/*
 * Power supply driver for the Active-semi ACT8945A PMIC
 *
 * Copyright (C) 2015 Atmel Corporation
 *
 * Author: Wenyou Yang <wenyou.yang@atmel.com>
 *
 * 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/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#include <linux/gpio/consumer.h>

static const char *act8945a_charger_model = "ACT8945A";
static const char *act8945a_charger_manufacturer = "Active-semi";

/**
 * ACT8945A Charger Register Map
 */

/* 0x70: Reserved */
#define ACT8945A_APCH_CFG		0x71
#define ACT8945A_APCH_STATUS		0x78
#define ACT8945A_APCH_CTRL		0x79
#define ACT8945A_APCH_STATE		0x7A

/* ACT8945A_APCH_CFG */
#define APCH_CFG_OVPSET			(0x3 << 0)
#define APCH_CFG_OVPSET_6V6		(0x0 << 0)
#define APCH_CFG_OVPSET_7V		(0x1 << 0)
#define APCH_CFG_OVPSET_7V5		(0x2 << 0)
#define APCH_CFG_OVPSET_8V		(0x3 << 0)
#define APCH_CFG_PRETIMO		(0x3 << 2)
#define APCH_CFG_PRETIMO_40_MIN		(0x0 << 2)
#define APCH_CFG_PRETIMO_60_MIN		(0x1 << 2)
#define APCH_CFG_PRETIMO_80_MIN		(0x2 << 2)
#define APCH_CFG_PRETIMO_DISABLED	(0x3 << 2)
#define APCH_CFG_TOTTIMO		(0x3 << 4)
#define APCH_CFG_TOTTIMO_3_HOUR		(0x0 << 4)
#define APCH_CFG_TOTTIMO_4_HOUR		(0x1 << 4)
#define APCH_CFG_TOTTIMO_5_HOUR		(0x2 << 4)
#define APCH_CFG_TOTTIMO_DISABLED	(0x3 << 4)
#define APCH_CFG_SUSCHG			(0x1 << 7)

#define APCH_STATUS_CHGDAT		BIT(0)
#define APCH_STATUS_INDAT		BIT(1)
#define APCH_STATUS_TEMPDAT		BIT(2)
#define APCH_STATUS_TIMRDAT		BIT(3)
#define APCH_STATUS_CHGSTAT		BIT(4)
#define APCH_STATUS_INSTAT		BIT(5)
#define APCH_STATUS_TEMPSTAT		BIT(6)
#define APCH_STATUS_TIMRSTAT		BIT(7)

#define APCH_CTRL_CHGEOCOUT		BIT(0)
#define APCH_CTRL_INDIS			BIT(1)
#define APCH_CTRL_TEMPOUT		BIT(2)
#define APCH_CTRL_TIMRPRE		BIT(3)
#define APCH_CTRL_CHGEOCIN		BIT(4)
#define APCH_CTRL_INCON			BIT(5)
#define APCH_CTRL_TEMPIN		BIT(6)
#define APCH_CTRL_TIMRTOT		BIT(7)

#define APCH_STATE_ACINSTAT		(0x1 << 1)
#define APCH_STATE_CSTATE		(0x3 << 4)
#define APCH_STATE_CSTATE_SHIFT		4
#define APCH_STATE_CSTATE_DISABLED	0x00
#define APCH_STATE_CSTATE_EOC		0x01
#define APCH_STATE_CSTATE_FAST		0x02
#define APCH_STATE_CSTATE_PRE		0x03

struct act8945a_charger {
	struct power_supply *psy;
	struct power_supply_desc desc;
	struct regmap *regmap;
	struct work_struct work;

	bool init_done;
	struct gpio_desc *lbo_gpio;
	struct gpio_desc *chglev_gpio;
};

static int act8945a_get_charger_state(struct regmap *regmap, int *val)
{
	int ret;
	unsigned int status, state;

	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	state &= APCH_STATE_CSTATE;
	state >>= APCH_STATE_CSTATE_SHIFT;

	switch (state) {
	case APCH_STATE_CSTATE_PRE:
	case APCH_STATE_CSTATE_FAST:
		*val = POWER_SUPPLY_STATUS_CHARGING;
		break;
	case APCH_STATE_CSTATE_EOC:
		if (status & APCH_STATUS_CHGDAT)
			*val = POWER_SUPPLY_STATUS_FULL;
		else
			*val = POWER_SUPPLY_STATUS_CHARGING;
		break;
	case APCH_STATE_CSTATE_DISABLED:
	default:
		if (!(status & APCH_STATUS_INDAT))
			*val = POWER_SUPPLY_STATUS_DISCHARGING;
		else
			*val = POWER_SUPPLY_STATUS_NOT_CHARGING;
		break;
	}

	return 0;
}

static int act8945a_get_charge_type(struct regmap *regmap, int *val)
{
	int ret;
	unsigned int status, state;

	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	state &= APCH_STATE_CSTATE;
	state >>= APCH_STATE_CSTATE_SHIFT;

	switch (state) {
	case APCH_STATE_CSTATE_PRE:
		*val = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
		break;
	case APCH_STATE_CSTATE_FAST:
		*val = POWER_SUPPLY_CHARGE_TYPE_FAST;
		break;
	case APCH_STATE_CSTATE_EOC:
		*val = POWER_SUPPLY_CHARGE_TYPE_NONE;
		break;
	case APCH_STATE_CSTATE_DISABLED:
	default:
		if (!(status & APCH_STATUS_INDAT))
			*val = POWER_SUPPLY_CHARGE_TYPE_NONE;
		else
			*val = POWER_SUPPLY_CHARGE_TYPE_UNKNOWN;
		break;
	}

	return 0;
}

static int act8945a_get_battery_health(struct regmap *regmap, int *val)
{
	int ret;
	unsigned int status, state, config;

	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_CFG, &config);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	state &= APCH_STATE_CSTATE;
	state >>= APCH_STATE_CSTATE_SHIFT;

	switch (state) {
	case APCH_STATE_CSTATE_DISABLED:
		if (config & APCH_CFG_SUSCHG) {
			*val = POWER_SUPPLY_HEALTH_UNKNOWN;
		} else if (status & APCH_STATUS_INDAT) {
			if (!(status & APCH_STATUS_TEMPDAT))
				*val = POWER_SUPPLY_HEALTH_OVERHEAT;
			else if (status & APCH_STATUS_TIMRDAT)
				*val = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
			else
				*val = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
		} else {
			*val = POWER_SUPPLY_HEALTH_GOOD;
		}
		break;
	case APCH_STATE_CSTATE_PRE:
	case APCH_STATE_CSTATE_FAST:
	case APCH_STATE_CSTATE_EOC:
	default:
		*val = POWER_SUPPLY_HEALTH_GOOD;
		break;
	}

	return 0;
}

static int act8945a_get_capacity_level(struct act8945a_charger *charger,
				       struct regmap *regmap, int *val)
{
	int ret;
	unsigned int status, state, config;
	int lbo_level = gpiod_get_value(charger->lbo_gpio);

	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_CFG, &config);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	state &= APCH_STATE_CSTATE;
	state >>= APCH_STATE_CSTATE_SHIFT;

	switch (state) {
	case APCH_STATE_CSTATE_PRE:
		*val = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
		break;
	case APCH_STATE_CSTATE_FAST:
		if (lbo_level)
			*val = POWER_SUPPLY_CAPACITY_LEVEL_HIGH;
		else
			*val = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
		break;
	case APCH_STATE_CSTATE_EOC:
		if (status & APCH_STATUS_CHGDAT)
			*val = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
		else
			*val = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
		break;
	case APCH_STATE_CSTATE_DISABLED:
	default:
		if (config & APCH_CFG_SUSCHG) {
			*val = POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN;
		} else {
			*val = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
			if (!(status & APCH_STATUS_INDAT)) {
				if (!lbo_level)
					*val = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
			}
		}
		break;
	}

	return 0;
}

#define MAX_CURRENT_USB_HIGH	450000
#define MAX_CURRENT_USB_LOW	90000
#define MAX_CURRENT_USB_PRE	45000
/*
 * Riset(K) = 2336 * (1V/Ichg(mA)) - 0.205
 * Riset = 2.43K
 */
#define MAX_CURRENT_AC_HIGH		886527
#define MAX_CURRENT_AC_LOW		117305
#define MAX_CURRENT_AC_HIGH_PRE		88653
#define MAX_CURRENT_AC_LOW_PRE		11731

static int act8945a_get_current_max(struct act8945a_charger *charger,
				    struct regmap *regmap, int *val)
{
	int ret;
	unsigned int status, state;
	unsigned int acin_state;
	int chgin_level = gpiod_get_value(charger->chglev_gpio);

	ret = regmap_read(regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	acin_state = (state & APCH_STATE_ACINSTAT) >> 1;

	state &= APCH_STATE_CSTATE;
	state >>= APCH_STATE_CSTATE_SHIFT;

	switch (state) {
	case APCH_STATE_CSTATE_PRE:
		if (acin_state) {
			if (chgin_level)
				*val = MAX_CURRENT_AC_HIGH_PRE;
			else
				*val = MAX_CURRENT_AC_LOW_PRE;
		} else {
			*val = MAX_CURRENT_USB_PRE;
		}
		break;
	case APCH_STATE_CSTATE_FAST:
		if (acin_state) {
			if (chgin_level)
				*val = MAX_CURRENT_AC_HIGH;
			else
				*val = MAX_CURRENT_AC_LOW;
		} else {
			if (chgin_level)
				*val = MAX_CURRENT_USB_HIGH;
			else
				*val = MAX_CURRENT_USB_LOW;
		}
		break;
	case APCH_STATE_CSTATE_EOC:
	case APCH_STATE_CSTATE_DISABLED:
	default:
		*val = 0;
		break;
	}

	return 0;
}

static enum power_supply_property act8945a_charger_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_CHARGE_TYPE,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
	POWER_SUPPLY_PROP_CURRENT_MAX,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER
};

static int act8945a_charger_get_property(struct power_supply *psy,
					 enum power_supply_property prop,
					 union power_supply_propval *val)
{
	struct act8945a_charger *charger = power_supply_get_drvdata(psy);
	struct regmap *regmap = charger->regmap;
	int ret = 0;

	switch (prop) {
	case POWER_SUPPLY_PROP_STATUS:
		ret = act8945a_get_charger_state(regmap, &val->intval);
		break;
	case POWER_SUPPLY_PROP_CHARGE_TYPE:
		ret = act8945a_get_charge_type(regmap, &val->intval);
		break;
	case POWER_SUPPLY_PROP_TECHNOLOGY:
		val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
		break;
	case POWER_SUPPLY_PROP_HEALTH:
		ret = act8945a_get_battery_health(regmap, &val->intval);
		break;
	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
		ret = act8945a_get_capacity_level(charger,
						  regmap, &val->intval);
		break;
	case POWER_SUPPLY_PROP_CURRENT_MAX:
		ret = act8945a_get_current_max(charger,
					       regmap, &val->intval);
		break;
	case POWER_SUPPLY_PROP_MODEL_NAME:
		val->strval = act8945a_charger_model;
		break;
	case POWER_SUPPLY_PROP_MANUFACTURER:
		val->strval = act8945a_charger_manufacturer;
		break;
	default:
		return -EINVAL;
	}

	return ret;
}

static int act8945a_enable_interrupt(struct act8945a_charger *charger)
{
	struct regmap *regmap = charger->regmap;
	unsigned char ctrl;
	int ret;

	ctrl = APCH_CTRL_CHGEOCOUT | APCH_CTRL_CHGEOCIN |
	       APCH_CTRL_INDIS | APCH_CTRL_INCON |
	       APCH_CTRL_TEMPOUT | APCH_CTRL_TEMPIN |
	       APCH_CTRL_TIMRPRE | APCH_CTRL_TIMRTOT;
	ret = regmap_write(regmap, ACT8945A_APCH_CTRL, ctrl);
	if (ret)
		return ret;

	ctrl = APCH_STATUS_CHGSTAT | APCH_STATUS_INSTAT |
	       APCH_STATUS_TEMPSTAT | APCH_STATUS_TIMRSTAT;
	ret = regmap_write(regmap, ACT8945A_APCH_STATUS, ctrl);
	if (ret)
		return ret;

	return 0;
}

static unsigned int act8945a_set_supply_type(struct act8945a_charger *charger,
					     unsigned int *type)
{
	unsigned int status, state;
	int ret;

	ret = regmap_read(charger->regmap, ACT8945A_APCH_STATUS, &status);
	if (ret < 0)
		return ret;

	ret = regmap_read(charger->regmap, ACT8945A_APCH_STATE, &state);
	if (ret < 0)
		return ret;

	if (status & APCH_STATUS_INDAT) {
		if (state & APCH_STATE_ACINSTAT)
			*type = POWER_SUPPLY_TYPE_MAINS;
		else
			*type = POWER_SUPPLY_TYPE_USB;
	} else {
		*type = POWER_SUPPLY_TYPE_BATTERY;
	}

	return 0;
}

static void act8945a_work(struct work_struct *work)
{
	struct act8945a_charger *charger =
			container_of(work, struct act8945a_charger, work);

	act8945a_set_supply_type(charger, &charger->desc.type);

	power_supply_changed(charger->psy);
}

static irqreturn_t act8945a_status_changed(int irq, void *dev_id)
{
	struct act8945a_charger *charger = dev_id;

	if (charger->init_done)
		schedule_work(&charger->work);

	return IRQ_HANDLED;
}

#define DEFAULT_TOTAL_TIME_OUT		3
#define DEFAULT_PRE_TIME_OUT		40
#define DEFAULT_INPUT_OVP_THRESHOLD	6600

static int act8945a_charger_config(struct device *dev,
				   struct act8945a_charger *charger)
{
	struct device_node *np = dev->of_node;
	struct regmap *regmap = charger->regmap;

	u32 total_time_out;
	u32 pre_time_out;
	u32 input_voltage_threshold;
	int err, ret;

	unsigned int tmp;
	unsigned int value = 0;

	if (!np) {
		dev_err(dev, "no charger of node\n");
		return -EINVAL;
	}

	ret = regmap_read(regmap, ACT8945A_APCH_CFG, &tmp);
	if (ret)
		return ret;

	if (tmp & APCH_CFG_SUSCHG) {
		value |= APCH_CFG_SUSCHG;
		dev_info(dev, "have been suspended\n");
	}

	charger->lbo_gpio = devm_gpiod_get_optional(dev, "active-semi,lbo",
						    GPIOD_IN);
	if (IS_ERR(charger->lbo_gpio)) {
		err = PTR_ERR(charger->lbo_gpio);
		dev_err(dev, "unable to claim gpio \"lbo\": %d\n", err);
		return err;
	}

	ret = devm_request_irq(dev, gpiod_to_irq(charger->lbo_gpio),
			       act8945a_status_changed,
			       (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING),
			       "act8945a_lbo_detect", charger);
	if (ret)
		dev_info(dev, "failed to request gpio \"lbo\" IRQ\n");

	charger->chglev_gpio = devm_gpiod_get_optional(dev,
						       "active-semi,chglev",
						       GPIOD_IN);
	if (IS_ERR(charger->chglev_gpio)) {
		err = PTR_ERR(charger->chglev_gpio);
		dev_err(dev, "unable to claim gpio \"chglev\": %d\n", err);
		return err;
	}

	if (of_property_read_u32(np,
				 "active-semi,input-voltage-threshold-microvolt",
				 &input_voltage_threshold))
		input_voltage_threshold = DEFAULT_INPUT_OVP_THRESHOLD;

	if (of_property_read_u32(np,
				 "active-semi,precondition-timeout",
				 &pre_time_out))
		pre_time_out = DEFAULT_PRE_TIME_OUT;

	if (of_property_read_u32(np, "active-semi,total-timeout",
				 &total_time_out))
		total_time_out = DEFAULT_TOTAL_TIME_OUT;

	switch (input_voltage_threshold) {
	case 8000:
		value |= APCH_CFG_OVPSET_8V;
		break;
	case 7500:
		value |= APCH_CFG_OVPSET_7V5;
		break;
	case 7000:
		value |= APCH_CFG_OVPSET_7V;
		break;
	case 6600:
	default:
		value |= APCH_CFG_OVPSET_6V6;
		break;
	}

	switch (pre_time_out) {
	case 60:
		value |= APCH_CFG_PRETIMO_60_MIN;
		break;
	case 80:
		value |= APCH_CFG_PRETIMO_80_MIN;
		break;
	case 0:
		value |= APCH_CFG_PRETIMO_DISABLED;
		break;
	case 40:
	default:
		value |= APCH_CFG_PRETIMO_40_MIN;
		break;
	}

	switch (total_time_out) {
	case 4:
		value |= APCH_CFG_TOTTIMO_4_HOUR;
		break;
	case 5:
		value |= APCH_CFG_TOTTIMO_5_HOUR;
		break;
	case 0:
		value |= APCH_CFG_TOTTIMO_DISABLED;
		break;
	case 3:
	default:
		value |= APCH_CFG_TOTTIMO_3_HOUR;
		break;
	}

	return regmap_write(regmap, ACT8945A_APCH_CFG, value);
}

static int act8945a_charger_probe(struct platform_device *pdev)
{
	struct act8945a_charger *charger;
	struct power_supply_config psy_cfg = {};
	int irq, ret;

	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
	if (!charger)
		return -ENOMEM;

	charger->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!charger->regmap) {
		dev_err(&pdev->dev, "Parent did not provide regmap\n");
		return -EINVAL;
	}

	ret = act8945a_charger_config(&pdev->dev, charger);
	if (ret)
		return ret;

	irq = of_irq_get(pdev->dev.of_node, 0);
	if (irq <= 0) {
		dev_err(&pdev->dev, "failed to find IRQ number\n");
		return irq ?: -ENXIO;
	}

	ret = devm_request_irq(&pdev->dev, irq, act8945a_status_changed,
			       IRQF_TRIGGER_FALLING, "act8945a_interrupt",
			       charger);
	if (ret) {
		dev_err(&pdev->dev, "failed to request nIRQ pin IRQ\n");
		return ret;
	}

	charger->desc.name = "act8945a-charger";
	charger->desc.get_property = act8945a_charger_get_property;
	charger->desc.properties = act8945a_charger_props;
	charger->desc.num_properties = ARRAY_SIZE(act8945a_charger_props);

	ret = act8945a_set_supply_type(charger, &charger->desc.type);
	if (ret)
		return -EINVAL;

	psy_cfg.of_node	= pdev->dev.of_node;
	psy_cfg.drv_data = charger;

	charger->psy = devm_power_supply_register(&pdev->dev,
						  &charger->desc,
						  &psy_cfg);
	if (IS_ERR(charger->psy)) {
		dev_err(&pdev->dev, "failed to register power supply\n");
		return PTR_ERR(charger->psy);
	}

	platform_set_drvdata(pdev, charger);

	INIT_WORK(&charger->work, act8945a_work);

	ret = act8945a_enable_interrupt(charger);
	if (ret)
		return -EIO;

	charger->init_done = true;

	return 0;
}

static int act8945a_charger_remove(struct platform_device *pdev)
{
	struct act8945a_charger *charger = platform_get_drvdata(pdev);

	charger->init_done = false;
	cancel_work_sync(&charger->work);

	return 0;
}

static struct platform_driver act8945a_charger_driver = {
	.driver	= {
		.name = "act8945a-charger",
	},
	.probe	= act8945a_charger_probe,
	.remove = act8945a_charger_remove,
};
module_platform_driver(act8945a_charger_driver);

MODULE_DESCRIPTION("Active-semi ACT8945A ActivePath charger driver");
MODULE_AUTHOR("Wenyou Yang <wenyou.yang@atmel.com>");
MODULE_LICENSE("GPL");