Quelle  hid-ntrig.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  HID driver for N-Trig touchscreens
 *
 *  Copyright (c) 2008-2010 Rafi Rubin
 *  Copyright (c) 2009-2010 Stephane Chatty
 */

/*
 */

#include <linux/device.h>
#include <linux/hid.h>
#include <linux/usb.h>
#include "usbhid/usbhid.h"
#include <linux/module.h>
#include <linux/slab.h>

#include "hid-ids.h"

#define NTRIG_DUPLICATE_USAGES 0x001

static unsigned int min_width;
module_param(min_width, uint, 0644);
MODULE_PARM_DESC(min_width, "Minimum touch contact width to accept.");

static unsigned int min_height;
module_param(min_height, uint, 0644);
MODULE_PARM_DESC(min_height, "Minimum touch contact height to accept.");

static unsigned int activate_slack = 1;
module_param(activate_slack, uint, 0644);
MODULE_PARM_DESC(activate_slack, "Number of touch frames to ignore at "
   "the start of touch input.");

static unsigned int deactivate_slack = 4;
module_param(deactivate_slack, uint, 0644);
MODULE_PARM_DESC(deactivate_slack, "Number of empty frames to ignore before "
   "deactivating touch.");

static unsigned int activation_width = 64;
module_param(activation_width, uint, 0644);
MODULE_PARM_DESC(activation_width, "Width threshold to immediately start "
   "processing touch events.");

static unsigned int activation_height = 32;
module_param(activation_height, uint, 0644);
MODULE_PARM_DESC(activation_height, "Height threshold to immediately start "
   "processing touch events.");

struct ntrig_data {
 /* Incoming raw values for a single contact */
 __u16 x, y, w, h;
 __u16 id;

 bool tipswitch;
 bool confidence;
 bool first_contact_touch;

 bool reading_mt;

 __u8 mt_footer[4];
 __u8 mt_foot_count;

 /* The current activation state. */
 __s8 act_state;

 /* Empty frames to ignore before recognizing the end of activity */
 __s8 deactivate_slack;

 /* Frames to ignore before acknowledging the start of activity */
 __s8 activate_slack;

 /* Minimum size contact to accept */
 __u16 min_width;
 __u16 min_height;

 /* Threshold to override activation slack */
 __u16 activation_width;
 __u16 activation_height;

 __u16 sensor_logical_width;
 __u16 sensor_logical_height;
 __u16 sensor_physical_width;
 __u16 sensor_physical_height;
};


/*
 * This function converts the 4 byte raw firmware code into
 * a string containing 5 comma separated numbers.
 */
static int ntrig_version_string(unsigned char *raw, char *buf)
{
 __u8 a =  (raw[1] & 0x0e) >> 1;
 __u8 b =  (raw[0] & 0x3c) >> 2;
 __u8 c = ((raw[0] & 0x03) << 3) | ((raw[3] & 0xe0) >> 5);
 __u8 d = ((raw[3] & 0x07) << 3) | ((raw[2] & 0xe0) >> 5);
 __u8 e =   raw[2] & 0x07;

 /*
 * As yet unmapped bits:
 * 0b11000000 0b11110001 0b00011000 0b00011000
 */

 return sprintf(buf, "%u.%u.%u.%u.%u", a, b, c, d, e);
}

static inline int ntrig_get_mode(struct hid_device *hdev)
{
 struct hid_report *report = hdev->report_enum[HID_FEATURE_REPORT].
        report_id_hash[0x0d];

 if (!report || report->maxfield < 1 ||
     report->field[0]->report_count < 1)
  return -EINVAL;

 hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
 hid_hw_wait(hdev);
 return (int)report->field[0]->value[0];
}

static inline void ntrig_set_mode(struct hid_device *hdev, const int mode)
{
 struct hid_report *report;
 __u8 mode_commands[4] = { 0xe, 0xf, 0x1b, 0x10 };

 if (mode < 0 || mode > 3)
  return;

 report = hdev->report_enum[HID_FEATURE_REPORT].
   report_id_hash[mode_commands[mode]];

 if (!report)
  return;

 hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
}

static void ntrig_report_version(struct hid_device *hdev)
{
 int ret;
 char buf[20];
 struct usb_device *usb_dev = hid_to_usb_dev(hdev);
 unsigned char *data __free(kfree) = kmalloc(8, GFP_KERNEL);

 if (!hid_is_usb(hdev))
  return;

 if (!data)
  return;

 ret = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
         USB_REQ_CLEAR_FEATURE,
         USB_TYPE_CLASS | USB_RECIP_INTERFACE |
         USB_DIR_IN,
         0x30c, 1, data, 8,
         USB_CTRL_SET_TIMEOUT);

 if (ret == 8) {
  ret = ntrig_version_string(&data[2], buf);

  hid_info(hdev, "Firmware version: %s (%02x%02x %02x%02x)\n",
    buf, data[2], data[3], data[4], data[5]);
 }
}

static ssize_t show_phys_width(struct device *dev,
          struct device_attribute *attr,
          char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->sensor_physical_width);
}

static DEVICE_ATTR(sensor_physical_width, S_IRUGO, show_phys_width, NULL);

static ssize_t show_phys_height(struct device *dev,
    struct device_attribute *attr,
    char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->sensor_physical_height);
}

static DEVICE_ATTR(sensor_physical_height, S_IRUGO, show_phys_height, NULL);

static ssize_t show_log_width(struct device *dev,
         struct device_attribute *attr,
         char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->sensor_logical_width);
}

static DEVICE_ATTR(sensor_logical_width, S_IRUGO, show_log_width, NULL);

static ssize_t show_log_height(struct device *dev,
          struct device_attribute *attr,
          char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->sensor_logical_height);
}

static DEVICE_ATTR(sensor_logical_height, S_IRUGO, show_log_height, NULL);

static ssize_t show_min_width(struct device *dev,
         struct device_attribute *attr,
         char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->min_width *
        nd->sensor_physical_width /
        nd->sensor_logical_width);
}

static ssize_t set_min_width(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 if (val > nd->sensor_physical_width)
  return -EINVAL;

 nd->min_width = val * nd->sensor_logical_width /
         nd->sensor_physical_width;

 return count;
}

static DEVICE_ATTR(min_width, S_IWUSR | S_IRUGO, show_min_width, set_min_width);

static ssize_t show_min_height(struct device *dev,
          struct device_attribute *attr,
          char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->min_height *
        nd->sensor_physical_height /
        nd->sensor_logical_height);
}

static ssize_t set_min_height(struct device *dev,
         struct device_attribute *attr,
         const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 if (val > nd->sensor_physical_height)
  return -EINVAL;

 nd->min_height = val * nd->sensor_logical_height /
          nd->sensor_physical_height;

 return count;
}

static DEVICE_ATTR(min_height, S_IWUSR | S_IRUGO, show_min_height,
     set_min_height);

static ssize_t show_activate_slack(struct device *dev,
       struct device_attribute *attr,
       char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->activate_slack);
}

static ssize_t set_activate_slack(struct device *dev,
      struct device_attribute *attr,
      const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 if (val > 0x7f)
  return -EINVAL;

 nd->activate_slack = val;

 return count;
}

static DEVICE_ATTR(activate_slack, S_IWUSR | S_IRUGO, show_activate_slack,
     set_activate_slack);

static ssize_t show_activation_width(struct device *dev,
         struct device_attribute *attr,
         char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->activation_width *
        nd->sensor_physical_width /
        nd->sensor_logical_width);
}

static ssize_t set_activation_width(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 if (val > nd->sensor_physical_width)
  return -EINVAL;

 nd->activation_width = val * nd->sensor_logical_width /
         nd->sensor_physical_width;

 return count;
}

static DEVICE_ATTR(activation_width, S_IWUSR | S_IRUGO, show_activation_width,
     set_activation_width);

static ssize_t show_activation_height(struct device *dev,
          struct device_attribute *attr,
          char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", nd->activation_height *
        nd->sensor_physical_height /
        nd->sensor_logical_height);
}

static ssize_t set_activation_height(struct device *dev,
         struct device_attribute *attr,
         const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 if (val > nd->sensor_physical_height)
  return -EINVAL;

 nd->activation_height = val * nd->sensor_logical_height /
          nd->sensor_physical_height;

 return count;
}

static DEVICE_ATTR(activation_height, S_IWUSR | S_IRUGO,
     show_activation_height, set_activation_height);

static ssize_t show_deactivate_slack(struct device *dev,
         struct device_attribute *attr,
         char *buf)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 return sprintf(buf, "%d\n", -nd->deactivate_slack);
}

static ssize_t set_deactivate_slack(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t count)
{
 struct hid_device *hdev = to_hid_device(dev);
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 unsigned long val;

 if (kstrtoul(buf, 0, &val))
  return -EINVAL;

 /*
 * No more than 8 terminal frames have been observed so far
 * and higher slack is highly likely to leave the single
 * touch emulation stuck down.
 */
 if (val > 7)
  return -EINVAL;

 nd->deactivate_slack = -val;

 return count;
}

static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
     set_deactivate_slack);

static struct attribute *sysfs_attrs[] = {
 &dev_attr_sensor_physical_width.attr,
 &dev_attr_sensor_physical_height.attr,
 &dev_attr_sensor_logical_width.attr,
 &dev_attr_sensor_logical_height.attr,
 &dev_attr_min_height.attr,
 &dev_attr_min_width.attr,
 &dev_attr_activate_slack.attr,
 &dev_attr_activation_width.attr,
 &dev_attr_activation_height.attr,
 &dev_attr_deactivate_slack.attr,
 NULL
};

static const struct attribute_group ntrig_attribute_group = {
 .attrs = sysfs_attrs
};

/*
 * this driver is aimed at two firmware versions in circulation:
 *  - dual pen/finger single touch
 *  - finger multitouch, pen not working
 */

static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
          struct hid_field *field, struct hid_usage *usage,
          unsigned long **bit, int *max)
{
 struct ntrig_data *nd = hid_get_drvdata(hdev);

 /* No special mappings needed for the pen and single touch */
 if (field->physical)
  return 0;

 switch (usage->hid & HID_USAGE_PAGE) {
 case HID_UP_GENDESK:
  switch (usage->hid) {
  case HID_GD_X:
   hid_map_usage(hi, usage, bit, max,
     EV_ABS, ABS_MT_POSITION_X);
   input_set_abs_params(hi->input, ABS_X,
     field->logical_minimum,
     field->logical_maximum, 0, 0);

   if (!nd->sensor_logical_width) {
    nd->sensor_logical_width =
     field->logical_maximum -
     field->logical_minimum;
    nd->sensor_physical_width =
     field->physical_maximum -
     field->physical_minimum;
    nd->activation_width = activation_width *
     nd->sensor_logical_width /
     nd->sensor_physical_width;
    nd->min_width = min_width *
     nd->sensor_logical_width /
     nd->sensor_physical_width;
   }
   return 1;
  case HID_GD_Y:
   hid_map_usage(hi, usage, bit, max,
     EV_ABS, ABS_MT_POSITION_Y);
   input_set_abs_params(hi->input, ABS_Y,
     field->logical_minimum,
     field->logical_maximum, 0, 0);

   if (!nd->sensor_logical_height) {
    nd->sensor_logical_height =
     field->logical_maximum -
     field->logical_minimum;
    nd->sensor_physical_height =
     field->physical_maximum -
     field->physical_minimum;
    nd->activation_height = activation_height *
     nd->sensor_logical_height /
     nd->sensor_physical_height;
    nd->min_height = min_height *
     nd->sensor_logical_height /
     nd->sensor_physical_height;
   }
   return 1;
  }
  return 0;

 case HID_UP_DIGITIZER:
  switch (usage->hid) {
  /* we do not want to map these for now */
  case HID_DG_CONTACTID: /* Not trustworthy, squelch for now */
  case HID_DG_INPUTMODE:
  case HID_DG_DEVICEINDEX:
  case HID_DG_CONTACTMAX:
   return -1;

  /* width/height mapped on TouchMajor/TouchMinor/Orientation */
  case HID_DG_WIDTH:
   hid_map_usage(hi, usage, bit, max,
          EV_ABS, ABS_MT_TOUCH_MAJOR);
   return 1;
  case HID_DG_HEIGHT:
   hid_map_usage(hi, usage, bit, max,
          EV_ABS, ABS_MT_TOUCH_MINOR);
   input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
          0, 1, 0, 0);
   return 1;
  }
  return 0;

 case 0xff000000:
  /* we do not want to map these: no input-oriented meaning */
  return -1;
 }

 return 0;
}

static int ntrig_input_mapped(struct hid_device *hdev, struct hid_input *hi,
         struct hid_field *field, struct hid_usage *usage,
         unsigned long **bit, int *max)
{
 /* No special mappings needed for the pen and single touch */
 if (field->physical)
  return 0;

 if (usage->type == EV_KEY || usage->type == EV_REL
   || usage->type == EV_ABS)
  clear_bit(usage->code, *bit);

 return 0;
}

/*
 * this function is called upon all reports
 * so that we can filter contact point information,
 * decide whether we are in multi or single touch mode
 * and call input_mt_sync after each point if necessary
 */
static int ntrig_event (struct hid_device *hid, struct hid_field *field,
   struct hid_usage *usage, __s32 value)
{
 struct ntrig_data *nd = hid_get_drvdata(hid);
 struct input_dev *input;

 /* Skip processing if not a claimed input */
 if (!(hid->claimed & HID_CLAIMED_INPUT))
  goto not_claimed_input;

 /* This function is being called before the structures are fully
 * initialized */
 if(!(field->hidinput && field->hidinput->input))
  return -EINVAL;

 input = field->hidinput->input;

 /* No special handling needed for the pen */
 if (field->application == HID_DG_PEN)
  return 0;

 switch (usage->hid) {
 case 0xff000001:
  /* Tag indicating the start of a multitouch group */
  nd->reading_mt = true;
  nd->first_contact_touch = false;
  break;
 case HID_DG_TIPSWITCH:
  nd->tipswitch = value;
  /* Prevent emission of touch until validated */
  return 1;
 case HID_DG_CONFIDENCE:
  nd->confidence = value;
  break;
 case HID_GD_X:
  nd->x = value;
  /* Clear the contact footer */
  nd->mt_foot_count = 0;
  break;
 case HID_GD_Y:
  nd->y = value;
  break;
 case HID_DG_CONTACTID:
  nd->id = value;
  break;
 case HID_DG_WIDTH:
  nd->w = value;
  break;
 case HID_DG_HEIGHT:
  nd->h = value;
  /*
 * when in single touch mode, this is the last
 * report received in a finger event. We want
 * to emit a normal (X, Y) position
 */
  if (!nd->reading_mt) {
   /*
 * TipSwitch indicates the presence of a
 * finger in single touch mode.
 */
   input_report_key(input, BTN_TOUCH,
      nd->tipswitch);
   input_report_key(input, BTN_TOOL_DOUBLETAP,
      nd->tipswitch);
   input_event(input, EV_ABS, ABS_X, nd->x);
   input_event(input, EV_ABS, ABS_Y, nd->y);
  }
  break;
 case 0xff000002:
  /*
 * we receive this when the device is in multitouch
 * mode. The first of the three values tagged with
 * this usage tells if the contact point is real
 * or a placeholder
 */

  /* Shouldn't get more than 4 footer packets, so skip */
  if (nd->mt_foot_count >= 4)
   break;

  nd->mt_footer[nd->mt_foot_count++] = value;

  /* if the footer isn't complete break */
  if (nd->mt_foot_count != 4)
   break;

  /* Pen activity signal. */
  if (nd->mt_footer[2]) {
   /*
 * When the pen deactivates touch, we see a
 * bogus frame with ContactCount > 0.
 * We can
 * save a bit of work by ensuring act_state < 0
 * even if deactivation slack is turned off.
 */
   nd->act_state = deactivate_slack - 1;
   nd->confidence = false;
   break;
  }

  /*
 * The first footer value indicates the presence of a
 * finger.
 */
  if (nd->mt_footer[0]) {
   /*
 * We do not want to process contacts under
 * the size threshold, but do not want to
 * ignore them for activation state
 */
   if (nd->w < nd->min_width ||
       nd->h < nd->min_height)
    nd->confidence = false;
  } else
   break;

  if (nd->act_state > 0) {
   /*
 * Contact meets the activation size threshold
 */
   if (nd->w >= nd->activation_width &&
       nd->h >= nd->activation_height) {
    if (nd->id)
     /*
 * first contact, activate now
 */
     nd->act_state = 0;
    else {
     /*
 * avoid corrupting this frame
 * but ensure next frame will
 * be active
 */
     nd->act_state = 1;
     break;
    }
   } else
    /*
 * Defer adjusting the activation state
 * until the end of the frame.
 */
    break;
  }

  /* Discarding this contact */
  if (!nd->confidence)
   break;

  /* emit a normal (X, Y) for the first point only */
  if (nd->id == 0) {
   /*
 * TipSwitch is superfluous in multitouch
 * mode.  The footer events tell us
 * if there is a finger on the screen or
 * not.
 */
   nd->first_contact_touch = nd->confidence;
   input_event(input, EV_ABS, ABS_X, nd->x);
   input_event(input, EV_ABS, ABS_Y, nd->y);
  }

  /* Emit MT events */
  input_event(input, EV_ABS, ABS_MT_POSITION_X, nd->x);
  input_event(input, EV_ABS, ABS_MT_POSITION_Y, nd->y);

  /*
 * Translate from height and width to size
 * and orientation.
 */
  if (nd->w > nd->h) {
   input_event(input, EV_ABS,
     ABS_MT_ORIENTATION, 1);
   input_event(input, EV_ABS,
     ABS_MT_TOUCH_MAJOR, nd->w);
   input_event(input, EV_ABS,
     ABS_MT_TOUCH_MINOR, nd->h);
  } else {
   input_event(input, EV_ABS,
     ABS_MT_ORIENTATION, 0);
   input_event(input, EV_ABS,
     ABS_MT_TOUCH_MAJOR, nd->h);
   input_event(input, EV_ABS,
     ABS_MT_TOUCH_MINOR, nd->w);
  }
  input_mt_sync(field->hidinput->input);
  break;

 case HID_DG_CONTACTCOUNT: /* End of a multitouch group */
  if (!nd->reading_mt) /* Just to be sure */
   break;

  nd->reading_mt = false;


  /*
 * Activation state machine logic:
 *
 * Fundamental states:
 * state >  0: Inactive
 * state <= 0: Active
 * state <  -deactivate_slack:
 *  Pen termination of touch
 *
 * Specific values of interest
 * state == activate_slack
 *  no valid input since the last reset
 *
 * state == 0
 *  general operational state
 *
 * state == -deactivate_slack
 *  read sufficient empty frames to accept
 *  the end of input and reset
 */

  if (nd->act_state > 0) { /* Currently inactive */
   if (value)
    /*
 * Consider each live contact as
 * evidence of intentional activity.
 */
    nd->act_state = (nd->act_state > value)
      ? nd->act_state - value
      : 0;
   else
    /*
 * Empty frame before we hit the
 * activity threshold, reset.
 */
    nd->act_state = nd->activate_slack;

   /*
 * Entered this block inactive and no
 * coordinates sent this frame, so hold off
 * on button state.
 */
   break;
  } else { /* Currently active */
   if (value && nd->act_state >=
         nd->deactivate_slack)
    /*
 * Live point: clear accumulated
 * deactivation count.
 */
    nd->act_state = 0;
   else if (nd->act_state <= nd->deactivate_slack)
    /*
 * We've consumed the deactivation
 * slack, time to deactivate and reset.
 */
    nd->act_state =
     nd->activate_slack;
   else { /* Move towards deactivation */
    nd->act_state--;
    break;
   }
  }

  if (nd->first_contact_touch && nd->act_state <= 0) {
   /*
 * Check to see if we're ready to start
 * emitting touch events.
 *
 * Note: activation slack will decrease over
 * the course of the frame, and it will be
 * inconsistent from the start to the end of
 * the frame.  However if the frame starts
 * with slack, first_contact_touch will still
 * be 0 and we will not get to this point.
 */
   input_report_key(input, BTN_TOOL_DOUBLETAP, 1);
   input_report_key(input, BTN_TOUCH, 1);
  } else {
   input_report_key(input, BTN_TOOL_DOUBLETAP, 0);
   input_report_key(input, BTN_TOUCH, 0);
  }
  break;

 default:
  /* fall-back to the generic hidinput handling */
  return 0;
 }

not_claimed_input:

 /* we have handled the hidinput part, now remains hiddev */
 if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_hid_event)
  hid->hiddev_hid_event(hid, field, usage, value);

 return 1;
}

static int ntrig_input_configured(struct hid_device *hid,
  struct hid_input *hidinput)

{
 struct input_dev *input = hidinput->input;

 if (hidinput->report->maxfield < 1)
  return 0;

 switch (hidinput->report->field[0]->application) {
 case HID_DG_PEN:
  input->name = "N-Trig Pen";
  break;
 case HID_DG_TOUCHSCREEN:
  /* These keys are redundant for fingers, clear them
 * to prevent incorrect identification */
  __clear_bit(BTN_TOOL_PEN, input->keybit);
  __clear_bit(BTN_TOOL_FINGER, input->keybit);
  __clear_bit(BTN_0, input->keybit);
  __set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
  /*
 * The physical touchscreen (single touch)
 * input has a value for physical, whereas
 * the multitouch only has logical input
 * fields.
 */
  input->name = (hidinput->report->field[0]->physical) ?
       "N-Trig Touchscreen" :
       "N-Trig MultiTouch";
  break;
 }

 return 0;
}

static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
 int ret;
 struct ntrig_data *nd;
 struct hid_report *report;

 if (id->driver_data)
  hdev->quirks |= HID_QUIRK_MULTI_INPUT
    | HID_QUIRK_NO_INIT_REPORTS;

 nd = kmalloc(sizeof(struct ntrig_data), GFP_KERNEL);
 if (!nd) {
  hid_err(hdev, "cannot allocate N-Trig data\n");
  return -ENOMEM;
 }

 nd->reading_mt = false;
 nd->min_width = 0;
 nd->min_height = 0;
 nd->activate_slack = activate_slack;
 nd->act_state = activate_slack;
 nd->deactivate_slack = -deactivate_slack;
 nd->sensor_logical_width = 1;
 nd->sensor_logical_height = 1;
 nd->sensor_physical_width = 1;
 nd->sensor_physical_height = 1;

 hid_set_drvdata(hdev, nd);

 ret = hid_parse(hdev);
 if (ret) {
  hid_err(hdev, "parse failed\n");
  goto err_free;
 }

 ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
 if (ret) {
  hid_err(hdev, "hw start failed\n");
  goto err_free;
 }

 /* This is needed for devices with more recent firmware versions */
 report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
 if (report) {
  /* Let the device settle to ensure the wakeup message gets
 * through */
  hid_hw_wait(hdev);
  hid_hw_request(hdev, report, HID_REQ_GET_REPORT);

  /*
 * Sanity check: if the current mode is invalid reset it to
 * something reasonable.
 */
  if (ntrig_get_mode(hdev) >= 4)
   ntrig_set_mode(hdev, 3);
 }

 ntrig_report_version(hdev);

 ret = sysfs_create_group(&hdev->dev.kobj,
   &ntrig_attribute_group);
 if (ret)
  hid_err(hdev, "cannot create sysfs group\n");

 return 0;
err_free:
 kfree(nd);
 return ret;
}

static void ntrig_remove(struct hid_device *hdev)
{
 sysfs_remove_group(&hdev->dev.kobj,
      &ntrig_attribute_group);
 hid_hw_stop(hdev);
 kfree(hid_get_drvdata(hdev));
}

static const struct hid_device_id ntrig_devices[] = {
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_3),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_4),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_5),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_6),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_7),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_8),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_9),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_10),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_11),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_12),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_13),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_14),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_15),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_16),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18),
  .driver_data = NTRIG_DUPLICATE_USAGES },
 { }
};
MODULE_DEVICE_TABLE(hid, ntrig_devices);

static const struct hid_usage_id ntrig_grabbed_usages[] = {
 { HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
 { HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
};

static struct hid_driver ntrig_driver = {
 .name = "ntrig",
 .id_table = ntrig_devices,
 .probe = ntrig_probe,
 .remove = ntrig_remove,
 .input_mapping = ntrig_input_mapping,
 .input_mapped = ntrig_input_mapped,
 .input_configured = ntrig_input_configured,
 .usage_table = ntrig_grabbed_usages,
 .event = ntrig_event,
};
module_hid_driver(ntrig_driver);

MODULE_DESCRIPTION("HID driver for N-Trig touchscreens");
MODULE_LICENSE("GPL");