/*
   * 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
  ", 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
  ", 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 = dev_get_platdata(&client->dev);
  	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
  ");
  		goto err_free_input_dev;
  	}
  
  	error = input_register_device(dt->input);
  	if (error) {
  		dev_err(&client->dev, "device registration failed
  ");
  		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;
  }
  
  static int __maybe_unused 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 __maybe_unused 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;
  }
  
  static SIMPLE_DEV_PM_OPS(gp2a_pm, gp2a_suspend, gp2a_resume);
  
  static const struct i2c_device_id gp2a_i2c_id[] = {
  	{ GP2A_I2C_NAME, 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, gp2a_i2c_id);
  
  static struct i2c_driver gp2a_i2c_driver = {
  	.driver = {
  		.name	= GP2A_I2C_NAME,
  		.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");