/*
* 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/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/sysfs.h>
#include <linux/jiffies.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/kfifo.h>
#include <linux/spinlock.h>
#include <linux/iio/iio.h>
#include <linux/i2c-mux.h>
#include <linux/acpi.h>
#include "inv_mpu_iio.h"

/*
 * this is the gyro scale translated from dynamic range plus/minus
 * {250, 500, 1000, 2000} to rad/s
 */
static const int gyro_scale_6050[] = {133090, 266181, 532362, 1064724};

/*
 * this is the accel scale translated from dynamic range plus/minus
 * {2, 4, 8, 16} to m/s^2
 */
static const int accel_scale[] = {598, 1196, 2392, 4785};

static const struct inv_mpu6050_reg_map reg_set_6050 = {
        .sample_rate_div        = INV_MPU6050_REG_SAMPLE_RATE_DIV,
        .lpf                    = INV_MPU6050_REG_CONFIG,
        .user_ctrl              = INV_MPU6050_REG_USER_CTRL,
        .fifo_en                = INV_MPU6050_REG_FIFO_EN,
        .gyro_config            = INV_MPU6050_REG_GYRO_CONFIG,
        .accl_config            = INV_MPU6050_REG_ACCEL_CONFIG,
        .fifo_count_h           = INV_MPU6050_REG_FIFO_COUNT_H,
        .fifo_r_w               = INV_MPU6050_REG_FIFO_R_W,
        .raw_gyro               = INV_MPU6050_REG_RAW_GYRO,
        .raw_accl               = INV_MPU6050_REG_RAW_ACCEL,
        .temperature            = INV_MPU6050_REG_TEMPERATURE,
        .int_enable             = INV_MPU6050_REG_INT_ENABLE,
        .pwr_mgmt_1             = INV_MPU6050_REG_PWR_MGMT_1,
        .pwr_mgmt_2             = INV_MPU6050_REG_PWR_MGMT_2,
        .int_pin_cfg            = INV_MPU6050_REG_INT_PIN_CFG,
};

static const struct inv_mpu6050_chip_config chip_config_6050 = {
        .fsr = INV_MPU6050_FSR_2000DPS,
        .lpf = INV_MPU6050_FILTER_20HZ,
        .fifo_rate = INV_MPU6050_INIT_FIFO_RATE,
        .gyro_fifo_enable = false,
        .accl_fifo_enable = false,
        .accl_fs = INV_MPU6050_FS_02G,
};

static const struct inv_mpu6050_hw hw_info[INV_NUM_PARTS] = {
        {
                .num_reg = 117,
                .name = "MPU6050",
                .reg = &reg_set_6050,
                .config = &chip_config_6050,
        },
};

int inv_mpu6050_write_reg(struct inv_mpu6050_state *st, int reg, u8 d)
{
        return i2c_smbus_write_i2c_block_data(st->client, reg, 1, &d);
}

/*
 * 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 inv_mpu6050_state *st,
                                          u8 reg, u8 d)
{
        int ret;
        u8 buf[2];
        struct i2c_msg msg[1] = {
                {
                        .addr = st->client->addr,
                        .flags = 0,
                        .len = sizeof(buf),
                        .buf = buf,
                }
        };

        buf[0] = reg;
        buf[1] = d;
        ret = __i2c_transfer(st->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 iio_dev *indio_dev = mux_priv;
        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(st, st->reg->pwr_mgmt_1,
                                                     0);
                if (ret)
                        goto write_error;

                msleep(INV_MPU6050_REG_UP_TIME);
        }
        if (!ret) {
                st->powerup_count++;
                ret = inv_mpu6050_write_reg_unlocked(st, st->reg->int_pin_cfg,
                                                     st->client->irq |
                                                     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 iio_dev *indio_dev = mux_priv;
        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(st, st->reg->int_pin_cfg,
                                       st->client->irq);
        st->powerup_count--;
        if (!st->powerup_count)
                inv_mpu6050_write_reg_unlocked(st, st->reg->pwr_mgmt_1,
                                               INV_MPU6050_BIT_SLEEP);
        mutex_unlock(&indio_dev->mlock);

        return 0;
}

int inv_mpu6050_switch_engine(struct inv_mpu6050_state *st, bool en, u32 mask)
{
        u8 d, mgmt_1;
        int result;

        /* switch clock needs to be careful. Only when gyro is on, can
           clock source be switched to gyro. Otherwise, it must be set to
           internal clock */
        if (INV_MPU6050_BIT_PWR_GYRO_STBY == mask) {
                result = i2c_smbus_read_i2c_block_data(st->client,
                                       st->reg->pwr_mgmt_1, 1, &mgmt_1);
                if (result != 1)
                        return result;

                mgmt_1 &= ~INV_MPU6050_BIT_CLK_MASK;
        }

        if ((INV_MPU6050_BIT_PWR_GYRO_STBY == mask) && (!en)) {
                /* turning off gyro requires switch to internal clock first.
                   Then turn off gyro engine */
                mgmt_1 |= INV_CLK_INTERNAL;
                result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1, mgmt_1);
                if (result)
                        return result;
        }

        result = i2c_smbus_read_i2c_block_data(st->client,
                                       st->reg->pwr_mgmt_2, 1, &d);
        if (result != 1)
                return result;
        if (en)
                d &= ~mask;
        else
                d |= mask;
        result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_2, d);
        if (result)
                return result;

        if (en) {
                /* Wait for output stabilize */
                msleep(INV_MPU6050_TEMP_UP_TIME);
                if (INV_MPU6050_BIT_PWR_GYRO_STBY == mask) {
                        /* switch internal clock to PLL */
                        mgmt_1 |= INV_CLK_PLL;
                        result = inv_mpu6050_write_reg(st,
                                        st->reg->pwr_mgmt_1, mgmt_1);
                        if (result)
                                return result;
                }
        }

        return 0;
}

int inv_mpu6050_set_power_itg(struct inv_mpu6050_state *st, bool power_on)
{
        int result = 0;

        if (power_on) {
                /* Already under indio-dev->mlock mutex */
                if (!st->powerup_count)
                        result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1,
                                                       0);
                if (!result)
                        st->powerup_count++;
        } else {
                st->powerup_count--;
                if (!st->powerup_count)
                        result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1,
                                                       INV_MPU6050_BIT_SLEEP);
        }

        if (result)
                return result;

        if (power_on)
                msleep(INV_MPU6050_REG_UP_TIME);

        return 0;
}

/**
 *  inv_mpu6050_init_config() - Initialize hardware, disable FIFO.
 *
 *  Initial configuration:
 *  FSR: ± 2000DPS
 *  DLPF: 20Hz
 *  FIFO rate: 50Hz
 *  Clock source: Gyro PLL
 */
static int inv_mpu6050_init_config(struct iio_dev *indio_dev)
{
        int result;
        u8 d;
        struct inv_mpu6050_state *st = iio_priv(indio_dev);

        result = inv_mpu6050_set_power_itg(st, true);
        if (result)
                return result;
        d = (INV_MPU6050_FSR_2000DPS << INV_MPU6050_GYRO_CONFIG_FSR_SHIFT);
        result = inv_mpu6050_write_reg(st, st->reg->gyro_config, d);
        if (result)
                return result;

        d = INV_MPU6050_FILTER_20HZ;
        result = inv_mpu6050_write_reg(st, st->reg->lpf, d);
        if (result)
                return result;

        d = INV_MPU6050_ONE_K_HZ / INV_MPU6050_INIT_FIFO_RATE - 1;
        result = inv_mpu6050_write_reg(st, st->reg->sample_rate_div, d);
        if (result)
                return result;

        d = (INV_MPU6050_FS_02G << INV_MPU6050_ACCL_CONFIG_FSR_SHIFT);
        result = inv_mpu6050_write_reg(st, st->reg->accl_config, d);
        if (result)
                return result;

        memcpy(&st->chip_config, hw_info[st->chip_type].config,
                sizeof(struct inv_mpu6050_chip_config));
        result = inv_mpu6050_set_power_itg(st, false);

        return result;
}

static int inv_mpu6050_sensor_show(struct inv_mpu6050_state  *st, int reg,
                                int axis, int *val)
{
        int ind, result;
        __be16 d;

        ind = (axis - IIO_MOD_X) * 2;
        result = i2c_smbus_read_i2c_block_data(st->client, reg + ind,  2,
                                                (u8 *)&d);
        if (result != 2)
                return -EINVAL;
        *val = (short)be16_to_cpup(&d);

        return IIO_VAL_INT;
}

static int inv_mpu6050_read_raw(struct iio_dev *indio_dev,
                              struct iio_chan_spec const *chan,
                              int *val,
                              int *val2,
                              long mask) {
        struct inv_mpu6050_state  *st = iio_priv(indio_dev);

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
        {
                int ret, result;

                ret = IIO_VAL_INT;
                result = 0;
                mutex_lock(&indio_dev->mlock);
                if (!st->chip_config.enable) {
                        result = inv_mpu6050_set_power_itg(st, true);
                        if (result)
                                goto error_read_raw;
                }
                /* when enable is on, power is already on */
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        if (!st->chip_config.gyro_fifo_enable ||
                                        !st->chip_config.enable) {
                                result = inv_mpu6050_switch_engine(st, true,
                                                INV_MPU6050_BIT_PWR_GYRO_STBY);
                                if (result)
                                        goto error_read_raw;
                        }
                        ret =  inv_mpu6050_sensor_show(st, st->reg->raw_gyro,
                                                chan->channel2, val);
                        if (!st->chip_config.gyro_fifo_enable ||
                                        !st->chip_config.enable) {
                                result = inv_mpu6050_switch_engine(st, false,
                                                INV_MPU6050_BIT_PWR_GYRO_STBY);
                                if (result)
                                        goto error_read_raw;
                        }
                        break;
                case IIO_ACCEL:
                        if (!st->chip_config.accl_fifo_enable ||
                                        !st->chip_config.enable) {
                                result = inv_mpu6050_switch_engine(st, true,
                                                INV_MPU6050_BIT_PWR_ACCL_STBY);
                                if (result)
                                        goto error_read_raw;
                        }
                        ret = inv_mpu6050_sensor_show(st, st->reg->raw_accl,
                                                chan->channel2, val);
                        if (!st->chip_config.accl_fifo_enable ||
                                        !st->chip_config.enable) {
                                result = inv_mpu6050_switch_engine(st, false,
                                                INV_MPU6050_BIT_PWR_ACCL_STBY);
                                if (result)
                                        goto error_read_raw;
                        }
                        break;
                case IIO_TEMP:
                        /* wait for stablization */
                        msleep(INV_MPU6050_SENSOR_UP_TIME);
                        inv_mpu6050_sensor_show(st, st->reg->temperature,
                                                        IIO_MOD_X, val);
                        break;
                default:
                        ret = -EINVAL;
                        break;
                }
error_read_raw:
                if (!st->chip_config.enable)
                        result |= inv_mpu6050_set_power_itg(st, false);
                mutex_unlock(&indio_dev->mlock);
                if (result)
                        return result;

                return ret;
        }
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        *val  = 0;
                        *val2 = gyro_scale_6050[st->chip_config.fsr];

                        return IIO_VAL_INT_PLUS_NANO;
                case IIO_ACCEL:
                        *val = 0;
                        *val2 = accel_scale[st->chip_config.accl_fs];

                        return IIO_VAL_INT_PLUS_MICRO;
                case IIO_TEMP:
                        *val = 0;
                        *val2 = INV_MPU6050_TEMP_SCALE;

                        return IIO_VAL_INT_PLUS_MICRO;
                default:
                        return -EINVAL;
                }
        case IIO_CHAN_INFO_OFFSET:
                switch (chan->type) {
                case IIO_TEMP:
                        *val = INV_MPU6050_TEMP_OFFSET;

                        return IIO_VAL_INT;
                default:
                        return -EINVAL;
                }
        default:
                return -EINVAL;
        }
}

static int inv_mpu6050_write_gyro_scale(struct inv_mpu6050_state *st, int val)
{
        int result, i;
        u8 d;

        for (i = 0; i < ARRAY_SIZE(gyro_scale_6050); ++i) {
                if (gyro_scale_6050[i] == val) {
                        d = (i << INV_MPU6050_GYRO_CONFIG_FSR_SHIFT);
                        result = inv_mpu6050_write_reg(st,
                                        st->reg->gyro_config, d);
                        if (result)
                                return result;

                        st->chip_config.fsr = i;
                        return 0;
                }
        }

        return -EINVAL;
}

static int inv_mpu6050_write_accel_scale(struct inv_mpu6050_state *st, int val)
{
        int result, i;
        u8 d;

        for (i = 0; i < ARRAY_SIZE(accel_scale); ++i) {
                if (accel_scale[i] == val) {
                        d = (i << INV_MPU6050_ACCL_CONFIG_FSR_SHIFT);
                        result = inv_mpu6050_write_reg(st,
                                        st->reg->accl_config, d);
                        if (result)
                                return result;

                        st->chip_config.accl_fs = i;
                        return 0;
                }
        }

        return -EINVAL;
}

static int inv_mpu6050_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val,
                               int val2,
                               long mask) {
        struct inv_mpu6050_state  *st = iio_priv(indio_dev);
        int result;

        mutex_lock(&indio_dev->mlock);
        /* we should only update scale when the chip is disabled, i.e.,
                not running */
        if (st->chip_config.enable) {
                result = -EBUSY;
                goto error_write_raw;
        }
        result = inv_mpu6050_set_power_itg(st, true);
        if (result)
                goto error_write_raw;

        switch (mask) {
        case IIO_CHAN_INFO_SCALE:
                switch (chan->type) {
                case IIO_ANGL_VEL:
                        result = inv_mpu6050_write_gyro_scale(st, val2);
                        break;
                case IIO_ACCEL:
                        result = inv_mpu6050_write_accel_scale(st, val2);
                        break;
                default:
                        result = -EINVAL;
                        break;
                }
                break;
        default:
                result = -EINVAL;
                break;
        }

error_write_raw:
        result |= inv_mpu6050_set_power_itg(st, false);
        mutex_unlock(&indio_dev->mlock);

        return result;
}

/**
 *  inv_mpu6050_set_lpf() - set low pass filer based on fifo rate.
 *
 *                  Based on the Nyquist principle, the sampling rate must
 *                  exceed twice of the bandwidth of the signal, or there
 *                  would be alising. This function basically search for the
 *                  correct low pass parameters based on the fifo rate, e.g,
 *                  sampling frequency.
 */
static int inv_mpu6050_set_lpf(struct inv_mpu6050_state *st, int rate)
{
        const int hz[] = {188, 98, 42, 20, 10, 5};
        const int d[] = {INV_MPU6050_FILTER_188HZ, INV_MPU6050_FILTER_98HZ,
                        INV_MPU6050_FILTER_42HZ, INV_MPU6050_FILTER_20HZ,
                        INV_MPU6050_FILTER_10HZ, INV_MPU6050_FILTER_5HZ};
        int i, h, result;
        u8 data;

        h = (rate >> 1);
        i = 0;
        while ((h < hz[i]) && (i < ARRAY_SIZE(d) - 1))
                i++;
        data = d[i];
        result = inv_mpu6050_write_reg(st, st->reg->lpf, data);
        if (result)
                return result;
        st->chip_config.lpf = data;

        return 0;
}

/**
 * inv_mpu6050_fifo_rate_store() - Set fifo rate.
 */
static ssize_t inv_mpu6050_fifo_rate_store(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t count)
{
        s32 fifo_rate;
        u8 d;
        int result;
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct inv_mpu6050_state *st = iio_priv(indio_dev);

        if (kstrtoint(buf, 10, &fifo_rate))
                return -EINVAL;
        if (fifo_rate < INV_MPU6050_MIN_FIFO_RATE ||
                                fifo_rate > INV_MPU6050_MAX_FIFO_RATE)
                return -EINVAL;
        if (fifo_rate == st->chip_config.fifo_rate)
                return count;

        mutex_lock(&indio_dev->mlock);
        if (st->chip_config.enable) {
                result = -EBUSY;
                goto fifo_rate_fail;
        }
        result = inv_mpu6050_set_power_itg(st, true);
        if (result)
                goto fifo_rate_fail;

        d = INV_MPU6050_ONE_K_HZ / fifo_rate - 1;
        result = inv_mpu6050_write_reg(st, st->reg->sample_rate_div, d);
        if (result)
                goto fifo_rate_fail;
        st->chip_config.fifo_rate = fifo_rate;

        result = inv_mpu6050_set_lpf(st, fifo_rate);
        if (result)
                goto fifo_rate_fail;

fifo_rate_fail:
        result |= inv_mpu6050_set_power_itg(st, false);
        mutex_unlock(&indio_dev->mlock);
        if (result)
                return result;

        return count;
}

/**
 * inv_fifo_rate_show() - Get the current sampling rate.
 */
static ssize_t inv_fifo_rate_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct inv_mpu6050_state *st = iio_priv(dev_to_iio_dev(dev));

        return sprintf(buf, "%d\n", st->chip_config.fifo_rate);
}

/**
 * inv_attr_show() - calling this function will show current
 *                    parameters.
 */
static ssize_t inv_attr_show(struct device *dev,
        struct device_attribute *attr, char *buf)
{
        struct inv_mpu6050_state *st = iio_priv(dev_to_iio_dev(dev));
        struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
        s8 *m;

        switch (this_attr->address) {
        /* In MPU6050, the two matrix are the same because gyro and accel
           are integrated in one chip */
        case ATTR_GYRO_MATRIX:
        case ATTR_ACCL_MATRIX:
                m = st->plat_data.orientation;

                return sprintf(buf, "%d, %d, %d; %d, %d, %d; %d, %d, %d\n",
                        m[0], m[1], m[2], m[3], m[4], m[5], m[6], m[7], m[8]);
        default:
                return -EINVAL;
        }
}

/**
 * inv_mpu6050_validate_trigger() - validate_trigger callback for invensense
 *                                  MPU6050 device.
 * @indio_dev: The IIO device
 * @trig: The new trigger
 *
 * Returns: 0 if the 'trig' matches the trigger registered by the MPU6050
 * device, -EINVAL otherwise.
 */
static int inv_mpu6050_validate_trigger(struct iio_dev *indio_dev,
                                        struct iio_trigger *trig)
{
        struct inv_mpu6050_state *st = iio_priv(indio_dev);

        if (st->trig != trig)
                return -EINVAL;

        return 0;
}

#define INV_MPU6050_CHAN(_type, _channel2, _index)                    \
        {                                                             \
                .type = _type,                                        \
                .modified = 1,                                        \
                .channel2 = _channel2,                                \
                .info_mask_shared_by_type =  BIT(IIO_CHAN_INFO_SCALE), \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),         \
                .scan_index = _index,                                 \
                .scan_type = {                                        \
                                .sign = 's',                          \
                                .realbits = 16,                       \
                                .storagebits = 16,                    \
                                .shift = 0 ,                          \
                                .endianness = IIO_BE,                 \
                             },                                       \
        }

static const struct iio_chan_spec inv_mpu_channels[] = {
        IIO_CHAN_SOFT_TIMESTAMP(INV_MPU6050_SCAN_TIMESTAMP),
        /*
         * Note that temperature should only be via polled reading only,
         * not the final scan elements output.
         */
        {
                .type = IIO_TEMP,
                .info_mask_separate =  BIT(IIO_CHAN_INFO_RAW)
                                | BIT(IIO_CHAN_INFO_OFFSET)
                                | BIT(IIO_CHAN_INFO_SCALE),
                .scan_index = -1,
        },
        INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_X, INV_MPU6050_SCAN_GYRO_X),
        INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_Y, INV_MPU6050_SCAN_GYRO_Y),
        INV_MPU6050_CHAN(IIO_ANGL_VEL, IIO_MOD_Z, INV_MPU6050_SCAN_GYRO_Z),

        INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_X, INV_MPU6050_SCAN_ACCL_X),
        INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_Y, INV_MPU6050_SCAN_ACCL_Y),
        INV_MPU6050_CHAN(IIO_ACCEL, IIO_MOD_Z, INV_MPU6050_SCAN_ACCL_Z),
};

/* constant IIO attribute */
static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("10 20 50 100 200 500");
static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR, inv_fifo_rate_show,
        inv_mpu6050_fifo_rate_store);
static IIO_DEVICE_ATTR(in_gyro_matrix, S_IRUGO, inv_attr_show, NULL,
        ATTR_GYRO_MATRIX);
static IIO_DEVICE_ATTR(in_accel_matrix, S_IRUGO, inv_attr_show, NULL,
        ATTR_ACCL_MATRIX);

static struct attribute *inv_attributes[] = {
        &iio_dev_attr_in_gyro_matrix.dev_attr.attr,
        &iio_dev_attr_in_accel_matrix.dev_attr.attr,
        &iio_dev_attr_sampling_frequency.dev_attr.attr,
        &iio_const_attr_sampling_frequency_available.dev_attr.attr,
        NULL,
};

static const struct attribute_group inv_attribute_group = {
        .attrs = inv_attributes
};

static const struct iio_info mpu_info = {
        .driver_module = THIS_MODULE,
        .read_raw = &inv_mpu6050_read_raw,
        .write_raw = &inv_mpu6050_write_raw,
        .attrs = &inv_attribute_group,
        .validate_trigger = inv_mpu6050_validate_trigger,
};

/**
 *  inv_check_and_setup_chip() - check and setup chip.
 */
static int inv_check_and_setup_chip(struct inv_mpu6050_state *st,
                const struct i2c_device_id *id)
{
        int result;

        st->chip_type = INV_MPU6050;
        st->hw  = &hw_info[st->chip_type];
        st->reg = hw_info[st->chip_type].reg;

        /* reset to make sure previous state are not there */
        result = inv_mpu6050_write_reg(st, st->reg->pwr_mgmt_1,
                                        INV_MPU6050_BIT_H_RESET);
        if (result)
                return result;
        msleep(INV_MPU6050_POWER_UP_TIME);
        /* toggle power state. After reset, the sleep bit could be on
                or off depending on the OTP settings. Toggling power would
                make it in a definite state as well as making the hardware
                state align with the software state */
        result = inv_mpu6050_set_power_itg(st, false);
        if (result)
                return result;
        result = inv_mpu6050_set_power_itg(st, true);
        if (result)
                return result;

        result = inv_mpu6050_switch_engine(st, false,
                                        INV_MPU6050_BIT_PWR_ACCL_STBY);
        if (result)
                return result;
        result = inv_mpu6050_switch_engine(st, false,
                                        INV_MPU6050_BIT_PWR_GYRO_STBY);
        if (result)
                return result;

        return 0;
}

/**
 *  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;
        struct iio_dev *indio_dev;
        struct inv_mpu6050_platform_data *pdata;
        int result;

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

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
        if (!indio_dev)
                return -ENOMEM;

        st = iio_priv(indio_dev);
        st->client = client;
        st->powerup_count = 0;
        pdata = dev_get_platdata(&client->dev);
        if (pdata)
                st->plat_data = *pdata;
        /* power is turned on inside check chip type*/
        result = inv_check_and_setup_chip(st, id);
        if (result)
                return result;

        result = inv_mpu6050_init_config(indio_dev);
        if (result) {
                dev_err(&client->dev,
                        "Could not initialize device.\n");
                return result;
        }

        i2c_set_clientdata(client, indio_dev);
        indio_dev->dev.parent = &client->dev;
        /* id will be NULL when enumerated via ACPI */
        if (id)
                indio_dev->name = (char *)id->name;
        else
                indio_dev->name = (char *)dev_name(&client->dev);
        indio_dev->channels = inv_mpu_channels;
        indio_dev->num_channels = ARRAY_SIZE(inv_mpu_channels);

        indio_dev->info = &mpu_info;
        indio_dev->modes = INDIO_BUFFER_TRIGGERED;

        result = iio_triggered_buffer_setup(indio_dev,
                                            inv_mpu6050_irq_handler,
                                            inv_mpu6050_read_fifo,
                                            NULL);
        if (result) {
                dev_err(&st->client->dev, "configure buffer fail %d\n",
                                result);
                return result;
        }
        result = inv_mpu6050_probe_trigger(indio_dev);
        if (result) {
                dev_err(&st->client->dev, "trigger probe fail %d\n", result);
                goto out_unreg_ring;
        }

        INIT_KFIFO(st->timestamps);
        spin_lock_init(&st->time_stamp_lock);
        result = iio_device_register(indio_dev);
        if (result) {
                dev_err(&st->client->dev, "IIO register fail %d\n", result);
                goto out_remove_trigger;
        }

        st->mux_adapter = i2c_add_mux_adapter(client->adapter,
                                              &client->dev,
                                              indio_dev,
                                              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(st);
        if (result)
                goto out_del_mux;

        return 0;

out_del_mux:
        i2c_del_mux_adapter(st->mux_adapter);
out_unreg_device:
        iio_device_unregister(indio_dev);
out_remove_trigger:
        inv_mpu6050_remove_trigger(st);
out_unreg_ring:
        iio_triggered_buffer_cleanup(indio_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(st);
        i2c_del_mux_adapter(st->mux_adapter);
        iio_device_unregister(indio_dev);
        inv_mpu6050_remove_trigger(st);
        iio_triggered_buffer_cleanup(indio_dev);

        return 0;
}
#ifdef CONFIG_PM_SLEEP

static int inv_mpu_resume(struct device *dev)
{
        return inv_mpu6050_set_power_itg(
                iio_priv(i2c_get_clientdata(to_i2c_client(dev))), true);
}

static int inv_mpu_suspend(struct device *dev)
{
        return inv_mpu6050_set_power_itg(
                iio_priv(i2c_get_clientdata(to_i2c_client(dev))), false);
}
static SIMPLE_DEV_PM_OPS(inv_mpu_pmops, inv_mpu_suspend, inv_mpu_resume);

#define INV_MPU6050_PMOPS (&inv_mpu_pmops)
#else
#define INV_MPU6050_PMOPS NULL
#endif /* CONFIG_PM_SLEEP */

/*
 * 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 = {
                .owner  =       THIS_MODULE,
                .name   =       "inv-mpu6050",
                .pm     =       INV_MPU6050_PMOPS,
                .acpi_match_table = ACPI_PTR(inv_acpi_match),
        },
};

module_i2c_driver(inv_mpu_driver);

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