text: /*
   * Wacom Penabled Driver for I2C
   *
   * Copyright (c) 2011 Tatsunosuke Tobita, Wacom.
   * <tobita.tatsunosuke@wacom.co.jp>
   *
   * 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 of 2 of the License,
   * or (at your option) any later version.
   */
  
  #include <linux/module.h>
  #include <linux/input.h>
  #include <linux/i2c.h>
  #include <linux/slab.h>
  #include <linux/irq.h>
  #include <linux/interrupt.h>
  #include <linux/gpio.h>
  #include <asm/unaligned.h>
  
  #define WACOM_CMD_QUERY0	0x04
  #define WACOM_CMD_QUERY1	0x00
  #define WACOM_CMD_QUERY2	0x33
  #define WACOM_CMD_QUERY3	0x02
  #define WACOM_CMD_THROW0	0x05
  #define WACOM_CMD_THROW1	0x00
  #define WACOM_QUERY_SIZE	19
  #define WACOM_RETRY_CNT		100
  
  struct wacom_features {
  	int x_max;
  	int y_max;
  	int pressure_max;
  	char fw_version;
  };
  
  struct wacom_i2c {
  	struct i2c_client *client;
  	struct input_dev *input;
  	u8 data[WACOM_QUERY_SIZE];
  };
  
  static int wacom_query_device(struct i2c_client *client,
  			      struct wacom_features *features)
  {
  	int ret;
  	u8 cmd1[] = { WACOM_CMD_QUERY0, WACOM_CMD_QUERY1,
  			WACOM_CMD_QUERY2, WACOM_CMD_QUERY3 };
  	u8 cmd2[] = { WACOM_CMD_THROW0, WACOM_CMD_THROW1 };
  	u8 data[WACOM_QUERY_SIZE];
  	struct i2c_msg msgs[] = {
  		{
  			.addr = client->addr,
  			.flags = 0,
  			.len = sizeof(cmd1),
  			.buf = cmd1,
  		},
  		{
  			.addr = client->addr,
  			.flags = 0,
  			.len = sizeof(cmd2),
  			.buf = cmd2,
  		},
  		{
  			.addr = client->addr,
  			.flags = I2C_M_RD,
  			.len = sizeof(data),
  			.buf = data,
  		},
  	};
  
  	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
  	if (ret < 0)
  		return ret;
  	if (ret != ARRAY_SIZE(msgs))
  		return -EIO;
  
  	features->x_max = get_unaligned_le16(&data[3]);
  	features->y_max = get_unaligned_le16(&data[5]);
  	features->pressure_max = get_unaligned_le16(&data[11]);
  	features->fw_version = get_unaligned_le16(&data[13]);
  
  	dev_dbg(&client->dev,
  		"x_max:%d, y_max:%d, pressure:%d, fw:%d\n",
  		features->x_max, features->y_max,
  		features->pressure_max, features->fw_version);
  
  	return 0;
  }
  
  static irqreturn_t wacom_i2c_irq(int irq, void *dev_id)
  {
  	struct wacom_i2c *wac_i2c = dev_id;
  	struct input_dev *input = wac_i2c->input;
  	u8 *data = wac_i2c->data;
  	unsigned int x, y, pressure;
  	unsigned char tsw, f1, f2, ers;
  	int error;
  
  	error = i2c_master_recv(wac_i2c->client,
  				wac_i2c->data, sizeof(wac_i2c->data));
  	if (error < 0)
  		goto out;
  
  	tsw = data[3] & 0x01;
  	ers = data[3] & 0x04;
  	f1 = data[3] & 0x02;
  	f2 = data[3] & 0x10;
  	x = le16_to_cpup((__le16 *)&data[4]);
  	y = le16_to_cpup((__le16 *)&data[6]);
  	pressure = le16_to_cpup((__le16 *)&data[8]);
  
  	input_report_key(input, BTN_TOUCH, tsw || ers);
  	input_report_key(input, BTN_TOOL_PEN, tsw);
  	input_report_key(input, BTN_TOOL_RUBBER, ers);
  	input_report_key(input, BTN_STYLUS, f1);
  	input_report_key(input, BTN_STYLUS2, f2);
  	input_report_abs(input, ABS_X, x);
  	input_report_abs(input, ABS_Y, y);
  	input_report_abs(input, ABS_PRESSURE, pressure);
  	input_sync(input);
  
  out:
  	return IRQ_HANDLED;
  }
  
  static int wacom_i2c_open(struct input_dev *dev)
  {
  	struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
  	struct i2c_client *client = wac_i2c->client;
  
  	enable_irq(client->irq);
  
  	return 0;
  }
  
  static void wacom_i2c_close(struct input_dev *dev)
  {
  	struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
  	struct i2c_client *client = wac_i2c->client;
  
  	disable_irq(client->irq);
  }
  
  static int __devinit wacom_i2c_probe(struct i2c_client *client,
  				     const struct i2c_device_id *id)
  {
  	struct wacom_i2c *wac_i2c;
  	struct input_dev *input;
  	struct wacom_features features;
  	int error;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  		dev_err(&client->dev, "i2c_check_functionality error\n");
  		return -EIO;
  	}
  
  	error = wacom_query_device(client, &features);
  	if (error)
  		return error;
  
  	wac_i2c = kzalloc(sizeof(*wac_i2c), GFP_KERNEL);
  	input = input_allocate_device();
  	if (!wac_i2c || !input) {
  		error = -ENOMEM;
  		goto err_free_mem;
  	}
  
  	wac_i2c->client = client;
  	wac_i2c->input = input;
  
  	input->name = "Wacom I2C Digitizer";
  	input->id.bustype = BUS_I2C;
  	input->id.vendor = 0x56a;
  	input->id.version = features.fw_version;
  	input->dev.parent = &client->dev;
  	input->open = wacom_i2c_open;
  	input->close = wacom_i2c_close;
  
  	input->evbit[0] |= BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  
  	__set_bit(BTN_TOOL_PEN, input->keybit);
  	__set_bit(BTN_TOOL_RUBBER, input->keybit);
  	__set_bit(BTN_STYLUS, input->keybit);
  	__set_bit(BTN_STYLUS2, input->keybit);
  	__set_bit(BTN_TOUCH, input->keybit);
  
  	input_set_abs_params(input, ABS_X, 0, features.x_max, 0, 0);
  	input_set_abs_params(input, ABS_Y, 0, features.y_max, 0, 0);
  	input_set_abs_params(input, ABS_PRESSURE,
  			     0, features.pressure_max, 0, 0);
  
  	input_set_drvdata(input, wac_i2c);
  
  	error = request_threaded_irq(client->irq, NULL, wacom_i2c_irq,
  				     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
  				     "wacom_i2c", wac_i2c);
  	if (error) {
  		dev_err(&client->dev,
  			"Failed to enable IRQ, error: %d\n", error);
  		goto err_free_mem;
  	}
  
  	/* Disable the IRQ, we'll enable it in wac_i2c_open() */
  	disable_irq(client->irq);
  
  	error = input_register_device(wac_i2c->input);
  	if (error) {
  		dev_err(&client->dev,
  			"Failed to register input device, error: %d\n", error);
  		goto err_free_irq;
  	}
  
  	i2c_set_clientdata(client, wac_i2c);
  	return 0;
  
  err_free_irq:
  	free_irq(client->irq, wac_i2c);
  err_free_mem:
  	input_free_device(input);
  	kfree(wac_i2c);
  
  	return error;
  }
  
  static int __devexit wacom_i2c_remove(struct i2c_client *client)
  {
  	struct wacom_i2c *wac_i2c = i2c_get_clientdata(client);
  
  	free_irq(client->irq, wac_i2c);
  	input_unregister_device(wac_i2c->input);
  	kfree(wac_i2c);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int wacom_i2c_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	disable_irq(client->irq);
  
  	return 0;
  }
  
  static int wacom_i2c_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	enable_irq(client->irq);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(wacom_i2c_pm, wacom_i2c_suspend, wacom_i2c_resume);
  
  static const struct i2c_device_id wacom_i2c_id[] = {
  	{ "WAC_I2C_EMR", 0 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, wacom_i2c_id);
  
  static struct i2c_driver wacom_i2c_driver = {
  	.driver	= {
  		.name	= "wacom_i2c",
  		.owner	= THIS_MODULE,
  		.pm	= &wacom_i2c_pm,
  	},
  
  	.probe		= wacom_i2c_probe,
  	.remove		= __devexit_p(wacom_i2c_remove),
  	.id_table	= wacom_i2c_id,
  };
  module_i2c_driver(wacom_i2c_driver);
  
  MODULE_AUTHOR("Tatsunosuke Tobita <tobita.tatsunosuke@wacom.co.jp>");
  MODULE_DESCRIPTION("WACOM EMR I2C Driver");
  MODULE_LICENSE("GPL");
  