/*
 * DA9150 Charger Driver
 *
 * Copyright (c) 2014 Dialog Semiconductor
 *
 * Author: Adam Thomson <Adam.Thomson.Opensource@diasemi.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.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/interrupt.h>
#include <linux/power_supply.h>
#include <linux/notifier.h>
#include <linux/usb/phy.h>
#include <linux/iio/consumer.h>
#include <linux/mfd/da9150/core.h>
#include <linux/mfd/da9150/registers.h>

/* Private data */
struct da9150_charger {
	struct da9150 *da9150;
	struct device *dev;

	struct power_supply *usb;
	struct power_supply *battery;
	struct power_supply *supply_online;

	struct usb_phy *usb_phy;
	struct notifier_block otg_nb;
	struct work_struct otg_work;
	unsigned long usb_event;

	struct iio_channel *ibus_chan;
	struct iio_channel *vbus_chan;
	struct iio_channel *tjunc_chan;
	struct iio_channel *vbat_chan;
};

static inline int da9150_charger_supply_online(struct da9150_charger *charger,
					       struct power_supply *psy,
					       union power_supply_propval *val)
{
	val->intval = (psy == charger->supply_online) ? 1 : 0;

	return 0;
}

/* Charger Properties */
static int da9150_charger_vbus_voltage_now(struct da9150_charger *charger,
					   union power_supply_propval *val)
{
	int v_val, ret;

	/* Read processed value - mV units */
	ret = iio_read_channel_processed(charger->vbus_chan, &v_val);
	if (ret < 0)
		return ret;

	/* Convert voltage to expected uV units */
	val->intval = v_val * 1000;

	return 0;
}

static int da9150_charger_ibus_current_avg(struct da9150_charger *charger,
					   union power_supply_propval *val)
{
	int i_val, ret;

	/* Read processed value - mA units */
	ret = iio_read_channel_processed(charger->ibus_chan, &i_val);
	if (ret < 0)
		return ret;

	/* Convert current to expected uA units */
	val->intval = i_val * 1000;

	return 0;
}

static int da9150_charger_tjunc_temp(struct da9150_charger *charger,
				     union power_supply_propval *val)
{
	int t_val, ret;

	/* Read processed value - 0.001 degrees C units */
	ret = iio_read_channel_processed(charger->tjunc_chan, &t_val);
	if (ret < 0)
		return ret;

	/* Convert temp to expect 0.1 degrees C units */
	val->intval = t_val / 100;

	return 0;
}

static enum power_supply_property da9150_charger_props[] = {
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_AVG,
	POWER_SUPPLY_PROP_TEMP,
};

static int da9150_charger_get_prop(struct power_supply *psy,
				   enum power_supply_property psp,
				   union power_supply_propval *val)
{
	struct da9150_charger *charger = dev_get_drvdata(psy->dev.parent);
	int ret;

	switch (psp) {
	case POWER_SUPPLY_PROP_ONLINE:
		ret = da9150_charger_supply_online(charger, psy, val);
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = da9150_charger_vbus_voltage_now(charger, val);
		break;
	case POWER_SUPPLY_PROP_CURRENT_AVG:
		ret = da9150_charger_ibus_current_avg(charger, val);
		break;
	case POWER_SUPPLY_PROP_TEMP:
		ret = da9150_charger_tjunc_temp(charger, val);
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

/* Battery Properties */
static int da9150_charger_battery_status(struct da9150_charger *charger,
					 union power_supply_propval *val)
{
	u8 reg;

	/* Check to see if battery is discharging */
	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_H);

	if (((reg & DA9150_VBUS_STAT_MASK) == DA9150_VBUS_STAT_OFF) ||
	    ((reg & DA9150_VBUS_STAT_MASK) == DA9150_VBUS_STAT_WAIT)) {
		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;

		return 0;
	}

	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_J);

	/* Now check for other states */
	switch (reg & DA9150_CHG_STAT_MASK) {
	case DA9150_CHG_STAT_ACT:
	case DA9150_CHG_STAT_PRE:
	case DA9150_CHG_STAT_CC:
	case DA9150_CHG_STAT_CV:
		val->intval = POWER_SUPPLY_STATUS_CHARGING;
		break;
	case DA9150_CHG_STAT_OFF:
	case DA9150_CHG_STAT_SUSP:
	case DA9150_CHG_STAT_TEMP:
	case DA9150_CHG_STAT_TIME:
	case DA9150_CHG_STAT_BAT:
		val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
		break;
	case DA9150_CHG_STAT_FULL:
		val->intval = POWER_SUPPLY_STATUS_FULL;
		break;
	default:
		val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
		break;
	}

	return 0;
}

static int da9150_charger_battery_health(struct da9150_charger *charger,
					 union power_supply_propval *val)
{
	u8 reg;

	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_J);

	/* Check if temperature limit reached */
	switch (reg & DA9150_CHG_TEMP_MASK) {
	case DA9150_CHG_TEMP_UNDER:
		val->intval = POWER_SUPPLY_HEALTH_COLD;
		return 0;
	case DA9150_CHG_TEMP_OVER:
		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
		return 0;
	default:
		break;
	}

	/* Check for other health states */
	switch (reg & DA9150_CHG_STAT_MASK) {
	case DA9150_CHG_STAT_ACT:
	case DA9150_CHG_STAT_PRE:
		val->intval = POWER_SUPPLY_HEALTH_DEAD;
		break;
	case DA9150_CHG_STAT_TIME:
		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
		break;
	default:
		val->intval = POWER_SUPPLY_HEALTH_GOOD;
		break;
	}

	return 0;
}

static int da9150_charger_battery_present(struct da9150_charger *charger,
					  union power_supply_propval *val)
{
	u8 reg;

	/* Check if battery present or removed */
	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_J);
	if ((reg & DA9150_CHG_STAT_MASK) == DA9150_CHG_STAT_BAT)
		val->intval = 0;
	else
		val->intval = 1;

	return 0;
}

static int da9150_charger_battery_charge_type(struct da9150_charger *charger,
					      union power_supply_propval *val)
{
	u8 reg;

	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_J);

	switch (reg & DA9150_CHG_STAT_MASK) {
	case DA9150_CHG_STAT_CC:
		val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
		break;
	case DA9150_CHG_STAT_ACT:
	case DA9150_CHG_STAT_PRE:
	case DA9150_CHG_STAT_CV:
		val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
		break;
	default:
		val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
		break;
	}

	return 0;
}

static int da9150_charger_battery_voltage_min(struct da9150_charger *charger,
					      union power_supply_propval *val)
{
	u8 reg;

	reg = da9150_reg_read(charger->da9150, DA9150_PPR_CHGCTRL_C);

	/* Value starts at 2500 mV, 50 mV increments, presented in uV */
	val->intval = ((reg & DA9150_CHG_VFAULT_MASK) * 50000) + 2500000;

	return 0;
}

static int da9150_charger_battery_voltage_now(struct da9150_charger *charger,
					      union power_supply_propval *val)
{
	int v_val, ret;

	/* Read processed value - mV units */
	ret = iio_read_channel_processed(charger->vbat_chan, &v_val);
	if (ret < 0)
		return ret;

	val->intval = v_val * 1000;

	return 0;
}

static int da9150_charger_battery_current_max(struct da9150_charger *charger,
					      union power_supply_propval *val)
{
	int reg;

	reg = da9150_reg_read(charger->da9150, DA9150_PPR_CHGCTRL_D);

	/* 25mA increments */
	val->intval = reg * 25000;

	return 0;
}

static int da9150_charger_battery_voltage_max(struct da9150_charger *charger,
					      union power_supply_propval *val)
{
	u8 reg;

	reg = da9150_reg_read(charger->da9150, DA9150_PPR_CHGCTRL_B);

	/* Value starts at 3650 mV, 25 mV increments, presented in uV */
	val->intval = ((reg & DA9150_CHG_VBAT_MASK) * 25000) + 3650000;
	return 0;
}

static enum power_supply_property da9150_charger_bat_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_CHARGE_TYPE,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
};

static int da9150_charger_battery_get_prop(struct power_supply *psy,
					   enum power_supply_property psp,
					   union power_supply_propval *val)
{
	struct da9150_charger *charger = dev_get_drvdata(psy->dev.parent);
	int ret;

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		ret = da9150_charger_battery_status(charger, val);
		break;
	case POWER_SUPPLY_PROP_ONLINE:
		ret = da9150_charger_supply_online(charger, psy, val);
		break;
	case POWER_SUPPLY_PROP_HEALTH:
		ret = da9150_charger_battery_health(charger, val);
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		ret = da9150_charger_battery_present(charger, val);
		break;
	case POWER_SUPPLY_PROP_CHARGE_TYPE:
		ret = da9150_charger_battery_charge_type(charger, val);
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		ret = da9150_charger_battery_voltage_min(charger, val);
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = da9150_charger_battery_voltage_now(charger, val);
		break;
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
		ret = da9150_charger_battery_current_max(charger, val);
		break;
	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
		ret = da9150_charger_battery_voltage_max(charger, val);
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

static irqreturn_t da9150_charger_chg_irq(int irq, void *data)
{
	struct da9150_charger *charger = data;

	power_supply_changed(charger->battery);

	return IRQ_HANDLED;
}

static irqreturn_t da9150_charger_tjunc_irq(int irq, void *data)
{
	struct da9150_charger *charger = data;

	/* Nothing we can really do except report this. */
	dev_crit(charger->dev, "TJunc over temperature!!!\n");
	power_supply_changed(charger->usb);

	return IRQ_HANDLED;
}

static irqreturn_t da9150_charger_vfault_irq(int irq, void *data)
{
	struct da9150_charger *charger = data;

	/* Nothing we can really do except report this. */
	dev_crit(charger->dev, "VSYS under voltage!!!\n");
	power_supply_changed(charger->usb);
	power_supply_changed(charger->battery);

	return IRQ_HANDLED;
}

static irqreturn_t da9150_charger_vbus_irq(int irq, void *data)
{
	struct da9150_charger *charger = data;
	u8 reg;

	reg = da9150_reg_read(charger->da9150, DA9150_STATUS_H);

	/* Charger plugged in or battery only */
	switch (reg & DA9150_VBUS_STAT_MASK) {
	case DA9150_VBUS_STAT_OFF:
	case DA9150_VBUS_STAT_WAIT:
		charger->supply_online = charger->battery;
		break;
	case DA9150_VBUS_STAT_CHG:
		charger->supply_online = charger->usb;
		break;
	default:
		dev_warn(charger->dev, "Unknown VBUS state - reg = 0x%x\n",
			 reg);
		charger->supply_online = NULL;
		break;
	}

	power_supply_changed(charger->usb);
	power_supply_changed(charger->battery);

	return IRQ_HANDLED;
}

static void da9150_charger_otg_work(struct work_struct *data)
{
	struct da9150_charger *charger =
		container_of(data, struct da9150_charger, otg_work);

	switch (charger->usb_event) {
	case USB_EVENT_ID:
		/* Enable OTG Boost */
		da9150_set_bits(charger->da9150, DA9150_PPR_BKCTRL_A,
				DA9150_VBUS_MODE_MASK, DA9150_VBUS_MODE_OTG);
		break;
	case USB_EVENT_NONE:
		/* Revert to charge mode */
		power_supply_changed(charger->usb);
		power_supply_changed(charger->battery);
		da9150_set_bits(charger->da9150, DA9150_PPR_BKCTRL_A,
				DA9150_VBUS_MODE_MASK, DA9150_VBUS_MODE_CHG);
		break;
	}
}

static int da9150_charger_otg_ncb(struct notifier_block *nb, unsigned long val,
				  void *priv)
{
	struct da9150_charger *charger =
		container_of(nb, struct da9150_charger, otg_nb);

	dev_dbg(charger->dev, "DA9150 OTG notify %lu\n", val);

	charger->usb_event = val;
	schedule_work(&charger->otg_work);

	return NOTIFY_OK;
}

static int da9150_charger_register_irq(struct platform_device *pdev,
				       irq_handler_t handler,
				       const char *irq_name)
{
	struct device *dev = &pdev->dev;
	struct da9150_charger *charger = platform_get_drvdata(pdev);
	int irq, ret;

	irq = platform_get_irq_byname(pdev, irq_name);
	if (irq < 0) {
		dev_err(dev, "Failed to get IRQ CHG_STATUS: %d\n", irq);
		return irq;
	}

	ret = request_threaded_irq(irq, NULL, handler, IRQF_ONESHOT, irq_name,
				   charger);
	if (ret)
		dev_err(dev, "Failed to request IRQ %d: %d\n", irq, ret);

	return ret;
}

static void da9150_charger_unregister_irq(struct platform_device *pdev,
					  const char *irq_name)
{
	struct device *dev = &pdev->dev;
	struct da9150_charger *charger = platform_get_drvdata(pdev);
	int irq;

	irq = platform_get_irq_byname(pdev, irq_name);
	if (irq < 0) {
		dev_err(dev, "Failed to get IRQ CHG_STATUS: %d\n", irq);
		return;
	}

	free_irq(irq, charger);
}

static const struct power_supply_desc usb_desc = {
	.name		= "da9150-usb",
	.type		= POWER_SUPPLY_TYPE_USB,
	.properties	= da9150_charger_props,
	.num_properties	= ARRAY_SIZE(da9150_charger_props),
	.get_property	= da9150_charger_get_prop,
};

static const struct power_supply_desc battery_desc = {
	.name		= "da9150-battery",
	.type		= POWER_SUPPLY_TYPE_BATTERY,
	.properties	= da9150_charger_bat_props,
	.num_properties	= ARRAY_SIZE(da9150_charger_bat_props),
	.get_property	= da9150_charger_battery_get_prop,
};

static int da9150_charger_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct da9150 *da9150 = dev_get_drvdata(dev->parent);
	struct da9150_charger *charger;
	u8 reg;
	int ret;

	charger = devm_kzalloc(dev, sizeof(struct da9150_charger), GFP_KERNEL);
	if (!charger)
		return -ENOMEM;

	platform_set_drvdata(pdev, charger);
	charger->da9150 = da9150;
	charger->dev = dev;

	/* Acquire ADC channels */
	charger->ibus_chan = iio_channel_get(dev, "CHAN_IBUS");
	if (IS_ERR(charger->ibus_chan)) {
		ret = PTR_ERR(charger->ibus_chan);
		goto ibus_chan_fail;
	}

	charger->vbus_chan = iio_channel_get(dev, "CHAN_VBUS");
	if (IS_ERR(charger->vbus_chan)) {
		ret = PTR_ERR(charger->vbus_chan);
		goto vbus_chan_fail;
	}

	charger->tjunc_chan = iio_channel_get(dev, "CHAN_TJUNC");
	if (IS_ERR(charger->tjunc_chan)) {
		ret = PTR_ERR(charger->tjunc_chan);
		goto tjunc_chan_fail;
	}

	charger->vbat_chan = iio_channel_get(dev, "CHAN_VBAT");
	if (IS_ERR(charger->vbat_chan)) {
		ret = PTR_ERR(charger->vbat_chan);
		goto vbat_chan_fail;
	}

	/* Register power supplies */
	charger->usb = power_supply_register(dev, &usb_desc, NULL);
	if (IS_ERR(charger->usb)) {
		ret = PTR_ERR(charger->usb);
		goto usb_fail;
	}

	charger->battery = power_supply_register(dev, &battery_desc, NULL);
	if (IS_ERR(charger->battery)) {
		ret = PTR_ERR(charger->battery);
		goto battery_fail;
	}

	/* Get initial online supply */
	reg = da9150_reg_read(da9150, DA9150_STATUS_H);

	switch (reg & DA9150_VBUS_STAT_MASK) {
	case DA9150_VBUS_STAT_OFF:
	case DA9150_VBUS_STAT_WAIT:
		charger->supply_online = charger->battery;
		break;
	case DA9150_VBUS_STAT_CHG:
		charger->supply_online = charger->usb;
		break;
	default:
		dev_warn(dev, "Unknown VBUS state - reg = 0x%x\n", reg);
		charger->supply_online = NULL;
		break;
	}

	/* Setup OTG reporting & configuration */
	charger->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
	if (!IS_ERR_OR_NULL(charger->usb_phy)) {
		INIT_WORK(&charger->otg_work, da9150_charger_otg_work);
		charger->otg_nb.notifier_call = da9150_charger_otg_ncb;
		usb_register_notifier(charger->usb_phy, &charger->otg_nb);
	}

	/* Register IRQs */
	ret = da9150_charger_register_irq(pdev, da9150_charger_chg_irq,
					  "CHG_STATUS");
	if (ret < 0)
		goto chg_irq_fail;

	ret = da9150_charger_register_irq(pdev, da9150_charger_tjunc_irq,
					  "CHG_TJUNC");
	if (ret < 0)
		goto tjunc_irq_fail;

	ret = da9150_charger_register_irq(pdev, da9150_charger_vfault_irq,
					  "CHG_VFAULT");
	if (ret < 0)
		goto vfault_irq_fail;

	ret = da9150_charger_register_irq(pdev, da9150_charger_vbus_irq,
					  "CHG_VBUS");
	if (ret < 0)
		goto vbus_irq_fail;

	return 0;


vbus_irq_fail:
	da9150_charger_unregister_irq(pdev, "CHG_VFAULT");
vfault_irq_fail:
	da9150_charger_unregister_irq(pdev, "CHG_TJUNC");
tjunc_irq_fail:
	da9150_charger_unregister_irq(pdev, "CHG_STATUS");
chg_irq_fail:
	if (!IS_ERR_OR_NULL(charger->usb_phy))
		usb_unregister_notifier(charger->usb_phy, &charger->otg_nb);
battery_fail:
	power_supply_unregister(charger->usb);

usb_fail:
	iio_channel_release(charger->vbat_chan);

vbat_chan_fail:
	iio_channel_release(charger->tjunc_chan);

tjunc_chan_fail:
	iio_channel_release(charger->vbus_chan);

vbus_chan_fail:
	iio_channel_release(charger->ibus_chan);

ibus_chan_fail:
	return ret;
}

static int da9150_charger_remove(struct platform_device *pdev)
{
	struct da9150_charger *charger = platform_get_drvdata(pdev);
	int irq;

	/* Make sure IRQs are released before unregistering power supplies */
	irq = platform_get_irq_byname(pdev, "CHG_VBUS");
	free_irq(irq, charger);

	irq = platform_get_irq_byname(pdev, "CHG_VFAULT");
	free_irq(irq, charger);

	irq = platform_get_irq_byname(pdev, "CHG_TJUNC");
	free_irq(irq, charger);

	irq = platform_get_irq_byname(pdev, "CHG_STATUS");
	free_irq(irq, charger);

	if (!IS_ERR_OR_NULL(charger->usb_phy))
		usb_unregister_notifier(charger->usb_phy, &charger->otg_nb);

	power_supply_unregister(charger->battery);
	power_supply_unregister(charger->usb);

	/* Release ADC channels */
	iio_channel_release(charger->ibus_chan);
	iio_channel_release(charger->vbus_chan);
	iio_channel_release(charger->tjunc_chan);
	iio_channel_release(charger->vbat_chan);

	return 0;
}

static struct platform_driver da9150_charger_driver = {
	.driver = {
		.name = "da9150-charger",
	},
	.probe = da9150_charger_probe,
	.remove = da9150_charger_remove,
};

module_platform_driver(da9150_charger_driver);

MODULE_DESCRIPTION("Charger Driver for DA9150");
MODULE_AUTHOR("Adam Thomson <Adam.Thomson.Opensource@diasemi.com>");
MODULE_LICENSE("GPL");