// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * max1586.c  --  Voltage and current regulation for the Maxim 1586
 *
 * Copyright (C) 2008 Robert Jarzmik
 */
#include <linux/module.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/slab.h>
#include <linux/regulator/max1586.h>
#include <linux/of.h>
#include <linux/regulator/of_regulator.h>

#define MAX1586_V3_MAX_VSEL 31
#define MAX1586_V6_MAX_VSEL 3

#define MAX1586_V3_MIN_UV   700000
#define MAX1586_V3_MAX_UV  1475000

#define MAX1586_V6_MIN_UV        0
#define MAX1586_V6_MAX_UV  3000000

#define I2C_V3_SELECT (0 << 5)
#define I2C_V6_SELECT (1 << 5)

struct max1586_data {
        struct i2c_client *client;

        /* min/max V3 voltage */
        unsigned int min_uV;
        unsigned int max_uV;

        unsigned int v3_curr_sel;
        unsigned int v6_curr_sel;
};

/*
 * V6 voltage
 * On I2C bus, sending a "x" byte to the max1586 means :
 *   set V6 to either 0V, 1.8V, 2.5V, 3V depending on (x & 0x3)
 * As regulator framework doesn't accept voltages to be 0V, we use 1uV.
 */
static const unsigned int v6_voltages_uv[] = { 1, 1800000, 2500000, 3000000 };

/*
 * V3 voltage
 * On I2C bus, sending a "x" byte to the max1586 means :
 *   set V3 to 0.700V + (x & 0x1f) * 0.025V
 * This voltage can be increased by external resistors
 * R24 and R25=100kOhm as described in the data sheet.
 * The gain is approximately: 1 + R24/R25 + R24/185.5kOhm
 */
static int max1586_v3_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max1586_data *max1586 = rdev_get_drvdata(rdev);

        return max1586->v3_curr_sel;
}

static int max1586_v3_set_voltage_sel(struct regulator_dev *rdev,
                                      unsigned selector)
{
        struct max1586_data *max1586 = rdev_get_drvdata(rdev);
        struct i2c_client *client = max1586->client;
        int ret;
        u8 v3_prog;

        dev_dbg(&client->dev, "changing voltage v3 to %dmv\n",
                regulator_list_voltage_linear(rdev, selector) / 1000);

        v3_prog = I2C_V3_SELECT | (u8) selector;
        ret = i2c_smbus_write_byte(client, v3_prog);
        if (ret)
                return ret;

        max1586->v3_curr_sel = selector;

        return 0;
}

static int max1586_v6_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max1586_data *max1586 = rdev_get_drvdata(rdev);

        return max1586->v6_curr_sel;
}

static int max1586_v6_set_voltage_sel(struct regulator_dev *rdev,
                                      unsigned int selector)
{
        struct max1586_data *max1586 = rdev_get_drvdata(rdev);
        struct i2c_client *client = max1586->client;
        u8 v6_prog;
        int ret;

        dev_dbg(&client->dev, "changing voltage v6 to %dmv\n",
                rdev->desc->volt_table[selector] / 1000);

        v6_prog = I2C_V6_SELECT | (u8) selector;
        ret = i2c_smbus_write_byte(client, v6_prog);
        if (ret)
                return ret;

        max1586->v6_curr_sel = selector;

        return 0;
}

/*
 * The Maxim 1586 controls V3 and V6 voltages, but offers no way of reading back
 * the set up value.
 */
static const struct regulator_ops max1586_v3_ops = {
        .get_voltage_sel = max1586_v3_get_voltage_sel,
        .set_voltage_sel = max1586_v3_set_voltage_sel,
        .list_voltage = regulator_list_voltage_linear,
        .map_voltage = regulator_map_voltage_linear,
};

static const struct regulator_ops max1586_v6_ops = {
        .get_voltage_sel = max1586_v6_get_voltage_sel,
        .set_voltage_sel = max1586_v6_set_voltage_sel,
        .list_voltage = regulator_list_voltage_table,
};

static struct regulator_desc max1586_reg[] = {
        {
                .name = "Output_V3",
                .id = MAX1586_V3,
                .ops = &max1586_v3_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX1586_V3_MAX_VSEL + 1,
                .owner = THIS_MODULE,
        },
        {
                .name = "Output_V6",
                .id = MAX1586_V6,
                .ops = &max1586_v6_ops,
                .type = REGULATOR_VOLTAGE,
                .n_voltages = MAX1586_V6_MAX_VSEL + 1,
                .volt_table = v6_voltages_uv,
                .owner = THIS_MODULE,
        },
};

static int of_get_max1586_platform_data(struct device *dev,
                                 struct max1586_platform_data *pdata)
{
        struct max1586_subdev_data *sub;
        struct of_regulator_match rmatch[ARRAY_SIZE(max1586_reg)] = { };
        struct device_node *np = dev->of_node;
        int i, matched;

        if (of_property_read_u32(np, "v3-gain",
                                 &pdata->v3_gain) < 0) {
                dev_err(dev, "%pOF has no 'v3-gain' property\n", np);
                return -EINVAL;
        }

        np = of_get_child_by_name(np, "regulators");
        if (!np) {
                dev_err(dev, "missing 'regulators' subnode in DT\n");
                return -EINVAL;
        }

        for (i = 0; i < ARRAY_SIZE(rmatch); i++)
                rmatch[i].name = max1586_reg[i].name;

        matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
        of_node_put(np);
        /*
         * If matched is 0, ie. neither Output_V3 nor Output_V6 have been found,
         * return 0, which signals the normal situation where no subregulator is
         * available. This is normal because the max1586 doesn't provide any
         * readback support, so the subregulators can't report any status
         * anyway.  If matched < 0, return the error.
         */
        if (matched <= 0)
                return matched;

        pdata->subdevs = devm_kcalloc(dev,
                                      matched,
                                      sizeof(struct max1586_subdev_data),
                                      GFP_KERNEL);
        if (!pdata->subdevs)
                return -ENOMEM;

        pdata->num_subdevs = matched;
        sub = pdata->subdevs;

        for (i = 0; i < matched; i++) {
                sub->id = i;
                sub->name = rmatch[i].of_node->name;
                sub->platform_data = rmatch[i].init_data;
                sub++;
        }

        return 0;
}

static const struct of_device_id __maybe_unused max1586_of_match[] = {
        { .compatible = "maxim,max1586", },
        {},
};
MODULE_DEVICE_TABLE(of, max1586_of_match);

static int max1586_pmic_probe(struct i2c_client *client)
{
        struct max1586_platform_data *pdata, pdata_of;
        struct regulator_config config = { };
        struct max1586_data *max1586;
        int i, id, ret;

        pdata = dev_get_platdata(&client->dev);
        if (client->dev.of_node && !pdata) {
                ret = of_get_max1586_platform_data(&client->dev, &pdata_of);
                if (ret < 0)
                        return ret;
                pdata = &pdata_of;
        }

        max1586 = devm_kzalloc(&client->dev, sizeof(struct max1586_data),
                        GFP_KERNEL);
        if (!max1586)
                return -ENOMEM;

        max1586->client = client;

        if (!pdata->v3_gain)
                return -EINVAL;

        max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
        max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;

        /* Set curr_sel to default voltage on power-up */
        max1586->v3_curr_sel = 24; /* 1.3V */
        max1586->v6_curr_sel = 0;

        for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
                struct regulator_dev *rdev;

                id = pdata->subdevs[i].id;
                if (!pdata->subdevs[i].platform_data)
                        continue;
                if (id < MAX1586_V3 || id > MAX1586_V6) {
                        dev_err(&client->dev, "invalid regulator id %d\n", id);
                        return -EINVAL;
                }

                if (id == MAX1586_V3) {
                        max1586_reg[id].min_uV = max1586->min_uV;
                        max1586_reg[id].uV_step =
                                        (max1586->max_uV - max1586->min_uV) /
                                        MAX1586_V3_MAX_VSEL;
                }

                config.dev = &client->dev;
                config.init_data = pdata->subdevs[i].platform_data;
                config.driver_data = max1586;

                rdev = devm_regulator_register(&client->dev,
                                                  &max1586_reg[id], &config);
                if (IS_ERR(rdev)) {
                        dev_err(&client->dev, "failed to register %s\n",
                                max1586_reg[id].name);
                        return PTR_ERR(rdev);
                }
        }

        i2c_set_clientdata(client, max1586);
        dev_info(&client->dev, "Maxim 1586 regulator driver loaded\n");
        return 0;
}

static const struct i2c_device_id max1586_id[] = {
        { "max1586" },
        { }
};
MODULE_DEVICE_TABLE(i2c, max1586_id);

static struct i2c_driver max1586_pmic_driver = {
        .probe = max1586_pmic_probe,
        .driver         = {
                .name   = "max1586",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = of_match_ptr(max1586_of_match),
        },
        .id_table       = max1586_id,
};

static int __init max1586_pmic_init(void)
{
        return i2c_add_driver(&max1586_pmic_driver);
}
subsys_initcall(max1586_pmic_init);

static void __exit max1586_pmic_exit(void)
{
        i2c_del_driver(&max1586_pmic_driver);
}
module_exit(max1586_pmic_exit);

/* Module information */
MODULE_DESCRIPTION("MAXIM 1586 voltage regulator driver");
MODULE_AUTHOR("Robert Jarzmik");
MODULE_LICENSE("GPL");