// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2019 MediaTek Inc.
 */

#include <linux/delay.h>
#include <linux/list.h>
#include <linux/list_sort.h>
#include <linux/interrupt.h>
#include <linux/mfd/mt6359/registers.h>
#include <linux/mfd/mt6397/core.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/pm_wakeup.h>
#include <linux/regmap.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/workqueue.h>

#include "pmic_lbat_service.h"

#define USER_NAME_MAXLEN	30
#define USER_SIZE		16
#define THD_VOLT_MAX		5400
#define THD_VOLT_MIN		2650
#define VOLT_FULL		1800
#define LBAT_RES		12

/* DEBT_SEL: {0: 1, 1: 2, 2: 4, 3: 8}*/
#define DEF_DEBT_MAX_SEL	3
#define DEF_DEBT_MIN_SEL	0
/* DET_PRD_SEL: {0: 15, 1: 30, 2: 45, 3: 60}*/
#define DEF_DET_PRD_SEL		0

#define DEF_R_RATIO_0		7
#define DEF_R_RATIO_1		2

#define LBAT_SERVICE_DBG 0

enum lbat_thd_type {
	LBAT_HV,
	LBAT_LV,
};

struct lbat_thd_t {
	unsigned int thd_volt;
	struct lbat_user *user;
	struct list_head list;
};

#if 0
struct lbat_user {
	char name[USER_NAME_MAXLEN];
	struct lbat_thd_t *hv_thd;
	struct lbat_thd_t *lv1_thd;
	struct lbat_thd_t *lv2_thd;
	void (*callback)(unsigned int thd_volt);
	unsigned int deb_cnt;
	struct lbat_thd_t *deb_thd_ptr;
	unsigned int hv_deb_prd;
	unsigned int hv_deb_times;
	unsigned int lv_deb_prd;
	unsigned int lv_deb_times;
	struct timer_list deb_timer;
	struct work_struct deb_work;
};
#endif

struct reg_t {
	unsigned int addr;
	unsigned int mask;
};

struct lbat_regs_t {
	struct reg_t en;
	struct reg_t debt_max;
	struct reg_t debt_min;
	struct reg_t det_prd;
	struct reg_t max_en;
	struct reg_t volt_max;
	struct reg_t min_en;
	struct reg_t volt_min;
	struct reg_t adc_out;
};

struct lbat_regs_t mt6359_lbat_regs = {
	.en = {MT6359_AUXADC_LBAT0, 0x1},
	.debt_max = {MT6359_AUXADC_LBAT1, 0xC},
	.debt_min = {MT6359_AUXADC_LBAT1, 0x30},
	.det_prd = {MT6359_AUXADC_LBAT1, 0x3},
	.max_en = {MT6359_AUXADC_LBAT2, 0x3000},
	.volt_max = {MT6359_AUXADC_LBAT2, 0xFFF},
	.min_en = {MT6359_AUXADC_LBAT3, 0x3000},
	.volt_min = {MT6359_AUXADC_LBAT3, 0xFFF},
	.adc_out = {MT6359_AUXADC_LBAT7, 0xFFF},
};

static DEFINE_MUTEX(lbat_mutex);
static struct list_head lbat_hv_list = LIST_HEAD_INIT(lbat_hv_list);
static struct list_head lbat_lv_list = LIST_HEAD_INIT(lbat_lv_list);

/* workqueue for SW de-bounce */
static struct workqueue_struct *lbat_wq;

struct regmap *regmap;
const struct lbat_regs_t *lbat_regs;
static struct lbat_thd_t *cur_hv_ptr;
static struct lbat_thd_t *cur_lv_ptr;
static struct lbat_user *lbat_user_table[USER_SIZE];
static unsigned int user_count;
static unsigned int r_ratio[2];

static unsigned int VOLT_TO_RAW(unsigned int volt)
{
	return (volt << LBAT_RES) / (VOLT_FULL * r_ratio[0] / r_ratio[1]);
}

static void lbat_max_en_setting(bool en)
{
	unsigned int val;

	val = en ? lbat_regs->max_en.mask : 0;
	regmap_update_bits(regmap, lbat_regs->max_en.addr,
			   lbat_regs->max_en.mask, val);
}

static void lbat_min_en_setting(bool en)
{
	unsigned int val;

	val = en ? lbat_regs->min_en.mask : 0;
	regmap_update_bits(regmap, lbat_regs->min_en.addr,
			   lbat_regs->min_en.mask, val);
}

static void lbat_irq_enable(void)
{
	if (cur_hv_ptr != NULL)
		lbat_max_en_setting(true);
	if (cur_lv_ptr != NULL)
		lbat_min_en_setting(true);
	regmap_write(regmap, lbat_regs->en.addr, 1);
}

static void lbat_irq_disable(void)
{
	regmap_write(regmap, lbat_regs->en.addr, 0);
	lbat_max_en_setting(false);
	lbat_min_en_setting(false);
}

static int hv_list_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct lbat_thd_t *thd_a, *thd_b;

	thd_a = list_entry(a, struct lbat_thd_t, list);
	thd_b = list_entry(b, struct lbat_thd_t, list);

	return thd_a->thd_volt - thd_b->thd_volt;
}

static int lv_list_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct lbat_thd_t *thd_a, *thd_b;

	thd_a = list_entry(a, struct lbat_thd_t, list);
	thd_b = list_entry(b, struct lbat_thd_t, list);

	return thd_b->thd_volt - thd_a->thd_volt;
}

static void modify_lbat_list(enum lbat_thd_type type, struct lbat_thd_t *thd)
{
	switch (type) {
	case LBAT_HV:
		list_add(&thd->list, &lbat_hv_list);
		list_sort(NULL, &lbat_hv_list, hv_list_cmp);
		thd = list_first_entry(&lbat_hv_list, struct lbat_thd_t, list);
		if (cur_hv_ptr != thd) {
			cur_hv_ptr = thd;
			regmap_update_bits(regmap,
					   lbat_regs->volt_max.addr,
					   lbat_regs->volt_max.mask,
					   VOLT_TO_RAW(cur_hv_ptr->thd_volt));
		}
		break;
	case LBAT_LV:
		list_add(&thd->list, &lbat_lv_list);
		list_sort(NULL, &lbat_lv_list, lv_list_cmp);
		thd = list_first_entry(&lbat_lv_list, struct lbat_thd_t, list);
		if (cur_lv_ptr != thd) {
			cur_lv_ptr = thd;
			regmap_update_bits(regmap,
					   lbat_regs->volt_min.addr,
					   lbat_regs->volt_min.mask,
					   VOLT_TO_RAW(cur_lv_ptr->thd_volt));
		}
		break;
	}
}

/*
 * After execute lbat_user's callback, set next thd node to wait event
 */
static void lbat_set_next_thd(struct lbat_user *user, struct lbat_thd_t *thd)
{
	if (thd == user->hv_thd) {
		modify_lbat_list(LBAT_LV, user->lv1_thd);
		if (user->lv2_thd && !list_empty(&user->lv2_thd->list))
			list_del_init(&user->lv2_thd->list);
	} else if (thd == user->lv1_thd) {
		modify_lbat_list(LBAT_HV, user->hv_thd);
		if (user->lv2_thd && list_empty(&user->lv2_thd->list))
			modify_lbat_list(LBAT_LV, user->lv2_thd);
	}
}

/*
 * Execute user's callback and set its next threshold if reach deb_times,
 * otherwise ignore this event and reset lbat_list
 */
static void lbat_deb_handler(struct work_struct *work)
{
	enum lbat_thd_type type;
	unsigned int deb_times;
	struct lbat_user *user = container_of(work, struct lbat_user, deb_work);

	mutex_lock(&lbat_mutex);
	if (user->deb_thd_ptr == user->hv_thd) {
		type = LBAT_HV;
		deb_times = user->hv_deb_times;
	} else {
		type = LBAT_LV;
		deb_times = user->lv_deb_times;
	}
	if (user->deb_cnt >= deb_times) {
		/* execute user's callback after de-bounce */
		user->callback(user->deb_thd_ptr->thd_volt);
		lbat_set_next_thd(user, user->deb_thd_ptr);
	} else {
		/* ignore this event and reset lbat_list */
		modify_lbat_list(type, user->deb_thd_ptr);
	}
	/* de-bounce done, reset deb_cnt and deb_thd_ptr */
	user->deb_cnt = 0;
	user->deb_thd_ptr = NULL;
	lbat_irq_disable();
	udelay(200);
	lbat_irq_enable();
	mutex_unlock(&lbat_mutex);
}

static void lbat_timer_func(struct timer_list *t)
{
	unsigned int deb_prd = 0;
	unsigned int deb_times = 0;
	struct lbat_user *user = from_timer(user, t, deb_timer);

	if (user->deb_thd_ptr == user->hv_thd) {
		/* LBAT user HV de-bounce */
		if (lbat_read_volt() < user->deb_thd_ptr->thd_volt) {
			/* queue deb_work to reset lbat_list */
			goto wq_handler;
		}
		deb_prd = user->hv_deb_prd;
		deb_times = user->hv_deb_times;
	} else if (user->deb_thd_ptr == user->lv1_thd ||
		   user->deb_thd_ptr == user->lv2_thd) {
		/* LBAT user LV de-bounce */
		if (lbat_read_volt() > user->deb_thd_ptr->thd_volt) {
			/* queue deb_work to reset lbat_list */
			goto wq_handler;
		}
		deb_prd = user->lv_deb_prd;
		deb_times = user->lv_deb_times;
	} else {
		pr_notice("[%s] LBAT debounce threshold not match\n", __func__);
		return;
	}
	user->deb_cnt++;
#if LBAT_SERVICE_DBG
	pr_info("[%s] name:%s, thd_volt:%d, de-bounce times:%d\n",
		__func__, user->name,
		user->deb_thd_ptr->thd_volt, user->deb_cnt);
#endif
	if (user->deb_cnt < deb_times) {
		mod_timer(&user->deb_timer,
			  jiffies + msecs_to_jiffies(deb_prd));
		return;
	}
wq_handler:
	/* queue deb_work to execute user's callback or reset lbat_list */
	queue_work(lbat_wq, &user->deb_work);
}

static void lbat_user_init_timer(struct lbat_user *user)
{
	user->deb_cnt = 0;
	user->hv_deb_prd = 0;
	user->hv_deb_times = 0;
	user->lv_deb_prd = 0;
	user->lv_deb_times = 0;
	timer_setup(&user->deb_timer, lbat_timer_func, 0);
}

static int lbat_user_update(struct lbat_user *user)
{
	/*
	 * add lv_thd to lbat_lv_list
	 * and assign first entry of lv_list to cur_lv_ptr
	 */
	modify_lbat_list(LBAT_LV, user->lv1_thd);
	if (user_count == 0)
		lbat_irq_enable();
	lbat_user_table[user_count++] = user;

	return 0;
}

static struct lbat_thd_t *lbat_thd_init(unsigned int thd_volt,
					struct lbat_user *user)
{
	struct lbat_thd_t *thd;

	if (thd_volt == 0)
		return NULL;
	thd = kzalloc(sizeof(*thd), GFP_KERNEL);
	if (thd == NULL)
		return NULL;
	thd->thd_volt = thd_volt;
	thd->user = user;
	INIT_LIST_HEAD(&thd->list);
	return thd;
}

struct lbat_user *lbat_user_register(const char *name, unsigned int hv_thd_volt,
				     unsigned int lv1_thd_volt,
				     unsigned int lv2_thd_volt,
				     void (*callback)(unsigned int thd_volt))
{
	int ret = 0;
	struct lbat_user *user;

	if (!regmap)
		return ERR_PTR(-EPROBE_DEFER);
	mutex_lock(&lbat_mutex);
	user = kzalloc(sizeof(*user), GFP_KERNEL);
	if (user == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	strncpy(user->name, name, USER_NAME_MAXLEN - 1);
	if (hv_thd_volt >= THD_VOLT_MAX || lv1_thd_volt <= THD_VOLT_MIN) {
		ret = -EINVAL;
		goto out;
	} else if (hv_thd_volt < lv1_thd_volt || lv1_thd_volt < lv2_thd_volt) {
		ret = -EINVAL;
		goto out;
	} else if (callback == NULL) {
		ret = -EINVAL;
		goto out;
	}
	user->hv_thd = lbat_thd_init(hv_thd_volt, user);
	user->lv1_thd = lbat_thd_init(lv1_thd_volt, user);
	user->lv2_thd = lbat_thd_init(lv2_thd_volt, user);
	if (!user->hv_thd || !user->lv1_thd || !user->lv2_thd) {
		ret = -EINVAL;
		goto out;
	}
	user->callback = callback;
	lbat_user_init_timer(user);
	INIT_WORK(&user->deb_work, lbat_deb_handler);
	pr_info("[%s] hv=%d, lv1=%d, lv2=%d\n",
		__func__, hv_thd_volt, lv1_thd_volt, lv2_thd_volt);
	ret = lbat_user_update(user);
out:
	if (ret) {
		pr_notice("[%s] error ret=%d\n", __func__, ret);
		if (ret == -EINVAL)
			kfree(user);
		return ERR_PTR(ret);
	}
	mutex_unlock(&lbat_mutex);
	return user;
}
EXPORT_SYMBOL(lbat_user_register);

int lbat_user_set_debounce(struct lbat_user *user,
			   unsigned int hv_deb_prd, unsigned int hv_deb_times,
			   unsigned int lv_deb_prd, unsigned int lv_deb_times)
{
	if (IS_ERR(user))
		return PTR_ERR(user);
	user->hv_deb_prd = hv_deb_prd;
	user->hv_deb_times = hv_deb_times;
	user->lv_deb_prd = lv_deb_prd;
	user->lv_deb_times = lv_deb_times;
	return 0;
}
EXPORT_SYMBOL(lbat_user_set_debounce);

unsigned int lbat_read_raw(void)
{
	unsigned int adc_out = 0;

	if (!regmap)
		return 0;
	regmap_read(regmap, lbat_regs->adc_out.addr, &adc_out);
	adc_out &= lbat_regs->adc_out.mask;
	return adc_out;
}
EXPORT_SYMBOL(lbat_read_raw);

unsigned int lbat_read_volt(void)
{
	unsigned int raw_data = lbat_read_raw();

	return (raw_data * VOLT_FULL * r_ratio[0] / r_ratio[1]) >> LBAT_RES;
}
EXPORT_SYMBOL(lbat_read_volt);

static irqreturn_t bat_h_int_handler(int irq, void *data)
{
	struct lbat_user *user;

	if (cur_hv_ptr == NULL) {
		lbat_max_en_setting(0);
		return IRQ_NONE;
	}
	mutex_lock(&lbat_mutex);
	pr_info("[%s] cur_thd_volt=%d\n", __func__, cur_hv_ptr->thd_volt);

	user = cur_hv_ptr->user;
	list_del_init(&cur_hv_ptr->list);
	if (user->hv_deb_times) {
		user->deb_cnt = 0;
		user->deb_thd_ptr = cur_hv_ptr;
		mod_timer(&user->deb_timer,
			jiffies + msecs_to_jiffies(user->hv_deb_prd));
	} else {
		user->callback(cur_hv_ptr->thd_volt);
		lbat_set_next_thd(user, cur_hv_ptr);
	}

	/* Since cur_hv_ptr is removed, assign new thd for cur_hv_ptr */
	if (list_empty(&lbat_hv_list)) {
		cur_hv_ptr = NULL;
		goto out;
	}
	cur_hv_ptr = list_first_entry(&lbat_hv_list, struct lbat_thd_t, list);
	regmap_update_bits(regmap, lbat_regs->volt_max.addr,
			   lbat_regs->volt_max.mask,
			   VOLT_TO_RAW(cur_hv_ptr->thd_volt));
out:
	lbat_irq_disable();
	udelay(200);
	lbat_irq_enable();
	mutex_unlock(&lbat_mutex);
	return IRQ_HANDLED;
}

static irqreturn_t bat_l_int_handler(int irq, void *data)
{
	struct lbat_user *user;

	if (cur_lv_ptr == NULL) {
		lbat_min_en_setting(0);
		return IRQ_NONE;
	}
	mutex_lock(&lbat_mutex);
	pr_info("[%s] cur_thd_volt=%d\n", __func__, cur_lv_ptr->thd_volt);

	user = cur_lv_ptr->user;
	list_del_init(&cur_lv_ptr->list);
	if (user->lv_deb_times) {
		user->deb_cnt = 0;
		user->deb_thd_ptr = cur_lv_ptr;
		mod_timer(&user->deb_timer,
			  jiffies + msecs_to_jiffies(user->lv_deb_prd));
	} else {
		user->callback(cur_lv_ptr->thd_volt);
		lbat_set_next_thd(user, cur_lv_ptr);
	}

	/* Since cur_lv_ptr is removed, assign new thd for cur_lv_ptr */
	if (list_empty(&lbat_lv_list)) {
		cur_lv_ptr = NULL;
		goto out;
	}
	cur_lv_ptr = list_first_entry(&lbat_lv_list, struct lbat_thd_t, list);
	regmap_update_bits(regmap, lbat_regs->volt_min.addr,
			   lbat_regs->volt_min.mask,
			   VOLT_TO_RAW(cur_lv_ptr->thd_volt));
out:
	lbat_irq_disable();
	udelay(200);
	lbat_irq_enable();
	mutex_unlock(&lbat_mutex);
	return IRQ_HANDLED;
}

static int pmic_lbat_service_probe(struct platform_device *pdev)
{
	int ret, irq;
	unsigned int val;
	struct device_node *np;
	struct mt6397_chip *chip;

	chip = dev_get_drvdata(pdev->dev.parent);
	regmap = chip->regmap;
	lbat_regs = of_device_get_match_data(&pdev->dev);
	/* Selects debounce as 8 */
	val = DEF_DEBT_MAX_SEL << (ffs(lbat_regs->debt_max.mask) - 1);
	regmap_update_bits(regmap, lbat_regs->debt_max.addr,
			   lbat_regs->debt_max.mask, val);
	/* Selects debounce as 1 */
	val = DEF_DEBT_MIN_SEL << (ffs(lbat_regs->debt_min.mask) - 1);
	regmap_update_bits(regmap, lbat_regs->debt_min.addr,
			   lbat_regs->debt_min.mask, val);
	/* Set LBAT_PRD as 15ms */
	val = DEF_DET_PRD_SEL << (ffs(lbat_regs->det_prd.mask) - 1);
	regmap_update_bits(regmap, lbat_regs->det_prd.addr,
			   lbat_regs->det_prd.mask, val);

	irq = platform_get_irq_byname(pdev, "bat_h");
	if (irq < 0) {
		dev_notice(&pdev->dev, "failed to get bat_h irq, ret=%d\n",
			   irq);
		return irq;
	}
	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
					bat_h_int_handler, IRQF_TRIGGER_NONE,
					"bat_h", NULL);
	if (ret < 0)
		dev_notice(&pdev->dev, "request bat_h irq fail\n");
	irq = platform_get_irq_byname(pdev, "bat_l");
	if (irq < 0) {
		dev_notice(&pdev->dev, "failed to get bat_l irq, ret=%d\n",
			   irq);
		return irq;
	}
	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
					bat_l_int_handler, IRQF_TRIGGER_NONE,
					"bat_l", NULL);
	if (ret < 0)
		dev_notice(&pdev->dev, "request bat_l irq fail\n");

	lbat_wq = create_singlethread_workqueue("lbat_service");

	/* get LBAT r_ratio */
	np = of_find_node_by_name(pdev->dev.parent->of_node, "batadc");
	if (!np) {
		dev_notice(&pdev->dev, "get batadc node fail\n");
		r_ratio[0] = DEF_R_RATIO_0;
		r_ratio[1] = DEF_R_RATIO_1;
		return 0;
	}
	ret = of_property_read_u32_array(np, "resistance-ratio", r_ratio, 2);
	dev_info(&pdev->dev, "r_ratio = %d/%d\n", r_ratio[0], r_ratio[1]);

	return ret;
}

static int __maybe_unused lbat_service_suspend(struct device *d)
{
	lbat_irq_disable();
	return 0;
}

static int __maybe_unused lbat_service_resume(struct device *d)
{
	lbat_irq_enable();
	return 0;
}

static SIMPLE_DEV_PM_OPS(lbat_service_pm_ops, lbat_service_suspend,
			 lbat_service_resume);

static const struct of_device_id lbat_service_of_match[] = {
	{
		.compatible = "mediatek,mt6359-lbat_service",
		.data = &mt6359_lbat_regs,
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(of, lbat_service_of_match);

static struct platform_driver pmic_lbat_service_driver = {
	.driver = {
		.name = "pmic_lbat_service",
		.of_match_table = lbat_service_of_match,
		.pm = &lbat_service_pm_ops,
	},
	.probe	= pmic_lbat_service_probe,
};
module_platform_driver(pmic_lbat_service_driver);