/*
 * 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/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/mfd/core.h>
#include <linux/power_supply.h>

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

struct jz_battery {
	struct jz_battery_platform_data *pdata;
	struct platform_device *pdev;

	void __iomem *base;

	int irq;
	int charge_irq;

	const struct mfd_cell *cell;

	int status;
	long voltage;

	struct completion read_completion;

	struct power_supply *battery;
	struct power_supply_desc battery_desc;
	struct delayed_work work;

	struct mutex lock;
};

static inline struct jz_battery *psy_to_jz_battery(struct power_supply *psy)
{
	return power_supply_get_drvdata(psy);
}

static irqreturn_t jz_battery_irq_handler(int irq, void *devid)
{
	struct jz_battery *battery = devid;

	complete(&battery->read_completion);
	return IRQ_HANDLED;
}

static long jz_battery_read_voltage(struct jz_battery *battery)
{
	long t;
	unsigned long val;
	long voltage;

	mutex_lock(&battery->lock);

	reinit_completion(&battery->read_completion);

	enable_irq(battery->irq);
	battery->cell->enable(battery->pdev);

	t = wait_for_completion_interruptible_timeout(&battery->read_completion,
		HZ);

	if (t > 0) {
		val = readw(battery->base) & 0xfff;

		if (battery->pdata->info.voltage_max_design <= 2500000)
			val = (val * 78125UL) >> 7UL;
		else
			val = ((val * 924375UL) >> 9UL) + 33000;
		voltage = (long)val;
	} else {
		voltage = t ? t : -ETIMEDOUT;
	}

	battery->cell->disable(battery->pdev);
	disable_irq(battery->irq);

	mutex_unlock(&battery->lock);

	return voltage;
}

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);

	mod_delayed_work(system_wq, &jz_battery->work, 0);
}

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

	mod_delayed_work(system_wq, &jz_battery->work, 0);

	return IRQ_HANDLED;
}

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

	if (gpio_is_valid(jz_battery->pdata->gpio_charge)) {
		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 = true;
		}
	}

	voltage = jz_battery_read_voltage(jz_battery);
	if (voltage >= 0 && abs(voltage - jz_battery->voltage) > 50000) {
		jz_battery->voltage = voltage;
		has_changed = true;
	}

	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.parent->platform_data;
	struct power_supply_config psy_cfg = {};
	struct jz_battery *jz_battery;
	struct power_supply_desc *battery_desc;
	struct resource *mem;

	if (!pdata) {
		dev_err(&pdev->dev, "No platform_data supplied\n");
		return -ENXIO;
	}

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

	jz_battery->cell = mfd_get_cell(pdev);

	jz_battery->irq = platform_get_irq(pdev, 0);
	if (jz_battery->irq < 0) {
		dev_err(&pdev->dev, "Failed to get platform irq: %d\n", ret);
		return jz_battery->irq;
	}

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	jz_battery->base = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(jz_battery->base))
		return PTR_ERR(jz_battery->base);

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

	psy_cfg.drv_data = jz_battery;

	jz_battery->pdata = pdata;
	jz_battery->pdev = pdev;

	init_completion(&jz_battery->read_completion);
	mutex_init(&jz_battery->lock);

	INIT_DELAYED_WORK(&jz_battery->work, jz_battery_work);

	ret = request_irq(jz_battery->irq, jz_battery_irq_handler, 0, pdev->name,
			jz_battery);
	if (ret) {
		dev_err(&pdev->dev, "Failed to request irq %d\n", ret);
		return ret;
	}
	disable_irq(jz_battery->irq);

	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_irq;
		}
		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;
	}

	if (jz_battery->pdata->info.voltage_max_design <= 2500000)
		jz4740_adc_set_config(pdev->dev.parent, JZ_ADC_CONFIG_BAT_MB,
			JZ_ADC_CONFIG_BAT_MB);
	else
		jz4740_adc_set_config(pdev->dev.parent, JZ_ADC_CONFIG_BAT_MB, 0);

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

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

	return 0;

err_free_charge_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_irq:
	free_irq(jz_battery->irq, 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);

	free_irq(jz_battery->irq, jz_battery);

	return 0;
}

#ifdef CONFIG_PM
static int jz_battery_suspend(struct device *dev)
{
	struct jz_battery *jz_battery = dev_get_drvdata(dev);

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

	return 0;
}

static int jz_battery_resume(struct device *dev)
{
	struct jz_battery *jz_battery = dev_get_drvdata(dev);

	schedule_delayed_work(&jz_battery->work, 0);

	return 0;
}

static const struct dev_pm_ops jz_battery_pm_ops = {
	.suspend	= jz_battery_suspend,
	.resume		= jz_battery_resume,
};

#define JZ_BATTERY_PM_OPS (&jz_battery_pm_ops)
#else
#define JZ_BATTERY_PM_OPS NULL
#endif

static struct platform_driver jz_battery_driver = {
	.probe		= jz_battery_probe,
	.remove		= jz_battery_remove,
	.driver = {
		.name = "jz4740-battery",
		.pm = JZ_BATTERY_PM_OPS,
	},
};

module_platform_driver(jz_battery_driver);

MODULE_ALIAS("platform:jz4740-battery");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("JZ4740 SoC battery driver");