/*
   * Driver for LP8727 Micro/Mini USB IC with integrated charger
   *
   *			Copyright (C) 2011 Texas Instruments
   *			Copyright (C) 2011 National Semiconductor
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/interrupt.h>
  #include <linux/i2c.h>
  #include <linux/power_supply.h>
  #include <linux/platform_data/lp8727.h>
  #include <linux/of.h>
  
  #define LP8788_NUM_INTREGS	2
  #define DEFAULT_DEBOUNCE_MSEC	270
  
  /* Registers */
  #define LP8727_CTRL1		0x1
  #define LP8727_CTRL2		0x2
  #define LP8727_SWCTRL		0x3
  #define LP8727_INT1		0x4
  #define LP8727_INT2		0x5
  #define LP8727_STATUS1		0x6
  #define LP8727_STATUS2		0x7
  #define LP8727_CHGCTRL2		0x9
  
  /* CTRL1 register */
  #define LP8727_CP_EN		BIT(0)
  #define LP8727_ADC_EN		BIT(1)
  #define LP8727_ID200_EN		BIT(4)
  
  /* CTRL2 register */
  #define LP8727_CHGDET_EN	BIT(1)
  #define LP8727_INT_EN		BIT(6)
  
  /* SWCTRL register */
  #define LP8727_SW_DM1_DM	(0x0 << 0)
  #define LP8727_SW_DM1_HiZ	(0x7 << 0)
  #define LP8727_SW_DP2_DP	(0x0 << 3)
  #define LP8727_SW_DP2_HiZ	(0x7 << 3)
  
  /* INT1 register */
  #define LP8727_IDNO		(0xF << 0)
  #define LP8727_VBUS		BIT(4)
  
  /* STATUS1 register */
  #define LP8727_CHGSTAT		(3 << 4)
  #define LP8727_CHPORT		BIT(6)
  #define LP8727_DCPORT		BIT(7)
  #define LP8727_STAT_EOC		0x30
  
  /* STATUS2 register */
  #define LP8727_TEMP_STAT	(3 << 5)
  #define LP8727_TEMP_SHIFT	5
  
  /* CHGCTRL2 register */
  #define LP8727_ICHG_SHIFT	4
  
  enum lp8727_dev_id {
  	LP8727_ID_NONE,
  	LP8727_ID_TA,
  	LP8727_ID_DEDICATED_CHG,
  	LP8727_ID_USB_CHG,
  	LP8727_ID_USB_DS,
  	LP8727_ID_MAX,
  };
  
  enum lp8727_die_temp {
  	LP8788_TEMP_75C,
  	LP8788_TEMP_95C,
  	LP8788_TEMP_115C,
  	LP8788_TEMP_135C,
  };
  
  struct lp8727_psy {
  	struct power_supply ac;
  	struct power_supply usb;
  	struct power_supply batt;
  };
  
  struct lp8727_chg {
  	struct device *dev;
  	struct i2c_client *client;
  	struct mutex xfer_lock;
  	struct lp8727_psy *psy;
  	struct lp8727_platform_data *pdata;
  
  	/* Charger Data */
  	enum lp8727_dev_id devid;
  	struct lp8727_chg_param *chg_param;
  
  	/* Interrupt Handling */
  	int irq;
  	struct delayed_work work;
  	unsigned long debounce_jiffies;
  };
  
  static int lp8727_read_bytes(struct lp8727_chg *pchg, u8 reg, u8 *data, u8 len)
  {
  	s32 ret;
  
  	mutex_lock(&pchg->xfer_lock);
  	ret = i2c_smbus_read_i2c_block_data(pchg->client, reg, len, data);
  	mutex_unlock(&pchg->xfer_lock);
  
  	return (ret != len) ? -EIO : 0;
  }
  
  static inline int lp8727_read_byte(struct lp8727_chg *pchg, u8 reg, u8 *data)
  {
  	return lp8727_read_bytes(pchg, reg, data, 1);
  }
  
  static int lp8727_write_byte(struct lp8727_chg *pchg, u8 reg, u8 data)
  {
  	int ret;
  
  	mutex_lock(&pchg->xfer_lock);
  	ret = i2c_smbus_write_byte_data(pchg->client, reg, data);
  	mutex_unlock(&pchg->xfer_lock);
  
  	return ret;
  }
  
  static bool lp8727_is_charger_attached(const char *name, int id)
  {
  	if (!strcmp(name, "ac"))
  		return id == LP8727_ID_TA || id == LP8727_ID_DEDICATED_CHG;
  	else if (!strcmp(name, "usb"))
  		return id == LP8727_ID_USB_CHG;
  
  	return id >= LP8727_ID_TA && id <= LP8727_ID_USB_CHG;
  }
  
  static int lp8727_init_device(struct lp8727_chg *pchg)
  {
  	u8 val;
  	int ret;
  	u8 intstat[LP8788_NUM_INTREGS];
  
  	/* clear interrupts */
  	ret = lp8727_read_bytes(pchg, LP8727_INT1, intstat, LP8788_NUM_INTREGS);
  	if (ret)
  		return ret;
  
  	val = LP8727_ID200_EN | LP8727_ADC_EN | LP8727_CP_EN;
  	ret = lp8727_write_byte(pchg, LP8727_CTRL1, val);
  	if (ret)
  		return ret;
  
  	val = LP8727_INT_EN | LP8727_CHGDET_EN;
  	return lp8727_write_byte(pchg, LP8727_CTRL2, val);
  }
  
  static int lp8727_is_dedicated_charger(struct lp8727_chg *pchg)
  {
  	u8 val;
  
  	lp8727_read_byte(pchg, LP8727_STATUS1, &val);
  	return val & LP8727_DCPORT;
  }
  
  static int lp8727_is_usb_charger(struct lp8727_chg *pchg)
  {
  	u8 val;
  
  	lp8727_read_byte(pchg, LP8727_STATUS1, &val);
  	return val & LP8727_CHPORT;
  }
  
  static inline void lp8727_ctrl_switch(struct lp8727_chg *pchg, u8 sw)
  {
  	lp8727_write_byte(pchg, LP8727_SWCTRL, sw);
  }
  
  static void lp8727_id_detection(struct lp8727_chg *pchg, u8 id, int vbusin)
  {
  	struct lp8727_platform_data *pdata = pchg->pdata;
  	u8 devid = LP8727_ID_NONE;
  	u8 swctrl = LP8727_SW_DM1_HiZ | LP8727_SW_DP2_HiZ;
  
  	switch (id) {
  	case 0x5:
  		devid = LP8727_ID_TA;
  		pchg->chg_param = pdata ? pdata->ac : NULL;
  		break;
  	case 0xB:
  		if (lp8727_is_dedicated_charger(pchg)) {
  			pchg->chg_param = pdata ? pdata->ac : NULL;
  			devid = LP8727_ID_DEDICATED_CHG;
  		} else if (lp8727_is_usb_charger(pchg)) {
  			pchg->chg_param = pdata ? pdata->usb : NULL;
  			devid = LP8727_ID_USB_CHG;
  			swctrl = LP8727_SW_DM1_DM | LP8727_SW_DP2_DP;
  		} else if (vbusin) {
  			devid = LP8727_ID_USB_DS;
  			swctrl = LP8727_SW_DM1_DM | LP8727_SW_DP2_DP;
  		}
  		break;
  	default:
  		devid = LP8727_ID_NONE;
  		pchg->chg_param = NULL;
  		break;
  	}
  
  	pchg->devid = devid;
  	lp8727_ctrl_switch(pchg, swctrl);
  }
  
  static void lp8727_enable_chgdet(struct lp8727_chg *pchg)
  {
  	u8 val;
  
  	lp8727_read_byte(pchg, LP8727_CTRL2, &val);
  	val |= LP8727_CHGDET_EN;
  	lp8727_write_byte(pchg, LP8727_CTRL2, val);
  }
  
  static void lp8727_delayed_func(struct work_struct *_work)
  {
  	struct lp8727_chg *pchg = container_of(_work, struct lp8727_chg,
  						work.work);
  	u8 intstat[LP8788_NUM_INTREGS];
  	u8 idno;
  	u8 vbus;
  
  	if (lp8727_read_bytes(pchg, LP8727_INT1, intstat, LP8788_NUM_INTREGS)) {
  		dev_err(pchg->dev, "can not read INT registers
  ");
  		return;
  	}
  
  	idno = intstat[0] & LP8727_IDNO;
  	vbus = intstat[0] & LP8727_VBUS;
  
  	lp8727_id_detection(pchg, idno, vbus);
  	lp8727_enable_chgdet(pchg);
  
  	power_supply_changed(&pchg->psy->ac);
  	power_supply_changed(&pchg->psy->usb);
  	power_supply_changed(&pchg->psy->batt);
  }
  
  static irqreturn_t lp8727_isr_func(int irq, void *ptr)
  {
  	struct lp8727_chg *pchg = ptr;
  
  	schedule_delayed_work(&pchg->work, pchg->debounce_jiffies);
  	return IRQ_HANDLED;
  }
  
  static int lp8727_setup_irq(struct lp8727_chg *pchg)
  {
  	int ret;
  	int irq = pchg->client->irq;
  	unsigned delay_msec = pchg->pdata ? pchg->pdata->debounce_msec :
  						DEFAULT_DEBOUNCE_MSEC;
  
  	INIT_DELAYED_WORK(&pchg->work, lp8727_delayed_func);
  
  	if (irq <= 0) {
  		dev_warn(pchg->dev, "invalid irq number: %d
  ", irq);
  		return 0;
  	}
  
  	ret = request_threaded_irq(irq,	NULL, lp8727_isr_func,
  				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				"lp8727_irq", pchg);
  
  	if (ret)
  		return ret;
  
  	pchg->irq = irq;
  	pchg->debounce_jiffies = msecs_to_jiffies(delay_msec);
  
  	return 0;
  }
  
  static void lp8727_release_irq(struct lp8727_chg *pchg)
  {
  	cancel_delayed_work_sync(&pchg->work);
  
  	if (pchg->irq)
  		free_irq(pchg->irq, pchg);
  }
  
  static enum power_supply_property lp8727_charger_prop[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  };
  
  static enum power_supply_property lp8727_battery_prop[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_PRESENT,
  	POWER_SUPPLY_PROP_VOLTAGE_NOW,
  	POWER_SUPPLY_PROP_CAPACITY,
  	POWER_SUPPLY_PROP_TEMP,
  };
  
  static char *battery_supplied_to[] = {
  	"main_batt",
  };
  
  static int lp8727_charger_get_property(struct power_supply *psy,
  				       enum power_supply_property psp,
  				       union power_supply_propval *val)
  {
  	struct lp8727_chg *pchg = dev_get_drvdata(psy->dev->parent);
  
  	if (psp != POWER_SUPPLY_PROP_ONLINE)
  		return -EINVAL;
  
  	val->intval = lp8727_is_charger_attached(psy->name, pchg->devid);
  
  	return 0;
  }
  
  static bool lp8727_is_high_temperature(enum lp8727_die_temp temp)
  {
  	switch (temp) {
  	case LP8788_TEMP_95C:
  	case LP8788_TEMP_115C:
  	case LP8788_TEMP_135C:
  		return true;
  	default:
  		return false;
  	}
  }
  
  static int lp8727_battery_get_property(struct power_supply *psy,
  				       enum power_supply_property psp,
  				       union power_supply_propval *val)
  {
  	struct lp8727_chg *pchg = dev_get_drvdata(psy->dev->parent);
  	struct lp8727_platform_data *pdata = pchg->pdata;
  	enum lp8727_die_temp temp;
  	u8 read;
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:
  		if (!lp8727_is_charger_attached(psy->name, pchg->devid)) {
  			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  			return 0;
  		}
  
  		lp8727_read_byte(pchg, LP8727_STATUS1, &read);
  
  		val->intval = (read & LP8727_CHGSTAT) == LP8727_STAT_EOC ?
  				POWER_SUPPLY_STATUS_FULL :
  				POWER_SUPPLY_STATUS_CHARGING;
  		break;
  	case POWER_SUPPLY_PROP_HEALTH:
  		lp8727_read_byte(pchg, LP8727_STATUS2, &read);
  		temp = (read & LP8727_TEMP_STAT) >> LP8727_TEMP_SHIFT;
  
  		val->intval = lp8727_is_high_temperature(temp) ?
  			POWER_SUPPLY_HEALTH_OVERHEAT :
  			POWER_SUPPLY_HEALTH_GOOD;
  		break;
  	case POWER_SUPPLY_PROP_PRESENT:
  		if (!pdata)
  			return -EINVAL;
  
  		if (pdata->get_batt_present)
  			val->intval = pdata->get_batt_present();
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  		if (!pdata)
  			return -EINVAL;
  
  		if (pdata->get_batt_level)
  			val->intval = pdata->get_batt_level();
  		break;
  	case POWER_SUPPLY_PROP_CAPACITY:
  		if (!pdata)
  			return -EINVAL;
  
  		if (pdata->get_batt_capacity)
  			val->intval = pdata->get_batt_capacity();
  		break;
  	case POWER_SUPPLY_PROP_TEMP:
  		if (!pdata)
  			return -EINVAL;
  
  		if (pdata->get_batt_temp)
  			val->intval = pdata->get_batt_temp();
  		break;
  	default:
  		break;
  	}
  
  	return 0;
  }
  
  static void lp8727_charger_changed(struct power_supply *psy)
  {
  	struct lp8727_chg *pchg = dev_get_drvdata(psy->dev->parent);
  	u8 eoc_level;
  	u8 ichg;
  	u8 val;
  
  	/* skip if no charger exists */
  	if (!lp8727_is_charger_attached(psy->name, pchg->devid))
  		return;
  
  	/* update charging parameters */
  	if (pchg->chg_param) {
  		eoc_level = pchg->chg_param->eoc_level;
  		ichg = pchg->chg_param->ichg;
  		val = (ichg << LP8727_ICHG_SHIFT) | eoc_level;
  		lp8727_write_byte(pchg, LP8727_CHGCTRL2, val);
  	}
  }
  
  static int lp8727_register_psy(struct lp8727_chg *pchg)
  {
  	struct lp8727_psy *psy;
  
  	psy = devm_kzalloc(pchg->dev, sizeof(*psy), GFP_KERNEL);
  	if (!psy)
  		return -ENOMEM;
  
  	pchg->psy = psy;
  
  	psy->ac.name = "ac";
  	psy->ac.type = POWER_SUPPLY_TYPE_MAINS;
  	psy->ac.properties = lp8727_charger_prop;
  	psy->ac.num_properties = ARRAY_SIZE(lp8727_charger_prop);
  	psy->ac.get_property = lp8727_charger_get_property;
  	psy->ac.supplied_to = battery_supplied_to;
  	psy->ac.num_supplicants = ARRAY_SIZE(battery_supplied_to);
  
  	if (power_supply_register(pchg->dev, &psy->ac))
  		goto err_psy_ac;
  
  	psy->usb.name = "usb";
  	psy->usb.type = POWER_SUPPLY_TYPE_USB;
  	psy->usb.properties = lp8727_charger_prop;
  	psy->usb.num_properties = ARRAY_SIZE(lp8727_charger_prop);
  	psy->usb.get_property = lp8727_charger_get_property;
  	psy->usb.supplied_to = battery_supplied_to;
  	psy->usb.num_supplicants = ARRAY_SIZE(battery_supplied_to);
  
  	if (power_supply_register(pchg->dev, &psy->usb))
  		goto err_psy_usb;
  
  	psy->batt.name = "main_batt";
  	psy->batt.type = POWER_SUPPLY_TYPE_BATTERY;
  	psy->batt.properties = lp8727_battery_prop;
  	psy->batt.num_properties = ARRAY_SIZE(lp8727_battery_prop);
  	psy->batt.get_property = lp8727_battery_get_property;
  	psy->batt.external_power_changed = lp8727_charger_changed;
  
  	if (power_supply_register(pchg->dev, &psy->batt))
  		goto err_psy_batt;
  
  	return 0;
  
  err_psy_batt:
  	power_supply_unregister(&psy->usb);
  err_psy_usb:
  	power_supply_unregister(&psy->ac);
  err_psy_ac:
  	return -EPERM;
  }
  
  static void lp8727_unregister_psy(struct lp8727_chg *pchg)
  {
  	struct lp8727_psy *psy = pchg->psy;
  
  	if (!psy)
  		return;
  
  	power_supply_unregister(&psy->ac);
  	power_supply_unregister(&psy->usb);
  	power_supply_unregister(&psy->batt);
  }
  
  #ifdef CONFIG_OF
  static struct lp8727_chg_param
  *lp8727_parse_charge_pdata(struct device *dev, struct device_node *np)
  {
  	struct lp8727_chg_param *param;
  
  	param = devm_kzalloc(dev, sizeof(*param), GFP_KERNEL);
  	if (!param)
  		goto out;
  
  	of_property_read_u8(np, "eoc-level", (u8 *)&param->eoc_level);
  	of_property_read_u8(np, "charging-current", (u8 *)&param->ichg);
  out:
  	return param;
  }
  
  static int lp8727_parse_dt(struct device *dev)
  {
  	struct device_node *np = dev->of_node;
  	struct device_node *child;
  	struct lp8727_platform_data *pdata;
  	const char *type;
  
  	/* If charging parameter is not defined, just skip parsing the dt */
  	if (of_get_child_count(np) == 0)
  		goto out;
  
  	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return -ENOMEM;
  
  	of_property_read_u32(np, "debounce-ms", &pdata->debounce_msec);
  
  	for_each_child_of_node(np, child) {
  		of_property_read_string(child, "charger-type", &type);
  
  		if (!strcmp(type, "ac"))
  			pdata->ac = lp8727_parse_charge_pdata(dev, child);
  
  		if (!strcmp(type, "usb"))
  			pdata->usb = lp8727_parse_charge_pdata(dev, child);
  	}
  
  	dev->platform_data = pdata;
  out:
  	return 0;
  }
  #else
  static int lp8727_parse_dt(struct device *dev)
  {
  	return 0;
  }
  #endif
  
  static int lp8727_probe(struct i2c_client *cl, const struct i2c_device_id *id)
  {
  	struct lp8727_chg *pchg;
  	int ret;
  
  	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
  		return -EIO;
  
  	if (cl->dev.of_node) {
  		ret = lp8727_parse_dt(&cl->dev);
  		if (ret)
  			return ret;
  	}
  
  	pchg = devm_kzalloc(&cl->dev, sizeof(*pchg), GFP_KERNEL);
  	if (!pchg)
  		return -ENOMEM;
  
  	pchg->client = cl;
  	pchg->dev = &cl->dev;
  	pchg->pdata = cl->dev.platform_data;
  	i2c_set_clientdata(cl, pchg);
  
  	mutex_init(&pchg->xfer_lock);
  
  	ret = lp8727_init_device(pchg);
  	if (ret) {
  		dev_err(pchg->dev, "i2c communication err: %d", ret);
  		return ret;
  	}
  
  	ret = lp8727_register_psy(pchg);
  	if (ret) {
  		dev_err(pchg->dev, "power supplies register err: %d", ret);
  		return ret;
  	}
  
  	ret = lp8727_setup_irq(pchg);
  	if (ret) {
  		dev_err(pchg->dev, "irq handler err: %d", ret);
  		lp8727_unregister_psy(pchg);
  		return ret;
  	}
  
  	return 0;
  }
  
  static int lp8727_remove(struct i2c_client *cl)
  {
  	struct lp8727_chg *pchg = i2c_get_clientdata(cl);
  
  	lp8727_release_irq(pchg);
  	lp8727_unregister_psy(pchg);
  	return 0;
  }
  
  static const struct of_device_id lp8727_dt_ids[] = {
  	{ .compatible = "ti,lp8727", },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, lp8727_dt_ids);
  
  static const struct i2c_device_id lp8727_ids[] = {
  	{"lp8727", 0},
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lp8727_ids);
  
  static struct i2c_driver lp8727_driver = {
  	.driver = {
  		   .name = "lp8727",
  		   .of_match_table = of_match_ptr(lp8727_dt_ids),
  		   },
  	.probe = lp8727_probe,
  	.remove = lp8727_remove,
  	.id_table = lp8727_ids,
  };
  module_i2c_driver(lp8727_driver);
  
  MODULE_DESCRIPTION("TI/National Semiconductor LP8727 charger driver");
  MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>, Daniel Jeong <daniel.jeong@ti.com>");
  MODULE_LICENSE("GPL");