/*
 * isl6271a-regulator.c
 *
 * Support for Intersil ISL6271A voltage regulator
 *
 * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/slab.h>

#define ISL6271A_VOLTAGE_MIN    850000
#define ISL6271A_VOLTAGE_MAX    1600000
#define ISL6271A_VOLTAGE_STEP   50000

/* PMIC details */
struct isl_pmic {
        struct i2c_client       *client;
        struct regulator_dev    *rdev[3];
        struct mutex            mtx;
};

static int isl6271a_get_voltage(struct regulator_dev *dev)
{
        struct isl_pmic *pmic = rdev_get_drvdata(dev);
        int idx, data;

        mutex_lock(&pmic->mtx);

        idx = i2c_smbus_read_byte(pmic->client);
        if (idx < 0) {
                dev_err(&pmic->client->dev, "Error getting voltage\n");
                data = idx;
                goto out;
        }

        /* Convert the data from chip to microvolts */
        data = ISL6271A_VOLTAGE_MIN + (ISL6271A_VOLTAGE_STEP * (idx & 0xf));

out:
        mutex_unlock(&pmic->mtx);
        return data;
}

static int isl6271a_set_voltage(struct regulator_dev *dev,
                                int minuV, int maxuV,
                                unsigned *selector)
{
        struct isl_pmic *pmic = rdev_get_drvdata(dev);
        int vsel, err, data;

        if (minuV < ISL6271A_VOLTAGE_MIN || minuV > ISL6271A_VOLTAGE_MAX)
                return -EINVAL;
        if (maxuV < ISL6271A_VOLTAGE_MIN || maxuV > ISL6271A_VOLTAGE_MAX)
                return -EINVAL;

        /* Align to 50000 mV */
        vsel = minuV - (minuV % ISL6271A_VOLTAGE_STEP);

        /* If the result fell out of [minuV,maxuV] range, put it back */
        if (vsel < minuV)
                vsel += ISL6271A_VOLTAGE_STEP;

        /* Convert the microvolts to data for the chip */
        data = (vsel - ISL6271A_VOLTAGE_MIN) / ISL6271A_VOLTAGE_STEP;

        *selector = data;

        mutex_lock(&pmic->mtx);

        err = i2c_smbus_write_byte(pmic->client, data);
        if (err < 0)
                dev_err(&pmic->client->dev, "Error setting voltage\n");

        mutex_unlock(&pmic->mtx);
        return err;
}

static int isl6271a_list_voltage(struct regulator_dev *dev, unsigned selector)
{
        return ISL6271A_VOLTAGE_MIN + (ISL6271A_VOLTAGE_STEP * selector);
}

static struct regulator_ops isl_core_ops = {
        .get_voltage    = isl6271a_get_voltage,
        .set_voltage    = isl6271a_set_voltage,
        .list_voltage   = isl6271a_list_voltage,
};

static int isl6271a_get_fixed_voltage(struct regulator_dev *dev)
{
        int id = rdev_get_id(dev);
        return (id == 1) ? 1100000 : 1300000;
}

static int isl6271a_list_fixed_voltage(struct regulator_dev *dev, unsigned selector)
{
        int id = rdev_get_id(dev);
        return (id == 1) ? 1100000 : 1300000;
}

static struct regulator_ops isl_fixed_ops = {
        .get_voltage    = isl6271a_get_fixed_voltage,
        .list_voltage   = isl6271a_list_fixed_voltage,
};

static struct regulator_desc isl_rd[] = {
        {
                .name           = "Core Buck",
                .id             = 0,
                .n_voltages     = 16,
                .ops            = &isl_core_ops,
                .type           = REGULATOR_VOLTAGE,
                .owner          = THIS_MODULE,
        }, {
                .name           = "LDO1",
                .id             = 1,
                .n_voltages     = 1,
                .ops            = &isl_fixed_ops,
                .type           = REGULATOR_VOLTAGE,
                .owner          = THIS_MODULE,
        }, {
                .name           = "LDO2",
                .id             = 2,
                .n_voltages     = 1,
                .ops            = &isl_fixed_ops,
                .type           = REGULATOR_VOLTAGE,
                .owner          = THIS_MODULE,
        },
};

static int __devinit isl6271a_probe(struct i2c_client *i2c,
                                     const struct i2c_device_id *id)
{
        struct regulator_init_data *init_data   = i2c->dev.platform_data;
        struct isl_pmic *pmic;
        int err, i;

        if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -EIO;

        if (!init_data) {
                dev_err(&i2c->dev, "no platform data supplied\n");
                return -EIO;
        }

        pmic = kzalloc(sizeof(struct isl_pmic), GFP_KERNEL);
        if (!pmic)
                return -ENOMEM;

        pmic->client = i2c;

        mutex_init(&pmic->mtx);

        for (i = 0; i < 3; i++) {
                pmic->rdev[i] = regulator_register(&isl_rd[i], &i2c->dev,
                                                init_data, pmic);
                if (IS_ERR(pmic->rdev[i])) {
                        dev_err(&i2c->dev, "failed to register %s\n", id->name);
                        err = PTR_ERR(pmic->rdev[i]);
                        goto error;
                }
        }

        i2c_set_clientdata(i2c, pmic);

        return 0;

error:
        while (--i >= 0)
                regulator_unregister(pmic->rdev[i]);

        kfree(pmic);
        return err;
}

static int __devexit isl6271a_remove(struct i2c_client *i2c)
{
        struct isl_pmic *pmic = i2c_get_clientdata(i2c);
        int i;

        for (i = 0; i < 3; i++)
                regulator_unregister(pmic->rdev[i]);

        kfree(pmic);

        return 0;
}

static const struct i2c_device_id isl6271a_id[] = {
        {.name = "isl6271a", 0 },
        { },
};

MODULE_DEVICE_TABLE(i2c, isl6271a_id);

static struct i2c_driver isl6271a_i2c_driver = {
        .driver = {
                .name = "isl6271a",
                .owner = THIS_MODULE,
        },
        .probe = isl6271a_probe,
        .remove = __devexit_p(isl6271a_remove),
        .id_table = isl6271a_id,
};

static int __init isl6271a_init(void)
{
        return i2c_add_driver(&isl6271a_i2c_driver);
}

static void __exit isl6271a_cleanup(void)
{
        i2c_del_driver(&isl6271a_i2c_driver);
}

subsys_initcall(isl6271a_init);
module_exit(isl6271a_cleanup);

MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION("Intersil ISL6271A voltage regulator driver");
MODULE_LICENSE("GPL v2");