/*
 * Battery measurement code for Ingenic JZ SOC.
 *
 * Copyright (C) 2009 Jiejing Zhang <kzjeef@gmail.com>
 * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
 *
 * based on tosa_battery.c
 *
 * Copyright (C) 2008 Marek Vasut <marek.vasut@gmail.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/kernel.h>
#include <linux/module.h>
#include <linux/power_supply.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>

#include <linux/power/jz4740-battery.h>
#include <linux/jz4740-adc.h>

struct jz_battery {
	struct jz_battery_platform_data *pdata;

	int charge_irq;

	int status;
	long voltage;

	struct power_supply battery;
	struct delayed_work work;
};

static inline struct jz_battery *psy_to_jz_battery(struct power_supply *psy)
{
	return container_of(psy, struct jz_battery, battery);
}

static long jz_battery_read_voltage(struct jz_battery *jz_battery)
{
	struct device *adc = jz_battery->battery.dev->parent->parent;
	enum jz_adc_battery_scale scale;

	if (jz_battery->pdata->info.voltage_max_design > 2500000)
		scale = JZ_ADC_BATTERY_SCALE_7V5;
	else
		scale = JZ_ADC_BATTERY_SCALE_2V5;

	return jz4740_adc_read_battery_voltage(adc, scale);
}

static int jz_battery_get_capacity(struct power_supply *psy)
{
	struct jz_battery *jz_battery = psy_to_jz_battery(psy);
	struct power_supply_info *info = &jz_battery->pdata->info;
	long voltage;
	int ret;
	int voltage_span;

	voltage = jz_battery_read_voltage(jz_battery);

	if (voltage < 0)
		return voltage;

	voltage_span = info->voltage_max_design - info->voltage_min_design;
	ret = ((voltage - info->voltage_min_design) * 100) / voltage_span;

	if (ret > 100)
		ret = 100;
	else if (ret < 0)
		ret = 0;

	return ret;
}

static int jz_battery_get_property(struct power_supply *psy,
				enum power_supply_property psp,
				union power_supply_propval *val)
{
	struct jz_battery *jz_battery = psy_to_jz_battery(psy);
	struct power_supply_info *info = &jz_battery->pdata->info;
	long voltage;

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		val->intval = jz_battery->status;
		break;
	case POWER_SUPPLY_PROP_TECHNOLOGY:
		val->intval = jz_battery->pdata->info.technology;
		break;
	case POWER_SUPPLY_PROP_HEALTH:
		voltage = jz_battery_read_voltage(jz_battery);
		if (voltage < info->voltage_min_design)
			val->intval = POWER_SUPPLY_HEALTH_DEAD;
		else
			val->intval = POWER_SUPPLY_HEALTH_GOOD;
		break;
	case POWER_SUPPLY_PROP_CAPACITY:
		val->intval = jz_battery_get_capacity(psy);
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		val->intval = jz_battery_read_voltage(jz_battery);
		if (val->intval < 0)
			return val->intval;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
		val->intval = info->voltage_max_design;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
		val->intval = info->voltage_min_design;
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = 1;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static void jz_battery_external_power_changed(struct power_supply *psy)
{
	struct jz_battery *jz_battery = psy_to_jz_battery(psy);

	cancel_delayed_work(&jz_battery->work);
	schedule_delayed_work(&jz_battery->work, 0);
}

static irqreturn_t jz_battery_charge_irq(int irq, void *data)
{
	struct jz_battery *jz_battery = data;

	cancel_delayed_work(&jz_battery->work);
	schedule_delayed_work(&jz_battery->work, 0);

	return IRQ_HANDLED;
}

static void jz_battery_update(struct jz_battery *jz_battery)
{
	int status;
	long voltage;
	long voltage_difference;
	bool has_changed = 0;

	if (gpio_is_valid(jz_battery->pdata->gpio_charge)) {
		int is_charging;

		is_charging = gpio_get_value(jz_battery->pdata->gpio_charge);
		is_charging ^= jz_battery->pdata->gpio_charge_active_low;
		if (is_charging)
			status = POWER_SUPPLY_STATUS_CHARGING;
		else
			status = POWER_SUPPLY_STATUS_NOT_CHARGING;

		if (status != jz_battery->status) {
			jz_battery->status = status;
			has_changed = 1;
		}
	}

	voltage = jz_battery_read_voltage(jz_battery);
	voltage_difference = voltage - jz_battery->voltage;
	if (voltage_difference > 50000 || voltage_difference < 50000) {
		jz_battery->voltage = voltage;
		has_changed = 1;
	}
	if (has_changed)
		power_supply_changed(&jz_battery->battery);
}

static enum power_supply_property jz_battery_properties[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_HEALTH,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_PRESENT,
};

static void jz_battery_work(struct work_struct *work)
{
	/* Too small interval will increase system workload */
	const int interval = HZ * 30;
	struct jz_battery *jz_battery = container_of(work, struct jz_battery,
					    work.work);

	jz_battery_update(jz_battery);
	schedule_delayed_work(&jz_battery->work, interval);
}

static int jz_battery_probe(struct platform_device *pdev)
{
	int ret = 0;
	struct jz_battery_platform_data *pdata = pdev->dev.platform_data;
	struct jz_battery *jz_battery;
	struct power_supply *battery;

	if (!pdev->dev.platform_data) {
		dev_err(&pdev->dev, "No platform data\n");
		return -EINVAL;
	}

	jz_battery = kzalloc(sizeof(*jz_battery), GFP_KERNEL);

	if (!jz_battery) {
		dev_err(&pdev->dev, "Failed to allocate driver structure\n");
		return -ENOMEM;
	}

	battery = &jz_battery->battery;
	battery->name = pdata->info.name;
	battery->type = POWER_SUPPLY_TYPE_BATTERY;
	battery->properties	= jz_battery_properties;
	battery->num_properties	= ARRAY_SIZE(jz_battery_properties);
	battery->get_property = jz_battery_get_property;
	battery->external_power_changed = jz_battery_external_power_changed;
	battery->use_for_apm = 1;

	jz_battery->pdata = pdata;

	INIT_DELAYED_WORK(&jz_battery->work, jz_battery_work);

	if (gpio_is_valid(pdata->gpio_charge)) {
		ret = gpio_request(pdata->gpio_charge, dev_name(&pdev->dev));
		if (ret) {
			dev_err(&pdev->dev, "charger state gpio request failed.\n");
			goto err_free;
		}
		ret = gpio_direction_input(pdata->gpio_charge);
		if (ret) {
			dev_err(&pdev->dev, "charger state gpio set direction failed.\n");
			goto err_free_gpio;
		}

		jz_battery->charge_irq = gpio_to_irq(pdata->gpio_charge);

		if (jz_battery->charge_irq >= 0) {
			ret = request_irq(jz_battery->charge_irq,
				    jz_battery_charge_irq,
				    IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
				    dev_name(&pdev->dev), jz_battery);
			if (ret) {
				dev_err(&pdev->dev, "Failed to request charge irq: %d\n", ret);
				goto err_free_gpio;
			}
		}
	} else {
		jz_battery->charge_irq = -1;
	}


	ret = power_supply_register(&pdev->dev, &jz_battery->battery);
	if (ret) {
		dev_err(&pdev->dev, "power supply battery register failed.\n");
		goto err_free_irq;
	}

	platform_set_drvdata(pdev, jz_battery);
	schedule_delayed_work(&jz_battery->work, 0);

	return 0;

err_free_irq:
	if (jz_battery->charge_irq >= 0)
		free_irq(jz_battery->charge_irq, jz_battery);
err_free_gpio:
	if (gpio_is_valid(pdata->gpio_charge))
		gpio_free(jz_battery->pdata->gpio_charge);
err_free:
	kfree(jz_battery);
	return ret;
}

static int jz_battery_remove(struct platform_device *pdev)
{
	struct jz_battery *jz_battery = platform_get_drvdata(pdev);

	cancel_delayed_work_sync(&jz_battery->work);

	if (gpio_is_valid(jz_battery->pdata->gpio_charge)) {
		if (jz_battery->charge_irq >= 0)
			free_irq(jz_battery->charge_irq, jz_battery);
		gpio_free(jz_battery->pdata->gpio_charge);
	}

	power_supply_unregister(&jz_battery->battery);

	return 0;
}

#ifdef CONFIG_PM
static int jz_battery_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct jz_battery *jz_battery = platform_get_drvdata(pdev);

	cancel_delayed_work_sync(&jz_battery->work);
	jz_battery->status =  POWER_SUPPLY_STATUS_UNKNOWN;

	return 0;
}

static int jz_battery_resume(struct platform_device *pdev)
{
	struct jz_battery *jz_battery = platform_get_drvdata(pdev);

	schedule_delayed_work(&jz_battery->work, 0);

	return 0;
}
#else
#define jz_battery_suspend NULL
#define jz_battery_resume NULL
#endif

static struct platform_driver jz_battery_driver = {
	.probe		= jz_battery_probe,
	.remove		= __devexit_p(jz_battery_remove),
	.suspend	= jz_battery_suspend,
	.resume		= jz_battery_resume,
	.driver = {
		.name = "jz4740-battery",
		.owner = THIS_MODULE,
	},
};

static int __init jz_battery_init(void)
{
	return platform_driver_register(&jz_battery_driver);
}
module_init(jz_battery_init);

static void __exit jz_battery_exit(void)
{
	platform_driver_unregister(&jz_battery_driver);
}
module_exit(jz_battery_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jiejing Zhang <kzjeef@gmail.com>");
MODULE_DESCRIPTION("JZ4720/JZ4740 SoC battery driver");
