in hid-ntrig.c [566:856]
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;
}