/*
 * AXP20x PMIC USB power supply status driver
 *
 * Copyright (C) 2015 Hans de Goede <hdegoede@redhat.com>
 * Copyright (C) 2014 Bruno Prémont <bonbons@linux-vserver.org>
 *
 * 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/device.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/axp20x.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#define DRVNAME "axp20x-usb-power-supply"

#define AXP20X_PWR_STATUS_VBUS_PRESENT	BIT(5)
#define AXP20X_PWR_STATUS_VBUS_USED	BIT(4)

#define AXP20X_USB_STATUS_VBUS_VALID	BIT(2)

#define AXP20X_VBUS_VHOLD_uV(b)		(4000000 + (((b) >> 3) & 7) * 100000)
#define AXP20X_VBUS_CLIMIT_MASK		3
#define AXP20X_VBUC_CLIMIT_900mA	0
#define AXP20X_VBUC_CLIMIT_500mA	1
#define AXP20X_VBUC_CLIMIT_100mA	2
#define AXP20X_VBUC_CLIMIT_NONE		3

#define AXP20X_ADC_EN1_VBUS_CURR	BIT(2)
#define AXP20X_ADC_EN1_VBUS_VOLT	BIT(3)

#define AXP20X_VBUS_MON_VBUS_VALID	BIT(3)

struct axp20x_usb_power {
	struct regmap *regmap;
	struct power_supply *supply;
};

static irqreturn_t axp20x_usb_power_irq(int irq, void *devid)
{
	struct axp20x_usb_power *power = devid;

	power_supply_changed(power->supply);

	return IRQ_HANDLED;
}

static int axp20x_usb_power_get_property(struct power_supply *psy,
	enum power_supply_property psp, union power_supply_propval *val)
{
	struct axp20x_usb_power *power = power_supply_get_drvdata(psy);
	unsigned int input, v;
	int ret;

	switch (psp) {
	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
		ret = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
		if (ret)
			return ret;

		val->intval = AXP20X_VBUS_VHOLD_uV(v);
		return 0;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		ret = axp20x_read_variable_width(power->regmap,
						 AXP20X_VBUS_V_ADC_H, 12);
		if (ret < 0)
			return ret;

		val->intval = ret * 1700; /* 1 step = 1.7 mV */
		return 0;
	case POWER_SUPPLY_PROP_CURRENT_MAX:
		ret = regmap_read(power->regmap, AXP20X_VBUS_IPSOUT_MGMT, &v);
		if (ret)
			return ret;

		switch (v & AXP20X_VBUS_CLIMIT_MASK) {
		case AXP20X_VBUC_CLIMIT_100mA:
			val->intval = 100000;
			break;
		case AXP20X_VBUC_CLIMIT_500mA:
			val->intval = 500000;
			break;
		case AXP20X_VBUC_CLIMIT_900mA:
			val->intval = 900000;
			break;
		case AXP20X_VBUC_CLIMIT_NONE:
			val->intval = -1;
			break;
		}
		return 0;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		ret = axp20x_read_variable_width(power->regmap,
						 AXP20X_VBUS_I_ADC_H, 12);
		if (ret < 0)
			return ret;

		val->intval = ret * 375; /* 1 step = 0.375 mA */
		return 0;
	default:
		break;
	}

	/* All the properties below need the input-status reg value */
	ret = regmap_read(power->regmap, AXP20X_PWR_INPUT_STATUS, &input);
	if (ret)
		return ret;

	switch (psp) {
	case POWER_SUPPLY_PROP_HEALTH:
		if (!(input & AXP20X_PWR_STATUS_VBUS_PRESENT)) {
			val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
			break;
		}

		ret = regmap_read(power->regmap, AXP20X_USB_OTG_STATUS, &v);
		if (ret)
			return ret;

		if (!(v & AXP20X_USB_STATUS_VBUS_VALID)) {
			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
			break;
		}

		val->intval = POWER_SUPPLY_HEALTH_GOOD;
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_PRESENT);
		break;
	case POWER_SUPPLY_PROP_ONLINE:
		val->intval = !!(input & AXP20X_PWR_STATUS_VBUS_USED);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static enum power_supply_property axp20x_usb_power_properties[] = {
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_VOLTAGE_MIN,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_MAX,
	POWER_SUPPLY_PROP_CURRENT_NOW,
};

static const struct power_supply_desc axp20x_usb_power_desc = {
	.name = "axp20x-usb",
	.type = POWER_SUPPLY_TYPE_USB,
	.properties = axp20x_usb_power_properties,
	.num_properties = ARRAY_SIZE(axp20x_usb_power_properties),
	.get_property = axp20x_usb_power_get_property,
};

static int axp20x_usb_power_probe(struct platform_device *pdev)
{
	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
	struct power_supply_config psy_cfg = {};
	struct axp20x_usb_power *power;
	static const char * const irq_names[] = { "VBUS_PLUGIN",
		"VBUS_REMOVAL", "VBUS_VALID", "VBUS_NOT_VALID" };
	int i, irq, ret;

	if (!of_device_is_available(pdev->dev.of_node))
		return -ENODEV;

	if (!axp20x) {
		dev_err(&pdev->dev, "Parent drvdata not set\n");
		return -EINVAL;
	}

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

	power->regmap = axp20x->regmap;

	/* Enable vbus valid checking */
	ret = regmap_update_bits(power->regmap, AXP20X_VBUS_MON,
		    AXP20X_VBUS_MON_VBUS_VALID, AXP20X_VBUS_MON_VBUS_VALID);
	if (ret)
		return ret;

	/* Enable vbus voltage and current measurement */
	ret = regmap_update_bits(power->regmap, AXP20X_ADC_EN1,
			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT,
			AXP20X_ADC_EN1_VBUS_CURR | AXP20X_ADC_EN1_VBUS_VOLT);
	if (ret)
		return ret;

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

	power->supply = devm_power_supply_register(&pdev->dev,
					&axp20x_usb_power_desc, &psy_cfg);
	if (IS_ERR(power->supply))
		return PTR_ERR(power->supply);

	/* Request irqs after registering, as irqs may trigger immediately */
	for (i = 0; i < ARRAY_SIZE(irq_names); i++) {
		irq = platform_get_irq_byname(pdev, irq_names[i]);
		if (irq < 0) {
			dev_warn(&pdev->dev, "No IRQ for %s: %d\n",
				 irq_names[i], irq);
			continue;
		}
		irq = regmap_irq_get_virq(axp20x->regmap_irqc, irq);
		ret = devm_request_any_context_irq(&pdev->dev, irq,
				axp20x_usb_power_irq, 0, DRVNAME, power);
		if (ret < 0)
			dev_warn(&pdev->dev, "Error requesting %s IRQ: %d\n",
				 irq_names[i], ret);
	}

	return 0;
}

static const struct of_device_id axp20x_usb_power_match[] = {
	{ .compatible = "x-powers,axp202-usb-power-supply" },
	{ }
};
MODULE_DEVICE_TABLE(of, axp20x_usb_power_match);

static struct platform_driver axp20x_usb_power_driver = {
	.probe = axp20x_usb_power_probe,
	.driver = {
		.name = DRVNAME,
		.of_match_table = axp20x_usb_power_match,
	},
};

module_platform_driver(axp20x_usb_power_driver);

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_DESCRIPTION("AXP20x PMIC USB power supply status driver");
MODULE_LICENSE("GPL");