/*
   * Battery charger driver for Dialog Semiconductor DA9030
   *
   * Copyright (C) 2008 Compulab, Ltd.
   * 	Mike Rapoport <mike@compulab.co.il>
   *
   * 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/kernel.h>
  #include <linux/slab.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/device.h>
  #include <linux/workqueue.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/power_supply.h>
  #include <linux/mfd/da903x.h>
  
  #include <linux/debugfs.h>
  #include <linux/seq_file.h>
  #include <linux/notifier.h>
  
  #define DA9030_FAULT_LOG		0x0a
  #define DA9030_FAULT_LOG_OVER_TEMP	(1 << 7)
  #define DA9030_FAULT_LOG_VBAT_OVER	(1 << 4)
  
  #define DA9030_CHARGE_CONTROL		0x28
  #define DA9030_CHRG_CHARGER_ENABLE	(1 << 7)
  
  #define DA9030_ADC_MAN_CONTROL		0x30
  #define DA9030_ADC_TBATREF_ENABLE	(1 << 5)
  #define DA9030_ADC_LDO_INT_ENABLE	(1 << 4)
  
  #define DA9030_ADC_AUTO_CONTROL		0x31
  #define DA9030_ADC_TBAT_ENABLE		(1 << 5)
  #define DA9030_ADC_VBAT_IN_TXON		(1 << 4)
  #define DA9030_ADC_VCH_ENABLE		(1 << 3)
  #define DA9030_ADC_ICH_ENABLE		(1 << 2)
  #define DA9030_ADC_VBAT_ENABLE		(1 << 1)
  #define DA9030_ADC_AUTO_SLEEP_ENABLE	(1 << 0)
  
  #define DA9030_VBATMON		0x32
  #define DA9030_VBATMONTXON	0x33
  #define DA9030_TBATHIGHP	0x34
  #define DA9030_TBATHIGHN	0x35
  #define DA9030_TBATLOW		0x36
  
  #define DA9030_VBAT_RES		0x41
  #define DA9030_VBATMIN_RES	0x42
  #define DA9030_VBATMINTXON_RES	0x43
  #define DA9030_ICHMAX_RES	0x44
  #define DA9030_ICHMIN_RES	0x45
  #define DA9030_ICHAVERAGE_RES	0x46
  #define DA9030_VCHMAX_RES	0x47
  #define DA9030_VCHMIN_RES	0x48
  #define DA9030_TBAT_RES		0x49
  
  struct da9030_adc_res {
  	uint8_t vbat_res;
  	uint8_t vbatmin_res;
  	uint8_t vbatmintxon;
  	uint8_t ichmax_res;
  	uint8_t ichmin_res;
  	uint8_t ichaverage_res;
  	uint8_t vchmax_res;
  	uint8_t vchmin_res;
  	uint8_t tbat_res;
  	uint8_t adc_in4_res;
  	uint8_t adc_in5_res;
  };
  
  struct da9030_battery_thresholds {
  	int tbat_low;
  	int tbat_high;
  	int tbat_restart;
  
  	int vbat_low;
  	int vbat_crit;
  	int vbat_charge_start;
  	int vbat_charge_stop;
  	int vbat_charge_restart;
  
  	int vcharge_min;
  	int vcharge_max;
  };
  
  struct da9030_charger {
  	struct power_supply psy;
  
  	struct device *master;
  
  	struct da9030_adc_res adc;
  	struct delayed_work work;
  	unsigned int interval;
  
  	struct power_supply_info *battery_info;
  
  	struct da9030_battery_thresholds thresholds;
  
  	unsigned int charge_milliamp;
  	unsigned int charge_millivolt;
  
  	/* charger status */
  	bool chdet;
  	uint8_t fault;
  	int mA;
  	int mV;
  	bool is_on;
  
  	struct notifier_block nb;
  
  	/* platform callbacks for battery low and critical events */
  	void (*battery_low)(void);
  	void (*battery_critical)(void);
  
  	struct dentry *debug_file;
  };
  
  static inline int da9030_reg_to_mV(int reg)
  {
  	return ((reg * 2650) >> 8) + 2650;
  }
  
  static inline int da9030_millivolt_to_reg(int mV)
  {
  	return ((mV - 2650) << 8) / 2650;
  }
  
  static inline int da9030_reg_to_mA(int reg)
  {
  	return ((reg * 24000) >> 8) / 15;
  }
  
  #ifdef CONFIG_DEBUG_FS
  static int bat_debug_show(struct seq_file *s, void *data)
  {
  	struct da9030_charger *charger = s->private;
  
  	seq_printf(s, "charger is %s
  ", charger->is_on ? "on" : "off");
  	if (charger->chdet) {
  		seq_printf(s, "iset = %dmA, vset = %dmV
  ",
  			   charger->mA, charger->mV);
  	}
  
  	seq_printf(s, "vbat_res = %d (%dmV)
  ",
  		   charger->adc.vbat_res,
  		   da9030_reg_to_mV(charger->adc.vbat_res));
  	seq_printf(s, "vbatmin_res = %d (%dmV)
  ",
  		   charger->adc.vbatmin_res,
  		   da9030_reg_to_mV(charger->adc.vbatmin_res));
  	seq_printf(s, "vbatmintxon = %d (%dmV)
  ",
  		   charger->adc.vbatmintxon,
  		   da9030_reg_to_mV(charger->adc.vbatmintxon));
  	seq_printf(s, "ichmax_res = %d (%dmA)
  ",
  		   charger->adc.ichmax_res,
  		   da9030_reg_to_mV(charger->adc.ichmax_res));
  	seq_printf(s, "ichmin_res = %d (%dmA)
  ",
  		   charger->adc.ichmin_res,
  		   da9030_reg_to_mA(charger->adc.ichmin_res));
  	seq_printf(s, "ichaverage_res = %d (%dmA)
  ",
  		   charger->adc.ichaverage_res,
  		   da9030_reg_to_mA(charger->adc.ichaverage_res));
  	seq_printf(s, "vchmax_res = %d (%dmV)
  ",
  		   charger->adc.vchmax_res,
  		   da9030_reg_to_mA(charger->adc.vchmax_res));
  	seq_printf(s, "vchmin_res = %d (%dmV)
  ",
  		   charger->adc.vchmin_res,
  		   da9030_reg_to_mV(charger->adc.vchmin_res));
  
  	return 0;
  }
  
  static int debug_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, bat_debug_show, inode->i_private);
  }
  
  static const struct file_operations bat_debug_fops = {
  	.open		= debug_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  static struct dentry *da9030_bat_create_debugfs(struct da9030_charger *charger)
  {
  	charger->debug_file = debugfs_create_file("charger", 0666, NULL,
  						  charger, &bat_debug_fops);
  	return charger->debug_file;
  }
  
  static void da9030_bat_remove_debugfs(struct da9030_charger *charger)
  {
  	debugfs_remove(charger->debug_file);
  }
  #else
  static inline struct dentry *da9030_bat_create_debugfs(struct da9030_charger *charger)
  {
  	return NULL;
  }
  static inline void da9030_bat_remove_debugfs(struct da9030_charger *charger)
  {
  }
  #endif
  
  static inline void da9030_read_adc(struct da9030_charger *charger,
  				   struct da9030_adc_res *adc)
  {
  	da903x_reads(charger->master, DA9030_VBAT_RES,
  		     sizeof(*adc), (uint8_t *)adc);
  }
  
  static void da9030_charger_update_state(struct da9030_charger *charger)
  {
  	uint8_t val;
  
  	da903x_read(charger->master, DA9030_CHARGE_CONTROL, &val);
  	charger->is_on = (val & DA9030_CHRG_CHARGER_ENABLE) ? 1 : 0;
  	charger->mA = ((val >> 3) & 0xf) * 100;
  	charger->mV = (val & 0x7) * 50 + 4000;
  
  	da9030_read_adc(charger, &charger->adc);
  	da903x_read(charger->master, DA9030_FAULT_LOG, &charger->fault);
  	charger->chdet = da903x_query_status(charger->master,
  						     DA9030_STATUS_CHDET);
  }
  
  static void da9030_set_charge(struct da9030_charger *charger, int on)
  {
  	uint8_t val;
  
  	if (on) {
  		val = DA9030_CHRG_CHARGER_ENABLE;
  		val |= (charger->charge_milliamp / 100) << 3;
  		val |= (charger->charge_millivolt - 4000) / 50;
  		charger->is_on = 1;
  	} else {
  		val = 0;
  		charger->is_on = 0;
  	}
  
  	da903x_write(charger->master, DA9030_CHARGE_CONTROL, val);
  
  	power_supply_changed(&charger->psy);
  }
  
  static void da9030_charger_check_state(struct da9030_charger *charger)
  {
  	da9030_charger_update_state(charger);
  
  	/* we wake or boot with external power on */
  	if (!charger->is_on) {
  		if ((charger->chdet) &&
  		    (charger->adc.vbat_res <
  		     charger->thresholds.vbat_charge_start)) {
  			da9030_set_charge(charger, 1);
  		}
  	} else {
  		/* Charger has been pulled out */
  		if (!charger->chdet) {
  			da9030_set_charge(charger, 0);
  			return;
  		}
  
  		if (charger->adc.vbat_res >=
  		    charger->thresholds.vbat_charge_stop) {
  			da9030_set_charge(charger, 0);
  			da903x_write(charger->master, DA9030_VBATMON,
  				       charger->thresholds.vbat_charge_restart);
  		} else if (charger->adc.vbat_res >
  			   charger->thresholds.vbat_low) {
  			/* we are charging and passed LOW_THRESH,
  			   so upate DA9030 VBAT threshold
  			 */
  			da903x_write(charger->master, DA9030_VBATMON,
  				     charger->thresholds.vbat_low);
  		}
  		if (charger->adc.vchmax_res > charger->thresholds.vcharge_max ||
  		    charger->adc.vchmin_res < charger->thresholds.vcharge_min ||
  		    /* Tempreture readings are negative */
  		    charger->adc.tbat_res < charger->thresholds.tbat_high ||
  		    charger->adc.tbat_res > charger->thresholds.tbat_low) {
  			/* disable charger */
  			da9030_set_charge(charger, 0);
  		}
  	}
  }
  
  static void da9030_charging_monitor(struct work_struct *work)
  {
  	struct da9030_charger *charger;
  
  	charger = container_of(work, struct da9030_charger, work.work);
  
  	da9030_charger_check_state(charger);
  
  	/* reschedule for the next time */
  	schedule_delayed_work(&charger->work, charger->interval);
  }
  
  static enum power_supply_property da9030_battery_props[] = {
  	POWER_SUPPLY_PROP_MODEL_NAME,
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_HEALTH,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
  	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
  	POWER_SUPPLY_PROP_VOLTAGE_NOW,
  	POWER_SUPPLY_PROP_CURRENT_AVG,
  };
  
  static void da9030_battery_check_status(struct da9030_charger *charger,
  				    union power_supply_propval *val)
  {
  	if (charger->chdet) {
  		if (charger->is_on)
  			val->intval = POWER_SUPPLY_STATUS_CHARGING;
  		else
  			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  	} else {
  		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  	}
  }
  
  static void da9030_battery_check_health(struct da9030_charger *charger,
  				    union power_supply_propval *val)
  {
  	if (charger->fault & DA9030_FAULT_LOG_OVER_TEMP)
  		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  	else if (charger->fault & DA9030_FAULT_LOG_VBAT_OVER)
  		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
  	else
  		val->intval = POWER_SUPPLY_HEALTH_GOOD;
  }
  
  static int da9030_battery_get_property(struct power_supply *psy,
  				   enum power_supply_property psp,
  				   union power_supply_propval *val)
  {
  	struct da9030_charger *charger;
  	charger = container_of(psy, struct da9030_charger, psy);
  
  	switch (psp) {
  	case POWER_SUPPLY_PROP_STATUS:
  		da9030_battery_check_status(charger, val);
  		break;
  	case POWER_SUPPLY_PROP_HEALTH:
  		da9030_battery_check_health(charger, val);
  		break;
  	case POWER_SUPPLY_PROP_TECHNOLOGY:
  		val->intval = charger->battery_info->technology;
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
  		val->intval = charger->battery_info->voltage_max_design;
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
  		val->intval = charger->battery_info->voltage_min_design;
  		break;
  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  		val->intval = da9030_reg_to_mV(charger->adc.vbat_res) * 1000;
  		break;
  	case POWER_SUPPLY_PROP_CURRENT_AVG:
  		val->intval =
  			da9030_reg_to_mA(charger->adc.ichaverage_res) * 1000;
  		break;
  	case POWER_SUPPLY_PROP_MODEL_NAME:
  		val->strval = charger->battery_info->name;
  		break;
  	default:
  		break;
  	}
  
  	return 0;
  }
  
  static void da9030_battery_vbat_event(struct da9030_charger *charger)
  {
  	da9030_read_adc(charger, &charger->adc);
  
  	if (charger->is_on)
  		return;
  
  	if (charger->adc.vbat_res < charger->thresholds.vbat_low) {
  		/* set VBAT threshold for critical */
  		da903x_write(charger->master, DA9030_VBATMON,
  			     charger->thresholds.vbat_crit);
  		if (charger->battery_low)
  			charger->battery_low();
  	} else if (charger->adc.vbat_res <
  		   charger->thresholds.vbat_crit) {
  		/* notify the system of battery critical */
  		if (charger->battery_critical)
  			charger->battery_critical();
  	}
  }
  
  static int da9030_battery_event(struct notifier_block *nb, unsigned long event,
  				void *data)
  {
  	struct da9030_charger *charger =
  		container_of(nb, struct da9030_charger, nb);
  
  	switch (event) {
  	case DA9030_EVENT_CHDET:
  		cancel_delayed_work_sync(&charger->work);
  		schedule_work(&charger->work.work);
  		break;
  	case DA9030_EVENT_VBATMON:
  		da9030_battery_vbat_event(charger);
  		break;
  	case DA9030_EVENT_CHIOVER:
  	case DA9030_EVENT_TBAT:
  		da9030_set_charge(charger, 0);
  		break;
  	}
  
  	return 0;
  }
  
  static void da9030_battery_convert_thresholds(struct da9030_charger *charger,
  					      struct da9030_battery_info *pdata)
  {
  	charger->thresholds.tbat_low = pdata->tbat_low;
  	charger->thresholds.tbat_high = pdata->tbat_high;
  	charger->thresholds.tbat_restart  = pdata->tbat_restart;
  
  	charger->thresholds.vbat_low =
  		da9030_millivolt_to_reg(pdata->vbat_low);
  	charger->thresholds.vbat_crit =
  		da9030_millivolt_to_reg(pdata->vbat_crit);
  	charger->thresholds.vbat_charge_start =
  		da9030_millivolt_to_reg(pdata->vbat_charge_start);
  	charger->thresholds.vbat_charge_stop =
  		da9030_millivolt_to_reg(pdata->vbat_charge_stop);
  	charger->thresholds.vbat_charge_restart =
  		da9030_millivolt_to_reg(pdata->vbat_charge_restart);
  
  	charger->thresholds.vcharge_min =
  		da9030_millivolt_to_reg(pdata->vcharge_min);
  	charger->thresholds.vcharge_max =
  		da9030_millivolt_to_reg(pdata->vcharge_max);
  }
  
  static void da9030_battery_setup_psy(struct da9030_charger *charger)
  {
  	struct power_supply *psy = &charger->psy;
  	struct power_supply_info *info = charger->battery_info;
  
  	psy->name = info->name;
  	psy->use_for_apm = info->use_for_apm;
  	psy->type = POWER_SUPPLY_TYPE_BATTERY;
  	psy->get_property = da9030_battery_get_property;
  
  	psy->properties = da9030_battery_props;
  	psy->num_properties = ARRAY_SIZE(da9030_battery_props);
  };
  
  static int da9030_battery_charger_init(struct da9030_charger *charger)
  {
  	char v[5];
  	int ret;
  
  	v[0] = v[1] = charger->thresholds.vbat_low;
  	v[2] = charger->thresholds.tbat_high;
  	v[3] = charger->thresholds.tbat_restart;
  	v[4] = charger->thresholds.tbat_low;
  
  	ret = da903x_writes(charger->master, DA9030_VBATMON, 5, v);
  	if (ret)
  		return ret;
  
  	/*
  	 * Enable reference voltage supply for ADC from the LDO_INTERNAL
  	 * regulator. Must be set before ADC measurements can be made.
  	 */
  	ret = da903x_write(charger->master, DA9030_ADC_MAN_CONTROL,
  			   DA9030_ADC_LDO_INT_ENABLE |
  			   DA9030_ADC_TBATREF_ENABLE);
  	if (ret)
  		return ret;
  
  	/* enable auto ADC measuremnts */
  	return da903x_write(charger->master, DA9030_ADC_AUTO_CONTROL,
  			    DA9030_ADC_TBAT_ENABLE | DA9030_ADC_VBAT_IN_TXON |
  			    DA9030_ADC_VCH_ENABLE | DA9030_ADC_ICH_ENABLE |
  			    DA9030_ADC_VBAT_ENABLE |
  			    DA9030_ADC_AUTO_SLEEP_ENABLE);
  }
  
  static int da9030_battery_probe(struct platform_device *pdev)
  {
  	struct da9030_charger *charger;
  	struct da9030_battery_info *pdata = pdev->dev.platform_data;
  	int ret;
  
  	if (pdata == NULL)
  		return -EINVAL;
  
  	if (pdata->charge_milliamp >= 1500 ||
  	    pdata->charge_millivolt < 4000 ||
  	    pdata->charge_millivolt > 4350)
  		return -EINVAL;
  
  	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
  	if (charger == NULL)
  		return -ENOMEM;
  
  	charger->master = pdev->dev.parent;
  
  	/* 10 seconds between monitor runs unless platform defines other
  	   interval */
  	charger->interval = msecs_to_jiffies(
  		(pdata->batmon_interval ? : 10) * 1000);
  
  	charger->charge_milliamp = pdata->charge_milliamp;
  	charger->charge_millivolt = pdata->charge_millivolt;
  	charger->battery_info = pdata->battery_info;
  	charger->battery_low = pdata->battery_low;
  	charger->battery_critical = pdata->battery_critical;
  
  	da9030_battery_convert_thresholds(charger, pdata);
  
  	ret = da9030_battery_charger_init(charger);
  	if (ret)
  		goto err_charger_init;
  
  	INIT_DELAYED_WORK(&charger->work, da9030_charging_monitor);
  	schedule_delayed_work(&charger->work, charger->interval);
  
  	charger->nb.notifier_call = da9030_battery_event;
  	ret = da903x_register_notifier(charger->master, &charger->nb,
  				       DA9030_EVENT_CHDET |
  				       DA9030_EVENT_VBATMON |
  				       DA9030_EVENT_CHIOVER |
  				       DA9030_EVENT_TBAT);
  	if (ret)
  		goto err_notifier;
  
  	da9030_battery_setup_psy(charger);
  	ret = power_supply_register(&pdev->dev, &charger->psy);
  	if (ret)
  		goto err_ps_register;
  
  	charger->debug_file = da9030_bat_create_debugfs(charger);
  	platform_set_drvdata(pdev, charger);
  	return 0;
  
  err_ps_register:
  	da903x_unregister_notifier(charger->master, &charger->nb,
  				   DA9030_EVENT_CHDET | DA9030_EVENT_VBATMON |
  				   DA9030_EVENT_CHIOVER | DA9030_EVENT_TBAT);
  err_notifier:
  	cancel_delayed_work(&charger->work);
  
  err_charger_init:
  	return ret;
  }
  
  static int da9030_battery_remove(struct platform_device *dev)
  {
  	struct da9030_charger *charger = platform_get_drvdata(dev);
  
  	da9030_bat_remove_debugfs(charger);
  
  	da903x_unregister_notifier(charger->master, &charger->nb,
  				   DA9030_EVENT_CHDET | DA9030_EVENT_VBATMON |
  				   DA9030_EVENT_CHIOVER | DA9030_EVENT_TBAT);
  	cancel_delayed_work_sync(&charger->work);
  	da9030_set_charge(charger, 0);
  	power_supply_unregister(&charger->psy);
  
  	return 0;
  }
  
  static struct platform_driver da903x_battery_driver = {
  	.driver	= {
  		.name	= "da903x-battery",
  		.owner	= THIS_MODULE,
  	},
  	.probe = da9030_battery_probe,
  	.remove = da9030_battery_remove,
  };
  
  module_platform_driver(da903x_battery_driver);
  
  MODULE_DESCRIPTION("DA9030 battery charger driver");
  MODULE_AUTHOR("Mike Rapoport, CompuLab");
  MODULE_LICENSE("GPL");