// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2022 Richtek Technology Corp.
 *
 * Author: ChiYuan Huang <cy_huang@richtek.com>
 *
 */

#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#define RT6190_REG_VID		0x00
#define RT6190_REG_OUTV		0x01
#define RT6190_REG_OUTC		0x03
#define RT6190_REG_SET1		0x0D
#define RT6190_REG_SET2		0x0E
#define RT6190_REG_SET4		0x10
#define RT6190_REG_RATIO	0x11
#define RT6190_REG_OUT_VOLT_L	0x12
#define RT6190_REG_TEMP_H	0x1B
#define RT6190_REG_STAT1	0x1C
#define RT6190_REG_ALERT1	0x1E
#define RT6190_REG_ALERT2	0x1F
#define RT6190_REG_MASK2	0x21
#define RT6190_REG_OCPEN	0x28
#define RT6190_REG_SET5		0x29
#define RT6190_REG_VBUSC_ADC	0x32
#define RT6190_REG_BUSC_VOLT_L	0x33
#define RT6190_REG_BUSC_VOLT_H	0x34
#define RT6190_REG_STAT3	0x37
#define RT6190_REG_ALERT3	0x38
#define RT6190_REG_MASK3	0x39

#define RT6190_ENPWM_MASK	BIT(7)
#define RT6190_ENDCHG_MASK	BIT(4)
#define RT6190_ALERT_OTPEVT	BIT(6)
#define RT6190_ALERT_UVPEVT	BIT(5)
#define RT6190_ALERT_OVPEVT	BIT(4)
#define RT6190_ENGCP_MASK	BIT(1)
#define RT6190_FCCM_MASK	BIT(7)

#define RICHTEK_VID		0x82
#define RT6190_OUT_MIN_UV	3000000
#define RT6190_OUT_MAX_UV	32000000
#define RT6190_OUT_STEP_UV	20000
#define RT6190_OUT_N_VOLT	(RT6190_OUT_MAX_UV / RT6190_OUT_STEP_UV + 1)
#define RT6190_OUTV_MINSEL	150
#define RT6190_OUT_MIN_UA	306000
#define RT6190_OUT_MAX_UA	12114000
#define RT6190_OUT_STEP_UA	24000
#define RT6190_OUTC_MINSEL	19
#define RT6190_EN_TIME_US	500

#define RT6190_PSM_MODE		0
#define RT6190_FCCM_MODE	1

struct rt6190_data {
	struct device *dev;
	struct regmap *regmap;
	struct gpio_desc *enable_gpio;
	unsigned int cached_alert_evt;
};

static int rt6190_out_set_voltage_sel(struct regulator_dev *rdev,
				      unsigned int selector)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	__le16 le_sel = cpu_to_le16(selector);

	return regmap_raw_write(regmap, RT6190_REG_OUTV, &le_sel,
				sizeof(le_sel));
}

static int rt6190_out_get_voltage_sel(struct regulator_dev *rdev)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	__le16 le_sel;
	int ret;

	ret = regmap_raw_read(regmap, RT6190_REG_OUTV, &le_sel, sizeof(le_sel));

	return ret ?: le16_to_cpu(le_sel);
}

static int rt6190_out_enable(struct regulator_dev *rdev)
{
	struct rt6190_data *data = rdev_get_drvdata(rdev);
	struct regmap *regmap = rdev_get_regmap(rdev);
	u8 out_cfg[4];
	int ret;

	pm_runtime_get_sync(data->dev);

	/*
	 * From off to on, vout config will restore to IC default.
	 * Read vout configs before enable, and restore them after enable
	 */
	ret = regmap_raw_read(regmap, RT6190_REG_OUTV, out_cfg,
			      sizeof(out_cfg));
	if (ret)
		return ret;

	ret = regulator_enable_regmap(rdev);
	if (ret)
		return ret;

	ret = regmap_raw_write(regmap, RT6190_REG_OUTV, out_cfg,
			       sizeof(out_cfg));
	if (ret)
		return ret;

	return regmap_update_bits(regmap, RT6190_REG_SET5, RT6190_ENGCP_MASK,
				  RT6190_ENGCP_MASK);
}

static int rt6190_out_disable(struct regulator_dev *rdev)
{
	struct rt6190_data *data = rdev_get_drvdata(rdev);
	struct regmap *regmap = rdev_get_regmap(rdev);
	int ret;

	ret = regmap_update_bits(regmap, RT6190_REG_SET5, RT6190_ENGCP_MASK, 0);
	if (ret)
		return ret;

	ret = regulator_disable_regmap(rdev);
	if (ret)
		return ret;

	/* cleared cached alert event */
	data->cached_alert_evt = 0;

	pm_runtime_put(data->dev);

	return 0;
}

static int rt6190_out_set_current_limit(struct regulator_dev *rdev, int min_uA,
					int max_uA)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	int csel, clim;
	__le16 le_csel;

	if (min_uA < RT6190_OUT_MIN_UA || max_uA > RT6190_OUT_MAX_UA)
		return -EINVAL;

	csel = DIV_ROUND_UP(min_uA - RT6190_OUT_MIN_UA, RT6190_OUT_STEP_UA);

	clim = RT6190_OUT_MIN_UA + RT6190_OUT_STEP_UA * csel;
	if (clim > max_uA)
		return -EINVAL;

	csel += RT6190_OUTC_MINSEL;
	le_csel = cpu_to_le16(csel);

	return regmap_raw_write(regmap, RT6190_REG_OUTC, &le_csel,
				sizeof(le_csel));
}

static int rt6190_out_get_current_limit(struct regulator_dev *rdev)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	__le16 le_csel;
	int csel, ret;

	ret = regmap_raw_read(regmap, RT6190_REG_OUTC, &le_csel,
			      sizeof(le_csel));
	if (ret)
		return ret;

	csel = le16_to_cpu(le_csel);
	csel -= RT6190_OUTC_MINSEL;

	return RT6190_OUT_MIN_UA + RT6190_OUT_STEP_UA * csel;
}

static int rt6190_out_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int val;

	switch (mode) {
	case REGULATOR_MODE_FAST:
		val = RT6190_FCCM_MASK;
		break;
	case REGULATOR_MODE_NORMAL:
		val = 0;
		break;
	default:
		return -EINVAL;
	}

	return regmap_update_bits(regmap, RT6190_REG_SET1, RT6190_FCCM_MASK,
				  val);
}

static unsigned int rt6190_out_get_mode(struct regulator_dev *rdev)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int config;
	int ret;

	ret = regmap_read(regmap, RT6190_REG_SET1, &config);
	if (ret)
		return REGULATOR_MODE_INVALID;

	if (config & RT6190_FCCM_MASK)
		return REGULATOR_MODE_FAST;

	return REGULATOR_MODE_NORMAL;
}

static int rt6190_out_get_error_flags(struct regulator_dev *rdev,
				      unsigned int *flags)
{
	struct rt6190_data *data = rdev_get_drvdata(rdev);
	unsigned int state, rpt_flags = 0;
	int ret;

	ret = regmap_read(data->regmap, RT6190_REG_STAT1, &state);
	if (ret)
		return ret;

	state |= data->cached_alert_evt;

	if (state & RT6190_ALERT_OTPEVT)
		rpt_flags |= REGULATOR_ERROR_OVER_TEMP;

	if (state & RT6190_ALERT_UVPEVT)
		rpt_flags |= REGULATOR_ERROR_UNDER_VOLTAGE;

	if (state & RT6190_ALERT_OVPEVT)
		rpt_flags |= REGULATOR_ERROR_REGULATION_OUT;

	*flags = rpt_flags;

	return 0;
}

static unsigned int rt6190_out_of_map_mode(unsigned int mode)
{
	switch (mode) {
	case RT6190_PSM_MODE:
		return REGULATOR_MODE_NORMAL;
	case RT6190_FCCM_MODE:
		return REGULATOR_MODE_FAST;
	default:
		return REGULATOR_MODE_INVALID;
	}
}

static const struct regulator_ops rt6190_regulator_ops = {
	.list_voltage = regulator_list_voltage_linear,
	.set_voltage_sel = rt6190_out_set_voltage_sel,
	.get_voltage_sel = rt6190_out_get_voltage_sel,
	.enable = rt6190_out_enable,
	.disable = rt6190_out_disable,
	.is_enabled = regulator_is_enabled_regmap,
	.set_current_limit = rt6190_out_set_current_limit,
	.get_current_limit = rt6190_out_get_current_limit,
	.set_active_discharge = regulator_set_active_discharge_regmap,
	.set_mode = rt6190_out_set_mode,
	.get_mode = rt6190_out_get_mode,
	.get_error_flags = rt6190_out_get_error_flags,
};

static const struct regulator_desc rt6190_regulator_desc = {
	.name = "rt6190-regulator",
	.type = REGULATOR_VOLTAGE,
	.owner = THIS_MODULE,
	.ops = &rt6190_regulator_ops,
	.min_uV = RT6190_OUT_MIN_UV,
	.uV_step = RT6190_OUT_STEP_UV,
	.n_voltages = RT6190_OUT_N_VOLT,
	.linear_min_sel = RT6190_OUTV_MINSEL,
	.enable_reg = RT6190_REG_SET2,
	.enable_mask = RT6190_ENPWM_MASK,
	.active_discharge_reg = RT6190_REG_SET2,
	.active_discharge_mask = RT6190_ENDCHG_MASK,
	.active_discharge_on = RT6190_ENDCHG_MASK,
	.of_map_mode = rt6190_out_of_map_mode,
};

static bool rt6190_is_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case RT6190_REG_OUT_VOLT_L ... RT6190_REG_ALERT2:
	case RT6190_REG_BUSC_VOLT_L ... RT6190_REG_BUSC_VOLT_H:
	case RT6190_REG_STAT3 ... RT6190_REG_ALERT3:
		return true;
	default:
		return false;
	}
}

static const struct regmap_config rt6190_regmap_config = {
	.name = "rt6190",
	.cache_type = REGCACHE_FLAT,
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = RT6190_REG_MASK3,
	.num_reg_defaults_raw = RT6190_REG_MASK3 + 1,
	.volatile_reg = rt6190_is_volatile_reg,
};

static irqreturn_t rt6190_irq_handler(int irq, void *devid)
{
	struct regulator_dev *rdev = devid;
	struct rt6190_data *data = rdev_get_drvdata(rdev);
	unsigned int alert;
	int ret;

	ret = regmap_read(data->regmap, RT6190_REG_ALERT1, &alert);
	if (ret)
		return IRQ_NONE;

	/* Write clear alert events */
	ret = regmap_write(data->regmap, RT6190_REG_ALERT1, alert);
	if (ret)
		return IRQ_NONE;

	data->cached_alert_evt |= alert;

	if (alert & RT6190_ALERT_OTPEVT)
		regulator_notifier_call_chain(rdev, REGULATOR_EVENT_OVER_TEMP, NULL);

	if (alert & RT6190_ALERT_UVPEVT)
		regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE, NULL);

	if (alert & RT6190_ALERT_OVPEVT)
		regulator_notifier_call_chain(rdev, REGULATOR_EVENT_REGULATION_OUT, NULL);

	return IRQ_HANDLED;
}

static int rt6190_init_registers(struct regmap *regmap)
{
	int ret;

	/* Enable_ADC = 1 */
	ret = regmap_write(regmap, RT6190_REG_SET4, 0x82);
	if (ret)
		return ret;

	/* Config default VOUT ratio to be higher */
	ret = regmap_write(regmap, RT6190_REG_RATIO, 0x20);

	/* Mask unused alert */
	ret = regmap_write(regmap, RT6190_REG_MASK2, 0);
	if (ret)
		return ret;

	/* OCP config */
	ret = regmap_write(regmap, RT6190_REG_OCPEN, 0);
	if (ret)
		return ret;

	/* Enable VBUSC ADC */
	return regmap_write(regmap, RT6190_REG_VBUSC_ADC, 0x02);
}

static int rt6190_probe(struct i2c_client *i2c)
{
	struct device *dev = &i2c->dev;
	struct rt6190_data *data;
	struct gpio_desc *enable_gpio;
	struct regmap *regmap;
	struct regulator_dev *rdev;
	struct regulator_config cfg = {};
	unsigned int vid;
	int ret;

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH);
	if (IS_ERR(enable_gpio))
		return dev_err_probe(dev, PTR_ERR(enable_gpio), "Failed to get 'enable' gpio\n");
	else if (enable_gpio)
		usleep_range(RT6190_EN_TIME_US, RT6190_EN_TIME_US * 2);

	regmap = devm_regmap_init_i2c(i2c, &rt6190_regmap_config);
	if (IS_ERR(regmap))
		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to init regmap\n");

	data->dev = dev;
	data->enable_gpio = enable_gpio;
	data->regmap = regmap;
	i2c_set_clientdata(i2c, data);

	ret = regmap_read(regmap, RT6190_REG_VID, &vid);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to read VID\n");

	if (vid != RICHTEK_VID)
		return dev_err_probe(dev, -ENODEV, "Incorrect VID 0x%02x\n", vid);

	ret = rt6190_init_registers(regmap);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to init registers\n");

	pm_runtime_set_active(dev);
	ret = devm_pm_runtime_enable(dev);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to set pm_runtime enable\n");

	cfg.dev = dev;
	cfg.of_node = dev->of_node;
	cfg.driver_data = data;
	cfg.init_data = of_get_regulator_init_data(dev, dev->of_node,
						   &rt6190_regulator_desc);

	rdev = devm_regulator_register(dev, &rt6190_regulator_desc, &cfg);
	if (IS_ERR(rdev))
		return dev_err_probe(dev, PTR_ERR(rdev), "Failed to register regulator\n");

	if (i2c->irq) {
		ret = devm_request_threaded_irq(dev, i2c->irq, NULL,
						rt6190_irq_handler,
						IRQF_ONESHOT, dev_name(dev),
						rdev);
		if (ret)
			return dev_err_probe(dev, ret, "Failed to register interrupt\n");
	}

	return 0;
}

static int rt6190_runtime_suspend(struct device *dev)
{
	struct rt6190_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;

	if (!data->enable_gpio)
		return 0;

	regcache_cache_only(regmap, true);
	regcache_mark_dirty(regmap);

	gpiod_set_value(data->enable_gpio, 0);

	return 0;
}

static int rt6190_runtime_resume(struct device *dev)
{
	struct rt6190_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;

	if (!data->enable_gpio)
		return 0;

	gpiod_set_value(data->enable_gpio, 1);
	usleep_range(RT6190_EN_TIME_US, RT6190_EN_TIME_US * 2);

	regcache_cache_only(regmap, false);
	return regcache_sync(regmap);
}

static const struct dev_pm_ops __maybe_unused rt6190_dev_pm = {
	RUNTIME_PM_OPS(rt6190_runtime_suspend, rt6190_runtime_resume, NULL)
};

static const struct of_device_id rt6190_of_dev_table[] = {
	{ .compatible = "richtek,rt6190" },
	{}
};
MODULE_DEVICE_TABLE(of, rt6190_of_dev_table);

static struct i2c_driver rt6190_driver = {
	.driver = {
		.name = "rt6190",
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
		.of_match_table = rt6190_of_dev_table,
		.pm = pm_ptr(&rt6190_dev_pm),
	},
	.probe = rt6190_probe,
};
module_i2c_driver(rt6190_driver);

MODULE_DESCRIPTION("Richtek RT6190 regulator driver");
MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_LICENSE("GPL"