/*
 * TWL4030/TPS65950 BCI (Battery Charger Interface) driver
 *
 * Copyright (C) 2010 Gražvydas Ignotas <notasas@gmail.com>
 *
 * based on twl4030_bci_battery.c by TI
 * Copyright (C) 2008 Texas Instruments, Inc.
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/i2c/twl.h>
#include <linux/power_supply.h>
#include <linux/notifier.h>
#include <linux/usb/otg.h>

#define TWL4030_BCIMSTATEC	0x02
#define TWL4030_BCIICHG		0x08
#define TWL4030_BCIVAC		0x0a
#define TWL4030_BCIVBUS		0x0c
#define TWL4030_BCIMFSTS3	0x0F
#define TWL4030_BCIMFSTS4	0x10
#define TWL4030_BCICTL1		0x23
#define TWL4030_BB_CFG		0x12

#define TWL4030_BCIMFSTS1	0x01

#define TWL4030_BCIAUTOWEN	BIT(5)
#define TWL4030_CONFIG_DONE	BIT(4)
#define TWL4030_BCIAUTOUSB	BIT(1)
#define TWL4030_BCIAUTOAC	BIT(0)
#define TWL4030_CGAIN		BIT(5)
#define TWL4030_USBFASTMCHG	BIT(2)
#define TWL4030_STS_VBUS	BIT(7)
#define TWL4030_STS_USB_ID	BIT(2)
#define TWL4030_BBCHEN		BIT(4)
#define TWL4030_BBSEL_MASK	0x0c
#define TWL4030_BBSEL_2V5	0x00
#define TWL4030_BBSEL_3V0	0x04
#define TWL4030_BBSEL_3V1	0x08
#define TWL4030_BBSEL_3V2	0x0c
#define TWL4030_BBISEL_MASK	0x03
#define TWL4030_BBISEL_25uA	0x00
#define TWL4030_BBISEL_150uA	0x01
#define TWL4030_BBISEL_500uA	0x02
#define TWL4030_BBISEL_1000uA	0x03

#define TWL4030_BATSTSPCHG	BIT(2)
#define TWL4030_BATSTSMCHG	BIT(6)

/* BCI interrupts */
#define TWL4030_WOVF		BIT(0) /* Watchdog overflow */
#define TWL4030_TMOVF		BIT(1) /* Timer overflow */
#define TWL4030_ICHGHIGH	BIT(2) /* Battery charge current high */
#define TWL4030_ICHGLOW		BIT(3) /* Battery cc. low / FSM state change */
#define TWL4030_ICHGEOC		BIT(4) /* Battery current end-of-charge */
#define TWL4030_TBATOR2		BIT(5) /* Battery temperature out of range 2 */
#define TWL4030_TBATOR1		BIT(6) /* Battery temperature out of range 1 */
#define TWL4030_BATSTS		BIT(7) /* Battery status */

#define TWL4030_VBATLVL		BIT(0) /* VBAT level */
#define TWL4030_VBATOV		BIT(1) /* VBAT overvoltage */
#define TWL4030_VBUSOV		BIT(2) /* VBUS overvoltage */
#define TWL4030_ACCHGOV		BIT(3) /* Ac charger overvoltage */

#define TWL4030_MSTATEC_USB		BIT(4)
#define TWL4030_MSTATEC_AC		BIT(5)
#define TWL4030_MSTATEC_MASK		0x0f
#define TWL4030_MSTATEC_QUICK1		0x02
#define TWL4030_MSTATEC_QUICK7		0x07
#define TWL4030_MSTATEC_COMPLETE1	0x0b
#define TWL4030_MSTATEC_COMPLETE4	0x0e

static bool allow_usb;
module_param(allow_usb, bool, 0644);
MODULE_PARM_DESC(allow_usb, "Allow USB charge drawing default current");

struct twl4030_bci {
	struct device		*dev;
	struct power_supply	*ac;
	struct power_supply	*usb;
	struct usb_phy		*transceiver;
	struct notifier_block	usb_nb;
	struct work_struct	work;
	int			irq_chg;
	int			irq_bci;
	int			usb_enabled;

	unsigned long		event;
};

/*
 * clear and set bits on an given register on a given module
 */
static int twl4030_clear_set(u8 mod_no, u8 clear, u8 set, u8 reg)
{
	u8 val = 0;
	int ret;

	ret = twl_i2c_read_u8(mod_no, &val, reg);
	if (ret)
		return ret;

	val &= ~clear;
	val |= set;

	return twl_i2c_write_u8(mod_no, val, reg);
}

static int twl4030_bci_read(u8 reg, u8 *val)
{
	return twl_i2c_read_u8(TWL_MODULE_MAIN_CHARGE, val, reg);
}

static int twl4030_clear_set_boot_bci(u8 clear, u8 set)
{
	return twl4030_clear_set(TWL_MODULE_PM_MASTER, clear,
			TWL4030_CONFIG_DONE | TWL4030_BCIAUTOWEN | set,
			TWL4030_PM_MASTER_BOOT_BCI);
}

static int twl4030bci_read_adc_val(u8 reg)
{
	int ret, temp;
	u8 val;

	/* read MSB */
	ret = twl4030_bci_read(reg + 1, &val);
	if (ret)
		return ret;

	temp = (int)(val & 0x03) << 8;

	/* read LSB */
	ret = twl4030_bci_read(reg, &val);
	if (ret)
		return ret;

	return temp | val;
}

/*
 * Check if Battery Pack was present
 */
static int twl4030_is_battery_present(struct twl4030_bci *bci)
{
	int ret;
	u8 val = 0;

	/* Battery presence in Main charge? */
	ret = twl_i2c_read_u8(TWL_MODULE_MAIN_CHARGE, &val, TWL4030_BCIMFSTS3);
	if (ret)
		return ret;
	if (val & TWL4030_BATSTSMCHG)
		return 0;

	/*
	 * OK, It could be that bootloader did not enable main charger,
	 * pre-charge is h/w auto. So, Battery presence in Pre-charge?
	 */
	ret = twl_i2c_read_u8(TWL4030_MODULE_PRECHARGE, &val,
			      TWL4030_BCIMFSTS1);
	if (ret)
		return ret;
	if (val & TWL4030_BATSTSPCHG)
		return 0;

	return -ENODEV;
}

/*
 * TI provided formulas:
 * CGAIN == 0: ICHG = (BCIICHG * 1.7) / (2^10 - 1) - 0.85
 * CGAIN == 1: ICHG = (BCIICHG * 3.4) / (2^10 - 1) - 1.7
 * Here we use integer approximation of:
 * CGAIN == 0: val * 1.6618 - 0.85 * 1000
 * CGAIN == 1: (val * 1.6618 - 0.85 * 1000) * 2
 */
/*
 * convert twl register value for currents into uA
 */
static int regval2ua(int regval, bool cgain)
{
	if (cgain)
		return (regval * 16618 - 8500 * 1000) / 5;
	else
		return (regval * 16618 - 8500 * 1000) / 10;
}

/*
 * convert uA currents into twl register value
 */
static int ua2regval(int ua, bool cgain)
{
	int ret;
	if (cgain)
		ua /= 2;
	ret = (ua * 10 + 8500 * 1000) / 16618;
	/* rounding problems */
	if (ret < 512)
		ret = 512;
	return ret;
}

/*
 * Enable/Disable USB Charge functionality.
 */
static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable)
{
	int ret;

	if (enable && !IS_ERR_OR_NULL(bci->transceiver)) {
		/*
		 * Until we can find out what current the device can provide,
		 * require a module param to enable USB charging.
		 */
		if (!allow_usb) {
			dev_warn(bci->dev, "USB charging is disabled.\n");
			return -EACCES;
		}

		/* Need to keep phy powered */
		if (!bci->usb_enabled) {
			pm_runtime_get_sync(bci->transceiver->dev);
			bci->usb_enabled = 1;
		}

		/* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */
		ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB);
		if (ret < 0)
			return ret;

		/* forcing USBFASTMCHG(BCIMFSTS4[2]) to 1 */
		ret = twl4030_clear_set(TWL_MODULE_MAIN_CHARGE, 0,
			TWL4030_USBFASTMCHG, TWL4030_BCIMFSTS4);
	} else {
		ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOUSB, 0);
		if (bci->usb_enabled) {
			pm_runtime_mark_last_busy(bci->transceiver->dev);
			pm_runtime_put_autosuspend(bci->transceiver->dev);
			bci->usb_enabled = 0;
		}
	}

	return ret;
}

/*
 * Enable/Disable AC Charge funtionality.
 */
static int twl4030_charger_enable_ac(bool enable)
{
	int ret;

	if (enable)
		ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOAC);
	else
		ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOAC, 0);

	return ret;
}

/*
 * Enable/Disable charging of Backup Battery.
 */
static int twl4030_charger_enable_backup(int uvolt, int uamp)
{
	int ret;
	u8 flags;

	if (uvolt < 2500000 ||
	    uamp < 25) {
		/* disable charging of backup battery */
		ret = twl4030_clear_set(TWL_MODULE_PM_RECEIVER,
					TWL4030_BBCHEN, 0, TWL4030_BB_CFG);
		return ret;
	}

	flags = TWL4030_BBCHEN;
	if (uvolt >= 3200000)
		flags |= TWL4030_BBSEL_3V2;
	else if (uvolt >= 3100000)
		flags |= TWL4030_BBSEL_3V1;
	else if (uvolt >= 3000000)
		flags |= TWL4030_BBSEL_3V0;
	else
		flags |= TWL4030_BBSEL_2V5;

	if (uamp >= 1000)
		flags |= TWL4030_BBISEL_1000uA;
	else if (uamp >= 500)
		flags |= TWL4030_BBISEL_500uA;
	else if (uamp >= 150)
		flags |= TWL4030_BBISEL_150uA;
	else
		flags |= TWL4030_BBISEL_25uA;

	ret = twl4030_clear_set(TWL_MODULE_PM_RECEIVER,
				TWL4030_BBSEL_MASK | TWL4030_BBISEL_MASK,
				flags,
				TWL4030_BB_CFG);

	return ret;
}

/*
 * TWL4030 CHG_PRES (AC charger presence) events
 */
static irqreturn_t twl4030_charger_interrupt(int irq, void *arg)
{
	struct twl4030_bci *bci = arg;

	dev_dbg(bci->dev, "CHG_PRES irq\n");
	power_supply_changed(bci->ac);
	power_supply_changed(bci->usb);

	return IRQ_HANDLED;
}

/*
 * TWL4030 BCI monitoring events
 */
static irqreturn_t twl4030_bci_interrupt(int irq, void *arg)
{
	struct twl4030_bci *bci = arg;
	u8 irqs1, irqs2;
	int ret;

	ret = twl_i2c_read_u8(TWL4030_MODULE_INTERRUPTS, &irqs1,
			      TWL4030_INTERRUPTS_BCIISR1A);
	if (ret < 0)
		return IRQ_HANDLED;

	ret = twl_i2c_read_u8(TWL4030_MODULE_INTERRUPTS, &irqs2,
			      TWL4030_INTERRUPTS_BCIISR2A);
	if (ret < 0)
		return IRQ_HANDLED;

	dev_dbg(bci->dev, "BCI irq %02x %02x\n", irqs2, irqs1);

	if (irqs1 & (TWL4030_ICHGLOW | TWL4030_ICHGEOC)) {
		/* charger state change, inform the core */
		power_supply_changed(bci->ac);
		power_supply_changed(bci->usb);
	}

	/* various monitoring events, for now we just log them here */
	if (irqs1 & (TWL4030_TBATOR2 | TWL4030_TBATOR1))
		dev_warn(bci->dev, "battery temperature out of range\n");

	if (irqs1 & TWL4030_BATSTS)
		dev_crit(bci->dev, "battery disconnected\n");

	if (irqs2 & TWL4030_VBATOV)
		dev_crit(bci->dev, "VBAT overvoltage\n");

	if (irqs2 & TWL4030_VBUSOV)
		dev_crit(bci->dev, "VBUS overvoltage\n");

	if (irqs2 & TWL4030_ACCHGOV)
		dev_crit(bci->dev, "Ac charger overvoltage\n");

	return IRQ_HANDLED;
}

static void twl4030_bci_usb_work(struct work_struct *data)
{
	struct twl4030_bci *bci = container_of(data, struct twl4030_bci, work);

	switch (bci->event) {
	case USB_EVENT_VBUS:
	case USB_EVENT_CHARGER:
		twl4030_charger_enable_usb(bci, true);
		break;
	case USB_EVENT_NONE:
		twl4030_charger_enable_usb(bci, false);
		break;
	}
}

static int twl4030_bci_usb_ncb(struct notifier_block *nb, unsigned long val,
			       void *priv)
{
	struct twl4030_bci *bci = container_of(nb, struct twl4030_bci, usb_nb);

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

	bci->event = val;
	schedule_work(&bci->work);

	return NOTIFY_OK;
}

static int twl4030_charger_get_current(void)
{
	int curr;
	int ret;
	u8 bcictl1;

	curr = twl4030bci_read_adc_val(TWL4030_BCIICHG);
	if (curr < 0)
		return curr;

	ret = twl4030_bci_read(TWL4030_BCICTL1, &bcictl1);
	if (ret)
		return ret;

	return regval2ua(curr, bcictl1 & TWL4030_CGAIN);
}

/*
 * Returns the main charge FSM state
 * Or < 0 on failure.
 */
static int twl4030bci_state(struct twl4030_bci *bci)
{
	int ret;
	u8 state;

	ret = twl4030_bci_read(TWL4030_BCIMSTATEC, &state);
	if (ret) {
		pr_err("twl4030_bci: error reading BCIMSTATEC\n");
		return ret;
	}

	dev_dbg(bci->dev, "state: %02x\n", state);

	return state;
}

static int twl4030_bci_state_to_status(int state)
{
	state &= TWL4030_MSTATEC_MASK;
	if (TWL4030_MSTATEC_QUICK1 <= state && state <= TWL4030_MSTATEC_QUICK7)
		return POWER_SUPPLY_STATUS_CHARGING;
	else if (TWL4030_MSTATEC_COMPLETE1 <= state &&
					state <= TWL4030_MSTATEC_COMPLETE4)
		return POWER_SUPPLY_STATUS_FULL;
	else
		return POWER_SUPPLY_STATUS_NOT_CHARGING;
}

static int twl4030_bci_get_property(struct power_supply *psy,
				    enum power_supply_property psp,
				    union power_supply_propval *val)
{
	struct twl4030_bci *bci = dev_get_drvdata(psy->dev.parent);
	int is_charging;
	int state;
	int ret;

	state = twl4030bci_state(bci);
	if (state < 0)
		return state;

	if (psy->desc->type == POWER_SUPPLY_TYPE_USB)
		is_charging = state & TWL4030_MSTATEC_USB;
	else
		is_charging = state & TWL4030_MSTATEC_AC;

	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		if (is_charging)
			val->intval = twl4030_bci_state_to_status(state);
		else
			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		/* charging must be active for meaningful result */
		if (!is_charging)
			return -ENODATA;
		if (psy->desc->type == POWER_SUPPLY_TYPE_USB) {
			ret = twl4030bci_read_adc_val(TWL4030_BCIVBUS);
			if (ret < 0)
				return ret;
			/* BCIVBUS uses ADCIN8, 7/1023 V/step */
			val->intval = ret * 6843;
		} else {
			ret = twl4030bci_read_adc_val(TWL4030_BCIVAC);
			if (ret < 0)
				return ret;
			/* BCIVAC uses ADCIN11, 10/1023 V/step */
			val->intval = ret * 9775;
		}
		break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
		if (!is_charging)
			return -ENODATA;
		/* current measurement is shared between AC and USB */
		ret = twl4030_charger_get_current();
		if (ret < 0)
			return ret;
		val->intval = ret;
		break;
	case POWER_SUPPLY_PROP_ONLINE:
		val->intval = is_charging &&
			twl4030_bci_state_to_status(state) !=
				POWER_SUPPLY_STATUS_NOT_CHARGING;
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static enum power_supply_property twl4030_charger_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_ONLINE,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
};

#ifdef CONFIG_OF
static const struct twl4030_bci_platform_data *
twl4030_bci_parse_dt(struct device *dev)
{
	struct device_node *np = dev->of_node;
	struct twl4030_bci_platform_data *pdata;
	u32 num;

	if (!np)
		return NULL;
	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
	if (!pdata)
		return pdata;

	if (of_property_read_u32(np, "ti,bb-uvolt", &num) == 0)
		pdata->bb_uvolt = num;
	if (of_property_read_u32(np, "ti,bb-uamp", &num) == 0)
		pdata->bb_uamp = num;
	return pdata;
}
#else
static inline const struct twl4030_bci_platform_data *
twl4030_bci_parse_dt(struct device *dev)
{
	return NULL;
}
#endif

static const struct power_supply_desc twl4030_bci_ac_desc = {
	.name		= "twl4030_ac",
	.type		= POWER_SUPPLY_TYPE_MAINS,
	.properties	= twl4030_charger_props,
	.num_properties	= ARRAY_SIZE(twl4030_charger_props),
	.get_property	= twl4030_bci_get_property,
};

static const struct power_supply_desc twl4030_bci_usb_desc = {
	.name		= "twl4030_usb",
	.type		= POWER_SUPPLY_TYPE_USB,
	.properties	= twl4030_charger_props,
	.num_properties	= ARRAY_SIZE(twl4030_charger_props),
	.get_property	= twl4030_bci_get_property,
};

static int twl4030_bci_probe(struct platform_device *pdev)
{
	struct twl4030_bci *bci;
	const struct twl4030_bci_platform_data *pdata = pdev->dev.platform_data;
	int ret;
	u32 reg;

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

	if (!pdata)
		pdata = twl4030_bci_parse_dt(&pdev->dev);

	bci->dev = &pdev->dev;
	bci->irq_chg = platform_get_irq(pdev, 0);
	bci->irq_bci = platform_get_irq(pdev, 1);

	/* Only proceed further *IF* battery is physically present */
	ret = twl4030_is_battery_present(bci);
	if  (ret) {
		dev_crit(&pdev->dev, "Battery was not detected:%d\n", ret);
		return ret;
	}

	platform_set_drvdata(pdev, bci);

	bci->ac = devm_power_supply_register(&pdev->dev, &twl4030_bci_ac_desc,
					     NULL);
	if (IS_ERR(bci->ac)) {
		ret = PTR_ERR(bci->ac);
		dev_err(&pdev->dev, "failed to register ac: %d\n", ret);
		return ret;
	}

	bci->usb = devm_power_supply_register(&pdev->dev, &twl4030_bci_usb_desc,
					      NULL);
	if (IS_ERR(bci->usb)) {
		ret = PTR_ERR(bci->usb);
		dev_err(&pdev->dev, "failed to register usb: %d\n", ret);
		return ret;
	}

	ret = devm_request_threaded_irq(&pdev->dev, bci->irq_chg, NULL,
			twl4030_charger_interrupt, IRQF_ONESHOT, pdev->name,
			bci);
	if (ret < 0) {
		dev_err(&pdev->dev, "could not request irq %d, status %d\n",
			bci->irq_chg, ret);
		return ret;
	}

	ret = devm_request_threaded_irq(&pdev->dev, bci->irq_bci, NULL,
			twl4030_bci_interrupt, IRQF_ONESHOT, pdev->name, bci);
	if (ret < 0) {
		dev_err(&pdev->dev, "could not request irq %d, status %d\n",
			bci->irq_bci, ret);
		return ret;
	}

	INIT_WORK(&bci->work, twl4030_bci_usb_work);

	bci->usb_nb.notifier_call = twl4030_bci_usb_ncb;
	if (bci->dev->of_node) {
		struct device_node *phynode;

		phynode = of_find_compatible_node(bci->dev->of_node->parent,
						  NULL, "ti,twl4030-usb");
		if (phynode) {
			bci->transceiver = devm_usb_get_phy_by_node(
				bci->dev, phynode, &bci->usb_nb);
			if (IS_ERR(bci->transceiver) &&
			    PTR_ERR(bci->transceiver) == -EPROBE_DEFER)
				return -EPROBE_DEFER;
		}
	}

	/* Enable interrupts now. */
	reg = ~(u32)(TWL4030_ICHGLOW | TWL4030_ICHGEOC | TWL4030_TBATOR2 |
		TWL4030_TBATOR1 | TWL4030_BATSTS);
	ret = twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, reg,
			       TWL4030_INTERRUPTS_BCIIMR1A);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to unmask interrupts: %d\n", ret);
		return ret;
	}

	reg = ~(u32)(TWL4030_VBATOV | TWL4030_VBUSOV | TWL4030_ACCHGOV);
	ret = twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, reg,
			       TWL4030_INTERRUPTS_BCIIMR2A);
	if (ret < 0)
		dev_warn(&pdev->dev, "failed to unmask interrupts: %d\n", ret);

	twl4030_charger_enable_ac(true);
	if (!IS_ERR_OR_NULL(bci->transceiver))
		twl4030_bci_usb_ncb(&bci->usb_nb,
				    bci->transceiver->last_event,
				    NULL);
	else
		twl4030_charger_enable_usb(bci, false);
	if (pdata)
		twl4030_charger_enable_backup(pdata->bb_uvolt,
					      pdata->bb_uamp);
	else
		twl4030_charger_enable_backup(0, 0);

	return 0;
}

static int __exit twl4030_bci_remove(struct platform_device *pdev)
{
	struct twl4030_bci *bci = platform_get_drvdata(pdev);

	twl4030_charger_enable_ac(false);
	twl4030_charger_enable_usb(bci, false);
	twl4030_charger_enable_backup(0, 0);

	/* mask interrupts */
	twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
			 TWL4030_INTERRUPTS_BCIIMR1A);
	twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
			 TWL4030_INTERRUPTS_BCIIMR2A);

	return 0;
}

static const struct of_device_id twl_bci_of_match[] = {
	{.compatible = "ti,twl4030-bci", },
	{ }
};
MODULE_DEVICE_TABLE(of, twl_bci_of_match);

static struct platform_driver twl4030_bci_driver = {
	.probe = twl4030_bci_probe,
	.driver	= {
		.name	= "twl4030_bci",
		.of_match_table = of_match_ptr(twl_bci_of_match),
	},
	.remove	= __exit_p(twl4030_bci_remove),
};
module_platform_driver(twl4030_bci_driver);

MODULE_AUTHOR("Gražvydas Ignotas");
MODULE_DESCRIPTION("TWL4030 Battery Charger Interface driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:twl4030_bci");