/*
   * Elo serial touchscreen driver
   *
   * Copyright (c) 2004 Vojtech Pavlik
   */
  
  /*
   * 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.
   */
  
  /*
   * This driver can handle serial Elo touchscreens using either the Elo standard
   * 'E271-2210' 10-byte protocol, Elo legacy 'E281A-4002' 6-byte protocol, Elo
   * legacy 'E271-140' 4-byte protocol and Elo legacy 'E261-280' 3-byte protocol.
   */
  
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/input.h>
  #include <linux/serio.h>
  #include <linux/ctype.h>
  
  #define DRIVER_DESC	"Elo serial touchscreen driver"
  
  MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");
  
  /*
   * Definitions & global arrays.
   */
  
  #define ELO_MAX_LENGTH		10
  
  #define ELO10_PACKET_LEN	8
  #define ELO10_TOUCH		0x03
  #define ELO10_PRESSURE		0x80
  
  #define ELO10_LEAD_BYTE		'U'
  
  #define ELO10_ID_CMD		'i'
  
  #define ELO10_TOUCH_PACKET	'T'
  #define ELO10_ACK_PACKET	'A'
  #define ELI10_ID_PACKET		'I'
  
  /*
   * Per-touchscreen data.
   */
  
  struct elo {
  	struct input_dev *dev;
  	struct serio *serio;
  	struct mutex cmd_mutex;
  	struct completion cmd_done;
  	int id;
  	int idx;
  	unsigned char expected_packet;
  	unsigned char csum;
  	unsigned char data[ELO_MAX_LENGTH];
  	unsigned char response[ELO10_PACKET_LEN];
  	char phys[32];
  };
  
  static void elo_process_data_10(struct elo *elo, unsigned char data)
  {
  	struct input_dev *dev = elo->dev;
  
  	elo->data[elo->idx] = data;
  
  	switch (elo->idx++) {
  	case 0:
  		elo->csum = 0xaa;
  		if (data != ELO10_LEAD_BYTE) {
  			dev_dbg(&elo->serio->dev,
  				"unsynchronized data: 0x%02x
  ", data);
  			elo->idx = 0;
  		}
  		break;
  
  	case 9:
  		elo->idx = 0;
  		if (data != elo->csum) {
  			dev_dbg(&elo->serio->dev,
  				"bad checksum: 0x%02x, expected 0x%02x
  ",
  				 data, elo->csum);
  			break;
  		}
  		if (elo->data[1] != elo->expected_packet) {
  			if (elo->data[1] != ELO10_TOUCH_PACKET)
  				dev_dbg(&elo->serio->dev,
  					"unexpected packet: 0x%02x
  ",
  					 elo->data[1]);
  			break;
  		}
  		if (likely(elo->data[1] == ELO10_TOUCH_PACKET)) {
  			input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);
  			input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);
  			if (elo->data[2] & ELO10_PRESSURE)
  				input_report_abs(dev, ABS_PRESSURE,
  						(elo->data[8] << 8) | elo->data[7]);
  			input_report_key(dev, BTN_TOUCH, elo->data[2] & ELO10_TOUCH);
  			input_sync(dev);
  		} else if (elo->data[1] == ELO10_ACK_PACKET) {
  			if (elo->data[2] == '0')
  				elo->expected_packet = ELO10_TOUCH_PACKET;
  			complete(&elo->cmd_done);
  		} else {
  			memcpy(elo->response, &elo->data[1], ELO10_PACKET_LEN);
  			elo->expected_packet = ELO10_ACK_PACKET;
  		}
  		break;
  	}
  	elo->csum += data;
  }
  
  static void elo_process_data_6(struct elo *elo, unsigned char data)
  {
  	struct input_dev *dev = elo->dev;
  
  	elo->data[elo->idx] = data;
  
  	switch (elo->idx++) {
  
  	case 0:
  		if ((data & 0xc0) != 0xc0)
  			elo->idx = 0;
  		break;
  
  	case 1:
  		if ((data & 0xc0) != 0x80)
  			elo->idx = 0;
  		break;
  
  	case 2:
  		if ((data & 0xc0) != 0x40)
  			elo->idx = 0;
  		break;
  
  	case 3:
  		if (data & 0xc0) {
  			elo->idx = 0;
  			break;
  		}
  
  		input_report_abs(dev, ABS_X, ((elo->data[0] & 0x3f) << 6) | (elo->data[1] & 0x3f));
  		input_report_abs(dev, ABS_Y, ((elo->data[2] & 0x3f) << 6) | (elo->data[3] & 0x3f));
  
  		if (elo->id == 2) {
  			input_report_key(dev, BTN_TOUCH, 1);
  			input_sync(dev);
  			elo->idx = 0;
  		}
  
  		break;
  
  	case 4:
  		if (data) {
  			input_sync(dev);
  			elo->idx = 0;
  		}
  		break;
  
  	case 5:
  		if ((data & 0xf0) == 0) {
  			input_report_abs(dev, ABS_PRESSURE, elo->data[5]);
  			input_report_key(dev, BTN_TOUCH, !!elo->data[5]);
  		}
  		input_sync(dev);
  		elo->idx = 0;
  		break;
  	}
  }
  
  static void elo_process_data_3(struct elo *elo, unsigned char data)
  {
  	struct input_dev *dev = elo->dev;
  
  	elo->data[elo->idx] = data;
  
  	switch (elo->idx++) {
  
  	case 0:
  		if ((data & 0x7f) != 0x01)
  			elo->idx = 0;
  		break;
  	case 2:
  		input_report_key(dev, BTN_TOUCH, !(elo->data[1] & 0x80));
  		input_report_abs(dev, ABS_X, elo->data[1]);
  		input_report_abs(dev, ABS_Y, elo->data[2]);
  		input_sync(dev);
  		elo->idx = 0;
  		break;
  	}
  }
  
  static irqreturn_t elo_interrupt(struct serio *serio,
  		unsigned char data, unsigned int flags)
  {
  	struct elo *elo = serio_get_drvdata(serio);
  
  	switch (elo->id) {
  	case 0:
  		elo_process_data_10(elo, data);
  		break;
  
  	case 1:
  	case 2:
  		elo_process_data_6(elo, data);
  		break;
  
  	case 3:
  		elo_process_data_3(elo, data);
  		break;
  	}
  
  	return IRQ_HANDLED;
  }
  
  static int elo_command_10(struct elo *elo, unsigned char *packet)
  {
  	int rc = -1;
  	int i;
  	unsigned char csum = 0xaa + ELO10_LEAD_BYTE;
  
  	mutex_lock(&elo->cmd_mutex);
  
  	serio_pause_rx(elo->serio);
  	elo->expected_packet = toupper(packet[0]);
  	init_completion(&elo->cmd_done);
  	serio_continue_rx(elo->serio);
  
  	if (serio_write(elo->serio, ELO10_LEAD_BYTE))
  		goto out;
  
  	for (i = 0; i < ELO10_PACKET_LEN; i++) {
  		csum += packet[i];
  		if (serio_write(elo->serio, packet[i]))
  			goto out;
  	}
  
  	if (serio_write(elo->serio, csum))
  		goto out;
  
  	wait_for_completion_timeout(&elo->cmd_done, HZ);
  
  	if (elo->expected_packet == ELO10_TOUCH_PACKET) {
  		/* We are back in reporting mode, the command was ACKed */
  		memcpy(packet, elo->response, ELO10_PACKET_LEN);
  		rc = 0;
  	}
  
   out:
  	mutex_unlock(&elo->cmd_mutex);
  	return rc;
  }
  
  static int elo_setup_10(struct elo *elo)
  {
  	static const char *elo_types[] = { "Accu", "Dura", "Intelli", "Carroll" };
  	struct input_dev *dev = elo->dev;
  	unsigned char packet[ELO10_PACKET_LEN] = { ELO10_ID_CMD };
  
  	if (elo_command_10(elo, packet))
  		return -1;
  
  	dev->id.version = (packet[5] << 8) | packet[4];
  
  	input_set_abs_params(dev, ABS_X, 96, 4000, 0, 0);
  	input_set_abs_params(dev, ABS_Y, 96, 4000, 0, 0);
  	if (packet[3] & ELO10_PRESSURE)
  		input_set_abs_params(dev, ABS_PRESSURE, 0, 255, 0, 0);
  
  	dev_info(&elo->serio->dev,
  		 "%sTouch touchscreen, fw: %02x.%02x, features: 0x%02x, controller: 0x%02x
  ",
  		 elo_types[(packet[1] -'0') & 0x03],
  		 packet[5], packet[4], packet[3], packet[7]);
  
  	return 0;
  }
  
  /*
   * elo_disconnect() is the opposite of elo_connect()
   */
  
  static void elo_disconnect(struct serio *serio)
  {
  	struct elo *elo = serio_get_drvdata(serio);
  
  	input_get_device(elo->dev);
  	input_unregister_device(elo->dev);
  	serio_close(serio);
  	serio_set_drvdata(serio, NULL);
  	input_put_device(elo->dev);
  	kfree(elo);
  }
  
  /*
   * elo_connect() is the routine that is called when someone adds a
   * new serio device that supports Gunze protocol and registers it as
   * an input device.
   */
  
  static int elo_connect(struct serio *serio, struct serio_driver *drv)
  {
  	struct elo *elo;
  	struct input_dev *input_dev;
  	int err;
  
  	elo = kzalloc(sizeof(struct elo), GFP_KERNEL);
  	input_dev = input_allocate_device();
  	if (!elo || !input_dev) {
  		err = -ENOMEM;
  		goto fail1;
  	}
  
  	elo->serio = serio;
  	elo->id = serio->id.id;
  	elo->dev = input_dev;
  	elo->expected_packet = ELO10_TOUCH_PACKET;
  	mutex_init(&elo->cmd_mutex);
  	init_completion(&elo->cmd_done);
  	snprintf(elo->phys, sizeof(elo->phys), "%s/input0", serio->phys);
  
  	input_dev->name = "Elo Serial TouchScreen";
  	input_dev->phys = elo->phys;
  	input_dev->id.bustype = BUS_RS232;
  	input_dev->id.vendor = SERIO_ELO;
  	input_dev->id.product = elo->id;
  	input_dev->id.version = 0x0100;
  	input_dev->dev.parent = &serio->dev;
  
  	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
  	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
  
  	serio_set_drvdata(serio, elo);
  	err = serio_open(serio, drv);
  	if (err)
  		goto fail2;
  
  	switch (elo->id) {
  
  	case 0: /* 10-byte protocol */
  		if (elo_setup_10(elo))
  			goto fail3;
  
  		break;
  
  	case 1: /* 6-byte protocol */
  		input_set_abs_params(input_dev, ABS_PRESSURE, 0, 15, 0, 0);
  
  	case 2: /* 4-byte protocol */
  		input_set_abs_params(input_dev, ABS_X, 96, 4000, 0, 0);
  		input_set_abs_params(input_dev, ABS_Y, 96, 4000, 0, 0);
  		break;
  
  	case 3: /* 3-byte protocol */
  		input_set_abs_params(input_dev, ABS_X, 0, 255, 0, 0);
  		input_set_abs_params(input_dev, ABS_Y, 0, 255, 0, 0);
  		break;
  	}
  
  	err = input_register_device(elo->dev);
  	if (err)
  		goto fail3;
  
  	return 0;
  
   fail3: serio_close(serio);
   fail2:	serio_set_drvdata(serio, NULL);
   fail1:	input_free_device(input_dev);
  	kfree(elo);
  	return err;
  }
  
  /*
   * The serio driver structure.
   */
  
  static struct serio_device_id elo_serio_ids[] = {
  	{
  		.type	= SERIO_RS232,
  		.proto	= SERIO_ELO,
  		.id	= SERIO_ANY,
  		.extra	= SERIO_ANY,
  	},
  	{ 0 }
  };
  
  MODULE_DEVICE_TABLE(serio, elo_serio_ids);
  
  static struct serio_driver elo_drv = {
  	.driver		= {
  		.name	= "elo",
  	},
  	.description	= DRIVER_DESC,
  	.id_table	= elo_serio_ids,
  	.interrupt	= elo_interrupt,
  	.connect	= elo_connect,
  	.disconnect	= elo_disconnect,
  };
  
  module_serio_driver(elo_drv);