/*
* Copyright (C) 2012 Invensense, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*/

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include "inv_mpu_iio.h"

static const struct regmap_config inv_mpu_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
};

/*
 * The i2c read/write needs to happen in unlocked mode. As the parent
 * adapter is common. If we use locked versions, it will fail as
 * the mux adapter will lock the parent i2c adapter, while calling
 * select/deselect functions.
 */
static int inv_mpu6050_write_reg_unlocked(struct i2c_client *client,
                                          u8 reg, u8 d)
{
        int ret;
        u8 buf[2] = {reg, d};
        struct i2c_msg msg[1] = {
                {
                        .addr = client->addr,
                        .flags = 0,
                        .len = sizeof(buf),
                        .buf = buf,
                }
        };

        ret = __i2c_transfer(client->adapter, msg, 1);
        if (ret != 1)
                return ret;

        return 0;
}

static int inv_mpu6050_select_bypass(struct i2c_adapter *adap, void *mux_priv,
                                     u32 chan_id)
{
        struct i2c_client *client = mux_priv;
        struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
        struct inv_mpu6050_state *st = iio_priv(indio_dev);
        int ret = 0;

        /* Use the same mutex which was used everywhere to protect power-op */
        mutex_lock(&indio_dev->mlock);
        if (!st->powerup_count) {
                ret = inv_mpu6050_write_reg_unlocked(client,
                                                     st->reg->pwr_mgmt_1, 0);
                if (ret)
                        goto write_error;

                usleep_range(INV_MPU6050_REG_UP_TIME_MIN,
                             INV_MPU6050_REG_UP_TIME_MAX);
        }
        if (!ret) {
                st->powerup_count++;
                ret = inv_mpu6050_write_reg_unlocked(client,
                                                     st->reg->int_pin_cfg,
                                                     INV_MPU6050_INT_PIN_CFG |
                                                     INV_MPU6050_BIT_BYPASS_EN);
        }
write_error:
        mutex_unlock(&indio_dev->mlock);

        return ret;
}

static int inv_mpu6050_deselect_bypass(struct i2c_adapter *adap,
                                       void *mux_priv, u32 chan_id)
{
        struct i2c_client *client = mux_priv;
        struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
        struct inv_mpu6050_state *st = iio_priv(indio_dev);

        mutex_lock(&indio_dev->mlock);
        /* It doesn't really mattter, if any of the calls fails */
        inv_mpu6050_write_reg_unlocked(client, st->reg->int_pin_cfg,
                                       INV_MPU6050_INT_PIN_CFG);
        st->powerup_count--;
        if (!st->powerup_count)
                inv_mpu6050_write_reg_unlocked(client, st->reg->pwr_mgmt_1,
                                               INV_MPU6050_BIT_SLEEP);
        mutex_unlock(&indio_dev->mlock);

        return 0;
}

static const char *inv_mpu_match_acpi_device(struct device *dev, int *chip_id)
{
        const struct acpi_device_id *id;

        id = acpi_match_device(dev->driver->acpi_match_table, dev);
        if (!id)
                return NULL;

        *chip_id = (int)id->driver_data;

        return dev_name(dev);
}

/**
 *  inv_mpu_probe() - probe function.
 *  @client:          i2c client.
 *  @id:              i2c device id.
 *
 *  Returns 0 on success, a negative error code otherwise.
 */
static int inv_mpu_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct inv_mpu6050_state *st;
        int result, chip_type;
        struct regmap *regmap;
        const char *name;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_I2C_BLOCK))
                return -EOPNOTSUPP;

        if (id) {
                chip_type = (int)id->driver_data;
                name = id->name;
        } else if (ACPI_HANDLE(&client->dev)) {
                name = inv_mpu_match_acpi_device(&client->dev, &chip_type);
                if (!name)
                        return -ENODEV;
        } else {
                return -ENOSYS;
        }

        regmap = devm_regmap_init_i2c(client, &inv_mpu_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "Failed to register i2c regmap %d\n",
                        (int)PTR_ERR(regmap));
                return PTR_ERR(regmap);
        }

        result = inv_mpu_core_probe(regmap, client->irq, name,
                                    NULL, chip_type);
        if (result < 0)
                return result;

        st = iio_priv(dev_get_drvdata(&client->dev));
        st->mux_adapter = i2c_add_mux_adapter(client->adapter,
                                              &client->dev,
                                              client,
                                              0, 0, 0,
                                              inv_mpu6050_select_bypass,
                                              inv_mpu6050_deselect_bypass);
        if (!st->mux_adapter) {
                result = -ENODEV;
                goto out_unreg_device;
        }

        result = inv_mpu_acpi_create_mux_client(client);
        if (result)
                goto out_del_mux;

        return 0;

out_del_mux:
        i2c_del_mux_adapter(st->mux_adapter);
out_unreg_device:
        inv_mpu_core_remove(&client->dev);
        return result;
}

static int inv_mpu_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct inv_mpu6050_state *st = iio_priv(indio_dev);

        inv_mpu_acpi_delete_mux_client(client);
        i2c_del_mux_adapter(st->mux_adapter);

        return inv_mpu_core_remove(&client->dev);
}

/*
 * device id table is used to identify what device can be
 * supported by this driver
 */
static const struct i2c_device_id inv_mpu_id[] = {
        {"mpu6050", INV_MPU6050},
        {"mpu6500", INV_MPU6500},
        {}
};

MODULE_DEVICE_TABLE(i2c, inv_mpu_id);

static const struct acpi_device_id inv_acpi_match[] = {
        {"INVN6500", 0},
        { },
};

MODULE_DEVICE_TABLE(acpi, inv_acpi_match);

static struct i2c_driver inv_mpu_driver = {
        .probe          =       inv_mpu_probe,
        .remove         =       inv_mpu_remove,
        .id_table       =       inv_mpu_id,
        .driver = {
                .acpi_match_table = ACPI_PTR(inv_acpi_match),
                .name   =       "inv-mpu6050-i2c",
                .pm     =       &inv_mpu_pmops,
        },
};

module_i2c_driver(inv_mpu_driver);

MODULE_AUTHOR("Invensense Corporation");
MODULE_DESCRIPTION("Invensense device MPU6050 driver");
MODULE_LICENSE("GPL");