differing devices.
Signed-off-by: Rafi Rubin <rafi@seas.upenn.edu>
---
Module parameters and sysfs nodes to adjust these filters will be
submitted in a separate patch. For now I think its important that users
can easily tune these parameters, since I can't be sure that I've picked
optimal values.
---
drivers/hid/hid-ntrig.c | 220 +++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 211 insertions(+), 9 deletions(-)
@@ -24,6 +24,13 @@
#define NTRIG_DUPLICATE_USAGES 0x001
+static unsigned int min_width;
+static unsigned int min_height;
+static unsigned int activate_slack = 1;
+static unsigned int deactivate_slack = 4;
+static unsigned int activation_width = 64;
+static unsigned int activation_height = 32;
+
struct ntrig_data {
/* Incoming raw values for a single contact */
__u16 x, y, w, h;
@@ -37,6 +44,28 @@ struct ntrig_data {
__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;
};
/*
@@ -49,6 +78,8 @@ 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;
@@ -62,6 +93,21 @@ static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
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,
@@ -69,6 +115,21 @@ static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
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;
@@ -201,20 +262,68 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
if (nd->mt_foot_count != 4)
break;
- /* Pen activity signal, trigger end of touch. */
+ /* 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 = 0;
break;
}
- /* If the contact was invalid */
- if (!(nd->confidence && nd->mt_footer[0])
- || nd->w <= 250
- || nd->h <= 190) {
- nd->confidence = 0;
+ /*
+ * 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 = 0;
+ } 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) {
/*
@@ -227,8 +336,15 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
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);
@@ -248,12 +364,88 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
break;
case HID_DG_CONTACTCOUNT: /* End of a multitouch group */
- if (!nd->reading_mt)
+ if (!nd->reading_mt) /* Just to be sure */
break;
nd->reading_mt = 0;
- if (nd->first_contact_touch) {
+
+ /*
+ * 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 {
@@ -263,7 +455,7 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
break;
default:
- /* fallback to the generic hidinput handling */
+ /* fall-back to the generic hidinput handling */
return 0;
}
}
@@ -293,6 +485,16 @@ static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
}
nd->reading_mt = 0;
+ 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 = 0;
+ nd->sensor_logical_height = 0;
+ nd->sensor_physical_width = 0;
+ nd->sensor_physical_height = 0;
+
hid_set_drvdata(hdev, nd);
ret = hid_parse(hdev);