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elo.c

/*
 * 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/init.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) {
                        pr_debug("elo: unsynchronized data: 0x%02x\n", data);
                        elo->idx = 0;
                  }
                  break;

            case 9:
                  elo->idx = 0;
                  if (data != elo->csum) {
                        pr_debug("elo: bad checksum: 0x%02x, expected 0x%02x\n",
                               data, elo->csum);
                        break;
                  }
                  if (elo->data[1] != elo->expected_packet) {
                        if (elo->data[1] != ELO10_TOUCH_PACKET)
                              pr_debug("elo: unexpected packet: 0x%02x\n",
                                     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);

      printk(KERN_INFO "elo: %sTouch touchscreen, fw: %02x.%02x, "
            "features: %x02x, controller: 0x%02x\n",
            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,
};

/*
 * The functions for inserting/removing us as a module.
 */

static int __init elo_init(void)
{
      return serio_register_driver(&elo_drv);
}

static void __exit elo_exit(void)
{
      serio_unregister_driver(&elo_drv);
}

module_init(elo_init);
module_exit(elo_exit);

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