/*
 * Copyright (C) 2011 Sony Ericsson Mobile Communications Inc.
 *
 * Author: Courtney Cavin <courtney.cavin@sonyericsson.com>
 * Prepared for up-stream by: Oskar Andero <oskar.andero@sonyericsson.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2, as
 * published by the Free Software Foundation.
 */

#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/input/gp2ap002a00f.h>

struct gp2a_data {
        struct input_dev *input;
        const struct gp2a_platform_data *pdata;
        struct i2c_client *i2c_client;
};

enum gp2a_addr {
        GP2A_ADDR_PROX  = 0x0,
        GP2A_ADDR_GAIN  = 0x1,
        GP2A_ADDR_HYS   = 0x2,
        GP2A_ADDR_CYCLE = 0x3,
        GP2A_ADDR_OPMOD = 0x4,
        GP2A_ADDR_CON   = 0x6
};

enum gp2a_controls {
        /* Software Shutdown control: 0 = shutdown, 1 = normal operation */
        GP2A_CTRL_SSD   = 0x01
};

static int gp2a_report(struct gp2a_data *dt)
{
        int vo = gpio_get_value(dt->pdata->vout_gpio);

        input_report_switch(dt->input, SW_FRONT_PROXIMITY, !vo);
        input_sync(dt->input);

        return 0;
}

static irqreturn_t gp2a_irq(int irq, void *handle)
{
        struct gp2a_data *dt = handle;

        gp2a_report(dt);

        return IRQ_HANDLED;
}

static int gp2a_enable(struct gp2a_data *dt)
{
        return i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_OPMOD,
                                         GP2A_CTRL_SSD);
}

static int gp2a_disable(struct gp2a_data *dt)
{
        return i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_OPMOD,
                                         0x00);
}

static int gp2a_device_open(struct input_dev *dev)
{
        struct gp2a_data *dt = input_get_drvdata(dev);
        int error;

        error = gp2a_enable(dt);
        if (error < 0) {
                dev_err(&dt->i2c_client->dev,
                        "unable to activate, err %d\n", error);
                return error;
        }

        gp2a_report(dt);

        return 0;
}

static void gp2a_device_close(struct input_dev *dev)
{
        struct gp2a_data *dt = input_get_drvdata(dev);
        int error;

        error = gp2a_disable(dt);
        if (error < 0)
                dev_err(&dt->i2c_client->dev,
                        "unable to deactivate, err %d\n", error);
}

static int gp2a_initialize(struct gp2a_data *dt)
{
        int error;

        error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_GAIN,
                                          0x08);
        if (error < 0)
                return error;

        error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_HYS,
                                          0xc2);
        if (error < 0)
                return error;

        error = i2c_smbus_write_byte_data(dt->i2c_client, GP2A_ADDR_CYCLE,
                                          0x04);
        if (error < 0)
                return error;

        error = gp2a_disable(dt);

        return error;
}

static int gp2a_probe(struct i2c_client *client,
                                const struct i2c_device_id *id)
{
        const struct gp2a_platform_data *pdata = client->dev.platform_data;
        struct gp2a_data *dt;
        int error;

        if (!pdata)
                return -EINVAL;

        if (pdata->hw_setup) {
                error = pdata->hw_setup(client);
                if (error < 0)
                        return error;
        }

        error = gpio_request_one(pdata->vout_gpio, GPIOF_IN, GP2A_I2C_NAME);
        if (error)
                goto err_hw_shutdown;

        dt = kzalloc(sizeof(struct gp2a_data), GFP_KERNEL);
        if (!dt) {
                error = -ENOMEM;
                goto err_free_gpio;
        }

        dt->pdata = pdata;
        dt->i2c_client = client;

        error = gp2a_initialize(dt);
        if (error < 0)
                goto err_free_mem;

        dt->input = input_allocate_device();
        if (!dt->input) {
                error = -ENOMEM;
                goto err_free_mem;
        }

        input_set_drvdata(dt->input, dt);

        dt->input->open = gp2a_device_open;
        dt->input->close = gp2a_device_close;
        dt->input->name = GP2A_I2C_NAME;
        dt->input->id.bustype = BUS_I2C;
        dt->input->dev.parent = &client->dev;

        input_set_capability(dt->input, EV_SW, SW_FRONT_PROXIMITY);

        error = request_threaded_irq(client->irq, NULL, gp2a_irq,
                        IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
                                IRQF_ONESHOT,
                        GP2A_I2C_NAME, dt);
        if (error) {
                dev_err(&client->dev, "irq request failed\n");
                goto err_free_input_dev;
        }

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

        device_init_wakeup(&client->dev, pdata->wakeup);
        i2c_set_clientdata(client, dt);

        return 0;

err_free_irq:
        free_irq(client->irq, dt);
err_free_input_dev:
        input_free_device(dt->input);
err_free_mem:
        kfree(dt);
err_free_gpio:
        gpio_free(pdata->vout_gpio);
err_hw_shutdown:
        if (pdata->hw_shutdown)
                pdata->hw_shutdown(client);
        return error;
}

static int gp2a_remove(struct i2c_client *client)
{
        struct gp2a_data *dt = i2c_get_clientdata(client);
        const struct gp2a_platform_data *pdata = dt->pdata;

        device_init_wakeup(&client->dev, false);

        free_irq(client->irq, dt);

        input_unregister_device(dt->input);
        kfree(dt);

        gpio_free(pdata->vout_gpio);

        if (pdata->hw_shutdown)
                pdata->hw_shutdown(client);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int gp2a_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct gp2a_data *dt = i2c_get_clientdata(client);
        int retval = 0;

        if (device_may_wakeup(&client->dev)) {
                enable_irq_wake(client->irq);
        } else {
                mutex_lock(&dt->input->mutex);
                if (dt->input->users)
                        retval = gp2a_disable(dt);
                mutex_unlock(&dt->input->mutex);
        }

        return retval;
}

static int gp2a_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct gp2a_data *dt = i2c_get_clientdata(client);
        int retval = 0;

        if (device_may_wakeup(&client->dev)) {
                disable_irq_wake(client->irq);
        } else {
                mutex_lock(&dt->input->mutex);
                if (dt->input->users)
                        retval = gp2a_enable(dt);
                mutex_unlock(&dt->input->mutex);
        }

        return retval;
}
#endif

static SIMPLE_DEV_PM_OPS(gp2a_pm, gp2a_suspend, gp2a_resume);

static const struct i2c_device_id gp2a_i2c_id[] = {
        { GP2A_I2C_NAME, 0 },
        { }
};

static struct i2c_driver gp2a_i2c_driver = {
        .driver = {
                .name   = GP2A_I2C_NAME,
                .owner  = THIS_MODULE,
                .pm     = &gp2a_pm,
        },
        .probe          = gp2a_probe,
        .remove         = gp2a_remove,
        .id_table       = gp2a_i2c_id,
};

module_i2c_driver(gp2a_i2c_driver);

MODULE_AUTHOR("Courtney Cavin <courtney.cavin@sonyericsson.com>");
MODULE_DESCRIPTION("Sharp GP2AP002A00F I2C Proximity/Opto sensor driver");
MODULE_LICENSE("GPL v2");