/*
 * MPU3050 Tri-axis gyroscope driver
 *
 * Copyright (C) 2011 Wistron Co.Ltd
 * Joseph Lai <joseph_lai@wistron.com>
 *
 * Trimmed down by Alan Cox <alan@linux.intel.com> to produce this version
 *
 * This is a 'lite' version of the driver, while we consider the right way
 * to present the other features to user space. In particular it requires the
 * device has an IRQ, and it only provides an input interface, so is not much
 * use for device orientation. A fuller version is available from the Meego
 * tree.
 *
 * This program is based on bma023.c.
 *
 * 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 of the License.
 *
 * 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/interrupt.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>

#define MPU3050_CHIP_ID         0x69

#define MPU3050_AUTO_DELAY      1000

#define MPU3050_MIN_VALUE       -32768
#define MPU3050_MAX_VALUE       32767

#define MPU3050_DEFAULT_POLL_INTERVAL   200
#define MPU3050_DEFAULT_FS_RANGE        3

/* Register map */
#define MPU3050_CHIP_ID_REG     0x00
#define MPU3050_SMPLRT_DIV      0x15
#define MPU3050_DLPF_FS_SYNC    0x16
#define MPU3050_INT_CFG         0x17
#define MPU3050_XOUT_H          0x1D
#define MPU3050_PWR_MGM         0x3E
#define MPU3050_PWR_MGM_POS     6

/* Register bits */

/* DLPF_FS_SYNC */
#define MPU3050_EXT_SYNC_NONE           0x00
#define MPU3050_EXT_SYNC_TEMP           0x20
#define MPU3050_EXT_SYNC_GYROX          0x40
#define MPU3050_EXT_SYNC_GYROY          0x60
#define MPU3050_EXT_SYNC_GYROZ          0x80
#define MPU3050_EXT_SYNC_ACCELX 0xA0
#define MPU3050_EXT_SYNC_ACCELY 0xC0
#define MPU3050_EXT_SYNC_ACCELZ 0xE0
#define MPU3050_EXT_SYNC_MASK           0xE0
#define MPU3050_FS_250DPS               0x00
#define MPU3050_FS_500DPS               0x08
#define MPU3050_FS_1000DPS              0x10
#define MPU3050_FS_2000DPS              0x18
#define MPU3050_FS_MASK         0x18
#define MPU3050_DLPF_CFG_256HZ_NOLPF2   0x00
#define MPU3050_DLPF_CFG_188HZ          0x01
#define MPU3050_DLPF_CFG_98HZ           0x02
#define MPU3050_DLPF_CFG_42HZ           0x03
#define MPU3050_DLPF_CFG_20HZ           0x04
#define MPU3050_DLPF_CFG_10HZ           0x05
#define MPU3050_DLPF_CFG_5HZ            0x06
#define MPU3050_DLPF_CFG_2100HZ_NOLPF   0x07
#define MPU3050_DLPF_CFG_MASK           0x07
/* INT_CFG */
#define MPU3050_RAW_RDY_EN              0x01
#define MPU3050_MPU_RDY_EN              0x02
#define MPU3050_LATCH_INT_EN            0x04
/* PWR_MGM */
#define MPU3050_PWR_MGM_PLL_X           0x01
#define MPU3050_PWR_MGM_PLL_Y           0x02
#define MPU3050_PWR_MGM_PLL_Z           0x03
#define MPU3050_PWR_MGM_CLKSEL          0x07
#define MPU3050_PWR_MGM_STBY_ZG 0x08
#define MPU3050_PWR_MGM_STBY_YG 0x10
#define MPU3050_PWR_MGM_STBY_XG 0x20
#define MPU3050_PWR_MGM_SLEEP           0x40
#define MPU3050_PWR_MGM_RESET           0x80
#define MPU3050_PWR_MGM_MASK            0x40

struct axis_data {
        s16 x;
        s16 y;
        s16 z;
};

struct mpu3050_sensor {
        struct i2c_client *client;
        struct device *dev;
        struct input_dev *idev;
};

/**
 *      mpu3050_xyz_read_reg    -       read the axes values
 *      @buffer: provide register addr and get register
 *      @length: length of register
 *
 *      Reads the register values in one transaction or returns a negative
 *      error code on failure.
 */
static int mpu3050_xyz_read_reg(struct i2c_client *client,
                               u8 *buffer, int length)
{
        /*
         * Annoying we can't make this const because the i2c layer doesn't
         * declare input buffers const.
         */
        char cmd = MPU3050_XOUT_H;
        struct i2c_msg msg[] = {
                {
                        .addr = client->addr,
                        .flags = 0,
                        .len = 1,
                        .buf = &cmd,
                },
                {
                        .addr = client->addr,
                        .flags = I2C_M_RD,
                        .len = length,
                        .buf = buffer,
                },
        };

        return i2c_transfer(client->adapter, msg, 2);
}

/**
 *      mpu3050_read_xyz        -       get co-ordinates from device
 *      @client: i2c address of sensor
 *      @coords: co-ordinates to update
 *
 *      Return the converted X Y and Z co-ordinates from the sensor device
 */
static void mpu3050_read_xyz(struct i2c_client *client,
                             struct axis_data *coords)
{
        u16 buffer[3];

        mpu3050_xyz_read_reg(client, (u8 *)buffer, 6);
        coords->x = be16_to_cpu(buffer[0]);
        coords->y = be16_to_cpu(buffer[1]);
        coords->z = be16_to_cpu(buffer[2]);
        dev_dbg(&client->dev, "%s: x %d, y %d, z %d\n", __func__,
                                        coords->x, coords->y, coords->z);
}

/**
 *      mpu3050_set_power_mode  -       set the power mode
 *      @client: i2c client for the sensor
 *      @val: value to switch on/off of power, 1: normal power, 0: low power
 *
 *      Put device to normal-power mode or low-power mode.
 */
static void mpu3050_set_power_mode(struct i2c_client *client, u8 val)
{
        u8 value;

        value = i2c_smbus_read_byte_data(client, MPU3050_PWR_MGM);
        value = (value & ~MPU3050_PWR_MGM_MASK) |
                (((val << MPU3050_PWR_MGM_POS) & MPU3050_PWR_MGM_MASK) ^
                 MPU3050_PWR_MGM_MASK);
        i2c_smbus_write_byte_data(client, MPU3050_PWR_MGM, value);
}

/**
 *      mpu3050_input_open      -       called on input event open
 *      @input: input dev of opened device
 *
 *      The input layer calls this function when input event is opened. The
 *      function will push the device to resume. Then, the device is ready
 *      to provide data.
 */
static int mpu3050_input_open(struct input_dev *input)
{
        struct mpu3050_sensor *sensor = input_get_drvdata(input);
        int error;

        pm_runtime_get(sensor->dev);

        /* Enable interrupts */
        error = i2c_smbus_write_byte_data(sensor->client, MPU3050_INT_CFG,
                                          MPU3050_LATCH_INT_EN |
                                          MPU3050_RAW_RDY_EN |
                                          MPU3050_MPU_RDY_EN);
        if (error < 0) {
                pm_runtime_put(sensor->dev);
                return error;
        }

        return 0;
}

/**
 *      mpu3050_input_close     -       called on input event close
 *      @input: input dev of closed device
 *
 *      The input layer calls this function when input event is closed. The
 *      function will push the device to suspend.
 */
static void mpu3050_input_close(struct input_dev *input)
{
        struct mpu3050_sensor *sensor = input_get_drvdata(input);

        pm_runtime_put(sensor->dev);
}

/**
 *      mpu3050_interrupt_thread        -       handle an IRQ
 *      @irq: interrupt numner
 *      @data: the sensor
 *
 *      Called by the kernel single threaded after an interrupt occurs. Read
 *      the sensor data and generate an input event for it.
 */
static irqreturn_t mpu3050_interrupt_thread(int irq, void *data)
{
        struct mpu3050_sensor *sensor = data;
        struct axis_data axis;

        mpu3050_read_xyz(sensor->client, &axis);

        input_report_abs(sensor->idev, ABS_X, axis.x);
        input_report_abs(sensor->idev, ABS_Y, axis.y);
        input_report_abs(sensor->idev, ABS_Z, axis.z);
        input_sync(sensor->idev);

        return IRQ_HANDLED;
}

/**
 *      mpu3050_hw_init -       initialize hardware
 *      @sensor: the sensor
 *
 *      Called during device probe; configures the sampling method.
 */
static int mpu3050_hw_init(struct mpu3050_sensor *sensor)
{
        struct i2c_client *client = sensor->client;
        int ret;
        u8 reg;

        /* Reset */
        ret = i2c_smbus_write_byte_data(client, MPU3050_PWR_MGM,
                                        MPU3050_PWR_MGM_RESET);
        if (ret < 0)
                return ret;

        ret = i2c_smbus_read_byte_data(client, MPU3050_PWR_MGM);
        if (ret < 0)
                return ret;

        ret &= ~MPU3050_PWR_MGM_CLKSEL;
        ret |= MPU3050_PWR_MGM_PLL_Z;
        ret = i2c_smbus_write_byte_data(client, MPU3050_PWR_MGM, ret);
        if (ret < 0)
                return ret;

        /* Output frequency divider. The poll interval */
        ret = i2c_smbus_write_byte_data(client, MPU3050_SMPLRT_DIV,
                                        MPU3050_DEFAULT_POLL_INTERVAL - 1);
        if (ret < 0)
                return ret;

        /* Set low pass filter and full scale */
        reg = MPU3050_DEFAULT_FS_RANGE;
        reg |= MPU3050_DLPF_CFG_42HZ << 3;
        reg |= MPU3050_EXT_SYNC_NONE << 5;
        ret = i2c_smbus_write_byte_data(client, MPU3050_DLPF_FS_SYNC, reg);
        if (ret < 0)
                return ret;

        return 0;
}

/**
 *      mpu3050_probe   -       device detection callback
 *      @client: i2c client of found device
 *      @id: id match information
 *
 *      The I2C layer calls us when it believes a sensor is present at this
 *      address. Probe to see if this is correct and to validate the device.
 *
 *      If present install the relevant sysfs interfaces and input device.
 */
static int mpu3050_probe(struct i2c_client *client,
                                   const struct i2c_device_id *id)
{
        struct mpu3050_sensor *sensor;
        struct input_dev *idev;
        int ret;
        int error;

        sensor = kzalloc(sizeof(struct mpu3050_sensor), GFP_KERNEL);
        idev = input_allocate_device();
        if (!sensor || !idev) {
                dev_err(&client->dev, "failed to allocate driver data\n");
                error = -ENOMEM;
                goto err_free_mem;
        }

        sensor->client = client;
        sensor->dev = &client->dev;
        sensor->idev = idev;

        mpu3050_set_power_mode(client, 1);
        msleep(10);

        ret = i2c_smbus_read_byte_data(client, MPU3050_CHIP_ID_REG);
        if (ret < 0) {
                dev_err(&client->dev, "failed to detect device\n");
                error = -ENXIO;
                goto err_free_mem;
        }

        if (ret != MPU3050_CHIP_ID) {
                dev_err(&client->dev, "unsupported chip id\n");
                error = -ENXIO;
                goto err_free_mem;
        }

        idev->name = "MPU3050";
        idev->id.bustype = BUS_I2C;
        idev->dev.parent = &client->dev;

        idev->open = mpu3050_input_open;
        idev->close = mpu3050_input_close;

        __set_bit(EV_ABS, idev->evbit);
        input_set_abs_params(idev, ABS_X,
                             MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);
        input_set_abs_params(idev, ABS_Y,
                             MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);
        input_set_abs_params(idev, ABS_Z,
                             MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);

        input_set_drvdata(idev, sensor);

        pm_runtime_set_active(&client->dev);

        error = mpu3050_hw_init(sensor);
        if (error)
                goto err_pm_set_suspended;

        error = request_threaded_irq(client->irq,
                                     NULL, mpu3050_interrupt_thread,
                                     IRQF_TRIGGER_RISING | IRQF_ONESHOT,
                                     "mpu3050", sensor);
        if (error) {
                dev_err(&client->dev,
                        "can't get IRQ %d, error %d\n", client->irq, error);
                goto err_pm_set_suspended;
        }

        error = input_register_device(idev);
        if (error) {
                dev_err(&client->dev, "failed to register input device\n");
                goto err_free_irq;
        }

        pm_runtime_enable(&client->dev);
        pm_runtime_set_autosuspend_delay(&client->dev, MPU3050_AUTO_DELAY);

        return 0;

err_free_irq:
        free_irq(client->irq, sensor);
err_pm_set_suspended:
        pm_runtime_set_suspended(&client->dev);
err_free_mem:
        input_free_device(idev);
        kfree(sensor);
        return error;
}

/**
 *      mpu3050_remove  -       remove a sensor
 *      @client: i2c client of sensor being removed
 *
 *      Our sensor is going away, clean up the resources.
 */
static int mpu3050_remove(struct i2c_client *client)
{
        struct mpu3050_sensor *sensor = i2c_get_clientdata(client);

        pm_runtime_disable(&client->dev);
        pm_runtime_set_suspended(&client->dev);

        free_irq(client->irq, sensor);
        input_unregister_device(sensor->idev);
        kfree(sensor);

        return 0;
}

#ifdef CONFIG_PM
/**
 *      mpu3050_suspend         -       called on device suspend
 *      @dev: device being suspended
 *
 *      Put the device into sleep mode before we suspend the machine.
 */
static int mpu3050_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        mpu3050_set_power_mode(client, 0);

        return 0;
}

/**
 *      mpu3050_resume          -       called on device resume
 *      @dev: device being resumed
 *
 *      Put the device into powered mode on resume.
 */
static int mpu3050_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        mpu3050_set_power_mode(client, 1);
        msleep(100);  /* wait for gyro chip resume */

        return 0;
}
#endif

static UNIVERSAL_DEV_PM_OPS(mpu3050_pm, mpu3050_suspend, mpu3050_resume, NULL);

static const struct i2c_device_id mpu3050_ids[] = {
        { "mpu3050", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, mpu3050_ids);

static const struct of_device_id mpu3050_of_match[] = {
        { .compatible = "invn,mpu3050", },
        { },
};
MODULE_DEVICE_TABLE(of, mpu3050_of_match);

static struct i2c_driver mpu3050_i2c_driver = {
        .driver = {
                .name   = "mpu3050",
                .owner  = THIS_MODULE,
                .pm     = &mpu3050_pm,
                .of_match_table = mpu3050_of_match,
        },
        .probe          = mpu3050_probe,
        .remove         = mpu3050_remove,
        .id_table       = mpu3050_ids,
};

module_i2c_driver(mpu3050_i2c_driver);

MODULE_AUTHOR("Wistron Corp.");
MODULE_DESCRIPTION("MPU3050 Tri-axis gyroscope driver");
MODULE_LICENSE("GPL");