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Input: s6sy761 - fix coordinate read bit shift
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commit 30b3f68 upstream.

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: 0145a71 ("Input: add support for the Samsung S6SY761 touchscreen")
Signed-off-by: Caleb Connolly <caleb@connolly.tech>
Reviewed-by: Andi Shyti <andi@etezian.org>
Link: https://lore.kernel.org/r/20210305185710.225168-1-caleb@connolly.tech
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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calebccff authored and gregkh committed Apr 21, 2021
1 parent 59b5f3e commit 1adc21f
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions drivers/input/touchscreen/s6sy761.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);

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