/*
 * 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 __devinit 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 __devinit 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 __devexit 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		= __devexit_p(gp2a_remove),
	.id_table	= gp2a_i2c_id,
};

static int __init gp2a_init(void)
{
	return i2c_add_driver(&gp2a_i2c_driver);
}

static void __exit gp2a_exit(void)
{
	i2c_del_driver(&gp2a_i2c_driver);
}

module_init(gp2a_init);
module_exit(gp2a_exit);

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