DESCRIPTION("generic battery driver using IIO");
  MODULE_LICENSE("GPL");