/*
   *  Copyright (c) 1999-2001 Vojtech Pavlik
   */
  
  /*
   * Magellan and Space Mouse 6dof controller driver for Linux
   */
  
  /*
   * 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 2 of the License, or
   * (at your option) any later version.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   *
   *  Should you need to contact me, the author, you can do so either by
   * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
   * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/input.h>
  #include <linux/serio.h>
  
  #define DRIVER_DESC	"Magellan and SpaceMouse 6dof controller driver"
  
  MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  
  /*
   * Definitions & global arrays.
   */
  
  #define	MAGELLAN_MAX_LENGTH	32
  
  static int magellan_buttons[] = { BTN_0, BTN_1, BTN_2, BTN_3, BTN_4, BTN_5, BTN_6, BTN_7, BTN_8 };
  static int magellan_axes[] = { ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ };
  
  /*
   * Per-Magellan data.
   */
  
  struct magellan {
  	struct input_dev *dev;
  	int idx;
  	unsigned char data[MAGELLAN_MAX_LENGTH];
  	char phys[32];
  };
  
  /*
   * magellan_crunch_nibbles() verifies that the bytes sent from the Magellan
   * have correct upper nibbles for the lower ones, if not, the packet will
   * be thrown away. It also strips these upper halves to simplify further
   * processing.
   */
  
  static int magellan_crunch_nibbles(unsigned char *data, int count)
  {
  	static unsigned char nibbles[16] = "0AB3D56GH9:K<MN?";
  
  	do {
  		if (data[count] == nibbles[data[count] & 0xf])
  			data[count] = data[count] & 0xf;
  		else
  			return -1;
  	} while (--count);
  
  	return 0;
  }
  
  static void magellan_process_packet(struct magellan* magellan)
  {
  	struct input_dev *dev = magellan->dev;
  	unsigned char *data = magellan->data;
  	int i, t;
  
  	if (!magellan->idx) return;
  
  	switch (magellan->data[0]) {
  
  		case 'd':				/* Axis data */
  			if (magellan->idx != 25) return;
  			if (magellan_crunch_nibbles(data, 24)) return;
  			for (i = 0; i < 6; i++)
  				input_report_abs(dev, magellan_axes[i],
  					(data[(i << 2) + 1] << 12 | data[(i << 2) + 2] << 8 |
  					 data[(i << 2) + 3] <<  4 | data[(i << 2) + 4]) - 32768);
  			break;
  
  		case 'k':				/* Button data */
  			if (magellan->idx != 4) return;
  			if (magellan_crunch_nibbles(data, 3)) return;
  			t = (data[1] << 1) | (data[2] << 5) | data[3];
  			for (i = 0; i < 9; i++) input_report_key(dev, magellan_buttons[i], (t >> i) & 1);
  			break;
  	}
  
  	input_sync(dev);
  }
  
  static irqreturn_t magellan_interrupt(struct serio *serio,
  		unsigned char data, unsigned int flags)
  {
  	struct magellan* magellan = serio_get_drvdata(serio);
  
  	if (data == '\r') {
  		magellan_process_packet(magellan);
  		magellan->idx = 0;
  	} else {
  		if (magellan->idx < MAGELLAN_MAX_LENGTH)
  			magellan->data[magellan->idx++] = data;
  	}
  	return IRQ_HANDLED;
  }
  
  /*
   * magellan_disconnect() is the opposite of magellan_connect()
   */
  
  static void magellan_disconnect(struct serio *serio)
  {
  	struct magellan* magellan = serio_get_drvdata(serio);
  
  	serio_close(serio);
  	serio_set_drvdata(serio, NULL);
  	input_unregister_device(magellan->dev);
  	kfree(magellan);
  }
  
  /*
   * magellan_connect() is the routine that is called when someone adds a
   * new serio device that supports Magellan protocol and registers it as
   * an input device.
   */
  
  static int magellan_connect(struct serio *serio, struct serio_driver *drv)
  {
  	struct magellan *magellan;
  	struct input_dev *input_dev;
  	int err = -ENOMEM;
  	int i;
  
  	magellan = kzalloc(sizeof(struct magellan), GFP_KERNEL);
  	input_dev = input_allocate_device();
  	if (!magellan || !input_dev)
  		goto fail1;
  
  	magellan->dev = input_dev;
  	snprintf(magellan->phys, sizeof(magellan->phys), "%s/input0", serio->phys);
  
  	input_dev->name = "LogiCad3D Magellan / SpaceMouse";
  	input_dev->phys = magellan->phys;
  	input_dev->id.bustype = BUS_RS232;
  	input_dev->id.vendor = SERIO_MAGELLAN;
  	input_dev->id.product = 0x0001;
  	input_dev->id.version = 0x0100;
  	input_dev->dev.parent = &serio->dev;
  
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  
  	for (i = 0; i < 9; i++)
  		set_bit(magellan_buttons[i], input_dev->keybit);
  
  	for (i = 0; i < 6; i++)
  		input_set_abs_params(input_dev, magellan_axes[i], -360, 360, 0, 0);
  
  	serio_set_drvdata(serio, magellan);
  
  	err = serio_open(serio, drv);
  	if (err)
  		goto fail2;
  
  	err = input_register_device(magellan->dev);
  	if (err)
  		goto fail3;
  
  	return 0;
  
   fail3:	serio_close(serio);
   fail2:	serio_set_drvdata(serio, NULL);
   fail1:	input_free_device(input_dev);
  	kfree(magellan);
  	return err;
  }
  
  /*
   * The serio driver structure.
   */
  
  static struct serio_device_id magellan_serio_ids[] = {
  	{
  		.type	= SERIO_RS232,
  		.proto	= SERIO_MAGELLAN,
  		.id	= SERIO_ANY,
  		.extra	= SERIO_ANY,
  	},
  	{ 0 }
  };
  
  MODULE_DEVICE_TABLE(serio, magellan_serio_ids);
  
  static struct serio_driver magellan_drv = {
  	.driver		= {
  		.name	= "magellan",
  	},
  	.description	= DRIVER_DESC,
  	.id_table	= magellan_serio_ids,
  	.interrupt	= magellan_interrupt,
  	.connect	= magellan_connect,
  	.disconnect	= magellan_disconnect,
  };
  
  module_serio_driver(magellan_drv);