// SPDX-License-Identifier: GPL-2.0
//
// SY8827N regulator driver
//
// Copyright (C) 2020 Synaptics Incorporated
//
// Author: Jisheng Zhang <jszhang@kernel.org>

#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#define SY8827N_VSEL0           0
#define   SY8827N_BUCK_EN       (1 << 7)
#define   SY8827N_MODE          (1 << 6)
#define SY8827N_VSEL1           1
#define SY8827N_CTRL            2
#define SY8827N_ID1             3
#define SY8827N_ID2             4
#define SY8827N_PGOOD           5
#define SY8827N_MAX             (SY8827N_PGOOD + 1)

#define SY8827N_NVOLTAGES       64
#define SY8827N_VSELMIN         600000
#define SY8827N_VSELSTEP        12500

struct sy8827n_device_info {
        struct device *dev;
        struct regulator_desc desc;
        struct regulator_init_data *regulator;
        struct gpio_desc *en_gpio;
        unsigned int vsel_reg;
};

static int sy8827n_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
        struct sy8827n_device_info *di = rdev_get_drvdata(rdev);

        switch (mode) {
        case REGULATOR_MODE_FAST:
                regmap_update_bits(rdev->regmap, di->vsel_reg,
                                   SY8827N_MODE, SY8827N_MODE);
                break;
        case REGULATOR_MODE_NORMAL:
                regmap_update_bits(rdev->regmap, di->vsel_reg,
                                   SY8827N_MODE, 0);
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static unsigned int sy8827n_get_mode(struct regulator_dev *rdev)
{
        struct sy8827n_device_info *di = rdev_get_drvdata(rdev);
        u32 val;
        int ret = 0;

        ret = regmap_read(rdev->regmap, di->vsel_reg, &val);
        if (ret < 0)
                return ret;
        if (val & SY8827N_MODE)
                return REGULATOR_MODE_FAST;
        else
                return REGULATOR_MODE_NORMAL;
}

static const struct regulator_ops sy8827n_regulator_ops = {
        .set_voltage_sel = regulator_set_voltage_sel_regmap,
        .get_voltage_sel = regulator_get_voltage_sel_regmap,
        .set_voltage_time_sel = regulator_set_voltage_time_sel,
        .map_voltage = regulator_map_voltage_linear,
        .list_voltage = regulator_list_voltage_linear,
        .enable = regulator_enable_regmap,
        .disable = regulator_disable_regmap,
        .is_enabled = regulator_is_enabled_regmap,
        .set_mode = sy8827n_set_mode,
        .get_mode = sy8827n_get_mode,
};

static int sy8827n_regulator_register(struct sy8827n_device_info *di,
                        struct regulator_config *config)
{
        struct regulator_desc *rdesc = &di->desc;
        struct regulator_dev *rdev;

        rdesc->name = "sy8827n-reg";
        rdesc->supply_name = "vin";
        rdesc->ops = &sy8827n_regulator_ops;
        rdesc->type = REGULATOR_VOLTAGE;
        rdesc->n_voltages = SY8827N_NVOLTAGES;
        rdesc->enable_reg = di->vsel_reg;
        rdesc->enable_mask = SY8827N_BUCK_EN;
        rdesc->min_uV = SY8827N_VSELMIN;
        rdesc->uV_step = SY8827N_VSELSTEP;
        rdesc->vsel_reg = di->vsel_reg;
        rdesc->vsel_mask = rdesc->n_voltages - 1;
        rdesc->owner = THIS_MODULE;

        rdev = devm_regulator_register(di->dev, &di->desc, config);
        return PTR_ERR_OR_ZERO(rdev);
}

static bool sy8827n_volatile_reg(struct device *dev, unsigned int reg)
{
        if (reg == SY8827N_PGOOD)
                return true;
        return false;
}

static const struct regmap_config sy8827n_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .volatile_reg = sy8827n_volatile_reg,
        .num_reg_defaults_raw = SY8827N_MAX,
        .cache_type = REGCACHE_FLAT,
};

static int sy8827n_i2c_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct device_node *np = dev->of_node;
        struct sy8827n_device_info *di;
        struct regulator_config config = { };
        struct regmap *regmap;
        int ret;

        di = devm_kzalloc(dev, sizeof(struct sy8827n_device_info), GFP_KERNEL);
        if (!di)
                return -ENOMEM;

        di->regulator = of_get_regulator_init_data(dev, np, &di->desc);
        if (!di->regulator) {
                dev_err(dev, "Platform data not found!\n");
                return -EINVAL;
        }

        di->en_gpio = devm_gpiod_get_optional(dev, "enable",
                        GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
        if (IS_ERR(di->en_gpio))
                return PTR_ERR(di->en_gpio);

        if (of_property_read_bool(np, "silergy,vsel-state-high"))
                di->vsel_reg = SY8827N_VSEL1;
        else
                di->vsel_reg = SY8827N_VSEL0;

        di->dev = dev;

        regmap = devm_regmap_init_i2c(client, &sy8827n_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(dev, "Failed to allocate regmap!\n");
                return PTR_ERR(regmap);
        }
        i2c_set_clientdata(client, di);

        config.dev = di->dev;
        config.init_data = di->regulator;
        config.regmap = regmap;
        config.driver_data = di;
        config.of_node = np;

        ret = sy8827n_regulator_register(di, &config);
        if (ret < 0)
                dev_err(dev, "Failed to register regulator!\n");
        return ret;
}

static const struct of_device_id sy8827n_dt_ids[] = {
        {
                .compatible = "silergy,sy8827n",
        },
        { }
};
MODULE_DEVICE_TABLE(of, sy8827n_dt_ids);

static const struct i2c_device_id sy8827n_id[] = {
        { "sy8827n", },
        { },
};
MODULE_DEVICE_TABLE(i2c, sy8827n_id);

static struct i2c_driver sy8827n_regulator_driver = {
        .driver = {
                .name = "sy8827n-regulator",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = sy8827n_dt_ids,
        },
        .probe = sy8827n_i2c_probe,
        .id_table = sy8827n_id,
};
module_i2c_driver(sy8827n_regulator_driver);

MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
MODULE_DESCRIPTION("SY8827N regulator driver");
MODULE_LICENSE("GPL v2");