max8952.c

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/*
 * max8952.c - Voltage and current regulation for the Maxim 8952
 *
 * Copyright (C) 2010 Samsung Electronics
 * MyungJoo Ham <[email protected]>
 *
 * 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 in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; 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/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/max8952.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/slab.h>

/* Registers */
enum {
    MAX8952_REG_MODE0,
    MAX8952_REG_MODE1,
    MAX8952_REG_MODE2,
    MAX8952_REG_MODE3,
    MAX8952_REG_CONTROL,
    MAX8952_REG_SYNC,
    MAX8952_REG_RAMP,
    MAX8952_REG_CHIP_ID1,
    MAX8952_REG_CHIP_ID2,
};

struct max8952_data {
    struct i2c_client   *client;
    struct device       *dev;
    struct max8952_platform_data *pdata;
    struct regulator_dev    *rdev;

    bool vid0;
    bool vid1;
};

static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
{
    int ret = i2c_smbus_read_byte_data(max8952->client, reg);
    if (ret > 0)
        ret &= 0xff;

    return ret;
}

static int max8952_write_reg(struct max8952_data *max8952,
        u8 reg, u8 value)
{
    return i2c_smbus_write_byte_data(max8952->client, reg, value);
}

static int max8952_list_voltage(struct regulator_dev *rdev,
        unsigned int selector)
{
    struct max8952_data *max8952 = rdev_get_drvdata(rdev);

    if (rdev_get_id(rdev) != 0)
        return -EINVAL;

    return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
}

static int max8952_get_voltage_sel(struct regulator_dev *rdev)
{
    struct max8952_data *max8952 = rdev_get_drvdata(rdev);
    u8 vid = 0;

    if (max8952->vid0)
        vid += 1;
    if (max8952->vid1)
        vid += 2;

    return vid;
}

static int max8952_set_voltage_sel(struct regulator_dev *rdev,
                   unsigned selector)
{
    struct max8952_data *max8952 = rdev_get_drvdata(rdev);

    if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
            !gpio_is_valid(max8952->pdata->gpio_vid1)) {
        /* DVS not supported */
        return -EPERM;
    }

    max8952->vid0 = selector & 0x1;
    max8952->vid1 = (selector >> 1) & 0x1;
    gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
    gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);

    return 0;
}

static struct regulator_ops max8952_ops = {
    .list_voltage       = max8952_list_voltage,
    .get_voltage_sel    = max8952_get_voltage_sel,
    .set_voltage_sel    = max8952_set_voltage_sel,
};

static const struct regulator_desc regulator = {
    .name       = "MAX8952_VOUT",
    .id     = 0,
    .n_voltages = MAX8952_NUM_DVS_MODE,
    .ops        = &max8952_ops,
    .type       = REGULATOR_VOLTAGE,
    .owner      = THIS_MODULE,
};

static int __devinit max8952_pmic_probe(struct i2c_client *client,
        const struct i2c_device_id *i2c_id)
{
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct max8952_platform_data *pdata = client->dev.platform_data;
    struct regulator_config config = { };
    struct max8952_data *max8952;

    int ret = 0, err = 0;

    if (!pdata) {
        dev_err(&client->dev, "Require the platform data\n");
        return -EINVAL;
    }

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
        return -EIO;

    max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
                   GFP_KERNEL);
    if (!max8952)
        return -ENOMEM;

    max8952->client = client;
    max8952->dev = &client->dev;
    max8952->pdata = pdata;

    config.dev = max8952->dev;
    config.init_data = &pdata->reg_data;
    config.driver_data = max8952;

    config.ena_gpio = pdata->gpio_en;
    if (pdata->reg_data.constraints.boot_on)
        config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;

    max8952->rdev = regulator_register(&regulator, &config);

    if (IS_ERR(max8952->rdev)) {
        ret = PTR_ERR(max8952->rdev);
        dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
        return ret;
    }

    max8952->vid0 = pdata->default_mode & 0x1;
    max8952->vid1 = (pdata->default_mode >> 1) & 0x1;

    if (gpio_is_valid(pdata->gpio_vid0) &&
            gpio_is_valid(pdata->gpio_vid1)) {
        if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
            gpio_direction_output(pdata->gpio_vid0,
                    (pdata->default_mode) & 0x1);
        else
            err = 1;

        if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
            gpio_direction_output(pdata->gpio_vid1,
                (pdata->default_mode >> 1) & 0x1);
        else {
            if (!err)
                gpio_free(pdata->gpio_vid0);
            err = 2;
        }

    } else
        err = 3;

    if (err) {
        dev_warn(max8952->dev, "VID0/1 gpio invalid: "
                "DVS not available.\n");
        max8952->vid0 = 0;
        max8952->vid1 = 0;
        /* Mark invalid */
        pdata->gpio_vid0 = -1;
        pdata->gpio_vid1 = -1;

        /* Disable Pulldown of EN only */
        max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);

        dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
                " do not have proper controls.\n");
    } else {
        /*
         * Disable Pulldown on EN, VID0, VID1 to reduce
         * leakage current of MAX8952 assuming that MAX8952
         * is turned on (EN==1). Note that without having VID0/1
         * properly connected, turning pulldown off can be
         * problematic. Thus, turn this off only when they are
         * controllable by GPIO.
         */
        max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
    }

    max8952_write_reg(max8952, MAX8952_REG_MODE0,
            (max8952_read_reg(max8952,
                      MAX8952_REG_MODE0) & 0xC0) |
            (pdata->dvs_mode[0] & 0x3F));
    max8952_write_reg(max8952, MAX8952_REG_MODE1,
            (max8952_read_reg(max8952,
                      MAX8952_REG_MODE1) & 0xC0) |
            (pdata->dvs_mode[1] & 0x3F));
    max8952_write_reg(max8952, MAX8952_REG_MODE2,
            (max8952_read_reg(max8952,
                      MAX8952_REG_MODE2) & 0xC0) |
            (pdata->dvs_mode[2] & 0x3F));
    max8952_write_reg(max8952, MAX8952_REG_MODE3,
            (max8952_read_reg(max8952,
                      MAX8952_REG_MODE3) & 0xC0) |
            (pdata->dvs_mode[3] & 0x3F));

    max8952_write_reg(max8952, MAX8952_REG_SYNC,
            (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
            ((pdata->sync_freq & 0x3) << 6));
    max8952_write_reg(max8952, MAX8952_REG_RAMP,
            (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
            ((pdata->ramp_speed & 0x7) << 5));

    i2c_set_clientdata(client, max8952);

    return 0;
}

static int __devexit max8952_pmic_remove(struct i2c_client *client)
{
    struct max8952_data *max8952 = i2c_get_clientdata(client);
    struct max8952_platform_data *pdata = max8952->pdata;
    struct regulator_dev *rdev = max8952->rdev;

    regulator_unregister(rdev);

    gpio_free(pdata->gpio_vid0);
    gpio_free(pdata->gpio_vid1);
    return 0;
}

static const struct i2c_device_id max8952_ids[] = {
    { "max8952", 0 },
    { },
};
MODULE_DEVICE_TABLE(i2c, max8952_ids);

static struct i2c_driver max8952_pmic_driver = {
    .probe      = max8952_pmic_probe,
    .remove     = __devexit_p(max8952_pmic_remove),
    .driver     = {
        .name   = "max8952",
    },
    .id_table   = max8952_ids,
};

static int __init max8952_pmic_init(void)
{
    return i2c_add_driver(&max8952_pmic_driver);
}
subsys_initcall(max8952_pmic_init);

static void __exit max8952_pmic_exit(void)
{
    i2c_del_driver(&max8952_pmic_driver);
}
module_exit(max8952_pmic_exit);

MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
MODULE_AUTHOR("MyungJoo Ham <[email protected]>");
MODULE_LICENSE("GPL");