/*
 * TI TPS65132 Regulator driver
 *
 * Copyright (C) 2017 NVIDIA CORPORATION. All rights reserved.
 *
 * Author: Venkat Reddy Talla <vreddytalla@nvidia.com>
 *              Laxman Dewangan <ldewangan@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
 * whether express or implied; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>

#define TPS65132_REG_VPOS               0x00
#define TPS65132_REG_VNEG               0x01
#define TPS65132_REG_APPS_DISP_DISN     0x03
#define TPS65132_REG_CONTROL            0x0FF

#define TPS65132_VOUT_MASK              0x1F
#define TPS65132_VOUT_N_VOLTAGE         0x15
#define TPS65132_VOUT_VMIN              4000000
#define TPS65132_VOUT_VMAX              6000000
#define TPS65132_VOUT_STEP              100000

#define TPS65132_REG_APPS_DIS_VPOS              BIT(0)
#define TPS65132_REG_APPS_DIS_VNEG              BIT(1)

#define TPS65132_REGULATOR_ID_VPOS      0
#define TPS65132_REGULATOR_ID_VNEG      1
#define TPS65132_MAX_REGULATORS         2

#define TPS65132_ACT_DIS_TIME_SLACK             1000

struct tps65132_reg_pdata {
        struct gpio_desc *en_gpiod;
        struct gpio_desc *act_dis_gpiod;
        unsigned int act_dis_time_us;
        int ena_gpio_state;
};

struct tps65132_regulator {
        struct device *dev;
        struct tps65132_reg_pdata reg_pdata[TPS65132_MAX_REGULATORS];
};

static int tps65132_regulator_enable(struct regulator_dev *rdev)
{
        struct tps65132_regulator *tps = rdev_get_drvdata(rdev);
        int id = rdev_get_id(rdev);
        struct tps65132_reg_pdata *rpdata = &tps->reg_pdata[id];
        int ret;

        if (!IS_ERR(rpdata->en_gpiod)) {
                gpiod_set_value_cansleep(rpdata->en_gpiod, 1);
                rpdata->ena_gpio_state = 1;
        }

        /* Hardware automatically enable discharge bit in enable */
        if (rdev->constraints->active_discharge ==
                        REGULATOR_ACTIVE_DISCHARGE_DISABLE) {
                ret = regulator_set_active_discharge_regmap(rdev, false);
                if (ret < 0) {
                        dev_err(tps->dev, "Failed to disable active discharge: %d\n",
                                ret);
                        return ret;
                }
        }

        return 0;
}

static int tps65132_regulator_disable(struct regulator_dev *rdev)
{
        struct tps65132_regulator *tps = rdev_get_drvdata(rdev);
        int id = rdev_get_id(rdev);
        struct tps65132_reg_pdata *rpdata = &tps->reg_pdata[id];

        if (!IS_ERR(rpdata->en_gpiod)) {
                gpiod_set_value_cansleep(rpdata->en_gpiod, 0);
                rpdata->ena_gpio_state = 0;
        }

        if (!IS_ERR(rpdata->act_dis_gpiod)) {
                gpiod_set_value_cansleep(rpdata->act_dis_gpiod, 1);
                usleep_range(rpdata->act_dis_time_us, rpdata->act_dis_time_us +
                             TPS65132_ACT_DIS_TIME_SLACK);
                gpiod_set_value_cansleep(rpdata->act_dis_gpiod, 0);
        }

        return 0;
}

static int tps65132_regulator_is_enabled(struct regulator_dev *rdev)
{
        struct tps65132_regulator *tps = rdev_get_drvdata(rdev);
        int id = rdev_get_id(rdev);
        struct tps65132_reg_pdata *rpdata = &tps->reg_pdata[id];

        if (!IS_ERR(rpdata->en_gpiod))
                return rpdata->ena_gpio_state;

        return 1;
}

static const struct regulator_ops tps65132_regulator_ops = {
        .enable = tps65132_regulator_enable,
        .disable = tps65132_regulator_disable,
        .is_enabled = tps65132_regulator_is_enabled,
        .list_voltage = regulator_list_voltage_linear,
        .map_voltage = regulator_map_voltage_linear,
        .get_voltage_sel = regulator_get_voltage_sel_regmap,
        .set_voltage_sel = regulator_set_voltage_sel_regmap,
        .set_active_discharge = regulator_set_active_discharge_regmap,
};

static int tps65132_of_parse_cb(struct device_node *np,
                                const struct regulator_desc *desc,
                                struct regulator_config *config)
{
        struct tps65132_regulator *tps = config->driver_data;
        struct tps65132_reg_pdata *rpdata = &tps->reg_pdata[desc->id];
        int ret;

        rpdata->en_gpiod = devm_fwnode_gpiod_get(tps->dev, of_fwnode_handle(np),
                                                 "enable", GPIOD_ASIS,
                                                 "enable");
        if (IS_ERR(rpdata->en_gpiod)) {
                ret = PTR_ERR(rpdata->en_gpiod);

                /* Ignore the error other than probe defer */
                if (ret == -EPROBE_DEFER)
                        return ret;
                return 0;
        }

        rpdata->act_dis_gpiod = devm_fwnode_gpiod_get(tps->dev,
                                                      of_fwnode_handle(np),
                                                      "active-discharge",
                                                      GPIOD_ASIS,
                                                      "active-discharge");
        if (IS_ERR(rpdata->act_dis_gpiod)) {
                ret = PTR_ERR(rpdata->act_dis_gpiod);

                /* Ignore the error other than probe defer */
                if (ret == -EPROBE_DEFER)
                        return ret;

                return 0;
        }

        ret = of_property_read_u32(np, "ti,active-discharge-time-us",
                                   &rpdata->act_dis_time_us);
        if (ret < 0) {
                dev_err(tps->dev, "Failed to read active discharge time:%d\n",
                        ret);
                return ret;
        }

        return 0;
}

#define TPS65132_REGULATOR_DESC(_id, _name)             \
        [TPS65132_REGULATOR_ID_##_id] = {               \
                .name = "tps65132-"#_name,              \
                .supply_name = "vin",                   \
                .id = TPS65132_REGULATOR_ID_##_id,      \
                .of_match = of_match_ptr(#_name),       \
                .of_parse_cb    = tps65132_of_parse_cb, \
                .ops = &tps65132_regulator_ops,         \
                .n_voltages = TPS65132_VOUT_N_VOLTAGE,  \
                .min_uV = TPS65132_VOUT_VMIN,           \
                .uV_step = TPS65132_VOUT_STEP,          \
                .enable_time = 500,                     \
                .vsel_mask = TPS65132_VOUT_MASK,        \
                .vsel_reg = TPS65132_REG_##_id,         \
                .active_discharge_off = 0,                      \
                .active_discharge_on = TPS65132_REG_APPS_DIS_##_id, \
                .active_discharge_mask = TPS65132_REG_APPS_DIS_##_id, \
                .active_discharge_reg = TPS65132_REG_APPS_DISP_DISN, \
                .type = REGULATOR_VOLTAGE,              \
                .owner = THIS_MODULE,                   \
        }

static const struct regulator_desc tps_regs_desc[TPS65132_MAX_REGULATORS] = {
        TPS65132_REGULATOR_DESC(VPOS, outp),
        TPS65132_REGULATOR_DESC(VNEG, outn),
};

static const struct regmap_range tps65132_no_reg_ranges[] = {
        regmap_reg_range(TPS65132_REG_APPS_DISP_DISN + 1,
                         TPS65132_REG_CONTROL - 1),
};

static const struct regmap_access_table tps65132_no_reg_table = {
        .no_ranges = tps65132_no_reg_ranges,
        .n_no_ranges = ARRAY_SIZE(tps65132_no_reg_ranges),
};

static const struct regmap_config tps65132_regmap_config = {
        .reg_bits       = 8,
        .val_bits       = 8,
        .max_register   = TPS65132_REG_CONTROL,
        .cache_type     = REGCACHE_NONE,
        .rd_table       = &tps65132_no_reg_table,
        .wr_table       = &tps65132_no_reg_table,
};

static int tps65132_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct tps65132_regulator *tps;
        struct regulator_dev *rdev;
        struct regmap *rmap;
        struct regulator_config config = { };
        int id;
        int ret;

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

        rmap = devm_regmap_init_i2c(client, &tps65132_regmap_config);
        if (IS_ERR(rmap)) {
                ret = PTR_ERR(rmap);
                dev_err(dev, "regmap init failed: %d\n", ret);
                return ret;
        }

        i2c_set_clientdata(client, tps);
        tps->dev = dev;

        for (id = 0; id < TPS65132_MAX_REGULATORS; ++id) {
                config.regmap = rmap;
                config.dev = dev;
                config.driver_data = tps;

                rdev = devm_regulator_register(dev, &tps_regs_desc[id],
                                               &config);
                if (IS_ERR(rdev)) {
                        ret = PTR_ERR(rdev);
                        dev_err(dev, "regulator %s register failed: %d\n",
                                tps_regs_desc[id].name, ret);
                        return ret;
                }
        }
        return 0;
}

static const struct i2c_device_id tps65132_id[] = {
        {.name = "tps65132",},
        {},
};
MODULE_DEVICE_TABLE(i2c, tps65132_id);

static const struct of_device_id __maybe_unused tps65132_of_match[] = {
        { .compatible = "ti,tps65132" },
        {},
};
MODULE_DEVICE_TABLE(of, tps65132_of_match);

static struct i2c_driver tps65132_i2c_driver = {
        .driver = {
                .name = "tps65132",
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .of_match_table = of_match_ptr(tps65132_of_match),
        },
        .probe = tps65132_probe,
        .id_table = tps65132_id,
};

module_i2c_driver(tps65132_i2c_driver);

MODULE_DESCRIPTION("tps65132 regulator driver");
MODULE_AUTHOR("Venkat Reddy Talla <vreddytalla@nvidia.com>");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL v2");