/*
   * Battery charger driver for the Maxim 14577
   *
   * Copyright (C) 2013 Samsung Electronics
   * Krzysztof Kozlowski <k.kozlowski@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.
   */
  
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/power_supply.h>
  #include <linux/mfd/max14577-private.h>
  
  struct max14577_charger {
  	struct device *dev;
  	struct max14577	*max14577;
  	struct power_supply	charger;
  
  	unsigned int	charging_state;
  	unsigned int	battery_state;
  };
  
  static int max14577_get_charger_state(struct max14577_charger *chg)
  {
  	struct regmap *rmap = chg->max14577->regmap;
  	int state = POWER_SUPPLY_STATUS_DISCHARGING;
  	u8 reg_data;
  
  	/*
  	 * Charging occurs only if:
  	 *  - CHGCTRL2/MBCHOSTEN == 1
  	 *  - STATUS2/CGMBC == 1
  	 *
  	 * TODO:
  	 *  - handle FULL after Top-off timer (EOC register may be off
  	 *    and the charger won't be charging although MBCHOSTEN is on)
  	 *  - handle properly dead-battery charging (respect timer)
  	 *  - handle timers (fast-charge and prequal) /MBCCHGERR/
  	 */
  	max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
  	if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0)
  		goto state_set;
  
  	max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
  	if (reg_data & STATUS3_CGMBC_MASK) {
  		/* Charger or USB-cable is connected */
  		if (reg_data & STATUS3_EOC_MASK)
  			state = POWER_SUPPLY_STATUS_FULL;
  		else
  			state = POWER_SUPPLY_STATUS_CHARGING;
  		goto state_set;
  	}
  
  state_set:
  	chg->charging_state = state;
  	return state;
  }
  
  /*
   * Supported charge types:
   *  - POWER_SUPPLY_CHARGE_TYPE_NONE
   *  - POWER_SUPPLY_CHARGE_TYPE_FAST
   */
  static int max14577_get_charge_type(struct max14577_charger *chg)
  {
  	/*
  	 * TODO: CHARGE_TYPE_TRICKLE (VCHGR_RC or EOC)?
  	 * As spec says:
  	 * [after reaching EOC interrupt]
  	 * "When the battery is fully charged, the 30-minute (typ)
  	 *  top-off timer starts. The device continues to trickle
  	 *  charge the battery until the top-off timer runs out."
  	 */
  	if (max14577_get_charger_state(chg) == POWER_SUPPLY_STATUS_CHARGING)
  		return POWER_SUPPLY_CHARGE_TYPE_FAST;
  	return POWER_SUPPLY_CHARGE_TYPE_NONE;
  }
  
  static int max14577_get_online(struct max14577_charger *chg)
  {
  	struct regmap *rmap = chg->max14577->regmap;
  	u8 reg_data;
  
  	max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
  	reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
  	switch (reg_data) {
  	case MAX14577_CHARGER_TYPE_USB:
  	case MAX14577_CHARGER_TYPE_DEDICATED_CHG:
  	case MAX14577_CHARGER_TYPE_SPECIAL_500MA:
  	case MAX14577_CHARGER_TYPE_SPECIAL_1A:
  	case MAX14577_CHARGER_TYPE_DEAD_BATTERY:
  		return 1;
  	case MAX14577_CHARGER_TYPE_NONE:
  	case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT:
  	case MAX14577_CHARGER_TYPE_RESERVED:
  	default:
  		return 0;
  	}
  }
  
  /*
   * Supported health statuses:
   *  - POWER_SUPPLY_HEALTH_DEAD
   *  - POWER_SUPPLY_HEALTH_OVERVOLTAGE
   *  - POWER_SUPPLY_HEALTH_GOOD
   */
  static int max14577_get_battery_health(struct max14577_charger *chg)
  {
  	struct regmap *rmap = chg->max14577->regmap;
  	int state = POWER_SUPPLY_HEALTH_GOOD;
  	u8 reg_data;
  
  	max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
  	reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
  	if (reg_data == MAX14577_CHARGER_TYPE_DEAD_BATTERY) {
  		state = POWER_SUPPLY_HEALTH_DEAD;
  		goto state_set;
  	}
  
  	max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
  	if (reg_data & STATUS3_OVP_MASK) {
  		state = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
  		goto state_set;
  	}
  
  state_set:
  	chg->battery_state = state;
  	return state;
  }
  
  /*
   * Always returns 1.
   * The max14577 chip doesn't report any status of battery presence.
   * Lets assume that it will always be used with some battery.
   */
  static int max14577_get_present(struct max14577_charger *chg)
  {
  	return 1;
  }
  
  /*
   * Sets charger registers to proper and safe default values.
   * Some of these values are equal to defaults in MAX14577E
   * data sheet but there are minor differences.
   */
  static void max14577_charger_reg_init(struct max14577_charger *chg)
  {
  	struct regmap *rmap = chg->max14577->regmap;
  	u8 reg_data;
  
  	/*
  	 * Charger-Type Manual Detection, default off (set CHGTYPMAN to 0)
  	 * Charger-Detection Enable, default on (set CHGDETEN to 1)
  	 * Combined mask of CHGDETEN and CHGTYPMAN will zero the CHGTYPMAN bit
  	 */
  	reg_data = 0x1 << CDETCTRL1_CHGDETEN_SHIFT;
  	max14577_update_reg(rmap, MAX14577_REG_CDETCTRL1,
  			CDETCTRL1_CHGDETEN_MASK | CDETCTRL1_CHGTYPMAN_MASK,
  			reg_data);
  
  	/* Battery Fast-Charge Timer, from SM-V700: 6hrs */
  	reg_data = 0x3 << CHGCTRL1_TCHW_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL1, reg_data);
  
  	/*
  	 * Wall-Adapter Rapid Charge, default on
  	 * Battery-Charger, default on
  	 */
  	reg_data = 0x1 << CHGCTRL2_VCHGR_RC_SHIFT;
  	reg_data |= 0x1 << CHGCTRL2_MBCHOSTEN_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL2, reg_data);
  
  	/* Battery-Charger Constant Voltage (CV) Mode, from SM-V700: 4.35V */
  	reg_data = 0xf << CHGCTRL3_MBCCVWRC_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL3, reg_data);
  
  	/*
  	 * Fast Battery-Charge Current Low, default 200-950mA
  	 * Fast Battery-Charge Current High, from SM-V700: 450mA
  	 */
  	reg_data = 0x1 << CHGCTRL4_MBCICHWRCL_SHIFT;
  	reg_data |= 0x5 << CHGCTRL4_MBCICHWRCH_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL4, reg_data);
  
  	/* End-of-Charge Current, from SM-V700: 50mA */
  	reg_data = 0x0 << CHGCTRL5_EOCS_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL5, reg_data);
  
  	/* Auto Charging Stop, default off */
  	reg_data = 0x0 << CHGCTRL6_AUTOSTOP_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL6, reg_data);
  
  	/* Overvoltage-Protection Threshold, from SM-V700: 6.5V */
  	reg_data = 0x2 << CHGCTRL7_OTPCGHCVS_SHIFT;
  	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL7, reg_data);
  }
  
  /* Support property from charger */
  static enum power_supply_property max14577_charger_props[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_CHARGE_TYPE,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_PRESENT,
  	POWER_SUPPLY_PROP_ONLINE,
  	POWER_SUPPLY_PROP_MODEL_NAME,
  	POWER_SUPPLY_PROP_MANUFACTURER,
  };
  
  static const char *model_name = "MAX14577";
  static const char *manufacturer = "Maxim Integrated";
  
  static int max14577_charger_get_property(struct power_supply *psy,
  			    enum power_supply_property psp,
  			    union power_supply_propval *val)
  {
  	struct max14577_charger *chg = container_of(psy,
  						  struct max14577_charger,
  						  charger);
  	int ret = 0;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:
  		val->intval = max14577_get_charger_state(chg);
  		break;
  	case POWER_SUPPLY_PROP_CHARGE_TYPE:
  		val->intval = max14577_get_charge_type(chg);
  		break;
  	case POWER_SUPPLY_PROP_HEALTH:
  		val->intval = max14577_get_battery_health(chg);
  		break;
  	case POWER_SUPPLY_PROP_PRESENT:
  		val->intval = max14577_get_present(chg);
  		break;
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = max14577_get_online(chg);
  		break;
  	case POWER_SUPPLY_PROP_MODEL_NAME:
  		val->strval = model_name;
  		break;
  	case POWER_SUPPLY_PROP_MANUFACTURER:
  		val->strval = manufacturer;
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return ret;
  }
  
  static int max14577_charger_probe(struct platform_device *pdev)
  {
  	struct max14577_charger *chg;
  	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
  	int ret;
  
  	chg = devm_kzalloc(&pdev->dev, sizeof(*chg), GFP_KERNEL);
  	if (!chg)
  		return -ENOMEM;
  
  	platform_set_drvdata(pdev, chg);
  	chg->dev = &pdev->dev;
  	chg->max14577 = max14577;
  
  	max14577_charger_reg_init(chg);
  
  	chg->charger.name = "max14577-charger",
  	chg->charger.type = POWER_SUPPLY_TYPE_BATTERY,
  	chg->charger.properties = max14577_charger_props,
  	chg->charger.num_properties = ARRAY_SIZE(max14577_charger_props),
  	chg->charger.get_property = max14577_charger_get_property,
  
  	ret = power_supply_register(&pdev->dev, &chg->charger);
  	if (ret) {
  		dev_err(&pdev->dev, "failed: power supply register
  ");
  		return ret;
  	}
  
  	return 0;
  }
  
  static int max14577_charger_remove(struct platform_device *pdev)
  {
  	struct max14577_charger *chg = platform_get_drvdata(pdev);
  
  	power_supply_unregister(&chg->charger);
  
  	return 0;
  }
  
  static struct platform_driver max14577_charger_driver = {
  	.driver = {
  		.owner	= THIS_MODULE,
  		.name	= "max14577-charger",
  	},
  	.probe		= max14577_charger_probe,
  	.remove		= max14577_charger_remove,
  };
  module_platform_driver(max14577_charger_driver);
  
  MODULE_AUTHOR("Krzysztof Kozlowski <k.kozlowski@samsung.com>");
  MODULE_DESCRIPTION("MAXIM 14577 charger driver");
  MODULE_LICENSE("GPL");