[PATCH 08/10] HID: hid-multitouch: support for hovering devices

[Benjamin Tissoires <benjamin.tissoires@gmail.com>]

Win8 devices supporting hovering must provides InRange HID field.
The information that the finger is here but is not touching the surface
is sent to the user space through ABS_MT_DISTANCE as required by the
multitouch protocol.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
---
 drivers/hid/hid-multitouch.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 6d4ad30..5aebbff 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -55,7 +55,7 @@ MODULE_LICENSE("GPL");
 #define MT_QUIRK_WIN_8_CERTIFIED	(1 << 10)
 
 struct mt_slot {
-	__s32 x, y, cx, cy, p, w, h;
+	__s32 x, y, cx, cy, z, p, w, h;
 	__s32 contactid;	/* the device ContactID assigned to this slot */
 	bool touch_state;	/* is the touch valid? */
 };
@@ -394,6 +394,12 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 	case HID_UP_DIGITIZER:
 		switch (usage->hid) {
 		case HID_DG_INRANGE:
+			if (cls->quirks & MT_QUIRK_WIN_8_CERTIFIED) {
+				hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_DISTANCE);
+				input_set_abs_params(hi->input,
+					ABS_MT_DISTANCE, 0, 1, 0, 0);
+			}
 			mt_store_field(usage, td, hi);
 			td->last_field_index = field->index;
 			return 1;
@@ -511,6 +517,11 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
 		struct mt_slot *s = &td->curdata;
 
 		if (td->mtclass.quirks & MT_QUIRK_WIN_8_CERTIFIED &&
+		    !test_bit(ABS_MT_DISTANCE, input->absbit))
+			/* If InRange is not present, rely on TipSwitch */
+			s->touch_state = !s->z;
+
+		if (td->mtclass.quirks & MT_QUIRK_WIN_8_CERTIFIED &&
 		    !s->touch_state) {
 			struct input_mt_slot *slot = &input->mt->slots[slotnum];
 			int prv_x = input_mt_get_value(slot, ABS_MT_POSITION_X);
@@ -543,6 +554,7 @@ static void mt_complete_slot(struct mt_device *td, struct input_dev *input)
 				input_event(input, EV_ABS, ABS_MT_TOOL_Y,
 					s->cy);
 			}
+			input_event(input, EV_ABS, ABS_MT_DISTANCE, s->z);
 			input_event(input, EV_ABS, ABS_MT_ORIENTATION, wide);
 			input_event(input, EV_ABS, ABS_MT_PRESSURE, s->p);
 			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, major);
@@ -575,11 +587,16 @@ static int mt_event(struct hid_device *hid, struct hid_field *field,
 		case HID_DG_INRANGE:
 			if (quirks & MT_QUIRK_VALID_IS_INRANGE)
 				td->curvalid = value;
+			if (quirks & MT_QUIRK_WIN_8_CERTIFIED)
+				td->curdata.touch_state = value;
 			break;
 		case HID_DG_TIPSWITCH:
 			if (quirks & MT_QUIRK_NOT_SEEN_MEANS_UP)
 				td->curvalid = value;
-			td->curdata.touch_state = value;
+			if (quirks & MT_QUIRK_WIN_8_CERTIFIED)
+				td->curdata.z = !value;
+			else
+				td->curdata.touch_state = value;
 			break;
 		case HID_DG_CONFIDENCE:
 			if (quirks & MT_QUIRK_VALID_IS_CONFIDENCE)
-- 
1.7.11.7