// SPDX-License-Identifier: GPL-2.0-only
/*
 * max8973-regulator.c -- Maxim max8973A
 *
 * Regulator driver for MAXIM 8973A DC-DC step-down switching regulator.
 *
 * Copyright (c) 2012, NVIDIA Corporation.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/max8973-regulator.h>
#include <linux/regulator/of_regulator.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>
#include <linux/thermal.h>
#include <linux/irq.h>
#include <linux/interrupt.h>

/* Register definitions */
#define MAX8973_VOUT                                    0x0
#define MAX8973_VOUT_DVS                                0x1
#define MAX8973_CONTROL1                                0x2
#define MAX8973_CONTROL2                                0x3
#define MAX8973_CHIPID1                                 0x4
#define MAX8973_CHIPID2                                 0x5

#define MAX8973_MAX_VOUT_REG                            2

/* MAX8973_VOUT */
#define MAX8973_VOUT_ENABLE                             BIT(7)
#define MAX8973_VOUT_MASK                               0x7F

/* MAX8973_VOUT_DVS */
#define MAX8973_DVS_VOUT_MASK                           0x7F

/* MAX8973_CONTROL1 */
#define MAX8973_SNS_ENABLE                              BIT(7)
#define MAX8973_FPWM_EN_M                               BIT(6)
#define MAX8973_NFSR_ENABLE                             BIT(5)
#define MAX8973_AD_ENABLE                               BIT(4)
#define MAX8973_BIAS_ENABLE                             BIT(3)
#define MAX8973_FREQSHIFT_9PER                          BIT(2)

#define MAX8973_RAMP_12mV_PER_US                        0x0
#define MAX8973_RAMP_25mV_PER_US                        0x1
#define MAX8973_RAMP_50mV_PER_US                        0x2
#define MAX8973_RAMP_200mV_PER_US                       0x3
#define MAX8973_RAMP_MASK                               0x3

/* MAX8973_CONTROL2 */
#define MAX8973_WDTMR_ENABLE                            BIT(6)
#define MAX8973_DISCH_ENBABLE                           BIT(5)
#define MAX8973_FT_ENABLE                               BIT(4)
#define MAX77621_T_JUNCTION_120                         BIT(7)

#define MAX8973_CKKADV_TRIP_MASK                        0xC
#define MAX8973_CKKADV_TRIP_DISABLE                     0xC
#define MAX8973_CKKADV_TRIP_75mV_PER_US                 0x0
#define MAX8973_CKKADV_TRIP_150mV_PER_US                0x4
#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS        0x8
#define MAX8973_CONTROL_CLKADV_TRIP_MASK                0x00030000

#define MAX8973_INDUCTOR_MIN_30_PER                     0x0
#define MAX8973_INDUCTOR_NOMINAL                        0x1
#define MAX8973_INDUCTOR_PLUS_30_PER                    0x2
#define MAX8973_INDUCTOR_PLUS_60_PER                    0x3
#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK             0x00300000

#define MAX8973_MIN_VOLATGE                             606250
#define MAX8973_MAX_VOLATGE                             1400000
#define MAX8973_VOLATGE_STEP                            6250
#define MAX8973_BUCK_N_VOLTAGE                          0x80

#define MAX77621_CHIPID_TJINT_S                         BIT(0)

#define MAX77621_NORMAL_OPERATING_TEMP                  100000
#define MAX77621_TJINT_WARNING_TEMP_120                 120000
#define MAX77621_TJINT_WARNING_TEMP_140                 140000

enum device_id {
        MAX8973,
        MAX77621
};

/* Maxim 8973 chip information */
struct max8973_chip {
        struct device *dev;
        struct regulator_desc desc;
        struct regmap *regmap;
        bool enable_external_control;
        struct gpio_desc *dvs_gpiod;
        int lru_index[MAX8973_MAX_VOUT_REG];
        int curr_vout_val[MAX8973_MAX_VOUT_REG];
        int curr_vout_reg;
        int curr_gpio_val;
        struct regulator_ops ops;
        enum device_id id;
        int junction_temp_warning;
        int irq;
        struct thermal_zone_device *tz_device;
};

/*
 * find_voltage_set_register: Find new voltage configuration register (VOUT).
 * The finding of the new VOUT register will be based on the LRU mechanism.
 * Each VOUT register will have different voltage configured . This
 * Function will look if any of the VOUT register have requested voltage set
 * or not.
 *     - If it is already there then it will make that register as most
 *       recently used and return as found so that caller need not to set
 *       the VOUT register but need to set the proper gpios to select this
 *       VOUT register.
 *     - If requested voltage is not found then it will use the least
 *       recently mechanism to get new VOUT register for new configuration
 *       and will return not_found so that caller need to set new VOUT
 *       register and then gpios (both).
 */
static bool find_voltage_set_register(struct max8973_chip *tps,
                int req_vsel, int *vout_reg, int *gpio_val)
{
        int i;
        bool found = false;
        int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1];
        int found_index = MAX8973_MAX_VOUT_REG - 1;

        for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) {
                if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) {
                        new_vout_reg = tps->lru_index[i];
                        found_index = i;
                        found = true;
                        goto update_lru_index;
                }
        }

update_lru_index:
        for (i = found_index; i > 0; i--)
                tps->lru_index[i] = tps->lru_index[i - 1];

        tps->lru_index[0] = new_vout_reg;
        *gpio_val = new_vout_reg;
        *vout_reg = MAX8973_VOUT + new_vout_reg;
        return found;
}

static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        unsigned int data;
        int ret;

        ret = regmap_read(max->regmap, max->curr_vout_reg, &data);
        if (ret < 0) {
                dev_err(max->dev, "register %d read failed, err = %d\n",
                        max->curr_vout_reg, ret);
                return ret;
        }
        return data & MAX8973_VOUT_MASK;
}

static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev,
             unsigned vsel)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        int ret;
        bool found = false;
        int vout_reg = max->curr_vout_reg;
        int gpio_val = max->curr_gpio_val;

        /*
         * If gpios are available to select the VOUT register then least
         * recently used register for new configuration.
         */
        if (max->dvs_gpiod)
                found = find_voltage_set_register(max, vsel,
                                        &vout_reg, &gpio_val);

        if (!found) {
                ret = regmap_update_bits(max->regmap, vout_reg,
                                        MAX8973_VOUT_MASK, vsel);
                if (ret < 0) {
                        dev_err(max->dev, "register %d update failed, err %d\n",
                                 vout_reg, ret);
                        return ret;
                }
                max->curr_vout_reg = vout_reg;
                max->curr_vout_val[gpio_val] = vsel;
        }

        /* Select proper VOUT register vio gpios */
        if (max->dvs_gpiod) {
                gpiod_set_value_cansleep(max->dvs_gpiod, gpio_val & 0x1);
                max->curr_gpio_val = gpio_val;
        }
        return 0;
}

static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        int ret;
        int pwm;

        /* Enable force PWM mode in FAST mode only. */
        switch (mode) {
        case REGULATOR_MODE_FAST:
                pwm = MAX8973_FPWM_EN_M;
                break;

        case REGULATOR_MODE_NORMAL:
                pwm = 0;
                break;

        default:
                return -EINVAL;
        }

        ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1,
                                MAX8973_FPWM_EN_M, pwm);
        if (ret < 0)
                dev_err(max->dev, "register %d update failed, err %d\n",
                                MAX8973_CONTROL1, ret);
        return ret;
}

static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        unsigned int data;
        int ret;

        ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
        if (ret < 0) {
                dev_err(max->dev, "register %d read failed, err %d\n",
                                MAX8973_CONTROL1, ret);
                return ret;
        }
        return (data & MAX8973_FPWM_EN_M) ?
                REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
}

static int max8973_set_current_limit(struct regulator_dev *rdev,
                int min_ua, int max_ua)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        unsigned int val;
        int ret;

        if (max_ua <= 9000000)
                val = MAX8973_CKKADV_TRIP_75mV_PER_US;
        else if (max_ua <= 12000000)
                val = MAX8973_CKKADV_TRIP_150mV_PER_US;
        else
                val = MAX8973_CKKADV_TRIP_DISABLE;

        ret = regmap_update_bits(max->regmap, MAX8973_CONTROL2,
                        MAX8973_CKKADV_TRIP_MASK, val);
        if (ret < 0) {
                dev_err(max->dev, "register %d update failed: %d\n",
                                MAX8973_CONTROL2, ret);
                return ret;
        }
        return 0;
}

static int max8973_get_current_limit(struct regulator_dev *rdev)
{
        struct max8973_chip *max = rdev_get_drvdata(rdev);
        unsigned int control2;
        int ret;

        ret = regmap_read(max->regmap, MAX8973_CONTROL2, &control2);
        if (ret < 0) {
                dev_err(max->dev, "register %d read failed: %d\n",
                                MAX8973_CONTROL2, ret);
                return ret;
        }
        switch (control2 & MAX8973_CKKADV_TRIP_MASK) {
        case MAX8973_CKKADV_TRIP_DISABLE:
                return 15000000;
        case MAX8973_CKKADV_TRIP_150mV_PER_US:
                return 12000000;
        case MAX8973_CKKADV_TRIP_75mV_PER_US:
                return 9000000;
        default:
                break;
        }
        return 9000000;
}

static const unsigned int max8973_buck_ramp_table[] = {
        12000, 25000, 50000, 200000
};

static const struct regulator_ops max8973_dcdc_ops = {
        .get_voltage_sel        = max8973_dcdc_get_voltage_sel,
        .set_voltage_sel        = max8973_dcdc_set_voltage_sel,
        .list_voltage           = regulator_list_voltage_linear,
        .set_mode               = max8973_dcdc_set_mode,
        .get_mode               = max8973_dcdc_get_mode,
        .set_voltage_time_sel   = regulator_set_voltage_time_sel,
        .set_ramp_delay         = regulator_set_ramp_delay_regmap,
};

static int max8973_init_dcdc(struct max8973_chip *max,
                             struct max8973_regulator_platform_data *pdata)
{
        int ret;
        uint8_t control1 = 0;
        uint8_t control2 = 0;
        unsigned int data;

        ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data);
        if (ret < 0) {
                dev_err(max->dev, "register %d read failed, err = %d",
                                MAX8973_CONTROL1, ret);
                return ret;
        }
        control1 = data & MAX8973_RAMP_MASK;
        switch (control1) {
        case MAX8973_RAMP_12mV_PER_US:
                max->desc.ramp_delay = 12000;
                break;
        case MAX8973_RAMP_25mV_PER_US:
                max->desc.ramp_delay = 25000;
                break;
        case MAX8973_RAMP_50mV_PER_US:
                max->desc.ramp_delay = 50000;
                break;
        case MAX8973_RAMP_200mV_PER_US:
                max->desc.ramp_delay = 200000;
                break;
        }

        if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE)
                control1 |= MAX8973_SNS_ENABLE;

        if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE))
                control1 |= MAX8973_NFSR_ENABLE;

        if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE)
                control1 |= MAX8973_AD_ENABLE;

        if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) {
                control1 |= MAX8973_BIAS_ENABLE;
                max->desc.enable_time = 20;
        } else {
                max->desc.enable_time = 240;
        }

        if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE)
                control1 |= MAX8973_FREQSHIFT_9PER;

        if ((pdata->junction_temp_warning == MAX77621_TJINT_WARNING_TEMP_120) &&
            (max->id == MAX77621))
                control2 |= MAX77621_T_JUNCTION_120;

        if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE))
                control2 |= MAX8973_DISCH_ENBABLE;

        /*  Clock advance trip configuration */
        switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) {
        case MAX8973_CONTROL_CLKADV_TRIP_DISABLED:
                control2 |= MAX8973_CKKADV_TRIP_DISABLE;
                break;

        case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US:
                control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US;
                break;

        case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US:
                control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US;
                break;

        case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS:
                control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS;
                break;
        }

        /* Configure inductor value */
        switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) {
        case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL:
                control2 |= MAX8973_INDUCTOR_NOMINAL;
                break;

        case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER:
                control2 |= MAX8973_INDUCTOR_MIN_30_PER;
                break;

        case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER:
                control2 |= MAX8973_INDUCTOR_PLUS_30_PER;
                break;

        case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER:
                control2 |= MAX8973_INDUCTOR_PLUS_60_PER;
                break;
        }

        ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1);
        if (ret < 0) {
                dev_err(max->dev, "register %d write failed, err = %d",
                                MAX8973_CONTROL1, ret);
                return ret;
        }

        ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2);
        if (ret < 0) {
                dev_err(max->dev, "register %d write failed, err = %d",
                                MAX8973_CONTROL2, ret);
                return ret;
        }

        /* If external control is enabled then disable EN bit */
        if (max->enable_external_control && (max->id == MAX8973)) {
                ret = regmap_update_bits(max->regmap, MAX8973_VOUT,
                                                MAX8973_VOUT_ENABLE, 0);
                if (ret < 0)
                        dev_err(max->dev, "register %d update failed, err = %d",
                                MAX8973_VOUT, ret);
        }
        return ret;
}

static int max8973_thermal_read_temp(struct thermal_zone_device *tz, int *temp)
{
        struct max8973_chip *mchip = thermal_zone_device_priv(tz);
        unsigned int val;
        int ret;

        ret = regmap_read(mchip->regmap, MAX8973_CHIPID1, &val);
        if (ret < 0) {
                dev_err(mchip->dev, "Failed to read register CHIPID1, %d", ret);
                return ret;
        }

        /* +1 degC to trigger cool device */
        if (val & MAX77621_CHIPID_TJINT_S)
                *temp = mchip->junction_temp_warning + 1000;
        else
                *temp = MAX77621_NORMAL_OPERATING_TEMP;

        return 0;
}

static irqreturn_t max8973_thermal_irq(int irq, void *data)
{
        struct max8973_chip *mchip = data;

        thermal_zone_device_update(mchip->tz_device,
                                   THERMAL_EVENT_UNSPECIFIED);

        return IRQ_HANDLED;
}

static const struct thermal_zone_device_ops max77621_tz_ops = {
        .get_temp = max8973_thermal_read_temp,
};

static int max8973_thermal_init(struct max8973_chip *mchip)
{
        struct thermal_zone_device *tzd;
        unsigned long irq_flags;
        int ret;

        if (mchip->id != MAX77621)
                return 0;

        tzd = devm_thermal_of_zone_register(mchip->dev, 0, mchip,
                                            &max77621_tz_ops);
        if (IS_ERR(tzd)) {
                ret = PTR_ERR(tzd);
                dev_err(mchip->dev, "Failed to register thermal sensor: %d\n",
                        ret);
                return ret;
        }

        if (mchip->irq <= 0)
                return 0;

        irq_flags = irq_get_trigger_type(mchip->irq);

        ret = devm_request_threaded_irq(mchip->dev, mchip->irq, NULL,
                                        max8973_thermal_irq,
                                        IRQF_ONESHOT | IRQF_SHARED | irq_flags,
                                        dev_name(mchip->dev), mchip);
        if (ret < 0) {
                dev_err(mchip->dev, "Failed to request irq %d, %d\n",
                        mchip->irq, ret);
                return ret;
        }

        return 0;
}

static const struct regmap_config max8973_regmap_config = {
        .reg_bits               = 8,
        .val_bits               = 8,
        .max_register           = MAX8973_CHIPID2,
        .cache_type             = REGCACHE_MAPLE,
};

static struct max8973_regulator_platform_data *max8973_parse_dt(
                struct device *dev)
{
        struct max8973_regulator_platform_data *pdata;
        struct device_node *np = dev->of_node;
        int ret;
        u32 pval;
        bool etr_enable;
        bool etr_sensitivity_high;

        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return NULL;

        pdata->enable_ext_control = of_property_read_bool(np,
                                                "maxim,externally-enable");

        ret = of_property_read_u32(np, "maxim,dvs-default-state", &pval);
        if (!ret)
                pdata->dvs_def_state = pval;

        if (of_property_read_bool(np, "maxim,enable-remote-sense"))
                pdata->control_flags  |= MAX8973_CONTROL_REMOTE_SENSE_ENABLE;

        if (of_property_read_bool(np, "maxim,enable-falling-slew-rate"))
                pdata->control_flags  |=
                                MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE;

        if (of_property_read_bool(np, "maxim,enable-active-discharge"))
                pdata->control_flags  |=
                                MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE;

        if (of_property_read_bool(np, "maxim,enable-frequency-shift"))
                pdata->control_flags  |= MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE;

        if (of_property_read_bool(np, "maxim,enable-bias-control"))
                pdata->control_flags  |= MAX8973_CONTROL_BIAS_ENABLE;

        etr_enable = of_property_read_bool(np, "maxim,enable-etr");
        etr_sensitivity_high = of_property_read_bool(np,
                                "maxim,enable-high-etr-sensitivity");
        if (etr_sensitivity_high)
                etr_enable = true;

        if (etr_enable) {
                if (etr_sensitivity_high)
                        pdata->control_flags |=
                                MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US;
                else
                        pdata->control_flags |=
                                MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US;
        } else {
                pdata->control_flags |= MAX8973_CONTROL_CLKADV_TRIP_DISABLED;
        }

        pdata->junction_temp_warning = MAX77621_TJINT_WARNING_TEMP_140;
        ret = of_property_read_u32(np, "junction-warn-millicelsius", &pval);
        if (!ret && (pval <= MAX77621_TJINT_WARNING_TEMP_120))
                pdata->junction_temp_warning = MAX77621_TJINT_WARNING_TEMP_120;

        return pdata;
}

static const struct of_device_id of_max8973_match_tbl[] = {
        { .compatible = "maxim,max8973", .data = (void *)MAX8973, },
        { .compatible = "maxim,max77621", .data = (void *)MAX77621, },
        { },
};
MODULE_DEVICE_TABLE(of, of_max8973_match_tbl);

static int max8973_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct max8973_regulator_platform_data *pdata;
        struct regulator_init_data *ridata;
        struct regulator_config config = { };
        struct regulator_dev *rdev;
        struct max8973_chip *max;
        bool pdata_from_dt = false;
        unsigned int chip_id;
        struct gpio_desc *gpiod;
        enum gpiod_flags gflags;
        int ret;

        pdata = dev_get_platdata(&client->dev);

        if (!pdata && client->dev.of_node) {
                pdata = max8973_parse_dt(&client->dev);
                pdata_from_dt = true;
        }

        if (!pdata) {
                dev_err(&client->dev, "No Platform data");
                return -EIO;
        }

        max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL);
        if (!max)
                return -ENOMEM;

        max->dvs_gpiod = devm_gpiod_get_optional(&client->dev, "maxim,dvs",
                         (pdata->dvs_def_state) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW);
        if (IS_ERR(max->dvs_gpiod))
                return dev_err_probe(&client->dev, PTR_ERR(max->dvs_gpiod),
                                     "failed to obtain dvs gpio\n");
        gpiod_set_consumer_name(max->dvs_gpiod, "max8973-dvs");

        max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config);
        if (IS_ERR(max->regmap)) {
                ret = PTR_ERR(max->regmap);
                dev_err(&client->dev, "regmap init failed, err %d\n", ret);
                return ret;
        }

        if (client->dev.of_node) {
                const struct of_device_id *match;

                match = of_match_device(of_match_ptr(of_max8973_match_tbl),
                                &client->dev);
                if (!match)
                        return -ENODATA;
                max->id = (u32)((uintptr_t)match->data);
        } else {
                max->id = id->driver_data;
        }

        ret = regmap_read(max->regmap, MAX8973_CHIPID1, &chip_id);
        if (ret < 0) {
                dev_err(&client->dev, "register CHIPID1 read failed, %d", ret);
                return ret;
        }

        dev_info(&client->dev, "CHIP-ID OTP: 0x%02x ID_M: 0x%02x\n",
                        (chip_id >> 4) & 0xF, (chip_id >> 1) & 0x7);

        i2c_set_clientdata(client, max);
        max->ops = max8973_dcdc_ops;
        max->dev = &client->dev;
        max->desc.name = id->name;
        max->desc.id = 0;
        max->desc.ops = &max->ops;
        max->desc.type = REGULATOR_VOLTAGE;
        max->desc.owner = THIS_MODULE;
        max->desc.min_uV = MAX8973_MIN_VOLATGE;
        max->desc.uV_step = MAX8973_VOLATGE_STEP;
        max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE;
        max->desc.ramp_reg = MAX8973_CONTROL1;
        max->desc.ramp_mask = MAX8973_RAMP_MASK;
        max->desc.ramp_delay_table = max8973_buck_ramp_table;
        max->desc.n_ramp_values = ARRAY_SIZE(max8973_buck_ramp_table);

        max->enable_external_control = pdata->enable_ext_control;
        max->curr_gpio_val = pdata->dvs_def_state;
        max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state;
        max->junction_temp_warning = pdata->junction_temp_warning;

        max->lru_index[0] = max->curr_vout_reg;

        if (max->dvs_gpiod) {
                int i;

                /*
                 * Initialize the lru index with vout_reg id
                 * The index 0 will be most recently used and
                 * set with the max->curr_vout_reg */
                for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i)
                        max->lru_index[i] = i;
                max->lru_index[0] = max->curr_vout_reg;
                max->lru_index[max->curr_vout_reg] = 0;
        } else {
                /*
                 * If there is no DVS GPIO, the VOUT register
                 * address is fixed.
                 */
                max->ops.set_voltage_sel = regulator_set_voltage_sel_regmap;
                max->ops.get_voltage_sel = regulator_get_voltage_sel_regmap;
                max->desc.vsel_reg = max->curr_vout_reg;
                max->desc.vsel_mask = MAX8973_VOUT_MASK;
        }

        if (pdata_from_dt)
                pdata->reg_init_data = of_get_regulator_init_data(&client->dev,
                                        client->dev.of_node, &max->desc);

        ridata = pdata->reg_init_data;
        switch (max->id) {
        case MAX8973:
                if (!pdata->enable_ext_control) {
                        max->desc.enable_reg = MAX8973_VOUT;
                        max->desc.enable_mask = MAX8973_VOUT_ENABLE;
                        max->ops.enable = regulator_enable_regmap;
                        max->ops.disable = regulator_disable_regmap;
                        max->ops.is_enabled = regulator_is_enabled_regmap;
                        break;
                }

                if (ridata && (ridata->constraints.always_on ||
                               ridata->constraints.boot_on))
                        gflags = GPIOD_OUT_HIGH;
                else
                        gflags = GPIOD_OUT_LOW;
                gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
                gpiod = devm_gpiod_get_optional(&client->dev,
                                                "maxim,enable",
                                                gflags);
                if (IS_ERR(gpiod))
                        return PTR_ERR(gpiod);
                if (gpiod) {
                        config.ena_gpiod = gpiod;
                        max->enable_external_control = true;
                }

                break;

        case MAX77621:
                /*
                 * We do not let the core switch this regulator on/off,
                 * we just leave it on.
                 */
                gpiod = devm_gpiod_get_optional(&client->dev,
                                                "maxim,enable",
                                                GPIOD_OUT_HIGH);
                if (IS_ERR(gpiod))
                        return PTR_ERR(gpiod);
                if (gpiod)
                        max->enable_external_control = true;

                max->desc.enable_reg = MAX8973_VOUT;
                max->desc.enable_mask = MAX8973_VOUT_ENABLE;
                max->ops.enable = regulator_enable_regmap;
                max->ops.disable = regulator_disable_regmap;
                max->ops.is_enabled = regulator_is_enabled_regmap;
                max->ops.set_current_limit = max8973_set_current_limit;
                max->ops.get_current_limit = max8973_get_current_limit;
                break;
        default:
                break;
        }

        ret = max8973_init_dcdc(max, pdata);
        if (ret < 0) {
                dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret);
                return ret;
        }

        config.dev = &client->dev;
        config.init_data = pdata->reg_init_data;
        config.driver_data = max;
        config.of_node = client->dev.of_node;
        config.regmap = max->regmap;

        /*
         * Register the regulators
         * Turn the GPIO descriptor over to the regulator core for
         * lifecycle management if we pass an ena_gpiod.
         */
        if (config.ena_gpiod)
                devm_gpiod_unhinge(&client->dev, config.ena_gpiod);
        rdev = devm_regulator_register(&client->dev, &max->desc, &config);
        if (IS_ERR(rdev)) {
                ret = PTR_ERR(rdev);
                dev_err(max->dev, "regulator register failed, err %d\n", ret);
                return ret;
        }

        max8973_thermal_init(max);
        return 0;
}

static const struct i2c_device_id max8973_id[] = {
        {.name = "max8973", .driver_data = MAX8973},
        {.name = "max77621", .driver_data = MAX77621},
        {},
};
MODULE_DEVICE_TABLE(i2c, max8973_id);

static struct i2c_driver max8973_i2c_driver = {
        .driver = {
                .name = "max8973",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = of_max8973_match_tbl,
        },
        .probe = max8973_probe,
        .id_table = max8973_id,
};

static int __init max8973_init(void)
{
        return i2c_add_driver(&max8973_i2c_driver);
}
subsys_initcall(max8973_init);

static void __exit max8973_cleanup(void)
{
        i2c_del_driver(&max8973_i2c_driver);
}
module_exit(max8973_cleanup);

MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("MAX8973 voltage regulator driver");
MODULE_LICENSE("GPL v2");