[PATCH 5.3 117/197] Input: st1232 - fix reporting multitouch coordinates

From: Greg Kroah-Hartman
Date: Sun Oct 27 2019 - 17:22:30 EST


From: Dixit Parmar <dixitparmar19@xxxxxxxxx>

commit b1a402e75a5f5127ff1ffff0615249f98df8b7b3 upstream.

For Sitronix st1633 multi-touch controller driver the coordinates reported
for multiple fingers were wrong, as it was always taking LSB of coordinates
from the first contact data.

Signed-off-by: Dixit Parmar <dixitparmar19@xxxxxxxxx>
Reviewed-by: Martin Kepplinger <martink@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 351e0592bfea ("Input: st1232 - add support for st1633")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204561
Link: https://lore.kernel.org/r/1566209314-21767-1-git-send-email-dixitparmar19@xxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/input/touchscreen/st1232.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -81,8 +81,10 @@ static int st1232_ts_read_data(struct st
for (i = 0, y = 0; i < ts->chip_info->max_fingers; i++, y += 3) {
finger[i].is_valid = buf[i + y] >> 7;
if (finger[i].is_valid) {
- finger[i].x = ((buf[i + y] & 0x0070) << 4) | buf[i + 1];
- finger[i].y = ((buf[i + y] & 0x0007) << 8) | buf[i + 2];
+ finger[i].x = ((buf[i + y] & 0x0070) << 4) |
+ buf[i + y + 1];
+ finger[i].y = ((buf[i + y] & 0x0007) << 8) |
+ buf[i + y + 2];

/* st1232 includes a z-axis / touch strength */
if (ts->chip_info->have_z)