+static int int_dist(int x1, int y1, int x2, int y2)
+{
+ int x = x2 - x1;
+ int y = y2 - y1;
+
+ return int_sqrt(x*x + y*y);
+}
+
+static int wacom_24hdt_irq(struct wacom_wac *wacom)
+{
+ struct input_dev *input = wacom->input;
+ char *data = wacom->data;
+ int i;
+ int current_num_contacts = data[61];
+ int contacts_to_send = 0;
+
+ /*
+ * First packet resets the counter since only the first
+ * packet in series will have non-zero current_num_contacts.
+ */
+ if (current_num_contacts)
+ wacom->num_contacts_left = current_num_contacts;
+
+ /* There are at most 4 contacts per packet */
+ contacts_to_send = min(4, wacom->num_contacts_left);
+
+ for (i = 0; i < contacts_to_send; i++) {
+ int offset = (WACOM_BYTES_PER_24HDT_PACKET * i) + 1;
+ bool touch = data[offset] & 0x1 && !wacom->shared->stylus_in_proximity;
+ int id = data[offset + 1];
+ int slot = find_slot_from_contactid(wacom, id);
+
+ if (slot < 0)
+ continue;
+ input_mt_slot(input, slot);
+ input_mt_report_slot_state(input, MT_TOOL_FINGER, touch);
+
+ if (touch) {
+ int t_x = le16_to_cpup((__le16 *)&data[offset + 2]);
+ int c_x = le16_to_cpup((__le16 *)&data[offset + 4]);
+ int t_y = le16_to_cpup((__le16 *)&data[offset + 6]);
+ int c_y = le16_to_cpup((__le16 *)&data[offset + 8]);
+ int w = le16_to_cpup((__le16 *)&data[offset + 10]);
+ int h = le16_to_cpup((__le16 *)&data[offset + 12]);
+
+ input_report_abs(input, ABS_MT_POSITION_X, t_x);
+ input_report_abs(input, ABS_MT_POSITION_Y, t_y);
+ input_report_abs(input, ABS_MT_TOUCH_MAJOR, min(w,h));
+ input_report_abs(input, ABS_MT_WIDTH_MAJOR, min(w, h) + int_dist(t_x, t_y, c_x, c_y));
+ input_report_abs(input, ABS_MT_WIDTH_MINOR, min(w, h));
+ input_report_abs(input, ABS_MT_ORIENTATION, w > h);
+ }
+ wacom->slots[slot] = touch ? id : -1;
+ }
+
+ input_mt_report_pointer_emulation(input, true);
+
+ wacom->num_contacts_left -= contacts_to_send;
+ if (wacom->num_contacts_left <= 0)
+ wacom->num_contacts_left = 0;
+
+ return 1;
+}
+