The touch coordinate register contains the following:
byte 3 byte 2 byte 1
+--------+--------+ +-----------------+ +-----------------+
| | | | | | |
| X[3:0] | Y[3:0] | | Y[11:4] | | X[11:4] |
| | | | | | |
+--------+--------+ +-----------------+ +-----------------+
Bytes 2 and 1 need to be shifted left by 4 bits, the least significant
nibble of each is stored in byte 3. Currently they are only
being shifted by 3 causing the reported coordinates to be incorrect.
This matches downstream examples, and has been confirmed on my
device (OnePlus 7 Pro).
Fixes: 0145a7141e59 ("Input: add support for the Samsung S6SY761
touchscreen")
Signed-off-by: Caleb Connolly <caleb@xxxxxxxxxxxxx>
---
Changes since v1:
* Use Andi's explanation in the commit message
* Add Fixes: tag
drivers/input/touchscreen/s6sy761.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/input/touchscreen/s6sy761.c b/drivers/input/touchscreen/s6sy761.c
index b63d7fdf0cd2..85a1f465c097 100644
--- a/drivers/input/touchscreen/s6sy761.c
+++ b/drivers/input/touchscreen/s6sy761.c
@@ -145,8 +145,8 @@ static void s6sy761_report_coordinates(struct s6sy761_data *sdata,
u8 major = event[4];
u8 minor = event[5];
u8 z = event[6] & S6SY761_MASK_Z;
- u16 x = (event[1] << 3) | ((event[3] & S6SY761_MASK_X) >> 4);
- u16 y = (event[2] << 3) | (event[3] & S6SY761_MASK_Y);
+ u16 x = (event[1] << 4) | ((event[3] & S6SY761_MASK_X) >> 4);
+ u16 y = (event[2] << 4) | (event[3] & S6SY761_MASK_Y);
input_mt_slot(sdata->input, tid);
--
2.29.2
