// SPDX-License-Identifier: GPL-2.0+
//
// sy8106a-regulator.c - Regulator device driver for SY8106A
//
// Copyright (C) 2016 Ondřej Jirman <megous@megous.com>
// Copyright (c) 2017-2018 Icenowy Zheng <icenowy@aosc.io>

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#define SY8106A_REG_VOUT1_SEL           0x01
#define SY8106A_REG_VOUT_COM            0x02
#define SY8106A_REG_VOUT1_SEL_MASK      0x7f
#define SY8106A_DISABLE_REG             BIT(0)
/*
 * The I2C controlled voltage will only work when this bit is set; otherwise
 * it will behave like a fixed regulator.
 */
#define SY8106A_GO_BIT                  BIT(7)

static const struct regmap_config sy8106a_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
};

static const struct regulator_ops sy8106a_ops = {
        .set_voltage_sel = regulator_set_voltage_sel_regmap,
        .set_voltage_time_sel = regulator_set_voltage_time_sel,
        .get_voltage_sel = regulator_get_voltage_sel_regmap,
        .list_voltage = regulator_list_voltage_linear,
        /* Enabling/disabling the regulator is not yet implemented */
};

/* Default limits measured in millivolts */
#define SY8106A_MIN_MV          680
#define SY8106A_MAX_MV          1950
#define SY8106A_STEP_MV         10

static const struct regulator_desc sy8106a_reg = {
        .name = "SY8106A",
        .id = 0,
        .ops = &sy8106a_ops,
        .type = REGULATOR_VOLTAGE,
        .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) / SY8106A_STEP_MV) + 1,
        .min_uV = (SY8106A_MIN_MV * 1000),
        .uV_step = (SY8106A_STEP_MV * 1000),
        .vsel_reg = SY8106A_REG_VOUT1_SEL,
        .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
        /*
         * This ramp_delay is a conservative default value which works on
         * H3/H5 boards VDD-CPUX situations.
         */
        .ramp_delay = 200,
        .owner = THIS_MODULE,
};

/*
 * I2C driver interface functions
 */
static int sy8106a_i2c_probe(struct i2c_client *i2c)
{
        struct device *dev = &i2c->dev;
        struct regulator_dev *rdev;
        struct regulator_config config = { };
        struct regmap *regmap;
        unsigned int reg, vsel;
        u32 fixed_voltage;
        int error;

        error = of_property_read_u32(dev->of_node, "silergy,fixed-microvolt",
                                     &fixed_voltage);
        if (error)
                return error;

        if (fixed_voltage < SY8106A_MIN_MV * 1000 ||
            fixed_voltage > SY8106A_MAX_MV * 1000)
                return -EINVAL;

        regmap = devm_regmap_init_i2c(i2c, &sy8106a_regmap_config);
        if (IS_ERR(regmap)) {
                error = PTR_ERR(regmap);
                dev_err(dev, "Failed to allocate register map: %d\n", error);
                return error;
        }

        config.dev = &i2c->dev;
        config.regmap = regmap;

        config.of_node = dev->of_node;
        config.init_data = of_get_regulator_init_data(dev, dev->of_node,
                                                      &sy8106a_reg);

        if (!config.init_data)
                return -ENOMEM;

        /* Ensure GO_BIT is enabled when probing */
        error = regmap_read(regmap, SY8106A_REG_VOUT1_SEL, &reg);
        if (error)
                return error;

        if (!(reg & SY8106A_GO_BIT)) {
                vsel = (fixed_voltage / 1000 - SY8106A_MIN_MV) /
                       SY8106A_STEP_MV;

                error = regmap_write(regmap, SY8106A_REG_VOUT1_SEL,
                                     vsel | SY8106A_GO_BIT);
                if (error)
                        return error;
        }

        /* Probe regulator */
        rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg, &config);
        if (IS_ERR(rdev)) {
                error = PTR_ERR(rdev);
                dev_err(&i2c->dev, "Failed to register SY8106A regulator: %d\n", error);
                return error;
        }

        return 0;
}

static const struct of_device_id sy8106a_i2c_of_match[] = {
        { .compatible = "silergy,sy8106a" },
        { },
};
MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);

static const struct i2c_device_id sy8106a_i2c_id[] = {
        { "sy8106a" },
        { }
};
MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);

static struct i2c_driver sy8106a_regulator_driver = {
        .driver = {
                .name = "sy8106a",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = sy8106a_i2c_of_match,
        },
        .probe = sy8106a_i2c_probe,
        .id_table = sy8106a_i2c_id,
};

module_i2c_driver(sy8106a_regulator_driver);

MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
MODULE_AUTHOR("Icenowy Zheng <icenowy@aosc.io>");
MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
MODULE_LICENSE("GPL");