/*
 * tps62360.c -- TI tps62360
 *
 * Driver for processor core supply tps62360, tps62361B, tps62362 and tps62363.
 *
 * Copyright (c) 2012, NVIDIA Corporation.
 *
 * Author: 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 version 2.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307, USA
 */

#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/of_gpio.h>
#include <linux/regulator/of_regulator.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/tps62360.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/regmap.h>

/* Register definitions */
#define REG_VSET0               0
#define REG_VSET1               1
#define REG_VSET2               2
#define REG_VSET3               3
#define REG_CONTROL             4
#define REG_TEMP                5
#define REG_RAMPCTRL            6
#define REG_CHIPID              8

#define FORCE_PWM_ENABLE        BIT(7)

enum chips {TPS62360, TPS62361, TPS62362, TPS62363};

#define TPS62360_BASE_VOLTAGE   770000
#define TPS62360_N_VOLTAGES     64

#define TPS62361_BASE_VOLTAGE   500000
#define TPS62361_N_VOLTAGES     128

/* tps 62360 chip information */
struct tps62360_chip {
        struct device *dev;
        struct regulator_desc desc;
        struct regulator_dev *rdev;
        struct regmap *regmap;
        int vsel0_gpio;
        int vsel1_gpio;
        u8 voltage_reg_mask;
        bool en_internal_pulldn;
        bool en_discharge;
        bool valid_gpios;
        int lru_index[4];
        int curr_vset_vsel[4];
        int curr_vset_id;
};

/*
 * find_voltage_set_register: Find new voltage configuration register
 * (VSET) id.
 * The finding of the new VSET register will be based on the LRU mechanism.
 * Each VSET register will have different voltage configured . This
 * Function will look if any of the VSET 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 VSET register but need to set the proper gpios to select this
 *       VSET register.
 *     - If requested voltage is not found then it will use the least
 *       recently mechanism to get new VSET register for new configuration
 *       and will return not_found so that caller need to set new VSET
 *       register and then gpios (both).
 */
static bool find_voltage_set_register(struct tps62360_chip *tps,
                int req_vsel, int *vset_reg_id)
{
        int i;
        bool found = false;
        int new_vset_reg = tps->lru_index[3];
        int found_index = 3;

        for (i = 0; i < 4; ++i) {
                if (tps->curr_vset_vsel[tps->lru_index[i]] == req_vsel) {
                        new_vset_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_vset_reg;
        *vset_reg_id = new_vset_reg;
        return found;
}

static int tps62360_dcdc_get_voltage_sel(struct regulator_dev *dev)
{
        struct tps62360_chip *tps = rdev_get_drvdata(dev);
        int vsel;
        unsigned int data;
        int ret;

        ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
        if (ret < 0) {
                dev_err(tps->dev, "%s(): register %d read failed with err %d\n",
                        __func__, REG_VSET0 + tps->curr_vset_id, ret);
                return ret;
        }
        vsel = (int)data & tps->voltage_reg_mask;
        return vsel;
}

static int tps62360_dcdc_set_voltage_sel(struct regulator_dev *dev,
                                         unsigned selector)
{
        struct tps62360_chip *tps = rdev_get_drvdata(dev);
        int ret;
        bool found = false;
        int new_vset_id = tps->curr_vset_id;

        /*
         * If gpios are available to select the VSET register then least
         * recently used register for new configuration.
         */
        if (tps->valid_gpios)
                found = find_voltage_set_register(tps, selector, &new_vset_id);

        if (!found) {
                ret = regmap_update_bits(tps->regmap, REG_VSET0 + new_vset_id,
                                tps->voltage_reg_mask, selector);
                if (ret < 0) {
                        dev_err(tps->dev,
                                "%s(): register %d update failed with err %d\n",
                                 __func__, REG_VSET0 + new_vset_id, ret);
                        return ret;
                }
                tps->curr_vset_id = new_vset_id;
                tps->curr_vset_vsel[new_vset_id] = selector;
        }

        /* Select proper VSET register vio gpios */
        if (tps->valid_gpios) {
                gpio_set_value_cansleep(tps->vsel0_gpio, new_vset_id & 0x1);
                gpio_set_value_cansleep(tps->vsel1_gpio,
                                        (new_vset_id >> 1) & 0x1);
        }
        return 0;
}

static int tps62360_set_mode(struct regulator_dev *rdev, unsigned int mode)
{
        struct tps62360_chip *tps = rdev_get_drvdata(rdev);
        int i;
        int val;
        int ret;

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

        case REGULATOR_MODE_NORMAL:
                val = 0;
                break;

        default:
                return -EINVAL;
        }

        if (!tps->valid_gpios) {
                ret = regmap_update_bits(tps->regmap,
                        REG_VSET0 + tps->curr_vset_id, FORCE_PWM_ENABLE, val);
                if (ret < 0)
                        dev_err(tps->dev,
                                "%s(): register %d update failed with err %d\n",
                                __func__, REG_VSET0 + tps->curr_vset_id, ret);
                return ret;
        }

        /* If gpios are valid then all register set need to be control */
        for (i = 0; i < 4; ++i) {
                ret = regmap_update_bits(tps->regmap,
                                        REG_VSET0 + i, FORCE_PWM_ENABLE, val);
                if (ret < 0) {
                        dev_err(tps->dev,
                                "%s(): register %d update failed with err %d\n",
                                __func__, REG_VSET0 + i, ret);
                        return ret;
                }
        }
        return ret;
}

static unsigned int tps62360_get_mode(struct regulator_dev *rdev)
{
        struct tps62360_chip *tps = rdev_get_drvdata(rdev);
        unsigned int data;
        int ret;

        ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
        if (ret < 0) {
                dev_err(tps->dev, "%s(): register %d read failed with err %d\n",
                        __func__, REG_VSET0 + tps->curr_vset_id, ret);
                return ret;
        }
        return (data & FORCE_PWM_ENABLE) ?
                                REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL;
}

static const struct regulator_ops tps62360_dcdc_ops = {
        .get_voltage_sel        = tps62360_dcdc_get_voltage_sel,
        .set_voltage_sel        = tps62360_dcdc_set_voltage_sel,
        .list_voltage           = regulator_list_voltage_linear,
        .map_voltage            = regulator_map_voltage_linear,
        .set_voltage_time_sel   = regulator_set_voltage_time_sel,
        .set_mode               = tps62360_set_mode,
        .get_mode               = tps62360_get_mode,
};

static int tps62360_init_dcdc(struct tps62360_chip *tps,
                struct tps62360_regulator_platform_data *pdata)
{
        int ret;
        unsigned int ramp_ctrl;

        /* Initialize internal pull up/down control */
        if (tps->en_internal_pulldn)
                ret = regmap_write(tps->regmap, REG_CONTROL, 0xE0);
        else
                ret = regmap_write(tps->regmap, REG_CONTROL, 0x0);
        if (ret < 0) {
                dev_err(tps->dev,
                        "%s(): register %d write failed with err %d\n",
                        __func__, REG_CONTROL, ret);
                return ret;
        }

        /* Reset output discharge path to reduce power consumption */
        ret = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), 0);
        if (ret < 0) {
                dev_err(tps->dev,
                        "%s(): register %d update failed with err %d\n",
                        __func__, REG_RAMPCTRL, ret);
                return ret;
        }

        /* Get ramp value from ramp control register */
        ret = regmap_read(tps->regmap, REG_RAMPCTRL, &ramp_ctrl);
        if (ret < 0) {
                dev_err(tps->dev,
                        "%s(): register %d read failed with err %d\n",
                        __func__, REG_RAMPCTRL, ret);
                return ret;
        }
        ramp_ctrl = (ramp_ctrl >> 5) & 0x7;

        /* ramp mV/us = 32/(2^ramp_ctrl) */
        tps->desc.ramp_delay = DIV_ROUND_UP(32000, BIT(ramp_ctrl));
        return ret;
}

static const struct regmap_config tps62360_regmap_config = {
        .reg_bits               = 8,
        .val_bits               = 8,
        .max_register           = REG_CHIPID,
        .cache_type             = REGCACHE_RBTREE,
};

static struct tps62360_regulator_platform_data *
        of_get_tps62360_platform_data(struct device *dev,
                                      const struct regulator_desc *desc)
{
        struct tps62360_regulator_platform_data *pdata;
        struct device_node *np = dev->of_node;

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

        pdata->reg_init_data = of_get_regulator_init_data(dev, dev->of_node,
                                                          desc);
        if (!pdata->reg_init_data) {
                dev_err(dev, "Not able to get OF regulator init data\n");
                return NULL;
        }

        pdata->vsel0_gpio = of_get_named_gpio(np, "vsel0-gpio", 0);
        pdata->vsel1_gpio = of_get_named_gpio(np, "vsel1-gpio", 0);

        if (of_find_property(np, "ti,vsel0-state-high", NULL))
                pdata->vsel0_def_state = 1;

        if (of_find_property(np, "ti,vsel1-state-high", NULL))
                pdata->vsel1_def_state = 1;

        if (of_find_property(np, "ti,enable-pull-down", NULL))
                pdata->en_internal_pulldn = true;

        if (of_find_property(np, "ti,enable-vout-discharge", NULL))
                pdata->en_discharge = true;

        return pdata;
}

#if defined(CONFIG_OF)
static const struct of_device_id tps62360_of_match[] = {
         { .compatible = "ti,tps62360", .data = (void *)TPS62360},
         { .compatible = "ti,tps62361", .data = (void *)TPS62361},
         { .compatible = "ti,tps62362", .data = (void *)TPS62362},
         { .compatible = "ti,tps62363", .data = (void *)TPS62363},
        {},
};
MODULE_DEVICE_TABLE(of, tps62360_of_match);
#endif

static int tps62360_probe(struct i2c_client *client,
                                     const struct i2c_device_id *id)
{
        struct regulator_config config = { };
        struct tps62360_regulator_platform_data *pdata;
        struct regulator_dev *rdev;
        struct tps62360_chip *tps;
        int ret;
        int i;
        int chip_id;

        pdata = dev_get_platdata(&client->dev);

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

        tps->desc.name = client->name;
        tps->desc.id = 0;
        tps->desc.ops = &tps62360_dcdc_ops;
        tps->desc.type = REGULATOR_VOLTAGE;
        tps->desc.owner = THIS_MODULE;
        tps->desc.uV_step = 10000;

        if (client->dev.of_node) {
                const struct of_device_id *match;
                match = of_match_device(of_match_ptr(tps62360_of_match),
                                &client->dev);
                if (!match) {
                        dev_err(&client->dev, "Error: No device match found\n");
                        return -ENODEV;
                }
                chip_id = (int)(long)match->data;
                if (!pdata)
                        pdata = of_get_tps62360_platform_data(&client->dev,
                                                              &tps->desc);
        } else if (id) {
                chip_id = id->driver_data;
        } else {
                dev_err(&client->dev, "No device tree match or id table match found\n");
                return -ENODEV;
        }

        if (!pdata) {
                dev_err(&client->dev, "%s(): Platform data not found\n",
                                                __func__);
                return -EIO;
        }

        tps->en_discharge = pdata->en_discharge;
        tps->en_internal_pulldn = pdata->en_internal_pulldn;
        tps->vsel0_gpio = pdata->vsel0_gpio;
        tps->vsel1_gpio = pdata->vsel1_gpio;
        tps->dev = &client->dev;

        switch (chip_id) {
        case TPS62360:
        case TPS62362:
                tps->desc.min_uV = TPS62360_BASE_VOLTAGE;
                tps->voltage_reg_mask = 0x3F;
                tps->desc.n_voltages = TPS62360_N_VOLTAGES;
                break;
        case TPS62361:
        case TPS62363:
                tps->desc.min_uV = TPS62361_BASE_VOLTAGE;
                tps->voltage_reg_mask = 0x7F;
                tps->desc.n_voltages = TPS62361_N_VOLTAGES;
                break;
        default:
                return -ENODEV;
        }

        tps->regmap = devm_regmap_init_i2c(client, &tps62360_regmap_config);
        if (IS_ERR(tps->regmap)) {
                ret = PTR_ERR(tps->regmap);
                dev_err(&client->dev,
                        "%s(): regmap allocation failed with err %d\n",
                        __func__, ret);
                return ret;
        }
        i2c_set_clientdata(client, tps);

        tps->curr_vset_id = (pdata->vsel1_def_state & 1) * 2 +
                                (pdata->vsel0_def_state & 1);
        tps->lru_index[0] = tps->curr_vset_id;
        tps->valid_gpios = false;

        if (gpio_is_valid(tps->vsel0_gpio) && gpio_is_valid(tps->vsel1_gpio)) {
                int gpio_flags;
                gpio_flags = (pdata->vsel0_def_state) ?
                                GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
                ret = devm_gpio_request_one(&client->dev, tps->vsel0_gpio,
                                gpio_flags, "tps62360-vsel0");
                if (ret) {
                        dev_err(&client->dev,
                                "%s(): Could not obtain vsel0 GPIO %d: %d\n",
                                __func__, tps->vsel0_gpio, ret);
                        return ret;
                }

                gpio_flags = (pdata->vsel1_def_state) ?
                                GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
                ret = devm_gpio_request_one(&client->dev, tps->vsel1_gpio,
                                gpio_flags, "tps62360-vsel1");
                if (ret) {
                        dev_err(&client->dev,
                                "%s(): Could not obtain vsel1 GPIO %d: %d\n",
                                __func__, tps->vsel1_gpio, ret);
                        return ret;
                }
                tps->valid_gpios = true;

                /*
                 * Initialize the lru index with vset_reg id
                 * The index 0 will be most recently used and
                 * set with the tps->curr_vset_id */
                for (i = 0; i < 4; ++i)
                        tps->lru_index[i] = i;
                tps->lru_index[0] = tps->curr_vset_id;
                tps->lru_index[tps->curr_vset_id] = 0;
        }

        ret = tps62360_init_dcdc(tps, pdata);
        if (ret < 0) {
                dev_err(tps->dev, "%s(): Init failed with err = %d\n",
                                __func__, ret);
                return ret;
        }

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

        /* Register the regulators */
        rdev = devm_regulator_register(&client->dev, &tps->desc, &config);
        if (IS_ERR(rdev)) {
                dev_err(tps->dev,
                        "%s(): regulator register failed with err %s\n",
                        __func__, id->name);
                return PTR_ERR(rdev);
        }

        tps->rdev = rdev;
        return 0;
}

static void tps62360_shutdown(struct i2c_client *client)
{
        struct tps62360_chip *tps = i2c_get_clientdata(client);
        int st;

        if (!tps->en_discharge)
                return;

        /* Configure the output discharge path */
        st = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), BIT(2));
        if (st < 0)
                dev_err(tps->dev,
                        "%s(): register %d update failed with err %d\n",
                        __func__, REG_RAMPCTRL, st);
}

static const struct i2c_device_id tps62360_id[] = {
        {.name = "tps62360", .driver_data = TPS62360},
        {.name = "tps62361", .driver_data = TPS62361},
        {.name = "tps62362", .driver_data = TPS62362},
        {.name = "tps62363", .driver_data = TPS62363},
        {},
};

MODULE_DEVICE_TABLE(i2c, tps62360_id);

static struct i2c_driver tps62360_i2c_driver = {
        .driver = {
                .name = "tps62360",
                .of_match_table = of_match_ptr(tps62360_of_match),
        },
        .probe = tps62360_probe,
        .shutdown = tps62360_shutdown,
        .id_table = tps62360_id,
};

static int __init tps62360_init(void)
{
        return i2c_add_driver(&tps62360_i2c_driver);
}
subsys_initcall(tps62360_init);

static void __exit tps62360_cleanup(void)
{
        i2c_del_driver(&tps62360_i2c_driver);
}
module_exit(tps62360_cleanup);

MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("TPS6236x voltage regulator driver");
MODULE_LICENSE("GPL v2");