/* Copyright (c) 2010-2011, Code Aurora Forum. 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 version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * 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/init.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/mfd/pm8xxx/core.h>

#define VIB_DRV                 0x4A

#define VIB_DRV_SEL_MASK        0xf8
#define VIB_DRV_SEL_SHIFT       0x03
#define VIB_DRV_EN_MANUAL_MASK  0xfc

#define VIB_MAX_LEVEL_mV        (3100)
#define VIB_MIN_LEVEL_mV        (1200)
#define VIB_MAX_LEVELS          (VIB_MAX_LEVEL_mV - VIB_MIN_LEVEL_mV)

#define MAX_FF_SPEED            0xff

/**
 * struct pm8xxx_vib - structure to hold vibrator data
 * @vib_input_dev: input device supporting force feedback
 * @work: work structure to set the vibration parameters
 * @dev: device supporting force feedback
 * @speed: speed of vibration set from userland
 * @active: state of vibrator
 * @level: level of vibration to set in the chip
 * @reg_vib_drv: VIB_DRV register value
 */
struct pm8xxx_vib {
        struct input_dev *vib_input_dev;
        struct work_struct work;
        struct device *dev;
        int speed;
        int level;
        bool active;
        u8  reg_vib_drv;
};

/**
 * pm8xxx_vib_read_u8 - helper to read a byte from pmic chip
 * @vib: pointer to vibrator structure
 * @data: placeholder for data to be read
 * @reg: register address
 */
static int pm8xxx_vib_read_u8(struct pm8xxx_vib *vib,
                                 u8 *data, u16 reg)
{
        int rc;

        rc = pm8xxx_readb(vib->dev->parent, reg, data);
        if (rc < 0)
                dev_warn(vib->dev, "Error reading pm8xxx reg 0x%x(0x%x)\n",
                                reg, rc);
        return rc;
}

/**
 * pm8xxx_vib_write_u8 - helper to write a byte to pmic chip
 * @vib: pointer to vibrator structure
 * @data: data to write
 * @reg: register address
 */
static int pm8xxx_vib_write_u8(struct pm8xxx_vib *vib,
                                 u8 data, u16 reg)
{
        int rc;

        rc = pm8xxx_writeb(vib->dev->parent, reg, data);
        if (rc < 0)
                dev_warn(vib->dev, "Error writing pm8xxx reg 0x%x(0x%x)\n",
                                reg, rc);
        return rc;
}

/**
 * pm8xxx_vib_set - handler to start/stop vibration
 * @vib: pointer to vibrator structure
 * @on: state to set
 */
static int pm8xxx_vib_set(struct pm8xxx_vib *vib, bool on)
{
        int rc;
        u8 val = vib->reg_vib_drv;

        if (on)
                val |= ((vib->level << VIB_DRV_SEL_SHIFT) & VIB_DRV_SEL_MASK);
        else
                val &= ~VIB_DRV_SEL_MASK;

        rc = pm8xxx_vib_write_u8(vib, val, VIB_DRV);
        if (rc < 0)
                return rc;

        vib->reg_vib_drv = val;
        return 0;
}

/**
 * pm8xxx_work_handler - worker to set vibration level
 * @work: pointer to work_struct
 */
static void pm8xxx_work_handler(struct work_struct *work)
{
        struct pm8xxx_vib *vib = container_of(work, struct pm8xxx_vib, work);
        int rc;
        u8 val;

        rc = pm8xxx_vib_read_u8(vib, &val, VIB_DRV);
        if (rc < 0)
                return;

        /*
         * pmic vibrator supports voltage ranges from 1.2 to 3.1V, so
         * scale the level to fit into these ranges.
         */
        if (vib->speed) {
                vib->active = true;
                vib->level = ((VIB_MAX_LEVELS * vib->speed) / MAX_FF_SPEED) +
                                                VIB_MIN_LEVEL_mV;
                vib->level /= 100;
        } else {
                vib->active = false;
                vib->level = VIB_MIN_LEVEL_mV / 100;
        }

        pm8xxx_vib_set(vib, vib->active);
}

/**
 * pm8xxx_vib_close - callback of input close callback
 * @dev: input device pointer
 *
 * Turns off the vibrator.
 */
static void pm8xxx_vib_close(struct input_dev *dev)
{
        struct pm8xxx_vib *vib = input_get_drvdata(dev);

        cancel_work_sync(&vib->work);
        if (vib->active)
                pm8xxx_vib_set(vib, false);
}

/**
 * pm8xxx_vib_play_effect - function to handle vib effects.
 * @dev: input device pointer
 * @data: data of effect
 * @effect: effect to play
 *
 * Currently this driver supports only rumble effects.
 */
static int pm8xxx_vib_play_effect(struct input_dev *dev, void *data,
                                  struct ff_effect *effect)
{
        struct pm8xxx_vib *vib = input_get_drvdata(dev);

        vib->speed = effect->u.rumble.strong_magnitude >> 8;
        if (!vib->speed)
                vib->speed = effect->u.rumble.weak_magnitude >> 9;

        schedule_work(&vib->work);

        return 0;
}

static int __devinit pm8xxx_vib_probe(struct platform_device *pdev)

{
        struct pm8xxx_vib *vib;
        struct input_dev *input_dev;
        int error;
        u8 val;

        vib = kzalloc(sizeof(*vib), GFP_KERNEL);
        input_dev = input_allocate_device();
        if (!vib || !input_dev) {
                dev_err(&pdev->dev, "couldn't allocate memory\n");
                error = -ENOMEM;
                goto err_free_mem;
        }

        INIT_WORK(&vib->work, pm8xxx_work_handler);
        vib->dev = &pdev->dev;
        vib->vib_input_dev = input_dev;

        /* operate in manual mode */
        error = pm8xxx_vib_read_u8(vib, &val, VIB_DRV);
        if (error < 0)
                goto err_free_mem;
        val &= ~VIB_DRV_EN_MANUAL_MASK;
        error = pm8xxx_vib_write_u8(vib, val, VIB_DRV);
        if (error < 0)
                goto err_free_mem;

        vib->reg_vib_drv = val;

        input_dev->name = "pm8xxx_vib_ffmemless";
        input_dev->id.version = 1;
        input_dev->dev.parent = &pdev->dev;
        input_dev->close = pm8xxx_vib_close;
        input_set_drvdata(input_dev, vib);
        input_set_capability(vib->vib_input_dev, EV_FF, FF_RUMBLE);

        error = input_ff_create_memless(input_dev, NULL,
                                        pm8xxx_vib_play_effect);
        if (error) {
                dev_err(&pdev->dev,
                        "couldn't register vibrator as FF device\n");
                goto err_free_mem;
        }

        error = input_register_device(input_dev);
        if (error) {
                dev_err(&pdev->dev, "couldn't register input device\n");
                goto err_destroy_memless;
        }

        platform_set_drvdata(pdev, vib);
        return 0;

err_destroy_memless:
        input_ff_destroy(input_dev);
err_free_mem:
        input_free_device(input_dev);
        kfree(vib);

        return error;
}

static int __devexit pm8xxx_vib_remove(struct platform_device *pdev)
{
        struct pm8xxx_vib *vib = platform_get_drvdata(pdev);

        input_unregister_device(vib->vib_input_dev);
        kfree(vib);

        platform_set_drvdata(pdev, NULL);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int pm8xxx_vib_suspend(struct device *dev)
{
        struct pm8xxx_vib *vib = dev_get_drvdata(dev);

        /* Turn off the vibrator */
        pm8xxx_vib_set(vib, false);

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(pm8xxx_vib_pm_ops, pm8xxx_vib_suspend, NULL);

static struct platform_driver pm8xxx_vib_driver = {
        .probe          = pm8xxx_vib_probe,
        .remove         = __devexit_p(pm8xxx_vib_remove),
        .driver         = {
                .name   = "pm8xxx-vib",
                .owner  = THIS_MODULE,
                .pm     = &pm8xxx_vib_pm_ops,
        },
};
module_platform_driver(pm8xxx_vib_driver);

MODULE_ALIAS("platform:pm8xxx_vib");
MODULE_DESCRIPTION("PMIC8xxx vibrator driver based on ff-memless framework");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Amy Maloche <amaloche@codeaurora.org>");