// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2023 Richtek Technology Corp.
 *
 * Author: ChiYuan Huang <cy_huang@richtek.com>
 */

#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#define RT4803_AUTO_MODE	1
#define RT4803_FPWM_MODE	2

#define RT4803_REG_CONFIG	0x01
#define RT4803_REG_VSELL	0x02
#define RT4803_REG_VSELH	0x03
#define RT4803_REG_ILIM		0x04
#define RT4803_REG_STAT		0x05

#define RT4803_MODE_MASK	GENMASK(1, 0)
#define RT4803_VSEL_MASK	GENMASK(4, 0)
#define RT4803_ILIM_MASK	GENMASK(3, 0)
#define RT4803_TSD_MASK		BIT(7)
#define RT4803_HOTDIE_MASK	BIT(6)
#define RT4803_FAULT_MASK	BIT(1)
#define RT4803_PGOOD_MASK	BIT(0)

#define RT4803_VOUT_MINUV	2850000
#define RT4803_VOUT_STEPUV	50000
#define RT4803_VOUT_NUM		32

static int rt4803_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int modeval;

	switch (mode) {
	case REGULATOR_MODE_NORMAL:
		modeval = RT4803_AUTO_MODE;
		break;
	case REGULATOR_MODE_FAST:
		modeval = RT4803_FPWM_MODE;
		break;
	default:
		return -EINVAL;
	}

	modeval <<= ffs(RT4803_MODE_MASK) - 1;

	return regmap_update_bits(regmap, RT4803_REG_CONFIG, RT4803_MODE_MASK, modeval);
}

static unsigned int rt4803_get_mode(struct regulator_dev *rdev)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int modeval;
	int ret;

	ret = regmap_read(regmap, RT4803_REG_CONFIG, &modeval);
	if (ret)
		return REGULATOR_MODE_INVALID;

	modeval >>= ffs(RT4803_MODE_MASK) - 1;

	switch (modeval) {
	case RT4803_AUTO_MODE:
		return REGULATOR_MODE_NORMAL;
	case RT4803_FPWM_MODE:
		return REGULATOR_MODE_FAST;
	default:
		return REGULATOR_MODE_INVALID;
	}
}

static int rt4803_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int state, events = 0;
	int ret;

	ret = regmap_read(regmap, RT4803_REG_STAT, &state);
	if (ret)
		return ret;

	if (state & RT4803_PGOOD_MASK)
		goto out_error_flag;

	if (state & RT4803_FAULT_MASK)
		events |= REGULATOR_ERROR_FAIL;

	if (state & RT4803_HOTDIE_MASK)
		events |= REGULATOR_ERROR_OVER_TEMP_WARN;

	if (state & RT4803_TSD_MASK)
		events |= REGULATOR_ERROR_OVER_TEMP;

out_error_flag:
	*flags = events;
	return 0;
}

static int rt4803_set_suspend_voltage(struct regulator_dev *rdev, int uV)
{
	struct regmap *regmap = rdev_get_regmap(rdev);
	unsigned int reg, vsel;

	if (rdev->desc->vsel_reg == RT4803_REG_VSELL)
		reg = RT4803_REG_VSELH;
	else
		reg = RT4803_REG_VSELL;

	vsel = (uV - rdev->desc->min_uV) / rdev->desc->uV_step;
	vsel <<= ffs(RT4803_VSEL_MASK) - 1;

	return regmap_update_bits(regmap, reg, RT4803_VSEL_MASK, vsel);
}

static const struct regulator_ops rt4803_regulator_ops = {
	.list_voltage = regulator_list_voltage_linear,
	.set_voltage_sel = regulator_set_voltage_sel_regmap,
	.get_voltage_sel = regulator_get_voltage_sel_regmap,
	.set_mode = rt4803_set_mode,
	.get_mode = rt4803_get_mode,
	.get_error_flags = rt4803_get_error_flags,
	.set_suspend_voltage = rt4803_set_suspend_voltage,
};

static unsigned int rt4803_of_map_mode(unsigned int mode)
{
	switch (mode) {
	case RT4803_AUTO_MODE:
		return REGULATOR_MODE_NORMAL;
	case RT4803_FPWM_MODE:
		return REGULATOR_MODE_FAST;
	default:
		return REGULATOR_MODE_INVALID;
	}
}

static const struct regmap_config rt4803_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = RT4803_REG_STAT,
};

static int rt4803_probe(struct i2c_client *i2c)
{
	struct device *dev = &i2c->dev;
	struct regmap *regmap;
	struct regulator_desc *desc;
	struct regulator_config cfg = {};
	struct regulator_dev *rdev;
	bool vsel_act_high;
	int ret;

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

	regmap = devm_regmap_init_i2c(i2c, &rt4803_regmap_config);
	if (IS_ERR(regmap))
		return dev_err_probe(dev, PTR_ERR(regmap), "Failed to init regmap\n");

	/* Always configure the input current limit to max 5A at initial */
	ret = regmap_update_bits(regmap, RT4803_REG_ILIM, RT4803_ILIM_MASK, 0xff);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to config ILIM to max\n");

	vsel_act_high = device_property_read_bool(dev, "richtek,vsel-active-high");

	desc->name = "rt4803-regulator";
	desc->type = REGULATOR_VOLTAGE;
	desc->owner = THIS_MODULE;
	desc->ops = &rt4803_regulator_ops;
	desc->min_uV = RT4803_VOUT_MINUV;
	desc->uV_step = RT4803_VOUT_STEPUV;
	desc->n_voltages = RT4803_VOUT_NUM;
	desc->vsel_mask = RT4803_VSEL_MASK;
	desc->of_map_mode = rt4803_of_map_mode;
	if (vsel_act_high)
		desc->vsel_reg = RT4803_REG_VSELH;
	else
		desc->vsel_reg = RT4803_REG_VSELL;

	cfg.dev = dev;
	cfg.of_node = dev_of_node(dev);
	cfg.init_data = of_get_regulator_init_data(dev, dev_of_node(dev), desc);

	rdev = devm_regulator_register(dev, desc, &cfg);
	return PTR_ERR_OR_ZERO(rdev);
}

static const struct of_device_id rt4803_device_match_table[] = {
	{ .compatible = "richtek,rt4803" },
	{}
};
MODULE_DEVICE_TABLE(of, rt4803_device_match_table);

static struct i2c_driver rt4803_driver = {
	.driver = {
		.name = "rt4803",
		.of_match_table = rt4803_device_match_table,
	},
	.probe = rt4803_probe,
};
module_i2c_driver(rt4803_driver);

MODULE_DESCRIPTION("Richtek RT4803 voltage regulator driver");
MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
MODULE_LICENSE("GPL"