/*
 *  Driver for Freescale's 3-Axis Accelerometer MMA8450
 *
 *  Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input-polldev.h>
#include <linux/of_device.h>

#define MMA8450_DRV_NAME        "mma8450"

#define MODE_CHANGE_DELAY_MS    100
#define POLL_INTERVAL           100
#define POLL_INTERVAL_MAX       500

/* register definitions */
#define MMA8450_STATUS          0x00
#define MMA8450_STATUS_ZXYDR    0x08

#define MMA8450_OUT_X8          0x01
#define MMA8450_OUT_Y8          0x02
#define MMA8450_OUT_Z8          0x03

#define MMA8450_OUT_X_LSB       0x05
#define MMA8450_OUT_X_MSB       0x06
#define MMA8450_OUT_Y_LSB       0x07
#define MMA8450_OUT_Y_MSB       0x08
#define MMA8450_OUT_Z_LSB       0x09
#define MMA8450_OUT_Z_MSB       0x0a

#define MMA8450_XYZ_DATA_CFG    0x16

#define MMA8450_CTRL_REG1       0x38
#define MMA8450_CTRL_REG2       0x39

/* mma8450 status */
struct mma8450 {
        struct i2c_client       *client;
        struct input_polled_dev *idev;
};

static int mma8450_read(struct mma8450 *m, unsigned off)
{
        struct i2c_client *c = m->client;
        int ret;

        ret = i2c_smbus_read_byte_data(c, off);
        if (ret < 0)
                dev_err(&c->dev,
                        "failed to read register 0x%02x, error %d\n",
                        off, ret);

        return ret;
}

static int mma8450_write(struct mma8450 *m, unsigned off, u8 v)
{
        struct i2c_client *c = m->client;
        int error;

        error = i2c_smbus_write_byte_data(c, off, v);
        if (error < 0) {
                dev_err(&c->dev,
                        "failed to write to register 0x%02x, error %d\n",
                        off, error);
                return error;
        }

        return 0;
}

static int mma8450_read_block(struct mma8450 *m, unsigned off,
                              u8 *buf, size_t size)
{
        struct i2c_client *c = m->client;
        int err;

        err = i2c_smbus_read_i2c_block_data(c, off, size, buf);
        if (err < 0) {
                dev_err(&c->dev,
                        "failed to read block data at 0x%02x, error %d\n",
                        MMA8450_OUT_X_LSB, err);
                return err;
        }

        return 0;
}

static void mma8450_poll(struct input_polled_dev *dev)
{
        struct mma8450 *m = dev->private;
        int x, y, z;
        int ret;
        u8 buf[6];

        ret = mma8450_read(m, MMA8450_STATUS);
        if (ret < 0)
                return;

        if (!(ret & MMA8450_STATUS_ZXYDR))
                return;

        ret = mma8450_read_block(m, MMA8450_OUT_X_LSB, buf, sizeof(buf));
        if (ret < 0)
                return;

        x = ((int)(s8)buf[1] << 4) | (buf[0] & 0xf);
        y = ((int)(s8)buf[3] << 4) | (buf[2] & 0xf);
        z = ((int)(s8)buf[5] << 4) | (buf[4] & 0xf);

        input_report_abs(dev->input, ABS_X, x);
        input_report_abs(dev->input, ABS_Y, y);
        input_report_abs(dev->input, ABS_Z, z);
        input_sync(dev->input);
}

/* Initialize the MMA8450 chip */
static void mma8450_open(struct input_polled_dev *dev)
{
        struct mma8450 *m = dev->private;
        int err;

        /* enable all events from X/Y/Z, no FIFO */
        err = mma8450_write(m, MMA8450_XYZ_DATA_CFG, 0x07);
        if (err)
                return;

        /*
         * Sleep mode poll rate - 50Hz
         * System output data rate - 400Hz
         * Full scale selection - Active, +/- 2G
         */
        err = mma8450_write(m, MMA8450_CTRL_REG1, 0x01);
        if (err < 0)
                return;

        msleep(MODE_CHANGE_DELAY_MS);
}

static void mma8450_close(struct input_polled_dev *dev)
{
        struct mma8450 *m = dev->private;

        mma8450_write(m, MMA8450_CTRL_REG1, 0x00);
        mma8450_write(m, MMA8450_CTRL_REG2, 0x01);
}

/*
 * I2C init/probing/exit functions
 */
static int mma8450_probe(struct i2c_client *c,
                         const struct i2c_device_id *id)
{
        struct input_polled_dev *idev;
        struct mma8450 *m;
        int err;

        m = devm_kzalloc(&c->dev, sizeof(*m), GFP_KERNEL);
        if (!m)
                return -ENOMEM;

        idev = devm_input_allocate_polled_device(&c->dev);
        if (!idev)
                return -ENOMEM;

        m->client = c;
        m->idev = idev;

        idev->private           = m;
        idev->input->name       = MMA8450_DRV_NAME;
        idev->input->id.bustype = BUS_I2C;
        idev->poll              = mma8450_poll;
        idev->poll_interval     = POLL_INTERVAL;
        idev->poll_interval_max = POLL_INTERVAL_MAX;
        idev->open              = mma8450_open;
        idev->close             = mma8450_close;

        __set_bit(EV_ABS, idev->input->evbit);
        input_set_abs_params(idev->input, ABS_X, -2048, 2047, 32, 32);
        input_set_abs_params(idev->input, ABS_Y, -2048, 2047, 32, 32);
        input_set_abs_params(idev->input, ABS_Z, -2048, 2047, 32, 32);

        err = input_register_polled_device(idev);
        if (err) {
                dev_err(&c->dev, "failed to register polled input device\n");
                return err;
        }

        return 0;
}

static const struct i2c_device_id mma8450_id[] = {
        { MMA8450_DRV_NAME, 0 },
        { },
};
MODULE_DEVICE_TABLE(i2c, mma8450_id);

static const struct of_device_id mma8450_dt_ids[] = {
        { .compatible = "fsl,mma8450", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mma8450_dt_ids);

static struct i2c_driver mma8450_driver = {
        .driver = {
                .name   = MMA8450_DRV_NAME,
                .of_match_table = mma8450_dt_ids,
        },
        .probe          = mma8450_probe,
        .id_table       = mma8450_id,
};

module_i2c_driver(mma8450_driver);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("MMA8450 3-Axis Accelerometer Driver");
MODULE_LICENSE("GPL");