[PATCH 4.5 50/88] Input: zforce_ts - fix dual touch recognition

From: Greg Kroah-Hartman
Date: Mon May 09 2016 - 03:38:03 EST


4.5-stable review patch. If anyone has any objections, please let me know.

------------------

From: Knut Wohlrab <Knut.Wohlrab@xxxxxxxxxxxx>

commit 6984ab1ab35f422292b7781c65284038bcc0f6a6 upstream.

A wrong decoding of the touch coordinate message causes a wrong touch
ID. Touch ID for dual touch must be 0 or 1.

According to the actual Neonode nine byte touch coordinate coding,
the state is transported in the lower nibble and the touch ID in
the higher nibble of payload byte five.

Signed-off-by: Knut Wohlrab <Knut.Wohlrab@xxxxxxxxxxxx>
Signed-off-by: Oleksij Rempel <linux@xxxxxxxxxxxxxxxx>
Signed-off-by: Dirk Behme <dirk.behme@xxxxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/input/touchscreen/zforce_ts.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/input/touchscreen/zforce_ts.c
+++ b/drivers/input/touchscreen/zforce_ts.c
@@ -370,8 +370,8 @@ static int zforce_touch_event(struct zfo
point.coord_x = point.coord_y = 0;
}

- point.state = payload[9 * i + 5] & 0x03;
- point.id = (payload[9 * i + 5] & 0xfc) >> 2;
+ point.state = payload[9 * i + 5] & 0x0f;
+ point.id = (payload[9 * i + 5] & 0xf0) >> 4;

/* determine touch major, minor and orientation */
point.area_major = max(payload[9 * i + 6],