HID: ntrig: fix touch events

This reinstates the lost unpressing of BTN_TOUCH.  To prevent undesireably
touch toggles this also deals with tip switch events.

Added a trap to prevent going out of bounds for hidinputs with empty reports.

Clear bits of unused buttons which result in misidentification.

Signed-off-by: Rafi Rubin <rafi@seas.upenn.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
index 3234c729a895..edcc0c4247bb 100644
--- a/drivers/hid/hid-ntrig.c
+++ b/drivers/hid/hid-ntrig.c
@@ -140,6 +140,9 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
                         nd->reading_mt = 1;
                         nd->first_contact_confidence = 0;
                         break;
+                case HID_DG_TIPSWITCH:
+                        /* Prevent emission of touch until validated */
+                        return 1;
                 case HID_DG_CONFIDENCE:
                         nd->confidence = value;
                         break;
@@ -259,6 +262,7 @@ static int ntrig_event (struct hid_device *hid, struct hid_field *field,
                                                 BTN_TOOL_TRIPLETAP, 0);
                                 input_report_key(input,
                                                 BTN_TOOL_QUADTAP, 0);
+                                input_report_key(input, BTN_TOUCH, 0);
                         }
                         break;
 
@@ -308,13 +312,20 @@ static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 
         list_for_each_entry(hidinput, &hdev->inputs, list) {
+                if (hidinput->report->maxfield < 1)
+                        continue;
+
                 input = hidinput->input;
                 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);
                         /*
                          * A little something special to enable
                          * two and three finger taps.